semihosting: create SemihostingConfig structure and semihost.h

Remove semihosting_enabled and semihosting_target and replace them with
SemihostingConfig structure containing equivalent fields. The structure
is defined in vl.c where it is actually set.

Also introduce separate header file include/exec/semihost.h allowing to
access semihosting config related stuff from target specific semihosting
code.

Signed-off-by: Leon Alrae <leon.alrae@imgtec.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 1434643256-16858-2-git-send-email-leon.alrae@imgtec.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

gdbstub.c

@@ -40,6 +40,7 @@
 #include "cpu.h"
 #include "qemu/sockets.h"
 #include "sysemu/kvm.h"
+#include "exec/semihost.h"
 
 #ifdef CONFIG_USER_ONLY
 #define GDB_ATTACHED "0"
@@ -323,8 +324,6 @@ static GDBState *gdbserver_state;
 
 bool gdb_has_xml;
 
-int semihosting_target = SEMIHOSTING_TARGET_AUTO;
-
 #ifdef CONFIG_USER_ONLY
 /* XXX: This is not thread safe.  Do we care?  */
 static int gdbserver_fd = -1;
@@ -362,10 +361,11 @@ static enum {
 /* Decide if either remote gdb syscalls or native file IO should be used. */
 int use_gdb_syscalls(void)
 {
-    if (semihosting_target == SEMIHOSTING_TARGET_NATIVE) {
+    SemihostingTarget target = semihosting_get_target();
+    if (target == SEMIHOSTING_TARGET_NATIVE) {
         /* -semihosting-config target=native */
         return false;
-    } else if (semihosting_target == SEMIHOSTING_TARGET_GDB) {
+    } else if (target == SEMIHOSTING_TARGET_GDB) {
         /* -semihosting-config target=gdb */
         return true;
     }

include/exec/gdbstub.h

@@ -95,10 +95,4 @@ extern bool gdb_has_xml;
 /* in gdbstub-xml.c, generated by scripts/feature_to_c.sh */
 extern const char *const xml_builtin[][2];
 
-/* Command line option defining whether semihosting should go via gdb or not */
-extern int semihosting_target;
-#define SEMIHOSTING_TARGET_AUTO     0
-#define SEMIHOSTING_TARGET_NATIVE   1
-#define SEMIHOSTING_TARGET_GDB      2
-
 #endif

include/exec/semihost.h

@@ -0,0 +1,44 @@
+/*
+ * Semihosting support
+ *
+ * Copyright (c) 2015 Imagination Technologies
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef SEMIHOST_H
+#define SEMIHOST_H
+
+typedef enum SemihostingTarget {
+    SEMIHOSTING_TARGET_AUTO = 0,
+    SEMIHOSTING_TARGET_NATIVE,
+    SEMIHOSTING_TARGET_GDB
+} SemihostingTarget;
+
+#ifdef CONFIG_USER_ONLY
+static inline bool semihosting_enabled(void)
+{
+    return true;
+}
+
+static inline SemihostingTarget semihosting_get_target(void)
+{
+    return SEMIHOSTING_TARGET_AUTO;
+}
+#else
+bool semihosting_enabled(void);
+SemihostingTarget semihosting_get_target(void);
+#endif
+
+#endif

include/sysemu/sysemu.h

@@ -126,7 +126,6 @@ extern int cursor_hide;
 extern int graphic_rotate;
 extern int no_quit;
 extern int no_shutdown;
-extern int semihosting_enabled;
 extern int old_param;
 extern int boot_menu;
 extern bool boot_strict;

target-arm/helper.c

@@ -10,6 +10,7 @@
 #include "exec/cpu_ldst.h"
 #include "arm_ldst.h"
 #include <zlib.h> /* For crc32 */
+#include "exec/semihost.h"
 
 #ifndef CONFIG_USER_ONLY
 static inline bool get_phys_addr(CPUARMState *env, target_ulong address,
@@ -4554,7 +4555,7 @@ void arm_v7m_cpu_do_interrupt(CPUState *cs)
         armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_MEM);
         return;
     case EXCP_BKPT:
-        if (semihosting_enabled) {
+        if (semihosting_enabled()) {
             int nr;
             nr = arm_lduw_code(env, env->regs[15], env->bswap_code) & 0xff;
             if (nr == 0xab) {
@@ -4866,7 +4867,7 @@ void arm_cpu_do_interrupt(CPUState *cs)
             offset = 4;
         break;
     case EXCP_SWI:
-        if (semihosting_enabled) {
+        if (semihosting_enabled()) {
             /* Check for semihosting interrupt.  */
             if (env->thumb) {
                 mask = arm_lduw_code(env, env->regs[15] - 2, env->bswap_code)
@@ -4893,7 +4894,7 @@ void arm_cpu_do_interrupt(CPUState *cs)
         break;
     case EXCP_BKPT:
         /* See if this is a semihosting syscall.  */
-        if (env->thumb && semihosting_enabled) {
+        if (env->thumb && semihosting_enabled()) {
             mask = arm_lduw_code(env, env->regs[15], env->bswap_code) & 0xff;
             if (mask == 0xab
                   && (env->uncached_cpsr & CPSR_M) != ARM_CPU_MODE_USR) {

target-lm32/helper.c

@@ -20,6 +20,7 @@
 #include "cpu.h"
 #include "qemu/host-utils.h"
 #include "sysemu/sysemu.h"
+#include "exec/semihost.h"
 
 int lm32_cpu_handle_mmu_fault(CPUState *cs, vaddr address, int rw,
                               int mmu_idx)
@@ -162,7 +163,7 @@ void lm32_cpu_do_interrupt(CPUState *cs)
 
     switch (cs->exception_index) {
     case EXCP_SYSTEMCALL:
-        if (unlikely(semihosting_enabled)) {
+        if (unlikely(semihosting_enabled())) {
             /* do_semicall() returns true if call was handled. Otherwise
              * do the normal exception handling. */
             if (lm32_cpu_do_semihosting(cs)) {

target-m68k/op_helper.c

@@ -19,6 +19,7 @@
 #include "cpu.h"
 #include "exec/helper-proto.h"
 #include "exec/cpu_ldst.h"
+#include "exec/semihost.h"
 
 #if defined(CONFIG_USER_ONLY)
 
@@ -33,8 +34,6 @@ static inline void do_interrupt_m68k_hardirq(CPUM68KState *env)
 
 #else
 
-extern int semihosting_enabled;
-
 /* Try to fill the TLB and return an exception if error. If retaddr is
    NULL, it means that the function was called in C code (i.e. not
    from generated code or from helper.c) */
@@ -85,7 +84,7 @@ static void do_interrupt_all(CPUM68KState *env, int is_hw)
             do_rte(env);
             return;
         case EXCP_HALT_INSN:
-            if (semihosting_enabled
+            if (semihosting_enabled()
                     && (env->sr & SR_S) != 0
                     && (env->pc & 3) == 0
                     && cpu_lduw_code(env, env->pc - 4) == 0x4e71

target-xtensa/translate.c

@@ -37,6 +37,7 @@
 #include "qemu/log.h"
 #include "sysemu/sysemu.h"
 #include "exec/cpu_ldst.h"
+#include "exec/semihost.h"
 
 #include "exec/helper-proto.h"
 #include "exec/helper-gen.h"
@@ -1216,7 +1217,7 @@ static void disas_xtensa_insn(CPUXtensaState *env, DisasContext *dc)
                         break;
 
                     case 1: /*SIMCALL*/
-                        if (semihosting_enabled) {
+                        if (semihosting_enabled()) {
                             if (gen_check_privilege(dc)) {
                                 gen_helper_simcall(cpu_env);
                             }

vl.c

@@ -119,6 +119,7 @@ int main(int argc, char **argv)
 #include "qapi/opts-visitor.h"
 #include "qom/object_interfaces.h"
 #include "qapi-event.h"
+#include "exec/semihost.h"
 
 #define MAX_VIRTIO_CONSOLES 1
 #define MAX_SCLP_CONSOLES 1
@@ -169,7 +170,6 @@ int graphic_rotate = 0;
 const char *watchdog;
 QEMUOptionRom option_rom[MAX_OPTION_ROMS];
 int nb_option_roms;
-int semihosting_enabled = 0;
 int old_param = 0;
 const char *qemu_name;
 int alt_grab = 0;
@@ -1245,6 +1245,26 @@ static void configure_msg(QemuOpts *opts)
     enable_timestamp_msg = qemu_opt_get_bool(opts, "timestamp", true);
 }
 
+/***********************************************************/
+/* Semihosting */
+
+typedef struct SemihostingConfig {
+    bool enabled;
+    SemihostingTarget target;
+} SemihostingConfig;
+
+static SemihostingConfig semihosting;
+
+bool semihosting_enabled(void)
+{
+    return semihosting.enabled;
+}
+
+SemihostingTarget semihosting_get_target(void)
+{
+    return semihosting.target;
+}
+
 /***********************************************************/
 /* USB devices */
 
@@ -3622,24 +3642,24 @@ int main(int argc, char **argv, char **envp)
                 nb_option_roms++;
                 break;
             case QEMU_OPTION_semihosting:
-                semihosting_enabled = 1;
+                semihosting.enabled = true;
-                semihosting_target = SEMIHOSTING_TARGET_AUTO;
+                semihosting.target = SEMIHOSTING_TARGET_AUTO;
                 break;
             case QEMU_OPTION_semihosting_config:
-                semihosting_enabled = 1;
+                semihosting.enabled = true;
                 opts = qemu_opts_parse(qemu_find_opts("semihosting-config"),
                                            optarg, 0);
                 if (opts != NULL) {
-                    semihosting_enabled = qemu_opt_get_bool(opts, "enable",
+                    semihosting.enabled = qemu_opt_get_bool(opts, "enable",
                                                             true);
                     const char *target = qemu_opt_get(opts, "target");
                     if (target != NULL) {
                         if (strcmp("native", target) == 0) {
-                            semihosting_target = SEMIHOSTING_TARGET_NATIVE;
+                            semihosting.target = SEMIHOSTING_TARGET_NATIVE;
                         } else if (strcmp("gdb", target) == 0) {
-                            semihosting_target = SEMIHOSTING_TARGET_GDB;
+                            semihosting.target = SEMIHOSTING_TARGET_GDB;
                         } else  if (strcmp("auto", target) == 0) {
-                            semihosting_target = SEMIHOSTING_TARGET_AUTO;
+                            semihosting.target = SEMIHOSTING_TARGET_AUTO;
                         } else {
                             fprintf(stderr, "Unsupported semihosting-config"
                                     " %s\n",
@@ -3647,7 +3667,7 @@ int main(int argc, char **argv, char **envp)
                             exit(1);
                         }
                     } else {
-                        semihosting_target = SEMIHOSTING_TARGET_AUTO;
+                        semihosting.target = SEMIHOSTING_TARGET_AUTO;
                     }
                 } else {
                     fprintf(stderr, "Unsupported semihosting-config %s\n",