gdbstub refactor:

- split user and softmmu code - use cleaner headers for tb_flush, target_ulong - probe for gdb multiarch support at configure - make syscall handling target independent - add update guest debug of accel ops -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEZoWumedRZ7yvyN81+9DbCVqeKkQFAmQHomMACgkQ+9DbCVqe KkTtFAf/aEyKY0iUNxtB4/oV1L2VnLaZi+iKoZT4RQgrhOhzr5WV6/3/V05cw1RJ SIwcl8wB4gowYILs44eM/Qzcixiugl++2rvM4YVXiQyWKzkH6sY4X2iFuPGTwHLp y+E7RM77QNS7M9xYaVkdsQawnbsgjG67wZKbb88aaekFEn61UuDg1V2Nqa2ICy7Y /8yGIB2ixDfXOF0z4g8NOG44BXTDBtJbcEzf5GMz6D4HGnPZUbENy1nT0OcBk3zK PqKPNkPFZ360pqA9MtougjZ3xTBb7Afe9nRRMquV2RoFmkkY2otSjdPBFQu5GBlm NyTXEzjIQ6tCZlbS0eqdPVrUHHUx9g== =Al36 -----END PGP SIGNATURE----- Merge tag 'pull-gdbstub-070323-3' of https://gitlab.com/stsquad/qemu into staging gdbstub refactor: - split user and softmmu code - use cleaner headers for tb_flush, target_ulong - probe for gdb multiarch support at configure - make syscall handling target independent - add update guest debug of accel ops # -----BEGIN PGP SIGNATURE----- # # iQEzBAABCgAdFiEEZoWumedRZ7yvyN81+9DbCVqeKkQFAmQHomMACgkQ+9DbCVqe # KkTtFAf/aEyKY0iUNxtB4/oV1L2VnLaZi+iKoZT4RQgrhOhzr5WV6/3/V05cw1RJ # SIwcl8wB4gowYILs44eM/Qzcixiugl++2rvM4YVXiQyWKzkH6sY4X2iFuPGTwHLp # y+E7RM77QNS7M9xYaVkdsQawnbsgjG67wZKbb88aaekFEn61UuDg1V2Nqa2ICy7Y # /8yGIB2ixDfXOF0z4g8NOG44BXTDBtJbcEzf5GMz6D4HGnPZUbENy1nT0OcBk3zK # PqKPNkPFZ360pqA9MtougjZ3xTBb7Afe9nRRMquV2RoFmkkY2otSjdPBFQu5GBlm # NyTXEzjIQ6tCZlbS0eqdPVrUHHUx9g== # =Al36 # -----END PGP SIGNATURE----- # gpg: Signature made Tue 07 Mar 2023 20:45:23 GMT # gpg: using RSA key 6685AE99E75167BCAFC8DF35FBD0DB095A9E2A44 # gpg: Good signature from "Alex Bennée (Master Work Key) <alex.bennee@linaro.org>" [full] # Primary key fingerprint: 6685 AE99 E751 67BC AFC8 DF35 FBD0 DB09 5A9E 2A44 * tag 'pull-gdbstub-070323-3' of https://gitlab.com/stsquad/qemu: (30 commits) gdbstub: move update guest debug to accel ops gdbstub: Build syscall.c once stubs: split semihosting_get_target from system only stubs gdbstub: Adjust gdb_do_syscall to only use uint32_t and uint64_t gdbstub: Remove gdb_do_syscallv gdbstub: split out softmmu/user specifics for syscall handling include: split target_long definition from cpu-defs testing: probe gdb for supported architectures ahead of time gdbstub: only compile gdbstub twice for whole build gdbstub: move syscall handling to new file gdbstub: move register helpers into standalone include gdbstub: don't use target_ulong while handling registers gdbstub: fix address type of gdb_set_cpu_pc gdbstub: specialise stub_can_reverse gdbstub: introduce gdb_get_max_cpus gdbstub: specialise target_memory_rw_debug gdbstub: specialise handle_query_attached gdbstub: abstract target specific details from gdb_put_packet_binary gdbstub: rationalise signal mapping in softmmu gdbstub: move chunks of user code into own files ... Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2023-03-09 16:54:51 +00:00 · 2023-03-09 16:54:51 +00:00 · b1224d8395
parent 66a6aa8f9a 412ae12647
commit b1224d8395
93 changed files with 2462 additions and 1818 deletions
--- a/4
+++ b/4
@ -136,6 +136,8 @@ F: docs/devel/decodetree.rst
 F: docs/devel/tcg*
 F: include/exec/cpu*.h
 F: include/exec/exec-all.h
+F: include/exec/tb-flush.h
+F: include/exec/target_long.h
 F: include/exec/helper*.h
 F: include/sysemu/cpus.h
 F: include/sysemu/tcg.h
@ -2751,9 +2753,11 @@ S: Maintained
 F: docs/system/gdb.rst
 F: gdbstub/*
 F: include/exec/gdbstub.h
+F: include/gdbstub/*
 F: gdb-xml/
 F: tests/tcg/multiarch/gdbstub/
 F: scripts/feature_to_c.sh
+F: scripts/probe-gdb-support.py

 Memory API
 M: Paolo Bonzini <pbonzini@redhat.com>
--- a/accel/kvm/kvm-accel-ops.c
+++ b/accel/kvm/kvm-accel-ops.c
@ -86,6 +86,13 @@ static bool kvm_cpus_are_resettable(void)
    return !kvm_enabled() || kvm_cpu_check_are_resettable();
 }

+#ifdef KVM_CAP_SET_GUEST_DEBUG
+static int kvm_update_guest_debug_ops(CPUState *cpu)
+{
+    return kvm_update_guest_debug(cpu, 0);
+}
+#endif
+
 static void kvm_accel_ops_class_init(ObjectClass *oc, void *data)
 {
    AccelOpsClass *ops = ACCEL_OPS_CLASS(oc);
@ -99,6 +106,7 @@ static void kvm_accel_ops_class_init(ObjectClass *oc, void *data)
    ops->synchronize_pre_loadvm = kvm_cpu_synchronize_pre_loadvm;

 #ifdef KVM_CAP_SET_GUEST_DEBUG
+    ops->update_guest_debug = kvm_update_guest_debug_ops;
    ops->supports_guest_debug = kvm_supports_guest_debug;
    ops->insert_breakpoint = kvm_insert_breakpoint;
    ops->remove_breakpoint = kvm_remove_breakpoint;
--- a/accel/stubs/tcg-stub.c
+++ b/accel/stubs/tcg-stub.c
@ -11,6 +11,7 @@
 */

 #include "qemu/osdep.h"
+#include "exec/tb-flush.h"
 #include "exec/exec-all.h"

 void tb_flush(CPUState *cpu)
--- a/accel/tcg/tb-maint.c
+++ b/accel/tcg/tb-maint.c
@ -22,6 +22,7 @@
 #include "exec/cputlb.h"
 #include "exec/log.h"
 #include "exec/exec-all.h"
+#include "exec/tb-flush.h"
 #include "exec/translate-all.h"
 #include "sysemu/tcg.h"
 #include "tcg/tcg.h"
--- a/accel/tcg/translate-all.c
+++ b/accel/tcg/translate-all.c
@ -47,6 +47,7 @@
 #include "exec/cputlb.h"
 #include "exec/translate-all.h"
 #include "exec/translator.h"
+#include "exec/tb-flush.h"
 #include "qemu/bitmap.h"
 #include "qemu/qemu-print.h"
 #include "qemu/main-loop.h"
--- a/bsd-user/freebsd/os-syscall.c
+++ b/bsd-user/freebsd/os-syscall.c
@ -38,6 +38,8 @@
 #include <sys/sysctl.h>
 #include <utime.h>

+#include "include/gdbstub/syscalls.h"
+
 #include "qemu.h"
 #include "signal-common.h"
 #include "user/syscall-trace.h"
--- a/bsd-user/main.c
+++ b/bsd-user/main.c
@ -44,6 +44,7 @@
 #include "trace/control.h"
 #include "crypto/init.h"
 #include "qemu/guest-random.h"
+#include "gdbstub/user.h"

 #include "host-os.h"
 #include "target_arch_cpu.h"
--- a/bsd-user/signal.c
+++ b/bsd-user/signal.c
@ -21,6 +21,7 @@
 #include "qemu/osdep.h"
 #include "qemu/log.h"
 #include "qemu.h"
+#include "gdbstub/user.h"
 #include "signal-common.h"
 #include "trace.h"
 #include "hw/core/tcg-cpu-ops.h"
--- a/8
+++ b/8
@ -230,6 +230,7 @@ stack_protector=""
 safe_stack=""
 use_containers="yes"
 gdb_bin=$(command -v "gdb-multiarch" || command -v "gdb")
+gdb_arches=""

 if test -e "$source_path/.git"
 then
@ -2396,6 +2397,7 @@ if test -n "$gdb_bin"; then
    gdb_version=$($gdb_bin --version | head -n 1)
    if version_ge ${gdb_version##* } 9.1; then
        echo "HAVE_GDB_BIN=$gdb_bin" >> $config_host_mak
+        gdb_arches=$("$source_path/scripts/probe-gdb-support.py" $gdb_bin)
    else
        gdb_bin=""
    fi
@ -2520,6 +2522,12 @@ for target in $target_list; do
      write_target_makefile "build-tcg-tests-$target" >> "$config_target_mak"
      echo "BUILD_STATIC=$build_static" >> "$config_target_mak"
      echo "QEMU=$PWD/$qemu" >> "$config_target_mak"
+
+      # will GDB work with these binaries?
+      if test "${gdb_arches#*$arch}" != "$gdb_arches"; then
+          echo "HOST_GDB_SUPPORTS_ARCH=y" >> "$config_target_mak"
+      fi
+
      echo "run-tcg-tests-$target: $qemu\$(EXESUF)" >> Makefile.prereqs
      tcg_tests_targets="$tcg_tests_targets $target"
  fi
--- a/cpu.c
+++ b/cpu.c
@ -31,11 +31,12 @@
 #include "hw/core/sysemu-cpu-ops.h"
 #include "exec/address-spaces.h"
 #endif
+#include "sysemu/cpus.h"
 #include "sysemu/tcg.h"
-#include "sysemu/kvm.h"
 #include "exec/replay-core.h"
 #include "exec/cpu-common.h"
 #include "exec/exec-all.h"
+#include "exec/tb-flush.h"
 #include "exec/translate-all.h"
 #include "exec/log.h"
 #include "hw/core/accel-cpu.h"
@ -325,9 +326,14 @@ void cpu_single_step(CPUState *cpu, int enabled)
 {
    if (cpu->singlestep_enabled != enabled) {
        cpu->singlestep_enabled = enabled;
-        if (kvm_enabled()) {
-            kvm_update_guest_debug(cpu, 0);
+
+#if !defined(CONFIG_USER_ONLY)
+        const AccelOpsClass *ops = cpus_get_accel();
+        if (ops->update_guest_debug) {
+            ops->update_guest_debug(cpu);
        }
+#endif
+
        trace_breakpoint_singlestep(cpu->cpu_index, enabled);
    }
 }
--- a/gdbstub/gdbstub.c
+++ b/gdbstub/gdbstub.c
--- a/gdbstub/internals.h
+++ b/gdbstub/internals.h
@ -6,14 +6,220 @@
 * SPDX-License-Identifier: GPL-2.0-or-later
 */

-#ifndef _INTERNALS_H_
-#define _INTERNALS_H_
+#ifndef GDBSTUB_INTERNALS_H
+#define GDBSTUB_INTERNALS_H

 #include "exec/cpu-common.h"

+#define MAX_PACKET_LENGTH 4096
+
+/*
+ * Shared structures and definitions
+ */
+
+enum {
+    GDB_SIGNAL_0 = 0,
+    GDB_SIGNAL_INT = 2,
+    GDB_SIGNAL_QUIT = 3,
+    GDB_SIGNAL_TRAP = 5,
+    GDB_SIGNAL_ABRT = 6,
+    GDB_SIGNAL_ALRM = 14,
+    GDB_SIGNAL_IO = 23,
+    GDB_SIGNAL_XCPU = 24,
+    GDB_SIGNAL_UNKNOWN = 143
+};
+
+typedef struct GDBProcess {
+    uint32_t pid;
+    bool attached;
+
+    char target_xml[1024];
+} GDBProcess;
+
+enum RSState {
+    RS_INACTIVE,
+    RS_IDLE,
+    RS_GETLINE,
+    RS_GETLINE_ESC,
+    RS_GETLINE_RLE,
+    RS_CHKSUM1,
+    RS_CHKSUM2,
+};
+
+typedef struct GDBState {
+    bool init;       /* have we been initialised? */
+    CPUState *c_cpu; /* current CPU for step/continue ops */
+    CPUState *g_cpu; /* current CPU for other ops */
+    CPUState *query_cpu; /* for q{f|s}ThreadInfo */
+    enum RSState state; /* parsing state */
+    char line_buf[MAX_PACKET_LENGTH];
+    int line_buf_index;
+    int line_sum; /* running checksum */
+    int line_csum; /* checksum at the end of the packet */
+    GByteArray *last_packet;
+    int signal;
+    bool multiprocess;
+    GDBProcess *processes;
+    int process_num;
+    GString *str_buf;
+    GByteArray *mem_buf;
+    int sstep_flags;
+    int supported_sstep_flags;
+} GDBState;
+
+/* lives in main gdbstub.c */
+extern GDBState gdbserver_state;
+
+/*
+ * Inline utility function, convert from int to hex and back
+ */
+
+static inline int fromhex(int v)
+{
+    if (v >= '0' && v <= '9') {
+        return v - '0';
+    } else if (v >= 'A' && v <= 'F') {
+        return v - 'A' + 10;
+    } else if (v >= 'a' && v <= 'f') {
+        return v - 'a' + 10;
+    } else {
+        return 0;
+    }
+}
+
+static inline int tohex(int v)
+{
+    if (v < 10) {
+        return v + '0';
+    } else {
+        return v - 10 + 'a';
+    }
+}
+
+/*
+ * Connection helpers for both softmmu and user backends
+ */
+
+void gdb_put_strbuf(void);
+int gdb_put_packet(const char *buf);
+int gdb_put_packet_binary(const char *buf, int len, bool dump);
+void gdb_hextomem(GByteArray *mem, const char *buf, int len);
+void gdb_memtohex(GString *buf, const uint8_t *mem, int len);
+void gdb_memtox(GString *buf, const char *mem, int len);
+void gdb_read_byte(uint8_t ch);
+
+/*
+ * Packet acknowledgement - we handle this slightly differently
+ * between user and softmmu mode, mainly to deal with the differences
+ * between the flexible chardev and the direct fd approaches.
+ *
+ * We currently don't support a negotiated QStartNoAckMode
+ */
+
+/**
+ * gdb_got_immediate_ack() - check ok to continue
+ *
+ * Returns true to continue, false to re-transmit for user only, the
+ * softmmu stub always returns true.
+ */
+bool gdb_got_immediate_ack(void);
+/* utility helpers */
+CPUState *gdb_first_attached_cpu(void);
+void gdb_append_thread_id(CPUState *cpu, GString *buf);
+int gdb_get_cpu_index(CPUState *cpu);
+unsigned int gdb_get_max_cpus(void); /* both */
+bool gdb_can_reverse(void); /* softmmu, stub for user */
+
+void gdb_create_default_process(GDBState *s);
+
+/* signal mapping, common for softmmu, specialised for user-mode */
+int gdb_signal_to_target(int sig);
+int gdb_target_signal_to_gdb(int sig);
+
+int gdb_get_char(void); /* user only */
+
+/**
+ * gdb_continue() - handle continue in mode specific way.
+ */
+void gdb_continue(void);
+
+/**
+ * gdb_continue_partial() - handle partial continue in mode specific way.
+ */
+int gdb_continue_partial(char *newstates);
+
+/*
+ * Helpers with separate softmmu and user implementations
+ */
+void gdb_put_buffer(const uint8_t *buf, int len);
+
+/*
+ * Command handlers - either specialised or softmmu or user only
+ */
+void gdb_init_gdbserver_state(void);
+
+typedef enum GDBThreadIdKind {
+    GDB_ONE_THREAD = 0,
+    GDB_ALL_THREADS,     /* One process, all threads */
+    GDB_ALL_PROCESSES,
+    GDB_READ_THREAD_ERR
+} GDBThreadIdKind;
+
+typedef union GdbCmdVariant {
+    const char *data;
+    uint8_t opcode;
+    unsigned long val_ul;
+    unsigned long long val_ull;
+    struct {
+        GDBThreadIdKind kind;
+        uint32_t pid;
+        uint32_t tid;
+    } thread_id;
+} GdbCmdVariant;
+
+#define get_param(p, i)    (&g_array_index(p, GdbCmdVariant, i))
+
+void gdb_handle_query_rcmd(GArray *params, void *user_ctx); /* softmmu */
+void gdb_handle_query_offsets(GArray *params, void *user_ctx); /* user */
+void gdb_handle_query_xfer_auxv(GArray *params, void *user_ctx); /*user */
+
+void gdb_handle_query_attached(GArray *params, void *user_ctx); /* both */
+
+/* softmmu only */
+void gdb_handle_query_qemu_phy_mem_mode(GArray *params, void *user_ctx);
+void gdb_handle_set_qemu_phy_mem_mode(GArray *params, void *user_ctx);
+
+/* sycall handling */
+void gdb_handle_file_io(GArray *params, void *user_ctx);
+bool gdb_handled_syscall(void);
+void gdb_disable_syscalls(void);
+void gdb_syscall_reset(void);
+
+/* user/softmmu specific syscall handling */
+void gdb_syscall_handling(const char *syscall_packet);
+
+/*
+ * Break/Watch point support - there is an implementation for softmmu
+ * and user mode.
+ */
 bool gdb_supports_guest_debug(void);
 int gdb_breakpoint_insert(CPUState *cs, int type, vaddr addr, vaddr len);
 int gdb_breakpoint_remove(CPUState *cs, int type, vaddr addr, vaddr len);
 void gdb_breakpoint_remove_all(CPUState *cs);

-#endif /* _INTERNALS_H_ */
+/**
+ * gdb_target_memory_rw_debug() - handle debug access to memory
+ * @cs: CPUState
+ * @addr: nominal address, could be an entire physical address
+ * @buf: data
+ * @len: length of access
+ * @is_write: is it a write operation
+ *
+ * This function is specialised depending on the mode we are running
+ * in. For softmmu guests we can switch the interpretation of the
+ * address to a physical address.
+ */
+int gdb_target_memory_rw_debug(CPUState *cs, hwaddr addr,
+                               uint8_t *buf, int len, bool is_write);
+
+#endif /* GDBSTUB_INTERNALS_H */
--- a/gdbstub/meson.build
+++ b/gdbstub/meson.build
@ -4,6 +4,34 @@
 # types such as hwaddr.
 #

-specific_ss.add(files('gdbstub.c'))
-softmmu_ss.add(files('softmmu.c'))
-user_ss.add(files('user.c'))
+# We need to build the core gdb code via a library to be able to tweak
+# cflags so:
+
+gdb_user_ss = ss.source_set()
+gdb_softmmu_ss = ss.source_set()
+
+# We build two versions of gdbstub, one for each mode
+gdb_user_ss.add(files('gdbstub.c', 'user.c'))
+gdb_softmmu_ss.add(files('gdbstub.c', 'softmmu.c'))
+
+gdb_user_ss = gdb_user_ss.apply(config_host, strict: false)
+gdb_softmmu_ss = gdb_softmmu_ss.apply(config_host, strict: false)
+
+libgdb_user = static_library('gdb_user',
+                             gdb_user_ss.sources() + genh,
+                             name_suffix: 'fa',
+                             c_args: '-DCONFIG_USER_ONLY')
+
+libgdb_softmmu = static_library('gdb_softmmu',
+                                gdb_softmmu_ss.sources() + genh,
+                                name_suffix: 'fa')
+
+gdb_user = declare_dependency(link_whole: libgdb_user)
+user_ss.add(gdb_user)
+gdb_softmmu = declare_dependency(link_whole: libgdb_softmmu)
+softmmu_ss.add(gdb_softmmu)
+
+common_ss.add(files('syscalls.c'))
+
+# The user-target is specialised by the guest
+specific_ss.add(when: 'CONFIG_USER_ONLY', if_true: files('user-target.c'))
--- a/gdbstub/softmmu.c
+++ b/gdbstub/softmmu.c
@ -4,16 +4,617 @@
 * Debug integration depends on support from the individual
 * accelerators so most of this involves calling the ops helpers.
 *
+ * Copyright (c) 2003-2005 Fabrice Bellard
 * Copyright (c) 2022 Linaro Ltd
 *
- * SPDX-License-Identifier: GPL-2.0-or-later
+ * SPDX-License-Identifier: LGPL-2.0+
 */

 #include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "qemu/error-report.h"
+#include "qemu/cutils.h"
 #include "exec/gdbstub.h"
+#include "gdbstub/syscalls.h"
+#include "exec/hwaddr.h"
+#include "exec/tb-flush.h"
 #include "sysemu/cpus.h"
+#include "sysemu/runstate.h"
+#include "sysemu/replay.h"
+#include "hw/core/cpu.h"
+#include "hw/cpu/cluster.h"
+#include "hw/boards.h"
+#include "chardev/char.h"
+#include "chardev/char-fe.h"
+#include "monitor/monitor.h"
+#include "trace.h"
 #include "internals.h"

+/* System emulation specific state */
+typedef struct {
+    CharBackend chr;
+    Chardev *mon_chr;
+} GDBSystemState;
+
+GDBSystemState gdbserver_system_state;
+
+static void reset_gdbserver_state(void)
+{
+    g_free(gdbserver_state.processes);
+    gdbserver_state.processes = NULL;
+    gdbserver_state.process_num = 0;
+}
+
+/*
+ * Return the GDB index for a given vCPU state.
+ *
+ * In system mode GDB numbers CPUs from 1 as 0 is reserved as an "any
+ * cpu" index.
+ */
+int gdb_get_cpu_index(CPUState *cpu)
+{
+    return cpu->cpu_index + 1;
+}
+
+/*
+ * We check the status of the last message in the chardev receive code
+ */
+bool gdb_got_immediate_ack(void)
+{
+    return true;
+}
+
+/*
+ * GDB Connection management. For system emulation we do all of this
+ * via our existing Chardev infrastructure which allows us to support
+ * network and unix sockets.
+ */
+
+void gdb_put_buffer(const uint8_t *buf, int len)
+{
+    /*
+     * XXX this blocks entire thread. Rewrite to use
+     * qemu_chr_fe_write and background I/O callbacks
+     */
+    qemu_chr_fe_write_all(&gdbserver_system_state.chr, buf, len);
+}
+
+static void gdb_chr_event(void *opaque, QEMUChrEvent event)
+{
+    int i;
+    GDBState *s = (GDBState *) opaque;
+
+    switch (event) {
+    case CHR_EVENT_OPENED:
+        /* Start with first process attached, others detached */
+        for (i = 0; i < s->process_num; i++) {
+            s->processes[i].attached = !i;
+        }
+
+        s->c_cpu = gdb_first_attached_cpu();
+        s->g_cpu = s->c_cpu;
+
+        vm_stop(RUN_STATE_PAUSED);
+        replay_gdb_attached();
+        gdb_has_xml = false;
+        break;
+    default:
+        break;
+    }
+}
+
+/*
+ * In softmmu mode we stop the VM and wait to send the syscall packet
+ * until notification that the CPU has stopped. This must be done
+ * because if the packet is sent now the reply from the syscall
+ * request could be received while the CPU is still in the running
+ * state, which can cause packets to be dropped and state transition
+ * 'T' packets to be sent while the syscall is still being processed.
+ */
+void gdb_syscall_handling(const char *syscall_packet)
+{
+    vm_stop(RUN_STATE_DEBUG);
+    qemu_cpu_kick(gdbserver_state.c_cpu);
+}
+
+static void gdb_vm_state_change(void *opaque, bool running, RunState state)
+{
+    CPUState *cpu = gdbserver_state.c_cpu;
+    g_autoptr(GString) buf = g_string_new(NULL);
+    g_autoptr(GString) tid = g_string_new(NULL);
+    const char *type;
+    int ret;
+
+    if (running || gdbserver_state.state == RS_INACTIVE) {
+        return;
+    }
+
+    /* Is there a GDB syscall waiting to be sent?  */
+    if (gdb_handled_syscall()) {
+        return;
+    }
+
+    if (cpu == NULL) {
+        /* No process attached */
+        return;
+    }
+
+    gdb_append_thread_id(cpu, tid);
+
+    switch (state) {
+    case RUN_STATE_DEBUG:
+        if (cpu->watchpoint_hit) {
+            switch (cpu->watchpoint_hit->flags & BP_MEM_ACCESS) {
+            case BP_MEM_READ:
+                type = "r";
+                break;
+            case BP_MEM_ACCESS:
+                type = "a";
+                break;
+            default:
+                type = "";
+                break;
+            }
+            trace_gdbstub_hit_watchpoint(type,
+                                         gdb_get_cpu_index(cpu),
+                                         cpu->watchpoint_hit->vaddr);
+            g_string_printf(buf, "T%02xthread:%s;%swatch:%" VADDR_PRIx ";",
+                            GDB_SIGNAL_TRAP, tid->str, type,
+                            cpu->watchpoint_hit->vaddr);
+            cpu->watchpoint_hit = NULL;
+            goto send_packet;
+        } else {
+            trace_gdbstub_hit_break();
+        }
+        tb_flush(cpu);
+        ret = GDB_SIGNAL_TRAP;
+        break;
+    case RUN_STATE_PAUSED:
+        trace_gdbstub_hit_paused();
+        ret = GDB_SIGNAL_INT;
+        break;
+    case RUN_STATE_SHUTDOWN:
+        trace_gdbstub_hit_shutdown();
+        ret = GDB_SIGNAL_QUIT;
+        break;
+    case RUN_STATE_IO_ERROR:
+        trace_gdbstub_hit_io_error();
+        ret = GDB_SIGNAL_IO;
+        break;
+    case RUN_STATE_WATCHDOG:
+        trace_gdbstub_hit_watchdog();
+        ret = GDB_SIGNAL_ALRM;
+        break;
+    case RUN_STATE_INTERNAL_ERROR:
+        trace_gdbstub_hit_internal_error();
+        ret = GDB_SIGNAL_ABRT;
+        break;
+    case RUN_STATE_SAVE_VM:
+    case RUN_STATE_RESTORE_VM:
+        return;
+    case RUN_STATE_FINISH_MIGRATE:
+        ret = GDB_SIGNAL_XCPU;
+        break;
+    default:
+        trace_gdbstub_hit_unknown(state);
+        ret = GDB_SIGNAL_UNKNOWN;
+        break;
+    }
+    gdb_set_stop_cpu(cpu);
+    g_string_printf(buf, "T%02xthread:%s;", ret, tid->str);
+
+send_packet:
+    gdb_put_packet(buf->str);
+
+    /* disable single step if it was enabled */
+    cpu_single_step(cpu, 0);
+}
+
+#ifndef _WIN32
+static void gdb_sigterm_handler(int signal)
+{
+    if (runstate_is_running()) {
+        vm_stop(RUN_STATE_PAUSED);
+    }
+}
+#endif
+
+static int gdb_monitor_write(Chardev *chr, const uint8_t *buf, int len)
+{
+    g_autoptr(GString) hex_buf = g_string_new("O");
+    gdb_memtohex(hex_buf, buf, len);
+    gdb_put_packet(hex_buf->str);
+    return len;
+}
+
+static void gdb_monitor_open(Chardev *chr, ChardevBackend *backend,
+                             bool *be_opened, Error **errp)
+{
+    *be_opened = false;
+}
+
+static void char_gdb_class_init(ObjectClass *oc, void *data)
+{
+    ChardevClass *cc = CHARDEV_CLASS(oc);
+
+    cc->internal = true;
+    cc->open = gdb_monitor_open;
+    cc->chr_write = gdb_monitor_write;
+}
+
+#define TYPE_CHARDEV_GDB "chardev-gdb"
+
+static const TypeInfo char_gdb_type_info = {
+    .name = TYPE_CHARDEV_GDB,
+    .parent = TYPE_CHARDEV,
+    .class_init = char_gdb_class_init,
+};
+
+static int gdb_chr_can_receive(void *opaque)
+{
+  /*
+   * We can handle an arbitrarily large amount of data.
+   * Pick the maximum packet size, which is as good as anything.
+   */
+  return MAX_PACKET_LENGTH;
+}
+
+static void gdb_chr_receive(void *opaque, const uint8_t *buf, int size)
+{
+    int i;
+
+    for (i = 0; i < size; i++) {
+        gdb_read_byte(buf[i]);
+    }
+}
+
+static int find_cpu_clusters(Object *child, void *opaque)
+{
+    if (object_dynamic_cast(child, TYPE_CPU_CLUSTER)) {
+        GDBState *s = (GDBState *) opaque;
+        CPUClusterState *cluster = CPU_CLUSTER(child);
+        GDBProcess *process;
+
+        s->processes = g_renew(GDBProcess, s->processes, ++s->process_num);
+
+        process = &s->processes[s->process_num - 1];
+
+        /*
+         * GDB process IDs -1 and 0 are reserved. To avoid subtle errors at
+         * runtime, we enforce here that the machine does not use a cluster ID
+         * that would lead to PID 0.
+         */
+        assert(cluster->cluster_id != UINT32_MAX);
+        process->pid = cluster->cluster_id + 1;
+        process->attached = false;
+        process->target_xml[0] = '\0';
+
+        return 0;
+    }
+
+    return object_child_foreach(child, find_cpu_clusters, opaque);
+}
+
+static int pid_order(const void *a, const void *b)
+{
+    GDBProcess *pa = (GDBProcess *) a;
+    GDBProcess *pb = (GDBProcess *) b;
+
+    if (pa->pid < pb->pid) {
+        return -1;
+    } else if (pa->pid > pb->pid) {
+        return 1;
+    } else {
+        return 0;
+    }
+}
+
+static void create_processes(GDBState *s)
+{
+    object_child_foreach(object_get_root(), find_cpu_clusters, s);
+
+    if (gdbserver_state.processes) {
+        /* Sort by PID */
+        qsort(gdbserver_state.processes,
+              gdbserver_state.process_num,
+              sizeof(gdbserver_state.processes[0]),
+              pid_order);
+    }
+
+    gdb_create_default_process(s);
+}
+
+int gdbserver_start(const char *device)
+{
+    trace_gdbstub_op_start(device);
+
+    char gdbstub_device_name[128];
+    Chardev *chr = NULL;
+    Chardev *mon_chr;
+
+    if (!first_cpu) {
+        error_report("gdbstub: meaningless to attach gdb to a "
+                     "machine without any CPU.");
+        return -1;
+    }
+
+    if (!gdb_supports_guest_debug()) {
+        error_report("gdbstub: current accelerator doesn't "
+                     "support guest debugging");
+        return -1;
+    }
+
+    if (!device) {
+        return -1;
+    }
+    if (strcmp(device, "none") != 0) {
+        if (strstart(device, "tcp:", NULL)) {
+            /* enforce required TCP attributes */
+            snprintf(gdbstub_device_name, sizeof(gdbstub_device_name),
+                     "%s,wait=off,nodelay=on,server=on", device);
+            device = gdbstub_device_name;
+        }
+#ifndef _WIN32
+        else if (strcmp(device, "stdio") == 0) {
+            struct sigaction act;
+
+            memset(&act, 0, sizeof(act));
+            act.sa_handler = gdb_sigterm_handler;
+            sigaction(SIGINT, &act, NULL);
+        }
+#endif
+        /*
+         * FIXME: it's a bit weird to allow using a mux chardev here
+         * and implicitly setup a monitor. We may want to break this.
+         */
+        chr = qemu_chr_new_noreplay("gdb", device, true, NULL);
+        if (!chr) {
+            return -1;
+        }
+    }
+
+    if (!gdbserver_state.init) {
+        gdb_init_gdbserver_state();
+
+        qemu_add_vm_change_state_handler(gdb_vm_state_change, NULL);
+
+        /* Initialize a monitor terminal for gdb */
+        mon_chr = qemu_chardev_new(NULL, TYPE_CHARDEV_GDB,
+                                   NULL, NULL, &error_abort);
+        monitor_init_hmp(mon_chr, false, &error_abort);
+    } else {
+        qemu_chr_fe_deinit(&gdbserver_system_state.chr, true);
+        mon_chr = gdbserver_system_state.mon_chr;
+        reset_gdbserver_state();
+    }
+
+    create_processes(&gdbserver_state);
+
+    if (chr) {
+        qemu_chr_fe_init(&gdbserver_system_state.chr, chr, &error_abort);
+        qemu_chr_fe_set_handlers(&gdbserver_system_state.chr,
+                                 gdb_chr_can_receive,
+                                 gdb_chr_receive, gdb_chr_event,
+                                 NULL, &gdbserver_state, NULL, true);
+    }
+    gdbserver_state.state = chr ? RS_IDLE : RS_INACTIVE;
+    gdbserver_system_state.mon_chr = mon_chr;
+    gdb_syscall_reset();
+
+    return 0;
+}
+
+static void register_types(void)
+{
+    type_register_static(&char_gdb_type_info);
+}
+
+type_init(register_types);
+
+/* Tell the remote gdb that the process has exited.  */
+void gdb_exit(int code)
+{
+    char buf[4];
+
+    if (!gdbserver_state.init) {
+        return;
+    }
+
+    trace_gdbstub_op_exiting((uint8_t)code);
+
+    snprintf(buf, sizeof(buf), "W%02x", (uint8_t)code);
+    gdb_put_packet(buf);
+
+    qemu_chr_fe_deinit(&gdbserver_system_state.chr, true);
+}
+
+/*
+ * Memory access
+ */
+static int phy_memory_mode;
+
+int gdb_target_memory_rw_debug(CPUState *cpu, hwaddr addr,
+                               uint8_t *buf, int len, bool is_write)
+{
+    CPUClass *cc;
+
+    if (phy_memory_mode) {
+        if (is_write) {
+            cpu_physical_memory_write(addr, buf, len);
+        } else {
+            cpu_physical_memory_read(addr, buf, len);
+        }
+        return 0;
+    }
+
+    cc = CPU_GET_CLASS(cpu);
+    if (cc->memory_rw_debug) {
+        return cc->memory_rw_debug(cpu, addr, buf, len, is_write);
+    }
+
+    return cpu_memory_rw_debug(cpu, addr, buf, len, is_write);
+}
+
+/*
+ * cpu helpers
+ */
+
+unsigned int gdb_get_max_cpus(void)
+{
+    MachineState *ms = MACHINE(qdev_get_machine());
+    return ms->smp.max_cpus;
+}
+
+bool gdb_can_reverse(void)
+{
+    return replay_mode == REPLAY_MODE_PLAY;
+}
+
+/*
+ * Softmmu specific command helpers
+ */
+
+void gdb_handle_query_qemu_phy_mem_mode(GArray *params,
+                                        void *user_ctx)
+{
+    g_string_printf(gdbserver_state.str_buf, "%d", phy_memory_mode);
+    gdb_put_strbuf();
+}
+
+void gdb_handle_set_qemu_phy_mem_mode(GArray *params, void *user_ctx)
+{
+    if (!params->len) {
+        gdb_put_packet("E22");
+        return;
+    }
+
+    if (!get_param(params, 0)->val_ul) {
+        phy_memory_mode = 0;
+    } else {
+        phy_memory_mode = 1;
+    }
+    gdb_put_packet("OK");
+}
+
+void gdb_handle_query_rcmd(GArray *params, void *user_ctx)
+{
+    const guint8 zero = 0;
+    int len;
+
+    if (!params->len) {
+        gdb_put_packet("E22");
+        return;
+    }
+
+    len = strlen(get_param(params, 0)->data);
+    if (len % 2) {
+        gdb_put_packet("E01");
+        return;
+    }
+
+    g_assert(gdbserver_state.mem_buf->len == 0);
+    len = len / 2;
+    gdb_hextomem(gdbserver_state.mem_buf, get_param(params, 0)->data, len);
+    g_byte_array_append(gdbserver_state.mem_buf, &zero, 1);
+    qemu_chr_be_write(gdbserver_system_state.mon_chr,
+                      gdbserver_state.mem_buf->data,
+                      gdbserver_state.mem_buf->len);
+    gdb_put_packet("OK");
+}
+
+/*
+ * Execution state helpers
+ */
+
+void gdb_handle_query_attached(GArray *params, void *user_ctx)
+{
+    gdb_put_packet("1");
+}
+
+void gdb_continue(void)
+{
+    if (!runstate_needs_reset()) {
+        trace_gdbstub_op_continue();
+        vm_start();
+    }
+}
+
+/*
+ * Resume execution, per CPU actions.
+ */
+int gdb_continue_partial(char *newstates)
+{
+    CPUState *cpu;
+    int res = 0;
+    int flag = 0;
+
+    if (!runstate_needs_reset()) {
+        bool step_requested = false;
+        CPU_FOREACH(cpu) {
+            if (newstates[cpu->cpu_index] == 's') {
+                step_requested = true;
+                break;
+            }
+        }
+
+        if (vm_prepare_start(step_requested)) {
+            return 0;
+        }
+
+        CPU_FOREACH(cpu) {
+            switch (newstates[cpu->cpu_index]) {
+            case 0:
+            case 1:
+                break; /* nothing to do here */
+            case 's':
+                trace_gdbstub_op_stepping(cpu->cpu_index);
+                cpu_single_step(cpu, gdbserver_state.sstep_flags);
+                cpu_resume(cpu);
+                flag = 1;
+                break;
+            case 'c':
+                trace_gdbstub_op_continue_cpu(cpu->cpu_index);
+                cpu_resume(cpu);
+                flag = 1;
+                break;
+            default:
+                res = -1;
+                break;
+            }
+        }
+    }
+    if (flag) {
+        qemu_clock_enable(QEMU_CLOCK_VIRTUAL, true);
+    }
+    return res;
+}
+
+/*
+ * Signal Handling - in system mode we only need SIGINT and SIGTRAP; other
+ * signals are not yet supported.
+ */
+
+enum {
+    TARGET_SIGINT = 2,
+    TARGET_SIGTRAP = 5
+};
+
+int gdb_signal_to_target(int sig)
+{
+    switch (sig) {
+    case 2:
+        return TARGET_SIGINT;
+    case 5:
+        return TARGET_SIGTRAP;
+    default:
+        return -1;
+    }
+}
+
+/*
+ * Break/Watch point helpers
+ */
+
 bool gdb_supports_guest_debug(void)
 {
    const AccelOpsClass *ops = cpus_get_accel();
--- a/gdbstub/syscalls.c
+++ b/gdbstub/syscalls.c
@ -0,0 +1,205 @@
+/*
+ * GDB Syscall Handling
+ *
+ * GDB can execute syscalls on the guests behalf, currently used by
+ * the various semihosting extensions.
+ *
+ * Copyright (c) 2003-2005 Fabrice Bellard
+ * Copyright (c) 2023 Linaro Ltd
+ *
+ * SPDX-License-Identifier: LGPL-2.0+
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/error-report.h"
+#include "semihosting/semihost.h"
+#include "sysemu/runstate.h"
+#include "gdbstub/user.h"
+#include "gdbstub/syscalls.h"
+#include "trace.h"
+#include "internals.h"
+
+/* Syscall specific state */
+typedef struct {
+    char syscall_buf[256];
+    gdb_syscall_complete_cb current_syscall_cb;
+} GDBSyscallState;
+
+static GDBSyscallState gdbserver_syscall_state;
+
+/*
+ * Return true if there is a GDB currently connected to the stub
+ * and attached to a CPU
+ */
+static bool gdb_attached(void)
+{
+    return gdbserver_state.init && gdbserver_state.c_cpu;
+}
+
+static enum {
+    GDB_SYS_UNKNOWN,
+    GDB_SYS_ENABLED,
+    GDB_SYS_DISABLED,
+} gdb_syscall_mode;
+
+/* Decide if either remote gdb syscalls or native file IO should be used. */
+int use_gdb_syscalls(void)
+{
+    SemihostingTarget target = semihosting_get_target();
+    if (target == SEMIHOSTING_TARGET_NATIVE) {
+        /* -semihosting-config target=native */
+        return false;
+    } else if (target == SEMIHOSTING_TARGET_GDB) {
+        /* -semihosting-config target=gdb */
+        return true;
+    }
+
+    /* -semihosting-config target=auto */
+    /* On the first call check if gdb is connected and remember. */
+    if (gdb_syscall_mode == GDB_SYS_UNKNOWN) {
+        gdb_syscall_mode = gdb_attached() ? GDB_SYS_ENABLED : GDB_SYS_DISABLED;
+    }
+    return gdb_syscall_mode == GDB_SYS_ENABLED;
+}
+
+/* called when the stub detaches */
+void gdb_disable_syscalls(void)
+{
+    gdb_syscall_mode = GDB_SYS_DISABLED;
+}
+
+void gdb_syscall_reset(void)
+{
+    gdbserver_syscall_state.current_syscall_cb = NULL;
+}
+
+bool gdb_handled_syscall(void)
+{
+    if (gdbserver_syscall_state.current_syscall_cb) {
+        gdb_put_packet(gdbserver_syscall_state.syscall_buf);
+        return true;
+    }
+
+    return false;
+}
+
+/*
+ * Send a gdb syscall request.
+ *  This accepts limited printf-style format specifiers, specifically:
+ *   %x  - target_ulong argument printed in hex.
+ *   %lx - 64-bit argument printed in hex.
+ *   %s  - string pointer (target_ulong) and length (int) pair.
+ */
+void gdb_do_syscall(gdb_syscall_complete_cb cb, const char *fmt, ...)
+{
+    char *p, *p_end;
+    va_list va;
+
+    if (!gdb_attached()) {
+        return;
+    }
+
+    gdbserver_syscall_state.current_syscall_cb = cb;
+    va_start(va, fmt);
+
+    p = gdbserver_syscall_state.syscall_buf;
+    p_end = p + sizeof(gdbserver_syscall_state.syscall_buf);
+    *(p++) = 'F';
+    while (*fmt) {
+        if (*fmt == '%') {
+            uint64_t i64;
+            uint32_t i32;
+
+            fmt++;
+            switch (*fmt++) {
+            case 'x':
+                i32 = va_arg(va, uint32_t);
+                p += snprintf(p, p_end - p, "%" PRIx32, i32);
+                break;
+            case 'l':
+                if (*(fmt++) != 'x') {
+                    goto bad_format;
+                }
+                i64 = va_arg(va, uint64_t);
+                p += snprintf(p, p_end - p, "%" PRIx64, i64);
+                break;
+            case 's':
+                i64 = va_arg(va, uint64_t);
+                i32 = va_arg(va, uint32_t);
+                p += snprintf(p, p_end - p, "%" PRIx64 "/%x" PRIx32, i64, i32);
+                break;
+            default:
+            bad_format:
+                error_report("gdbstub: Bad syscall format string '%s'",
+                             fmt - 1);
+                break;
+            }
+        } else {
+            *(p++) = *(fmt++);
+        }
+    }
+    *p = 0;
+
+    va_end(va);
+    gdb_syscall_handling(gdbserver_syscall_state.syscall_buf);
+}
+
+/*
+ * GDB Command Handlers
+ */
+
+void gdb_handle_file_io(GArray *params, void *user_ctx)
+{
+    if (params->len >= 1 && gdbserver_syscall_state.current_syscall_cb) {
+        uint64_t ret;
+        int err;
+
+        ret = get_param(params, 0)->val_ull;
+        if (params->len >= 2) {
+            err = get_param(params, 1)->val_ull;
+        } else {
+            err = 0;
+        }
+
+        /* Convert GDB error numbers back to host error numbers. */
+#define E(X)  case GDB_E##X: err = E##X; break
+        switch (err) {
+        case 0:
+            break;
+        E(PERM);
+        E(NOENT);
+        E(INTR);
+        E(BADF);
+        E(ACCES);
+        E(FAULT);
+        E(BUSY);
+        E(EXIST);
+        E(NODEV);
+        E(NOTDIR);
+        E(ISDIR);
+        E(INVAL);
+        E(NFILE);
+        E(MFILE);
+        E(FBIG);
+        E(NOSPC);
+        E(SPIPE);
+        E(ROFS);
+        E(NAMETOOLONG);
+        default:
+            err = EINVAL;
+            break;
+        }
+#undef E
+
+        gdbserver_syscall_state.current_syscall_cb(gdbserver_state.c_cpu,
+                                                   ret, err);
+        gdbserver_syscall_state.current_syscall_cb = NULL;
+    }
+
+    if (params->len >= 3 && get_param(params, 2)->opcode == (uint8_t)'C') {
+        gdb_put_packet("T02");
+        return;
+    }
+
+    gdb_continue();
+}
--- a/gdbstub/trace-events
+++ b/gdbstub/trace-events
@ -7,7 +7,6 @@ gdbstub_op_continue(void) "Continuing all CPUs"
 gdbstub_op_continue_cpu(int cpu_index) "Continuing CPU %d"
 gdbstub_op_stepping(int cpu_index) "Stepping CPU %d"
 gdbstub_op_extra_info(const char *info) "Thread extra info: %s"
-gdbstub_hit_watchpoint(const char *type, int cpu_gdb_index, uint64_t vaddr) "Watchpoint hit, type=\"%s\" cpu=%d, vaddr=0x%" PRIx64 ""
 gdbstub_hit_internal_error(void) "RUN_STATE_INTERNAL_ERROR"
 gdbstub_hit_break(void) "RUN_STATE_DEBUG"
 gdbstub_hit_paused(void) "RUN_STATE_PAUSED"
@ -27,3 +26,6 @@ gdbstub_err_invalid_repeat(uint8_t ch) "got invalid RLE count: 0x%02x"
 gdbstub_err_invalid_rle(void) "got invalid RLE sequence"
 gdbstub_err_checksum_invalid(uint8_t ch) "got invalid command checksum digit: 0x%02x"
 gdbstub_err_checksum_incorrect(uint8_t expected, uint8_t got) "got command packet with incorrect checksum, expected=0x%02x, received=0x%02x"
+
+# softmmu.c
+gdbstub_hit_watchpoint(const char *type, int cpu_gdb_index, uint64_t vaddr) "Watchpoint hit, type=\"%s\" cpu=%d, vaddr=0x%" PRIx64 ""
--- a/gdbstub/user-target.c
+++ b/gdbstub/user-target.c
@ -0,0 +1,283 @@
+/*
+ * Target specific user-mode handling
+ *
+ * Copyright (c) 2003-2005 Fabrice Bellard
+ * Copyright (c) 2022 Linaro Ltd
+ *
+ * SPDX-License-Identifier: LGPL-2.0+
+ */
+
+#include "qemu/osdep.h"
+#include "exec/gdbstub.h"
+#include "qemu.h"
+#include "internals.h"
+
+/*
+ * Map target signal numbers to GDB protocol signal numbers and vice
+ * versa.  For user emulation's currently supported systems, we can
+ * assume most signals are defined.
+ */
+
+static int gdb_signal_table[] = {
+    0,
+    TARGET_SIGHUP,
+    TARGET_SIGINT,
+    TARGET_SIGQUIT,
+    TARGET_SIGILL,
+    TARGET_SIGTRAP,
+    TARGET_SIGABRT,
+    -1, /* SIGEMT */
+    TARGET_SIGFPE,
+    TARGET_SIGKILL,
+    TARGET_SIGBUS,
+    TARGET_SIGSEGV,
+    TARGET_SIGSYS,
+    TARGET_SIGPIPE,
+    TARGET_SIGALRM,
+    TARGET_SIGTERM,
+    TARGET_SIGURG,
+    TARGET_SIGSTOP,
+    TARGET_SIGTSTP,
+    TARGET_SIGCONT,
+    TARGET_SIGCHLD,
+    TARGET_SIGTTIN,
+    TARGET_SIGTTOU,
+    TARGET_SIGIO,
+    TARGET_SIGXCPU,
+    TARGET_SIGXFSZ,
+    TARGET_SIGVTALRM,
+    TARGET_SIGPROF,
+    TARGET_SIGWINCH,
+    -1, /* SIGLOST */
+    TARGET_SIGUSR1,
+    TARGET_SIGUSR2,
+#ifdef TARGET_SIGPWR
+    TARGET_SIGPWR,
+#else
+    -1,
+#endif
+    -1, /* SIGPOLL */
+    -1,
+    -1,
+    -1,
+    -1,
+    -1,
+    -1,
+    -1,
+    -1,
+    -1,
+    -1,
+    -1,
+#ifdef __SIGRTMIN
+    __SIGRTMIN + 1,
+    __SIGRTMIN + 2,
+    __SIGRTMIN + 3,
+    __SIGRTMIN + 4,
+    __SIGRTMIN + 5,
+    __SIGRTMIN + 6,
+    __SIGRTMIN + 7,
+    __SIGRTMIN + 8,
+    __SIGRTMIN + 9,
+    __SIGRTMIN + 10,
+    __SIGRTMIN + 11,
+    __SIGRTMIN + 12,
+    __SIGRTMIN + 13,
+    __SIGRTMIN + 14,
+    __SIGRTMIN + 15,
+    __SIGRTMIN + 16,
+    __SIGRTMIN + 17,
+    __SIGRTMIN + 18,
+    __SIGRTMIN + 19,
+    __SIGRTMIN + 20,
+    __SIGRTMIN + 21,
+    __SIGRTMIN + 22,
+    __SIGRTMIN + 23,
+    __SIGRTMIN + 24,
+    __SIGRTMIN + 25,
+    __SIGRTMIN + 26,
+    __SIGRTMIN + 27,
+    __SIGRTMIN + 28,
+    __SIGRTMIN + 29,
+    __SIGRTMIN + 30,
+    __SIGRTMIN + 31,
+    -1, /* SIGCANCEL */
+    __SIGRTMIN,
+    __SIGRTMIN + 32,
+    __SIGRTMIN + 33,
+    __SIGRTMIN + 34,
+    __SIGRTMIN + 35,
+    __SIGRTMIN + 36,
+    __SIGRTMIN + 37,
+    __SIGRTMIN + 38,
+    __SIGRTMIN + 39,
+    __SIGRTMIN + 40,
+    __SIGRTMIN + 41,
+    __SIGRTMIN + 42,
+    __SIGRTMIN + 43,
+    __SIGRTMIN + 44,
+    __SIGRTMIN + 45,
+    __SIGRTMIN + 46,
+    __SIGRTMIN + 47,
+    __SIGRTMIN + 48,
+    __SIGRTMIN + 49,
+    __SIGRTMIN + 50,
+    __SIGRTMIN + 51,
+    __SIGRTMIN + 52,
+    __SIGRTMIN + 53,
+    __SIGRTMIN + 54,
+    __SIGRTMIN + 55,
+    __SIGRTMIN + 56,
+    __SIGRTMIN + 57,
+    __SIGRTMIN + 58,
+    __SIGRTMIN + 59,
+    __SIGRTMIN + 60,
+    __SIGRTMIN + 61,
+    __SIGRTMIN + 62,
+    __SIGRTMIN + 63,
+    __SIGRTMIN + 64,
+    __SIGRTMIN + 65,
+    __SIGRTMIN + 66,
+    __SIGRTMIN + 67,
+    __SIGRTMIN + 68,
+    __SIGRTMIN + 69,
+    __SIGRTMIN + 70,
+    __SIGRTMIN + 71,
+    __SIGRTMIN + 72,
+    __SIGRTMIN + 73,
+    __SIGRTMIN + 74,
+    __SIGRTMIN + 75,
+    __SIGRTMIN + 76,
+    __SIGRTMIN + 77,
+    __SIGRTMIN + 78,
+    __SIGRTMIN + 79,
+    __SIGRTMIN + 80,
+    __SIGRTMIN + 81,
+    __SIGRTMIN + 82,
+    __SIGRTMIN + 83,
+    __SIGRTMIN + 84,
+    __SIGRTMIN + 85,
+    __SIGRTMIN + 86,
+    __SIGRTMIN + 87,
+    __SIGRTMIN + 88,
+    __SIGRTMIN + 89,
+    __SIGRTMIN + 90,
+    __SIGRTMIN + 91,
+    __SIGRTMIN + 92,
+    __SIGRTMIN + 93,
+    __SIGRTMIN + 94,
+    __SIGRTMIN + 95,
+    -1, /* SIGINFO */
+    -1, /* UNKNOWN */
+    -1, /* DEFAULT */
+    -1,
+    -1,
+    -1,
+    -1,
+    -1,
+    -1
+#endif
+};
+
+int gdb_signal_to_target(int sig)
+{
+    if (sig < ARRAY_SIZE(gdb_signal_table)) {
+        return gdb_signal_table[sig];
+    } else {
+        return -1;
+    }
+}
+
+int gdb_target_signal_to_gdb(int sig)
+{
+    int i;
+    for (i = 0; i < ARRAY_SIZE(gdb_signal_table); i++) {
+        if (gdb_signal_table[i] == sig) {
+            return i;
+        }
+    }
+    return GDB_SIGNAL_UNKNOWN;
+}
+
+int gdb_get_cpu_index(CPUState *cpu)
+{
+    TaskState *ts = (TaskState *) cpu->opaque;
+    return ts ? ts->ts_tid : -1;
+}
+
+/*
+ * User-mode specific command helpers
+ */
+
+void gdb_handle_query_offsets(GArray *params, void *user_ctx)
+{
+    TaskState *ts;
+
+    ts = gdbserver_state.c_cpu->opaque;
+    g_string_printf(gdbserver_state.str_buf,
+                    "Text=" TARGET_ABI_FMT_lx
+                    ";Data=" TARGET_ABI_FMT_lx
+                    ";Bss=" TARGET_ABI_FMT_lx,
+                    ts->info->code_offset,
+                    ts->info->data_offset,
+                    ts->info->data_offset);
+    gdb_put_strbuf();
+}
+
+#if defined(CONFIG_LINUX)
+/* Partial user only duplicate of helper in gdbstub.c */
+static inline int target_memory_rw_debug(CPUState *cpu, target_ulong addr,
+                                         uint8_t *buf, int len, bool is_write)
+{
+    CPUClass *cc;
+    cc = CPU_GET_CLASS(cpu);
+    if (cc->memory_rw_debug) {
+        return cc->memory_rw_debug(cpu, addr, buf, len, is_write);
+    }
+    return cpu_memory_rw_debug(cpu, addr, buf, len, is_write);
+}
+
+void gdb_handle_query_xfer_auxv(GArray *params, void *user_ctx)
+{
+    TaskState *ts;
+    unsigned long offset, len, saved_auxv, auxv_len;
+
+    if (params->len < 2) {
+        gdb_put_packet("E22");
+        return;
+    }
+
+    offset = get_param(params, 0)->val_ul;
+    len = get_param(params, 1)->val_ul;
+    ts = gdbserver_state.c_cpu->opaque;
+    saved_auxv = ts->info->saved_auxv;
+    auxv_len = ts->info->auxv_len;
+
+    if (offset >= auxv_len) {
+        gdb_put_packet("E00");
+        return;
+    }
+
+    if (len > (MAX_PACKET_LENGTH - 5) / 2) {
+        len = (MAX_PACKET_LENGTH - 5) / 2;
+    }
+
+    if (len < auxv_len - offset) {
+        g_string_assign(gdbserver_state.str_buf, "m");
+    } else {
+        g_string_assign(gdbserver_state.str_buf, "l");
+        len = auxv_len - offset;
+    }
+
+    g_byte_array_set_size(gdbserver_state.mem_buf, len);
+    if (target_memory_rw_debug(gdbserver_state.g_cpu, saved_auxv + offset,
+                               gdbserver_state.mem_buf->data, len, false)) {
+        gdb_put_packet("E14");
+        return;
+    }
+
+    gdb_memtox(gdbserver_state.str_buf,
+           (const char *)gdbserver_state.mem_buf->data, len);
+    gdb_put_packet_binary(gdbserver_state.str_buf->str,
+                      gdbserver_state.str_buf->len, true);
+}
+#endif
--- a/gdbstub/user.c
+++ b/gdbstub/user.c
@ -3,16 +3,423 @@
 *
 * We know for user-mode we are using TCG so we can call stuff directly.
 *
+ * Copyright (c) 2003-2005 Fabrice Bellard
 * Copyright (c) 2022 Linaro Ltd
 *
- * SPDX-License-Identifier: GPL-2.0-or-later
+ * SPDX-License-Identifier: LGPL-2.0+
 */

 #include "qemu/osdep.h"
+#include "qemu/cutils.h"
+#include "qemu/sockets.h"
+#include "exec/hwaddr.h"
+#include "exec/tb-flush.h"
 #include "exec/gdbstub.h"
+#include "gdbstub/syscalls.h"
+#include "gdbstub/user.h"
 #include "hw/core/cpu.h"
+#include "trace.h"
 #include "internals.h"

+/* User-mode specific state */
+typedef struct {
+    int fd;
+    char *socket_path;
+    int running_state;
+} GDBUserState;
+
+static GDBUserState gdbserver_user_state;
+
+int gdb_get_char(void)
+{
+    uint8_t ch;
+    int ret;
+
+    for (;;) {
+        ret = recv(gdbserver_user_state.fd, &ch, 1, 0);
+        if (ret < 0) {
+            if (errno == ECONNRESET) {
+                gdbserver_user_state.fd = -1;
+            }
+            if (errno != EINTR) {
+                return -1;
+            }
+        } else if (ret == 0) {
+            close(gdbserver_user_state.fd);
+            gdbserver_user_state.fd = -1;
+            return -1;
+        } else {
+            break;
+        }
+    }
+    return ch;
+}
+
+bool gdb_got_immediate_ack(void)
+{
+    int i;
+
+    i = gdb_get_char();
+    if (i < 0) {
+        /* no response, continue anyway */
+        return true;
+    }
+
+    if (i == '+') {
+        /* received correctly, continue */
+        return true;
+    }
+
+    /* anything else, including '-' then try again */
+    return false;
+}
+
+void gdb_put_buffer(const uint8_t *buf, int len)
+{
+    int ret;
+
+    while (len > 0) {
+        ret = send(gdbserver_user_state.fd, buf, len, 0);
+        if (ret < 0) {
+            if (errno != EINTR) {
+                return;
+            }
+        } else {
+            buf += ret;
+            len -= ret;
+        }
+    }
+}
+
+/* Tell the remote gdb that the process has exited.  */
+void gdb_exit(int code)
+{
+    char buf[4];
+
+    if (!gdbserver_state.init) {
+        return;
+    }
+    if (gdbserver_user_state.socket_path) {
+        unlink(gdbserver_user_state.socket_path);
+    }
+    if (gdbserver_user_state.fd < 0) {
+        return;
+    }
+
+    trace_gdbstub_op_exiting((uint8_t)code);
+
+    snprintf(buf, sizeof(buf), "W%02x", (uint8_t)code);
+    gdb_put_packet(buf);
+}
+
+int gdb_handlesig(CPUState *cpu, int sig)
+{
+    char buf[256];
+    int n;
+
+    if (!gdbserver_state.init || gdbserver_user_state.fd < 0) {
+        return sig;
+    }
+
+    /* disable single step if it was enabled */
+    cpu_single_step(cpu, 0);
+    tb_flush(cpu);
+
+    if (sig != 0) {
+        gdb_set_stop_cpu(cpu);
+        g_string_printf(gdbserver_state.str_buf,
+                        "T%02xthread:", gdb_target_signal_to_gdb(sig));
+        gdb_append_thread_id(cpu, gdbserver_state.str_buf);
+        g_string_append_c(gdbserver_state.str_buf, ';');
+        gdb_put_strbuf();
+    }
+    /*
+     * gdb_put_packet() might have detected that the peer terminated the
+     * connection.
+     */
+    if (gdbserver_user_state.fd < 0) {
+        return sig;
+    }
+
+    sig = 0;
+    gdbserver_state.state = RS_IDLE;
+    gdbserver_user_state.running_state = 0;
+    while (gdbserver_user_state.running_state == 0) {
+        n = read(gdbserver_user_state.fd, buf, 256);
+        if (n > 0) {
+            int i;
+
+            for (i = 0; i < n; i++) {
+                gdb_read_byte(buf[i]);
+            }
+        } else {
+            /*
+             * XXX: Connection closed.  Should probably wait for another
+             * connection before continuing.
+             */
+            if (n == 0) {
+                close(gdbserver_user_state.fd);
+            }
+            gdbserver_user_state.fd = -1;
+            return sig;
+        }
+    }
+    sig = gdbserver_state.signal;
+    gdbserver_state.signal = 0;
+    return sig;
+}
+
+/* Tell the remote gdb that the process has exited due to SIG.  */
+void gdb_signalled(CPUArchState *env, int sig)
+{
+    char buf[4];
+
+    if (!gdbserver_state.init || gdbserver_user_state.fd < 0) {
+        return;
+    }
+
+    snprintf(buf, sizeof(buf), "X%02x", gdb_target_signal_to_gdb(sig));
+    gdb_put_packet(buf);
+}
+
+static void gdb_accept_init(int fd)
+{
+    gdb_init_gdbserver_state();
+    gdb_create_default_process(&gdbserver_state);
+    gdbserver_state.processes[0].attached = true;
+    gdbserver_state.c_cpu = gdb_first_attached_cpu();
+    gdbserver_state.g_cpu = gdbserver_state.c_cpu;
+    gdbserver_user_state.fd = fd;
+    gdb_has_xml = false;
+}
+
+static bool gdb_accept_socket(int gdb_fd)
+{
+    int fd;
+
+    for (;;) {
+        fd = accept(gdb_fd, NULL, NULL);
+        if (fd < 0 && errno != EINTR) {
+            perror("accept socket");
+            return false;
+        } else if (fd >= 0) {
+            qemu_set_cloexec(fd);
+            break;
+        }
+    }
+
+    gdb_accept_init(fd);
+    return true;
+}
+
+static int gdbserver_open_socket(const char *path)
+{
+    struct sockaddr_un sockaddr = {};
+    int fd, ret;
+
+    fd = socket(AF_UNIX, SOCK_STREAM, 0);
+    if (fd < 0) {
+        perror("create socket");
+        return -1;
+    }
+
+    sockaddr.sun_family = AF_UNIX;
+    pstrcpy(sockaddr.sun_path, sizeof(sockaddr.sun_path) - 1, path);
+    ret = bind(fd, (struct sockaddr *)&sockaddr, sizeof(sockaddr));
+    if (ret < 0) {
+        perror("bind socket");
+        close(fd);
+        return -1;
+    }
+    ret = listen(fd, 1);
+    if (ret < 0) {
+        perror("listen socket");
+        close(fd);
+        return -1;
+    }
+
+    return fd;
+}
+
+static bool gdb_accept_tcp(int gdb_fd)
+{
+    struct sockaddr_in sockaddr = {};
+    socklen_t len;
+    int fd;
+
+    for (;;) {
+        len = sizeof(sockaddr);
+        fd = accept(gdb_fd, (struct sockaddr *)&sockaddr, &len);
+        if (fd < 0 && errno != EINTR) {
+            perror("accept");
+            return false;
+        } else if (fd >= 0) {
+            qemu_set_cloexec(fd);
+            break;
+        }
+    }
+
+    /* set short latency */
+    if (socket_set_nodelay(fd)) {
+        perror("setsockopt");
+        close(fd);
+        return false;
+    }
+
+    gdb_accept_init(fd);
+    return true;
+}
+
+static int gdbserver_open_port(int port)
+{
+    struct sockaddr_in sockaddr;
+    int fd, ret;
+
+    fd = socket(PF_INET, SOCK_STREAM, 0);
+    if (fd < 0) {
+        perror("socket");
+        return -1;
+    }
+    qemu_set_cloexec(fd);
+
+    socket_set_fast_reuse(fd);
+
+    sockaddr.sin_family = AF_INET;
+    sockaddr.sin_port = htons(port);
+    sockaddr.sin_addr.s_addr = 0;
+    ret = bind(fd, (struct sockaddr *)&sockaddr, sizeof(sockaddr));
+    if (ret < 0) {
+        perror("bind");
+        close(fd);
+        return -1;
+    }
+    ret = listen(fd, 1);
+    if (ret < 0) {
+        perror("listen");
+        close(fd);
+        return -1;
+    }
+
+    return fd;
+}
+
+int gdbserver_start(const char *port_or_path)
+{
+    int port = g_ascii_strtoull(port_or_path, NULL, 10);
+    int gdb_fd;
+
+    if (port > 0) {
+        gdb_fd = gdbserver_open_port(port);
+    } else {
+        gdb_fd = gdbserver_open_socket(port_or_path);
+    }
+
+    if (gdb_fd < 0) {
+        return -1;
+    }
+
+    if (port > 0 && gdb_accept_tcp(gdb_fd)) {
+        return 0;
+    } else if (gdb_accept_socket(gdb_fd)) {
+        gdbserver_user_state.socket_path = g_strdup(port_or_path);
+        return 0;
+    }
+
+    /* gone wrong */
+    close(gdb_fd);
+    return -1;
+}
+
+/* Disable gdb stub for child processes.  */
+void gdbserver_fork(CPUState *cpu)
+{
+    if (!gdbserver_state.init || gdbserver_user_state.fd < 0) {
+        return;
+    }
+    close(gdbserver_user_state.fd);
+    gdbserver_user_state.fd = -1;
+    cpu_breakpoint_remove_all(cpu, BP_GDB);
+    /* no cpu_watchpoint_remove_all for user-mode */
+}
+
+/*
+ * Execution state helpers
+ */
+
+void gdb_handle_query_attached(GArray *params, void *user_ctx)
+{
+    gdb_put_packet("0");
+}
+
+void gdb_continue(void)
+{
+    gdbserver_user_state.running_state = 1;
+    trace_gdbstub_op_continue();
+}
+
+/*
+ * Resume execution, for user-mode emulation it's equivalent to
+ * gdb_continue.
+ */
+int gdb_continue_partial(char *newstates)
+{
+    CPUState *cpu;
+    int res = 0;
+    /*
+     * This is not exactly accurate, but it's an improvement compared to the
+     * previous situation, where only one CPU would be single-stepped.
+     */
+    CPU_FOREACH(cpu) {
+        if (newstates[cpu->cpu_index] == 's') {
+            trace_gdbstub_op_stepping(cpu->cpu_index);
+            cpu_single_step(cpu, gdbserver_state.sstep_flags);
+        }
+    }
+    gdbserver_user_state.running_state = 1;
+    return res;
+}
+
+/*
+ * Memory access helpers
+ */
+int gdb_target_memory_rw_debug(CPUState *cpu, hwaddr addr,
+                               uint8_t *buf, int len, bool is_write)
+{
+    CPUClass *cc;
+
+    cc = CPU_GET_CLASS(cpu);
+    if (cc->memory_rw_debug) {
+        return cc->memory_rw_debug(cpu, addr, buf, len, is_write);
+    }
+    return cpu_memory_rw_debug(cpu, addr, buf, len, is_write);
+}
+
+/*
+ * cpu helpers
+ */
+
+unsigned int gdb_get_max_cpus(void)
+{
+    CPUState *cpu;
+    unsigned int max_cpus = 1;
+
+    CPU_FOREACH(cpu) {
+        max_cpus = max_cpus <= cpu->cpu_index ? cpu->cpu_index + 1 : max_cpus;
+    }
+
+    return max_cpus;
+}
+
+/* replay not supported for user-mode */
+bool gdb_can_reverse(void)
+{
+    return false;
+}
+
+/*
+ * Break/Watch point helpers
+ */
+
 bool gdb_supports_guest_debug(void)
 {
    /* user-mode == TCG == supported */
@ -65,3 +472,17 @@ void gdb_breakpoint_remove_all(CPUState *cs)
 {
    cpu_breakpoint_remove_all(cs, BP_GDB);
 }
+
+/*
+ * For user-mode syscall support we send the system call immediately
+ * and then return control to gdb for it to process the syscall request.
+ * Since the protocol requires that gdb hands control back to us
+ * using a "here are the results" F packet, we don't need to check
+ * gdb_handlesig's return value (which is the signal to deliver if
+ * execution was resumed via a continue packet).
+ */
+void gdb_syscall_handling(const char *syscall_packet)
+{
+    gdb_put_packet(syscall_packet);
+    gdb_handlesig(gdbserver_state.c_cpu, 0);
+}
--- a/hw/ppc/spapr_hcall.c
+++ b/hw/ppc/spapr_hcall.c
@ -8,6 +8,7 @@
 #include "qemu/module.h"
 #include "qemu/error-report.h"
 #include "exec/exec-all.h"
+#include "exec/tb-flush.h"
 #include "helper_regs.h"
 #include "hw/ppc/ppc.h"
 #include "hw/ppc/spapr.h"
--- a/include/exec/cpu-defs.h
+++ b/include/exec/cpu-defs.h
@ -55,24 +55,7 @@
 # endif
 #endif

-#define TARGET_LONG_SIZE (TARGET_LONG_BITS / 8)
-
-/* target_ulong is the type of a virtual address */
-#if TARGET_LONG_SIZE == 4
-typedef int32_t target_long;
-typedef uint32_t target_ulong;
-#define TARGET_FMT_lx "%08x"
-#define TARGET_FMT_ld "%d"
-#define TARGET_FMT_lu "%u"
-#elif TARGET_LONG_SIZE == 8
-typedef int64_t target_long;
-typedef uint64_t target_ulong;
-#define TARGET_FMT_lx "%016" PRIx64
-#define TARGET_FMT_ld "%" PRId64
-#define TARGET_FMT_lu "%" PRIu64
-#else
-#error TARGET_LONG_SIZE undefined
-#endif
+#include "exec/target_long.h"

 #if !defined(CONFIG_USER_ONLY) && defined(CONFIG_TCG)

--- a/include/exec/exec-all.h
+++ b/include/exec/exec-all.h
@ -677,7 +677,6 @@ void tb_invalidate_phys_addr(target_ulong addr);
 #else
 void tb_invalidate_phys_addr(AddressSpace *as, hwaddr addr, MemTxAttrs attrs);
 #endif
-void tb_flush(CPUState *cpu);
 void tb_phys_invalidate(TranslationBlock *tb, tb_page_addr_t page_addr);
 void tb_invalidate_phys_range(tb_page_addr_t start, tb_page_addr_t end);
 void tb_set_jmp_target(TranslationBlock *tb, int n, uintptr_t addr);
--- a/include/exec/gdbstub.h
+++ b/include/exec/gdbstub.h
@ -10,122 +10,7 @@
 #define GDB_WATCHPOINT_READ      3
 #define GDB_WATCHPOINT_ACCESS    4

-/* For gdb file i/o remote protocol open flags. */
-#define GDB_O_RDONLY  0
-#define GDB_O_WRONLY  1
-#define GDB_O_RDWR    2
-#define GDB_O_APPEND  8
-#define GDB_O_CREAT   0x200
-#define GDB_O_TRUNC   0x400
-#define GDB_O_EXCL    0x800

-/* For gdb file i/o remote protocol errno values */
-#define GDB_EPERM           1
-#define GDB_ENOENT          2
-#define GDB_EINTR           4
-#define GDB_EBADF           9
-#define GDB_EACCES         13
-#define GDB_EFAULT         14
-#define GDB_EBUSY          16
-#define GDB_EEXIST         17
-#define GDB_ENODEV         19
-#define GDB_ENOTDIR        20
-#define GDB_EISDIR         21
-#define GDB_EINVAL         22
-#define GDB_ENFILE         23
-#define GDB_EMFILE         24
-#define GDB_EFBIG          27
-#define GDB_ENOSPC         28
-#define GDB_ESPIPE         29
-#define GDB_EROFS          30
-#define GDB_ENAMETOOLONG   91
-#define GDB_EUNKNOWN       9999
-
-/* For gdb file i/o remote protocol lseek whence. */
-#define GDB_SEEK_SET  0
-#define GDB_SEEK_CUR  1
-#define GDB_SEEK_END  2
-
-/* For gdb file i/o stat/fstat. */
-typedef uint32_t gdb_mode_t;
-typedef uint32_t gdb_time_t;
-
-struct gdb_stat {
-  uint32_t    gdb_st_dev;     /* device */
-  uint32_t    gdb_st_ino;     /* inode */
-  gdb_mode_t  gdb_st_mode;    /* protection */
-  uint32_t    gdb_st_nlink;   /* number of hard links */
-  uint32_t    gdb_st_uid;     /* user ID of owner */
-  uint32_t    gdb_st_gid;     /* group ID of owner */
-  uint32_t    gdb_st_rdev;    /* device type (if inode device) */
-  uint64_t    gdb_st_size;    /* total size, in bytes */
-  uint64_t    gdb_st_blksize; /* blocksize for filesystem I/O */
-  uint64_t    gdb_st_blocks;  /* number of blocks allocated */
-  gdb_time_t  gdb_st_atime;   /* time of last access */
-  gdb_time_t  gdb_st_mtime;   /* time of last modification */
-  gdb_time_t  gdb_st_ctime;   /* time of last change */
-} QEMU_PACKED;
-
-struct gdb_timeval {
-  gdb_time_t tv_sec;  /* second */
-  uint64_t tv_usec;   /* microsecond */
-} QEMU_PACKED;
-
-#ifdef NEED_CPU_H
-#include "cpu.h"
-
-typedef void (*gdb_syscall_complete_cb)(CPUState *cpu, uint64_t ret, int err);
-
-/**
- * gdb_do_syscall:
- * @cb: function to call when the system call has completed
- * @fmt: gdb syscall format string
- * ...: list of arguments to interpolate into @fmt
- *
- * Send a GDB syscall request. This function will return immediately;
- * the callback function will be called later when the remote system
- * call has completed.
- *
- * @fmt should be in the 'call-id,parameter,parameter...' format documented
- * for the F request packet in the GDB remote protocol. A limited set of
- * printf-style format specifiers is supported:
- *   %x  - target_ulong argument printed in hex
- *   %lx - 64-bit argument printed in hex
- *   %s  - string pointer (target_ulong) and length (int) pair
- */
-void gdb_do_syscall(gdb_syscall_complete_cb cb, const char *fmt, ...);
-/**
- * gdb_do_syscallv:
- * @cb: function to call when the system call has completed
- * @fmt: gdb syscall format string
- * @va: arguments to interpolate into @fmt
- *
- * As gdb_do_syscall, but taking a va_list rather than a variable
- * argument list.
- */
-void gdb_do_syscallv(gdb_syscall_complete_cb cb, const char *fmt, va_list va);
-int use_gdb_syscalls(void);
-
-#ifdef CONFIG_USER_ONLY
-/**
- * gdb_handlesig: yield control to gdb
- * @cpu: CPU
- * @sig: if non-zero, the signal number which caused us to stop
- *
- * This function yields control to gdb, when a user-mode-only target
- * needs to stop execution. If @sig is non-zero, then we will send a
- * stop packet to tell gdb that we have stopped because of this signal.
- *
- * This function will block (handling protocol requests from gdb)
- * until gdb tells us to continue target execution. When it does
- * return, the return value is a signal to deliver to the target,
- * or 0 if no signal should be delivered, ie the signal that caused
- * us to stop should be ignored.
- */
-int gdb_handlesig(CPUState *, int);
-void gdb_signalled(CPUArchState *, int);
-void gdbserver_fork(CPUState *);
-#endif
 /* Get or set a register.  Returns the size of the register.  */
 typedef int (*gdb_get_reg_cb)(CPUArchState *env, GByteArray *buf, int reg);
 typedef int (*gdb_set_reg_cb)(CPUArchState *env, uint8_t *buf, int reg);
@ -133,89 +18,6 @@ void gdb_register_coprocessor(CPUState *cpu,
                              gdb_get_reg_cb get_reg, gdb_set_reg_cb set_reg,
                              int num_regs, const char *xml, int g_pos);

-/*
- * The GDB remote protocol transfers values in target byte order. As
- * the gdbstub may be batching up several register values we always
- * append to the array.
- */
-
-static inline int gdb_get_reg8(GByteArray *buf, uint8_t val)
-{
-    g_byte_array_append(buf, &val, 1);
-    return 1;
-}
-
-static inline int gdb_get_reg16(GByteArray *buf, uint16_t val)
-{
-    uint16_t to_word = tswap16(val);
-    g_byte_array_append(buf, (uint8_t *) &to_word, 2);
-    return 2;
-}
-
-static inline int gdb_get_reg32(GByteArray *buf, uint32_t val)
-{
-    uint32_t to_long = tswap32(val);
-    g_byte_array_append(buf, (uint8_t *) &to_long, 4);
-    return 4;
-}
-
-static inline int gdb_get_reg64(GByteArray *buf, uint64_t val)
-{
-    uint64_t to_quad = tswap64(val);
-    g_byte_array_append(buf, (uint8_t *) &to_quad, 8);
-    return 8;
-}
-
-static inline int gdb_get_reg128(GByteArray *buf, uint64_t val_hi,
-                                 uint64_t val_lo)
-{
-    uint64_t to_quad;
-#if TARGET_BIG_ENDIAN
-    to_quad = tswap64(val_hi);
-    g_byte_array_append(buf, (uint8_t *) &to_quad, 8);
-    to_quad = tswap64(val_lo);
-    g_byte_array_append(buf, (uint8_t *) &to_quad, 8);
-#else
-    to_quad = tswap64(val_lo);
-    g_byte_array_append(buf, (uint8_t *) &to_quad, 8);
-    to_quad = tswap64(val_hi);
-    g_byte_array_append(buf, (uint8_t *) &to_quad, 8);
-#endif
-    return 16;
-}
-
-static inline int gdb_get_zeroes(GByteArray *array, size_t len)
-{
-    guint oldlen = array->len;
-    g_byte_array_set_size(array, oldlen + len);
-    memset(array->data + oldlen, 0, len);
-
-    return len;
-}
-
-/**
- * gdb_get_reg_ptr: get pointer to start of last element
- * @len: length of element
- *
- * This is a helper function to extract the pointer to the last
- * element for additional processing. Some front-ends do additional
- * dynamic swapping of the elements based on CPU state.
- */
-static inline uint8_t * gdb_get_reg_ptr(GByteArray *buf, int len)
-{
-    return buf->data + buf->len - len;
-}
-
-#if TARGET_LONG_BITS == 64
-#define gdb_get_regl(buf, val) gdb_get_reg64(buf, val)
-#define ldtul_p(addr) ldq_p(addr)
-#else
-#define gdb_get_regl(buf, val) gdb_get_reg32(buf, val)
-#define ldtul_p(addr) ldl_p(addr)
-#endif
-
-#endif /* NEED_CPU_H */
-
 /**
 * gdbserver_start: start the gdb server
 * @port_or_device: connection spec for gdb
@ -226,16 +28,6 @@ static inline uint8_t * gdb_get_reg_ptr(GByteArray *buf, int len)
 */
 int gdbserver_start(const char *port_or_device);

-/**
- * gdb_exit: exit gdb session, reporting inferior status
- * @code: exit code reported
- *
- * This closes the session and sends a final packet to GDB reporting
- * the exit status of the program. It also cleans up any connections
- * detritus before returning.
- */
-void gdb_exit(int code);
-
 void gdb_set_stop_cpu(CPUState *cpu);

 /**
--- a/include/exec/target_long.h
+++ b/include/exec/target_long.h
@ -0,0 +1,42 @@
+/*
+ * Target Long Definitions
+ *
+ * Copyright (c) 2003 Fabrice Bellard
+ * Copyright (c) 2023 Linaro Ltd
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#ifndef _TARGET_LONG_H_
+#define _TARGET_LONG_H_
+
+/*
+ * Usually this should only be included via cpu-defs.h however for
+ * certain cases where we want to build only two versions of a binary
+ * object we can include directly. However the build-system must
+ * ensure TARGET_LONG_BITS is defined directly.
+ */
+#ifndef TARGET_LONG_BITS
+#error TARGET_LONG_BITS not defined
+#endif
+
+#define TARGET_LONG_SIZE (TARGET_LONG_BITS / 8)
+
+/* target_ulong is the type of a virtual address */
+#if TARGET_LONG_SIZE == 4
+typedef int32_t target_long;
+typedef uint32_t target_ulong;
+#define TARGET_FMT_lx "%08x"
+#define TARGET_FMT_ld "%d"
+#define TARGET_FMT_lu "%u"
+#elif TARGET_LONG_SIZE == 8
+typedef int64_t target_long;
+typedef uint64_t target_ulong;
+#define TARGET_FMT_lx "%016" PRIx64
+#define TARGET_FMT_ld "%" PRId64
+#define TARGET_FMT_lu "%" PRIu64
+#else
+#error TARGET_LONG_SIZE undefined
+#endif
+
+#endif /* _TARGET_LONG_H_ */
--- a/include/exec/tb-flush.h
+++ b/include/exec/tb-flush.h
@ -0,0 +1,26 @@
+/*
+ * tb-flush prototype for use by the rest of the system.
+ *
+ * Copyright (c) 2022 Linaro Ltd
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+#ifndef _TB_FLUSH_H_
+#define _TB_FLUSH_H_
+
+/**
+ * tb_flush() - flush all translation blocks
+ * @cs: CPUState (must be valid, but treated as anonymous pointer)
+ *
+ * Used to flush all the translation blocks in the system. Sometimes
+ * it is simpler to flush everything than work out which individual
+ * translations are now invalid and ensure they are not called
+ * anymore.
+ *
+ * tb_flush() takes care of running the flush in an exclusive context
+ * if it is not already running in one. This means no guest code will
+ * run until this complete.
+ */
+void tb_flush(CPUState *cs);
+
+#endif /* _TB_FLUSH_H_ */
--- a/include/gdbstub/helpers.h
+++ b/include/gdbstub/helpers.h
@ -0,0 +1,103 @@
+/*
+ * gdbstub helpers
+ *
+ * These are all used by the various frontends and have to be host
+ * aware to ensure things are store in target order.
+ *
+ * Copyright (c) 2022 Linaro Ltd
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#ifndef _GDBSTUB_HELPERS_H_
+#define _GDBSTUB_HELPERS_H_
+
+#ifdef NEED_CPU_H
+#include "cpu.h"
+
+/*
+ * The GDB remote protocol transfers values in target byte order. As
+ * the gdbstub may be batching up several register values we always
+ * append to the array.
+ */
+
+static inline int gdb_get_reg8(GByteArray *buf, uint8_t val)
+{
+    g_byte_array_append(buf, &val, 1);
+    return 1;
+}
+
+static inline int gdb_get_reg16(GByteArray *buf, uint16_t val)
+{
+    uint16_t to_word = tswap16(val);
+    g_byte_array_append(buf, (uint8_t *) &to_word, 2);
+    return 2;
+}
+
+static inline int gdb_get_reg32(GByteArray *buf, uint32_t val)
+{
+    uint32_t to_long = tswap32(val);
+    g_byte_array_append(buf, (uint8_t *) &to_long, 4);
+    return 4;
+}
+
+static inline int gdb_get_reg64(GByteArray *buf, uint64_t val)
+{
+    uint64_t to_quad = tswap64(val);
+    g_byte_array_append(buf, (uint8_t *) &to_quad, 8);
+    return 8;
+}
+
+static inline int gdb_get_reg128(GByteArray *buf, uint64_t val_hi,
+                                 uint64_t val_lo)
+{
+    uint64_t to_quad;
+#if TARGET_BIG_ENDIAN
+    to_quad = tswap64(val_hi);
+    g_byte_array_append(buf, (uint8_t *) &to_quad, 8);
+    to_quad = tswap64(val_lo);
+    g_byte_array_append(buf, (uint8_t *) &to_quad, 8);
+#else
+    to_quad = tswap64(val_lo);
+    g_byte_array_append(buf, (uint8_t *) &to_quad, 8);
+    to_quad = tswap64(val_hi);
+    g_byte_array_append(buf, (uint8_t *) &to_quad, 8);
+#endif
+    return 16;
+}
+
+static inline int gdb_get_zeroes(GByteArray *array, size_t len)
+{
+    guint oldlen = array->len;
+    g_byte_array_set_size(array, oldlen + len);
+    memset(array->data + oldlen, 0, len);
+
+    return len;
+}
+
+/**
+ * gdb_get_reg_ptr: get pointer to start of last element
+ * @len: length of element
+ *
+ * This is a helper function to extract the pointer to the last
+ * element for additional processing. Some front-ends do additional
+ * dynamic swapping of the elements based on CPU state.
+ */
+static inline uint8_t *gdb_get_reg_ptr(GByteArray *buf, int len)
+{
+    return buf->data + buf->len - len;
+}
+
+#if TARGET_LONG_BITS == 64
+#define gdb_get_regl(buf, val) gdb_get_reg64(buf, val)
+#define ldtul_p(addr) ldq_p(addr)
+#else
+#define gdb_get_regl(buf, val) gdb_get_reg32(buf, val)
+#define ldtul_p(addr) ldl_p(addr)
+#endif
+
+#else
+#error "gdbstub helpers should only be included by target specific code"
+#endif
+
+#endif /* _GDBSTUB_HELPERS_H_ */
--- a/include/gdbstub/syscalls.h
+++ b/include/gdbstub/syscalls.h
@ -0,0 +1,113 @@
+/*
+ * GDB Syscall support
+ *
+ * Copyright (c) 2023 Linaro Ltd
+ *
+ * SPDX-License-Identifier: LGPL-2.0+
+ */
+
+#ifndef _SYSCALLS_H_
+#define _SYSCALLS_H_
+
+/* For gdb file i/o remote protocol open flags. */
+#define GDB_O_RDONLY  0
+#define GDB_O_WRONLY  1
+#define GDB_O_RDWR    2
+#define GDB_O_APPEND  8
+#define GDB_O_CREAT   0x200
+#define GDB_O_TRUNC   0x400
+#define GDB_O_EXCL    0x800
+
+/* For gdb file i/o remote protocol errno values */
+#define GDB_EPERM           1
+#define GDB_ENOENT          2
+#define GDB_EINTR           4
+#define GDB_EBADF           9
+#define GDB_EACCES         13
+#define GDB_EFAULT         14
+#define GDB_EBUSY          16
+#define GDB_EEXIST         17
+#define GDB_ENODEV         19
+#define GDB_ENOTDIR        20
+#define GDB_EISDIR         21
+#define GDB_EINVAL         22
+#define GDB_ENFILE         23
+#define GDB_EMFILE         24
+#define GDB_EFBIG          27
+#define GDB_ENOSPC         28
+#define GDB_ESPIPE         29
+#define GDB_EROFS          30
+#define GDB_ENAMETOOLONG   91
+#define GDB_EUNKNOWN       9999
+
+/* For gdb file i/o remote protocol lseek whence. */
+#define GDB_SEEK_SET  0
+#define GDB_SEEK_CUR  1
+#define GDB_SEEK_END  2
+
+/* For gdb file i/o stat/fstat. */
+typedef uint32_t gdb_mode_t;
+typedef uint32_t gdb_time_t;
+
+struct gdb_stat {
+  uint32_t    gdb_st_dev;     /* device */
+  uint32_t    gdb_st_ino;     /* inode */
+  gdb_mode_t  gdb_st_mode;    /* protection */
+  uint32_t    gdb_st_nlink;   /* number of hard links */
+  uint32_t    gdb_st_uid;     /* user ID of owner */
+  uint32_t    gdb_st_gid;     /* group ID of owner */
+  uint32_t    gdb_st_rdev;    /* device type (if inode device) */
+  uint64_t    gdb_st_size;    /* total size, in bytes */
+  uint64_t    gdb_st_blksize; /* blocksize for filesystem I/O */
+  uint64_t    gdb_st_blocks;  /* number of blocks allocated */
+  gdb_time_t  gdb_st_atime;   /* time of last access */
+  gdb_time_t  gdb_st_mtime;   /* time of last modification */
+  gdb_time_t  gdb_st_ctime;   /* time of last change */
+} QEMU_PACKED;
+
+struct gdb_timeval {
+  gdb_time_t tv_sec;  /* second */
+  uint64_t tv_usec;   /* microsecond */
+} QEMU_PACKED;
+
+typedef void (*gdb_syscall_complete_cb)(CPUState *cpu, uint64_t ret, int err);
+
+/**
+ * gdb_do_syscall:
+ * @cb: function to call when the system call has completed
+ * @fmt: gdb syscall format string
+ * ...: list of arguments to interpolate into @fmt
+ *
+ * Send a GDB syscall request. This function will return immediately;
+ * the callback function will be called later when the remote system
+ * call has completed.
+ *
+ * @fmt should be in the 'call-id,parameter,parameter...' format documented
+ * for the F request packet in the GDB remote protocol. A limited set of
+ * printf-style format specifiers is supported:
+ *   %x  - target_ulong argument printed in hex
+ *   %lx - 64-bit argument printed in hex
+ *   %s  - string pointer (target_ulong) and length (int) pair
+ */
+void gdb_do_syscall(gdb_syscall_complete_cb cb, const char *fmt, ...);
+
+/**
+ * use_gdb_syscalls() - report if GDB should be used for syscalls
+ *
+ * This is mostly driven by the semihosting mode the user configures
+ * but assuming GDB is allowed by that we report true if GDB is
+ * connected to the stub.
+ */
+int use_gdb_syscalls(void);
+
+/**
+ * gdb_exit: exit gdb session, reporting inferior status
+ * @code: exit code reported
+ *
+ * This closes the session and sends a final packet to GDB reporting
+ * the exit status of the program. It also cleans up any connections
+ * detritus before returning.
+ */
+void gdb_exit(int code);
+
+#endif /* _SYSCALLS_H_ */
--- a/include/gdbstub/user.h
+++ b/include/gdbstub/user.h
@ -0,0 +1,43 @@
+/*
+ * gdbstub user-mode only APIs
+ *
+ * Copyright (c) 2022 Linaro Ltd
+ *
+ * SPDX-License-Identifier: LGPL-2.0+
+ */
+
+#ifndef GDBSTUB_USER_H
+#define GDBSTUB_USER_H
+
+/**
+ * gdb_handlesig() - yield control to gdb
+ * @cpu: CPU
+ * @sig: if non-zero, the signal number which caused us to stop
+ *
+ * This function yields control to gdb, when a user-mode-only target
+ * needs to stop execution. If @sig is non-zero, then we will send a
+ * stop packet to tell gdb that we have stopped because of this signal.
+ *
+ * This function will block (handling protocol requests from gdb)
+ * until gdb tells us to continue target execution. When it does
+ * return, the return value is a signal to deliver to the target,
+ * or 0 if no signal should be delivered, ie the signal that caused
+ * us to stop should be ignored.
+ */
+int gdb_handlesig(CPUState *, int);
+
+/**
+ * gdb_signalled() - inform remote gdb of sig exit
+ * @as: current CPUArchState
+ * @sig: signal number
+ */
+void gdb_signalled(CPUArchState *as, int sig);
+
+/**
+ * gdbserver_fork() - disable gdb stub for child processes.
+ * @cs: CPU
+ */
+void gdbserver_fork(CPUState *cs);
+
+
+#endif /* GDBSTUB_USER_H */
--- a/include/sysemu/accel-ops.h
+++ b/include/sysemu/accel-ops.h
@ -48,6 +48,7 @@ struct AccelOpsClass {

    /* gdbstub hooks */
    bool (*supports_guest_debug)(void);
+    int (*update_guest_debug)(CPUState *cpu);
    int (*insert_breakpoint)(CPUState *cpu, int type, vaddr addr, vaddr len);
    int (*remove_breakpoint)(CPUState *cpu, int type, vaddr addr, vaddr len);
    void (*remove_all_breakpoints)(CPUState *cpu);
--- a/linux-user/exit.c
+++ b/linux-user/exit.c
@ -18,7 +18,7 @@
 */
 #include "qemu/osdep.h"
 #include "accel/tcg/perf.h"
-#include "exec/gdbstub.h"
+#include "gdbstub/syscalls.h"
 #include "qemu.h"
 #include "user-internals.h"
 #ifdef CONFIG_GPROF
--- a/linux-user/main.c
+++ b/linux-user/main.c
@ -40,6 +40,7 @@
 #include "qemu/plugin.h"
 #include "exec/exec-all.h"
 #include "exec/gdbstub.h"
+#include "gdbstub/user.h"
 #include "tcg/tcg.h"
 #include "qemu/timer.h"
 #include "qemu/envlist.h"
--- a/linux-user/signal.c
+++ b/linux-user/signal.c
@ -18,7 +18,7 @@
 */
 #include "qemu/osdep.h"
 #include "qemu/bitops.h"
-#include "exec/gdbstub.h"
+#include "gdbstub/user.h"
 #include "hw/core/tcg-cpu-ops.h"

 #include <sys/ucontext.h>
--- a/linux-user/user-internals.h
+++ b/linux-user/user-internals.h
@ -20,6 +20,7 @@

 #include "exec/user/thunk.h"
 #include "exec/exec-all.h"
+#include "exec/tb-flush.h"
 #include "qemu/log.h"

 extern char *exec_path;
--- a/plugins/core.c
+++ b/plugins/core.c
@ -24,6 +24,7 @@
 #include "exec/cpu-common.h"

 #include "exec/exec-all.h"
+#include "exec/tb-flush.h"
 #include "exec/helper-proto.h"
 #include "tcg/tcg.h"
 #include "tcg/tcg-op.h"
--- a/plugins/loader.c
+++ b/plugins/loader.c
@ -29,7 +29,7 @@
 #include "qemu/plugin.h"
 #include "qemu/memalign.h"
 #include "hw/core/cpu.h"
-#include "exec/exec-all.h"
+#include "exec/tb-flush.h"
 #ifndef CONFIG_USER_ONLY
 #include "hw/boards.h"
 #endif
--- a/scripts/probe-gdb-support.py
+++ b/scripts/probe-gdb-support.py
@ -0,0 +1,88 @@
+#!/usr/bin/env python3
+# coding: utf-8
+#
+# Probe gdb for supported architectures.
+#
+# This is required to support testing of the gdbstub as its hard to
+# handle errors gracefully during the test. Instead this script when
+# passed a GDB binary will probe its architecture support and return a
+# string of supported arches, stripped of guff.
+#
+# Copyright 2023 Linaro Ltd
+#
+# Author: Alex Bennée <alex.bennee@linaro.org>
+#
+# This work is licensed under the terms of the GNU GPL, version 2 or later.
+# See the COPYING file in the top-level directory.
+#
+# SPDX-License-Identifier: GPL-2.0-or-later
+
+import argparse
+import re
+from subprocess import check_output, STDOUT
+
+# mappings from gdb arch to QEMU target
+mappings = {
+    "alpha" : "alpha",
+    "aarch64" : ["aarch64", "aarch64_be"],
+    "armv7": "arm",
+    "armv8-a" : ["aarch64", "aarch64_be"],
+    "avr" : "avr",
+    "cris" : "cris",
+    # no hexagon in upstream gdb
+    "hppa1.0" : "hppa",
+    "i386" : "i386",
+    "i386:x86-64" : "x86_64",
+    "Loongarch64" : "loongarch64",
+    "m68k" : "m68k",
+    "MicroBlaze" : "microblaze",
+    "mips:isa64" : ["mips64", "mips64el"],
+    "nios2" : "nios2",
+    "or1k" : "or1k",
+    "powerpc:common" : "ppc",
+    "powerpc:common64" : ["ppc64", "ppc64le"],
+    "riscv:rv32" : "riscv32",
+    "riscv:rv64" : "riscv64",
+    "s390:64-bit" : "s390x",
+    "sh4" : ["sh4", "sh4eb"],
+    "sparc": "sparc",
+    "sparc:v8plus": "sparc32plus",
+    "sparc:v9a" : "sparc64",
+    # no tricore in upstream gdb
+    "xtensa" : ["xtensa", "xtensaeb"]
+}
+
+def do_probe(gdb):
+    gdb_out = check_output([gdb,
+                            "-ex", "set architecture",
+                            "-ex", "quit"], stderr=STDOUT)
+
+    m = re.search(r"Valid arguments are (.*)",
+                  gdb_out.decode("utf-8"))
+
+    valid_arches = set()
+
+    if m.group(1):
+        for arch in m.group(1).split(", "):
+            if arch in mappings:
+                mapping = mappings[arch]
+                if isinstance(mapping, str):
+                    valid_arches.add(mapping)
+                else:
+                    for entry in mapping:
+                        valid_arches.add(entry)
+
+    return valid_arches
+
+def main() -> None:
+    parser = argparse.ArgumentParser(description='Probe GDB Architectures')
+    parser.add_argument('gdb', help='Path to GDB binary.')
+
+    args = parser.parse_args()
+
+    supported = do_probe(args.gdb)
+
+    print(" ".join(supported))
+
+if __name__ == '__main__':
+    main()
--- a/semihosting/arm-compat-semi.c
+++ b/semihosting/arm-compat-semi.c
@ -34,6 +34,7 @@
 #include "qemu/osdep.h"
 #include "qemu/timer.h"
 #include "exec/gdbstub.h"
+#include "gdbstub/syscalls.h"
 #include "semihosting/semihost.h"
 #include "semihosting/console.h"
 #include "semihosting/common-semi.h"
--- a/semihosting/guestfd.c
+++ b/semihosting/guestfd.c
@ -9,7 +9,7 @@
 */

 #include "qemu/osdep.h"
-#include "exec/gdbstub.h"
+#include "gdbstub/syscalls.h"
 #include "semihosting/semihost.h"
 #include "semihosting/guestfd.h"
 #ifdef CONFIG_USER_ONLY
--- a/semihosting/syscalls.c
+++ b/semihosting/syscalls.c
@ -7,7 +7,8 @@
 */

 #include "qemu/osdep.h"
-#include "exec/gdbstub.h"
+#include "cpu.h"
+#include "gdbstub/syscalls.h"
 #include "semihosting/guestfd.h"
 #include "semihosting/syscalls.h"
 #include "semihosting/console.h"
@ -138,46 +139,48 @@ static void gdb_open(CPUState *cs, gdb_syscall_complete_cb complete,

    gdb_open_complete = complete;
    gdb_do_syscall(gdb_open_cb, "open,%s,%x,%x",
-                   fname, len, (target_ulong)gdb_flags, (target_ulong)mode);
+                   (uint64_t)fname, (uint32_t)len,
+                   (uint32_t)gdb_flags, (uint32_t)mode);
 }

 static void gdb_close(CPUState *cs, gdb_syscall_complete_cb complete,
                      GuestFD *gf)
 {
-    gdb_do_syscall(complete, "close,%x", (target_ulong)gf->hostfd);
+    gdb_do_syscall(complete, "close,%x", (uint32_t)gf->hostfd);
 }

 static void gdb_read(CPUState *cs, gdb_syscall_complete_cb complete,
                     GuestFD *gf, target_ulong buf, target_ulong len)
 {
-    gdb_do_syscall(complete, "read,%x,%x,%x",
-                   (target_ulong)gf->hostfd, buf, len);
+    gdb_do_syscall(complete, "read,%x,%lx,%lx",
+                   (uint32_t)gf->hostfd, (uint64_t)buf, (uint64_t)len);
 }

 static void gdb_write(CPUState *cs, gdb_syscall_complete_cb complete,
                      GuestFD *gf, target_ulong buf, target_ulong len)
 {
-    gdb_do_syscall(complete, "write,%x,%x,%x",
-                   (target_ulong)gf->hostfd, buf, len);
+    gdb_do_syscall(complete, "write,%x,%lx,%lx",
+                   (uint32_t)gf->hostfd, (uint64_t)buf, (uint64_t)len);
 }

 static void gdb_lseek(CPUState *cs, gdb_syscall_complete_cb complete,
                      GuestFD *gf, int64_t off, int gdb_whence)
 {
    gdb_do_syscall(complete, "lseek,%x,%lx,%x",
-                   (target_ulong)gf->hostfd, off, (target_ulong)gdb_whence);
+                   (uint32_t)gf->hostfd, off, (uint32_t)gdb_whence);
 }

 static void gdb_isatty(CPUState *cs, gdb_syscall_complete_cb complete,
                       GuestFD *gf)
 {
-    gdb_do_syscall(complete, "isatty,%x", (target_ulong)gf->hostfd);
+    gdb_do_syscall(complete, "isatty,%x", (uint32_t)gf->hostfd);
 }

 static void gdb_fstat(CPUState *cs, gdb_syscall_complete_cb complete,
                      GuestFD *gf, target_ulong addr)
 {
-    gdb_do_syscall(complete, "fstat,%x,%x", (target_ulong)gf->hostfd, addr);
+    gdb_do_syscall(complete, "fstat,%x,%lx",
+                   (uint32_t)gf->hostfd, (uint64_t)addr);
 }

 static void gdb_stat(CPUState *cs, gdb_syscall_complete_cb complete,
@ -190,7 +193,8 @@ static void gdb_stat(CPUState *cs, gdb_syscall_complete_cb complete,
        return;
    }

-    gdb_do_syscall(complete, "stat,%s,%x", fname, len, addr);
+    gdb_do_syscall(complete, "stat,%s,%lx",
+                   (uint64_t)fname, (uint32_t)len, (uint64_t)addr);
 }

 static void gdb_remove(CPUState *cs, gdb_syscall_complete_cb complete,
@ -202,7 +206,7 @@ static void gdb_remove(CPUState *cs, gdb_syscall_complete_cb complete,
        return;
    }

-    gdb_do_syscall(complete, "unlink,%s", fname, len);
+    gdb_do_syscall(complete, "unlink,%s", (uint64_t)fname, (uint32_t)len);
 }

 static void gdb_rename(CPUState *cs, gdb_syscall_complete_cb complete,
@ -222,7 +226,9 @@ static void gdb_rename(CPUState *cs, gdb_syscall_complete_cb complete,
        return;
    }

-    gdb_do_syscall(complete, "rename,%s,%s", oname, olen, nname, nlen);
+    gdb_do_syscall(complete, "rename,%s,%s",
+                   (uint64_t)oname, (uint32_t)olen,
+                   (uint64_t)nname, (uint32_t)nlen);
 }

 static void gdb_system(CPUState *cs, gdb_syscall_complete_cb complete,
@ -234,13 +240,14 @@ static void gdb_system(CPUState *cs, gdb_syscall_complete_cb complete,
        return;
    }

-    gdb_do_syscall(complete, "system,%s", cmd, len);
+    gdb_do_syscall(complete, "system,%s", (uint64_t)cmd, (uint32_t)len);
 }

 static void gdb_gettimeofday(CPUState *cs, gdb_syscall_complete_cb complete,
                             target_ulong tv_addr, target_ulong tz_addr)
 {
-    gdb_do_syscall(complete, "gettimeofday,%x,%x", tv_addr, tz_addr);
+    gdb_do_syscall(complete, "gettimeofday,%lx,%lx",
+                   (uint64_t)tv_addr, (uint64_t)tz_addr);
 }

 /*
--- a/softmmu/runstate.c
+++ b/softmmu/runstate.c
@ -30,7 +30,7 @@
 #include "crypto/cipher.h"
 #include "crypto/init.h"
 #include "exec/cpu-common.h"
-#include "exec/gdbstub.h"
+#include "gdbstub/syscalls.h"
 #include "hw/boards.h"
 #include "migration/misc.h"
 #include "migration/postcopy-ram.h"
--- a/stubs/meson.build
+++ b/stubs/meson.build
@ -61,4 +61,5 @@ if have_system
 else
  stub_ss.add(files('qdev.c'))
 endif
+stub_ss.add(files('semihost-all.c'))
 stub_ss.add(when: 'CONFIG_VFIO_USER_SERVER', if_false: files('vfio-user-obj.c'))
--- a/stubs/semihost-all.c
+++ b/stubs/semihost-all.c
@ -0,0 +1,17 @@
+/*
+ * Semihosting Stubs for all targets
+ *
+ * Copyright (c) 2023 Linaro Ltd
+ *
+ * Stubs for all targets that don't actually do semihosting.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "semihosting/semihost.h"
+
+SemihostingTarget semihosting_get_target(void)
+{
+    return SEMIHOSTING_TARGET_AUTO;
+}
--- a/stubs/semihost.c
+++ b/stubs/semihost.c
@ -28,11 +28,6 @@ bool semihosting_enabled(bool is_user)
    return false;
 }

-SemihostingTarget semihosting_get_target(void)
-{
-    return SEMIHOSTING_TARGET_AUTO;
-}
-
 /*
 * All the rest are empty subs. We could g_assert_not_reached() but
 * that adds extra weight to the final binary. Waste not want not.
--- a/target/alpha/gdbstub.c
+++ b/target/alpha/gdbstub.c
@ -19,7 +19,7 @@
 */
 #include "qemu/osdep.h"
 #include "cpu.h"
-#include "exec/gdbstub.h"
+#include "gdbstub/helpers.h"

 int alpha_cpu_gdb_read_register(CPUState *cs, GByteArray *mem_buf, int n)
 {
--- a/target/alpha/sys_helper.c
+++ b/target/alpha/sys_helper.c
@ -20,6 +20,7 @@
 #include "qemu/osdep.h"
 #include "cpu.h"
 #include "exec/exec-all.h"
+#include "exec/tb-flush.h"
 #include "exec/helper-proto.h"
 #include "sysemu/runstate.h"
 #include "sysemu/sysemu.h"
--- a/target/arm/gdbstub.c
+++ b/target/arm/gdbstub.c
@ -20,6 +20,7 @@
 #include "qemu/osdep.h"
 #include "cpu.h"
 #include "exec/gdbstub.h"
+#include "gdbstub/helpers.h"
 #include "internals.h"
 #include "cpregs.h"

--- a/target/arm/gdbstub64.c
+++ b/target/arm/gdbstub64.c
@ -20,7 +20,7 @@
 #include "qemu/log.h"
 #include "cpu.h"
 #include "internals.h"
-#include "exec/gdbstub.h"
+#include "gdbstub/helpers.h"

 int aarch64_cpu_gdb_read_register(CPUState *cs, GByteArray *mem_buf, int n)
 {
--- a/target/arm/tcg/helper-a64.c
+++ b/target/arm/tcg/helper-a64.c
@ -20,7 +20,7 @@
 #include "qemu/osdep.h"
 #include "qemu/units.h"
 #include "cpu.h"
-#include "exec/gdbstub.h"
+#include "gdbstub/helpers.h"
 #include "exec/helper-proto.h"
 #include "qemu/host-utils.h"
 #include "qemu/log.h"
--- a/target/arm/tcg/m_helper.c
+++ b/target/arm/tcg/m_helper.c
@ -9,6 +9,7 @@
 #include "qemu/osdep.h"
 #include "cpu.h"
 #include "internals.h"
+#include "gdbstub/helpers.h"
 #include "exec/helper-proto.h"
 #include "qemu/main-loop.h"
 #include "qemu/bitops.h"
--- a/target/avr/gdbstub.c
+++ b/target/avr/gdbstub.c
@ -19,7 +19,7 @@
 */

 #include "qemu/osdep.h"
-#include "exec/gdbstub.h"
+#include "gdbstub/helpers.h"

 int avr_cpu_gdb_read_register(CPUState *cs, GByteArray *mem_buf, int n)
 {
--- a/target/cris/gdbstub.c
+++ b/target/cris/gdbstub.c
@ -19,7 +19,7 @@
 */
 #include "qemu/osdep.h"
 #include "cpu.h"
-#include "exec/gdbstub.h"
+#include "gdbstub/helpers.h"

 int crisv10_cpu_gdb_read_register(CPUState *cs, GByteArray *mem_buf, int n)
 {
--- a/target/hexagon/gdbstub.c
+++ b/target/hexagon/gdbstub.c
@ -16,7 +16,7 @@
 */

 #include "qemu/osdep.h"
-#include "exec/gdbstub.h"
+#include "gdbstub/helpers.h"
 #include "cpu.h"
 #include "internal.h"

--- a/target/hppa/gdbstub.c
+++ b/target/hppa/gdbstub.c
@ -19,7 +19,7 @@

 #include "qemu/osdep.h"
 #include "cpu.h"
-#include "exec/gdbstub.h"
+#include "gdbstub/helpers.h"

 int hppa_cpu_gdb_read_register(CPUState *cs, GByteArray *mem_buf, int n)
 {
--- a/target/i386/gdbstub.c
+++ b/target/i386/gdbstub.c
@ -19,7 +19,7 @@
 */
 #include "qemu/osdep.h"
 #include "cpu.h"
-#include "exec/gdbstub.h"
+#include "include/gdbstub/helpers.h"

 #ifdef TARGET_X86_64
 static const int gpr_map[16] = {
--- a/target/i386/whpx/whpx-all.c
+++ b/target/i386/whpx/whpx-all.c
@ -12,7 +12,7 @@
 #include "cpu.h"
 #include "exec/address-spaces.h"
 #include "exec/ioport.h"
-#include "exec/gdbstub.h"
+#include "gdbstub/helpers.h"
 #include "qemu/accel.h"
 #include "sysemu/whpx.h"
 #include "sysemu/cpus.h"
--- a/target/loongarch/gdbstub.c
+++ b/target/loongarch/gdbstub.c
@ -10,6 +10,7 @@
 #include "cpu.h"
 #include "internals.h"
 #include "exec/gdbstub.h"
+#include "gdbstub/helpers.h"

 uint64_t read_fcc(CPULoongArchState *env)
 {
--- a/target/m68k/gdbstub.c
+++ b/target/m68k/gdbstub.c
@ -19,7 +19,7 @@
 */
 #include "qemu/osdep.h"
 #include "cpu.h"
-#include "exec/gdbstub.h"
+#include "gdbstub/helpers.h"

 int m68k_cpu_gdb_read_register(CPUState *cs, GByteArray *mem_buf, int n)
 {
--- a/target/m68k/helper.c
+++ b/target/m68k/helper.c
@ -23,6 +23,7 @@
 #include "exec/exec-all.h"
 #include "exec/gdbstub.h"
 #include "exec/helper-proto.h"
+#include "gdbstub/helpers.h"
 #include "fpu/softfloat.h"
 #include "qemu/qemu-print.h"

--- a/target/m68k/m68k-semi.c
+++ b/target/m68k/m68k-semi.c
@ -20,7 +20,8 @@
 #include "qemu/osdep.h"

 #include "cpu.h"
-#include "exec/gdbstub.h"
+#include "gdbstub/syscalls.h"
+#include "gdbstub/helpers.h"
 #include "semihosting/syscalls.h"
 #include "semihosting/softmmu-uaccess.h"
 #include "hw/boards.h"
--- a/target/microblaze/gdbstub.c
+++ b/target/microblaze/gdbstub.c
@ -19,7 +19,7 @@
 */
 #include "qemu/osdep.h"
 #include "cpu.h"
-#include "exec/gdbstub.h"
+#include "gdbstub/helpers.h"

 /*
 * GDB expects SREGs in the following order:
--- a/target/mips/gdbstub.c
+++ b/target/mips/gdbstub.c
@ -20,7 +20,7 @@
 #include "qemu/osdep.h"
 #include "cpu.h"
 #include "internal.h"
-#include "exec/gdbstub.h"
+#include "gdbstub/helpers.h"
 #include "fpu_helper.h"

 int mips_cpu_gdb_read_register(CPUState *cs, GByteArray *mem_buf, int n)
--- a/target/mips/tcg/sysemu/mips-semi.c
+++ b/target/mips/tcg/sysemu/mips-semi.c
@ -20,7 +20,8 @@
 #include "qemu/osdep.h"
 #include "cpu.h"
 #include "qemu/log.h"
-#include "exec/gdbstub.h"
+#include "gdbstub/syscalls.h"
+#include "gdbstub/helpers.h"
 #include "semihosting/softmmu-uaccess.h"
 #include "semihosting/semihost.h"
 #include "semihosting/console.h"
--- a/target/nios2/cpu.c
+++ b/target/nios2/cpu.c
@ -23,7 +23,7 @@
 #include "qapi/error.h"
 #include "cpu.h"
 #include "exec/log.h"
-#include "exec/gdbstub.h"
+#include "gdbstub/helpers.h"
 #include "hw/qdev-properties.h"

 static void nios2_cpu_set_pc(CPUState *cs, vaddr value)
--- a/target/nios2/nios2-semi.c
+++ b/target/nios2/nios2-semi.c
@ -23,7 +23,8 @@

 #include "qemu/osdep.h"
 #include "cpu.h"
-#include "exec/gdbstub.h"
+#include "gdbstub/syscalls.h"
+#include "gdbstub/helpers.h"
 #include "semihosting/syscalls.h"
 #include "semihosting/softmmu-uaccess.h"
 #include "qemu/log.h"
--- a/target/openrisc/gdbstub.c
+++ b/target/openrisc/gdbstub.c
@ -19,7 +19,7 @@
 */
 #include "qemu/osdep.h"
 #include "cpu.h"
-#include "exec/gdbstub.h"
+#include "gdbstub/helpers.h"

 int openrisc_cpu_gdb_read_register(CPUState *cs, GByteArray *mem_buf, int n)
 {
--- a/target/openrisc/interrupt.c
+++ b/target/openrisc/interrupt.c
@ -21,7 +21,7 @@
 #include "qemu/log.h"
 #include "cpu.h"
 #include "exec/exec-all.h"
-#include "exec/gdbstub.h"
+#include "gdbstub/helpers.h"
 #include "qemu/host-utils.h"
 #ifndef CONFIG_USER_ONLY
 #include "hw/loader.h"
--- a/target/openrisc/mmu.c
+++ b/target/openrisc/mmu.c
@ -22,7 +22,7 @@
 #include "qemu/log.h"
 #include "cpu.h"
 #include "exec/exec-all.h"
-#include "exec/gdbstub.h"
+#include "gdbstub/helpers.h"
 #include "qemu/host-utils.h"
 #include "hw/loader.h"

--- a/target/ppc/cpu_init.c
+++ b/target/ppc/cpu_init.c
@ -20,7 +20,7 @@

 #include "qemu/osdep.h"
 #include "disas/dis-asm.h"
-#include "exec/gdbstub.h"
+#include "gdbstub/helpers.h"
 #include "kvm_ppc.h"
 #include "sysemu/cpus.h"
 #include "sysemu/hw_accel.h"
--- a/target/ppc/gdbstub.c
+++ b/target/ppc/gdbstub.c
@ -20,6 +20,7 @@
 #include "qemu/osdep.h"
 #include "cpu.h"
 #include "exec/gdbstub.h"
+#include "gdbstub/helpers.h"
 #include "internal.h"

 static int ppc_gdb_register_len_apple(int n)
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@ -25,6 +25,7 @@
 #include "time_helper.h"
 #include "qemu/main-loop.h"
 #include "exec/exec-all.h"
+#include "exec/tb-flush.h"
 #include "sysemu/cpu-timers.h"
 #include "qemu/guest-random.h"
 #include "qapi/error.h"
--- a/target/riscv/gdbstub.c
+++ b/target/riscv/gdbstub.c
@ -18,6 +18,7 @@

 #include "qemu/osdep.h"
 #include "exec/gdbstub.h"
+#include "gdbstub/helpers.h"
 #include "cpu.h"

 struct TypeSize {
--- a/target/rx/gdbstub.c
+++ b/target/rx/gdbstub.c
@ -17,7 +17,7 @@
 */
 #include "qemu/osdep.h"
 #include "cpu.h"
-#include "exec/gdbstub.h"
+#include "gdbstub/helpers.h"

 int rx_cpu_gdb_read_register(CPUState *cs, GByteArray *mem_buf, int n)
 {
--- a/target/s390x/gdbstub.c
+++ b/target/s390x/gdbstub.c
@ -23,6 +23,7 @@
 #include "s390x-internal.h"
 #include "exec/exec-all.h"
 #include "exec/gdbstub.h"
+#include "gdbstub/helpers.h"
 #include "qemu/bitops.h"
 #include "sysemu/hw_accel.h"
 #include "sysemu/tcg.h"
--- a/target/s390x/helper.c
+++ b/target/s390x/helper.c
@ -21,7 +21,7 @@
 #include "qemu/osdep.h"
 #include "cpu.h"
 #include "s390x-internal.h"
-#include "exec/gdbstub.h"
+#include "gdbstub/helpers.h"
 #include "qemu/timer.h"
 #include "hw/s390x/ioinst.h"
 #include "hw/s390x/pv.h"
--- a/target/sh4/gdbstub.c
+++ b/target/sh4/gdbstub.c
@ -19,7 +19,7 @@
 */
 #include "qemu/osdep.h"
 #include "cpu.h"
-#include "exec/gdbstub.h"
+#include "gdbstub/helpers.h"

 /* Hint: Use "set architecture sh4" in GDB to see fpu registers */
 /* FIXME: We should use XML for this.  */
--- a/target/sparc/gdbstub.c
+++ b/target/sparc/gdbstub.c
@ -19,7 +19,7 @@
 */
 #include "qemu/osdep.h"
 #include "cpu.h"
-#include "exec/gdbstub.h"
+#include "gdbstub/helpers.h"

 #ifdef TARGET_ABI32
 #define gdb_get_rega(buf, val) gdb_get_reg32(buf, val)
--- a/target/tricore/gdbstub.c
+++ b/target/tricore/gdbstub.c
@ -18,7 +18,7 @@
 */

 #include "qemu/osdep.h"
-#include "exec/gdbstub.h"
+#include "gdbstub/helpers.h"


 #define LCX_REGNUM         32
--- a/target/xtensa/core-dc232b.c
+++ b/target/xtensa/core-dc232b.c
@ -27,7 +27,7 @@

 #include "qemu/osdep.h"
 #include "cpu.h"
-#include "exec/gdbstub.h"
+#include "gdbstub/helpers.h"
 #include "qemu/host-utils.h"
 #include "qemu/timer.h"

--- a/target/xtensa/core-dc233c.c
+++ b/target/xtensa/core-dc233c.c
@ -27,7 +27,7 @@

 #include "qemu/osdep.h"
 #include "cpu.h"
-#include "exec/gdbstub.h"
+#include "gdbstub/helpers.h"
 #include "qemu/host-utils.h"

 #include "core-dc233c/core-isa.h"
--- a/target/xtensa/core-de212.c
+++ b/target/xtensa/core-de212.c
@ -27,7 +27,7 @@

 #include "qemu/osdep.h"
 #include "cpu.h"
-#include "exec/gdbstub.h"
+#include "gdbstub/helpers.h"
 #include "qemu/host-utils.h"

 #include "core-de212/core-isa.h"
--- a/target/xtensa/core-de233_fpu.c
+++ b/target/xtensa/core-de233_fpu.c
@ -27,7 +27,7 @@

 #include "qemu/osdep.h"
 #include "cpu.h"
-#include "exec/gdbstub.h"
+#include "gdbstub/helpers.h"
 #include "qemu/host-utils.h"

 #include "core-de233_fpu/core-isa.h"
--- a/target/xtensa/core-dsp3400.c
+++ b/target/xtensa/core-dsp3400.c
@ -27,7 +27,7 @@

 #include "qemu/osdep.h"
 #include "cpu.h"
-#include "exec/gdbstub.h"
+#include "gdbstub/helpers.h"
 #include "qemu/host-utils.h"

 #include "core-dsp3400/core-isa.h"
--- a/target/xtensa/core-fsf.c
+++ b/target/xtensa/core-fsf.c
@ -27,7 +27,7 @@

 #include "qemu/osdep.h"
 #include "cpu.h"
-#include "exec/gdbstub.h"
+#include "gdbstub/helpers.h"
 #include "qemu/host-utils.h"

 #include "core-fsf/core-isa.h"
--- a/target/xtensa/core-lx106.c
+++ b/target/xtensa/core-lx106.c
@ -27,7 +27,7 @@

 #include "qemu/osdep.h"
 #include "cpu.h"
-#include "exec/gdbstub.h"
+#include "gdbstub/helpers.h"
 #include "qemu/host-utils.h"

 #include "core-lx106/core-isa.h"
--- a/target/xtensa/core-sample_controller.c
+++ b/target/xtensa/core-sample_controller.c
@ -27,7 +27,7 @@

 #include "qemu/osdep.h"
 #include "cpu.h"
-#include "exec/gdbstub.h"
+#include "gdbstub/helpers.h"
 #include "qemu/host-utils.h"

 #include "core-sample_controller/core-isa.h"
--- a/target/xtensa/core-test_kc705_be.c
+++ b/target/xtensa/core-test_kc705_be.c
@ -27,7 +27,7 @@

 #include "qemu/osdep.h"
 #include "cpu.h"
-#include "exec/gdbstub.h"
+#include "gdbstub/helpers.h"
 #include "qemu/host-utils.h"

 #include "core-test_kc705_be/core-isa.h"
--- a/target/xtensa/core-test_mmuhifi_c3.c
+++ b/target/xtensa/core-test_mmuhifi_c3.c
@ -27,7 +27,7 @@

 #include "qemu/osdep.h"
 #include "cpu.h"
-#include "exec/gdbstub.h"
+#include "gdbstub/helpers.h"
 #include "qemu/host-utils.h"

 #include "core-test_mmuhifi_c3/core-isa.h"
--- a/target/xtensa/gdbstub.c
+++ b/target/xtensa/gdbstub.c
@ -19,7 +19,7 @@
 */
 #include "qemu/osdep.h"
 #include "cpu.h"
-#include "exec/gdbstub.h"
+#include "gdbstub/helpers.h"
 #include "qemu/log.h"

 enum {
--- a/target/xtensa/helper.c
+++ b/target/xtensa/helper.c
@ -29,7 +29,7 @@
 #include "qemu/log.h"
 #include "cpu.h"
 #include "exec/exec-all.h"
-#include "exec/gdbstub.h"
+#include "gdbstub/helpers.h"
 #include "exec/helper-proto.h"
 #include "qemu/error-report.h"
 #include "qemu/qemu-print.h"
--- a/target/xtensa/import_core.sh
+++ b/target/xtensa/import_core.sh
@ -41,7 +41,7 @@ tar -xf "$OVERLAY" -O binutils/xtensa-modules.c | \
 cat <<EOF > "${TARGET}.c"
 #include "qemu/osdep.h"
 #include "cpu.h"
-#include "exec/gdbstub.h"
+#include "gdbstub/helpers.h"
 #include "qemu/host-utils.h"

 #include "core-$NAME/core-isa.h"
--- a/tests/tcg/aarch64/Makefile.target
+++ b/tests/tcg/aarch64/Makefile.target
@ -81,7 +81,7 @@ sha512-vector: sha512.c

 TESTS += sha512-vector

-ifneq ($(HAVE_GDB_BIN),)
+ifeq ($(HOST_GDB_SUPPORTS_ARCH),y)
 GDB_SCRIPT=$(SRC_PATH)/tests/guest-debug/run-test.py

 run-gdbstub-sysregs: sysregs
--- a/tests/tcg/multiarch/Makefile.target
+++ b/tests/tcg/multiarch/Makefile.target
@ -64,6 +64,7 @@ run-test-mmap-%: test-mmap
 	$(call run-test, test-mmap-$*, $(QEMU) -p $* $<, $< ($* byte pages))

 ifneq ($(HAVE_GDB_BIN),)
+ifeq ($(HOST_GDB_SUPPORTS_ARCH),y)
 GDB_SCRIPT=$(SRC_PATH)/tests/guest-debug/run-test.py

 run-gdbstub-sha1: sha1
@ -87,6 +88,10 @@ run-gdbstub-thread-breakpoint: testthread
 		--bin $< --test $(MULTIARCH_SRC)/gdbstub/test-thread-breakpoint.py, \
 	hitting a breakpoint on non-main thread)

+else
+run-gdbstub-%:
+	$(call skip-test, "gdbstub test $*", "no guest arch support")
+endif
 else
 run-gdbstub-%:
 	$(call skip-test, "gdbstub test $*", "need working gdb")
--- a/tests/tcg/multiarch/system/Makefile.softmmu-target
+++ b/tests/tcg/multiarch/system/Makefile.softmmu-target
@ -15,6 +15,7 @@ MULTIARCH_TEST_SRCS=$(wildcard $(MULTIARCH_SYSTEM_SRC)/*.c)
 MULTIARCH_TESTS = $(patsubst $(MULTIARCH_SYSTEM_SRC)/%.c, %, $(MULTIARCH_TEST_SRCS))

 ifneq ($(HAVE_GDB_BIN),)
+ifeq ($(HOST_GDB_SUPPORTS_ARCH),y)
 GDB_SCRIPT=$(SRC_PATH)/tests/guest-debug/run-test.py

 run-gdbstub-memory: memory
@ -26,7 +27,10 @@ run-gdbstub-memory: memory
 		"-monitor none -display none -chardev file$(COMMA)path=$<.out$(COMMA)id=output $(QEMU_OPTS)" \
 		--bin $< --test $(MULTIARCH_SRC)/gdbstub/memory.py, \
 	softmmu gdbstub support)
-
+else
+run-gdbstub-%:
+	$(call skip-test, "gdbstub test $*", "no guest arch support")
+endif
 else
 run-gdbstub-%:
 	$(call skip-test, "gdbstub test $*", "need working gdb")
--- a/tests/tcg/s390x/Makefile.target
+++ b/tests/tcg/s390x/Makefile.target
@ -51,7 +51,7 @@ $(Z15_TESTS): CFLAGS+=-march=z15 -O2
 TESTS+=$(Z15_TESTS)
 endif

-ifneq ($(HAVE_GDB_BIN),)
+ifeq ($(HOST_GDB_SUPPORTS_ARCH),y)
 GDB_SCRIPT=$(SRC_PATH)/tests/guest-debug/run-test.py

 run-gdbstub-signals-s390x: signals-s390x