gdbstub: Simplify XML lookup

Now we know all instances of GDBFeature that is used in CPU so we can
traverse them to find XML. This removes the need for a CPU-specific
lookup function for dynamic XMLs.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20231213-gdb-v17-7-777047380591@daynix.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20240227144335.1196131-12-alex.bennee@linaro.org>

gdbstub/gdbstub.c

@@ -352,6 +352,7 @@ static const char *get_feature_xml(const char *p, const char **newp,
 {
     CPUState *cpu = gdb_get_first_cpu_in_process(process);
     CPUClass *cc = CPU_GET_CLASS(cpu);
+    GDBRegisterState *r;
     size_t len;
 
     /*
@@ -365,7 +366,6 @@ static const char *get_feature_xml(const char *p, const char **newp,
     /* Is it the main target xml? */
     if (strncmp(p, "target.xml", len) == 0) {
         if (!process->target_xml) {
-            GDBRegisterState *r;
             g_autoptr(GPtrArray) xml = g_ptr_array_new_with_free_func(g_free);
 
             g_ptr_array_add(
@@ -380,18 +380,12 @@ static const char *get_feature_xml(const char *p, const char **newp,
                     g_markup_printf_escaped("<architecture>%s</architecture>",
                                             cc->gdb_arch_name(cpu)));
             }
-            g_ptr_array_add(
+            for (guint i = 0; i < cpu->gdb_regs->len; i++) {
-                xml,
+                r = &g_array_index(cpu->gdb_regs, GDBRegisterState, i);
-                g_markup_printf_escaped("<xi:include href=\"%s\"/>",
+                g_ptr_array_add(
-                                        cc->gdb_core_xml_file));
+                    xml,
-            if (cpu->gdb_regs) {
+                    g_markup_printf_escaped("<xi:include href=\"%s\"/>",
-                for (guint i = 0; i < cpu->gdb_regs->len; i++) {
+                                            r->feature->xmlname));
-                    r = &g_array_index(cpu->gdb_regs, GDBRegisterState, i);
-                    g_ptr_array_add(
-                        xml,
-                        g_markup_printf_escaped("<xi:include href=\"%s\"/>",
-                                                r->feature->xmlname));
-                }
             }
             g_ptr_array_add(xml, g_strdup("</target>"));
             g_ptr_array_add(xml, NULL);
@@ -400,20 +394,11 @@ static const char *get_feature_xml(const char *p, const char **newp,
         }
         return process->target_xml;
     }
-    /* Is it dynamically generated by the target? */
+    /* Is it one of the features? */
-    if (cc->gdb_get_dynamic_xml) {
+    for (guint i = 0; i < cpu->gdb_regs->len; i++) {
-        g_autofree char *xmlname = g_strndup(p, len);
+        r = &g_array_index(cpu->gdb_regs, GDBRegisterState, i);
-        const char *xml = cc->gdb_get_dynamic_xml(cpu, xmlname);
+        if (strncmp(p, r->feature->xmlname, len) == 0) {
-        if (xml) {
+            return r->feature->xml;
-            return xml;
-        }
-    }
-    /* Is it one of the encoded gdb-xml/ files? */
-    for (int i = 0; gdb_static_features[i].xmlname; i++) {
-        const char *name = gdb_static_features[i].xmlname;
-        if ((strncmp(name, p, len) == 0) &&
-            strlen(name) == len) {
-            return gdb_static_features[i].xml;
         }
     }
 
@@ -508,12 +493,10 @@ static int gdb_read_register(CPUState *cpu, GByteArray *buf, int reg)
         return cc->gdb_read_register(cpu, buf, reg);
     }
 
-    if (cpu->gdb_regs) {
+    for (guint i = 0; i < cpu->gdb_regs->len; i++) {
-        for (guint i = 0; i < cpu->gdb_regs->len; i++) {
+        r = &g_array_index(cpu->gdb_regs, GDBRegisterState, i);
-            r = &g_array_index(cpu->gdb_regs, GDBRegisterState, i);
+        if (r->base_reg <= reg && reg < r->base_reg + r->feature->num_regs) {
-            if (r->base_reg <= reg && reg < r->base_reg + r->feature->num_regs) {
+            return r->get_reg(cpu, buf, reg - r->base_reg);
-                return r->get_reg(cpu, buf, reg - r->base_reg);
-            }
         }
     }
     return 0;
@@ -528,51 +511,70 @@ static int gdb_write_register(CPUState *cpu, uint8_t *mem_buf, int reg)
         return cc->gdb_write_register(cpu, mem_buf, reg);
     }
 
-    if (cpu->gdb_regs) {
+    for (guint i = 0; i < cpu->gdb_regs->len; i++) {
-        for (guint i = 0; i < cpu->gdb_regs->len; i++) {
+        r =  &g_array_index(cpu->gdb_regs, GDBRegisterState, i);
-            r =  &g_array_index(cpu->gdb_regs, GDBRegisterState, i);
+        if (r->base_reg <= reg && reg < r->base_reg + r->feature->num_regs) {
-            if (r->base_reg <= reg && reg < r->base_reg + r->feature->num_regs) {
+            return r->set_reg(cpu, mem_buf, reg - r->base_reg);
-                return r->set_reg(cpu, mem_buf, reg - r->base_reg);
-            }
         }
     }
     return 0;
 }
 
+static void gdb_register_feature(CPUState *cpu, int base_reg,
+                                 gdb_get_reg_cb get_reg, gdb_set_reg_cb set_reg,
+                                 const GDBFeature *feature)
+{
+    GDBRegisterState s = {
+        .base_reg = base_reg,
+        .get_reg = get_reg,
+        .set_reg = set_reg,
+        .feature = feature
+    };
+
+    g_array_append_val(cpu->gdb_regs, s);
+}
+
+void gdb_init_cpu(CPUState *cpu)
+{
+    CPUClass *cc = CPU_GET_CLASS(cpu);
+    const GDBFeature *feature;
+
+    cpu->gdb_regs = g_array_new(false, false, sizeof(GDBRegisterState));
+
+    if (cc->gdb_core_xml_file) {
+        feature = gdb_find_static_feature(cc->gdb_core_xml_file);
+        gdb_register_feature(cpu, 0,
+                             cc->gdb_read_register, cc->gdb_write_register,
+                             feature);
+    }
+
+    cpu->gdb_num_regs = cpu->gdb_num_g_regs = cc->gdb_num_core_regs;
+}
+
 void gdb_register_coprocessor(CPUState *cpu,
                               gdb_get_reg_cb get_reg, gdb_set_reg_cb set_reg,
                               const GDBFeature *feature, int g_pos)
 {
     GDBRegisterState *s;
     guint i;
+    int base_reg = cpu->gdb_num_regs;
 
-    if (cpu->gdb_regs) {
+    for (i = 0; i < cpu->gdb_regs->len; i++) {
-        for (i = 0; i < cpu->gdb_regs->len; i++) {
+        /* Check for duplicates.  */
-            /* Check for duplicates.  */
+        s = &g_array_index(cpu->gdb_regs, GDBRegisterState, i);
-            s = &g_array_index(cpu->gdb_regs, GDBRegisterState, i);
+        if (s->feature == feature) {
-            if (s->feature == feature) {
+            return;
-                return;
-            }
         }
-    } else {
-        cpu->gdb_regs = g_array_new(false, false, sizeof(GDBRegisterState));
-        i = 0;
     }
 
-    g_array_set_size(cpu->gdb_regs, i + 1);
+    gdb_register_feature(cpu, base_reg, get_reg, set_reg, feature);
-    s = &g_array_index(cpu->gdb_regs, GDBRegisterState, i);
-    s->base_reg = cpu->gdb_num_regs;
-    s->get_reg = get_reg;
-    s->set_reg = set_reg;
-    s->feature = feature;
 
     /* Add to end of list.  */
     cpu->gdb_num_regs += feature->num_regs;
     if (g_pos) {
-        if (g_pos != s->base_reg) {
+        if (g_pos != base_reg) {
             error_report("Error: Bad gdb register numbering for '%s', "
-                         "expected %d got %d", feature->xml,
+                         "expected %d got %d", feature->xml, g_pos, base_reg);
-                         g_pos, s->base_reg);
         } else {
             cpu->gdb_num_g_regs = cpu->gdb_num_regs;
         }

hw/core/cpu-common.c

@@ -27,6 +27,7 @@
 #include "qemu/main-loop.h"
 #include "exec/log.h"
 #include "exec/cpu-common.h"
+#include "exec/gdbstub.h"
 #include "qemu/error-report.h"
 #include "qemu/qemu-print.h"
 #include "sysemu/tcg.h"
@@ -240,11 +241,10 @@ static void cpu_common_unrealizefn(DeviceState *dev)
 static void cpu_common_initfn(Object *obj)
 {
     CPUState *cpu = CPU(obj);
-    CPUClass *cc = CPU_GET_CLASS(obj);
 
+    gdb_init_cpu(cpu);
     cpu->cpu_index = UNASSIGNED_CPU_INDEX;
     cpu->cluster_index = UNASSIGNED_CLUSTER_INDEX;
-    cpu->gdb_num_regs = cpu->gdb_num_g_regs = cc->gdb_num_core_regs;
     /* user-mode doesn't have configurable SMP topology */
     /* the default value is changed by qemu_init_vcpu() for system-mode */
     cpu->nr_cores = 1;
@@ -264,6 +264,7 @@ static void cpu_common_finalize(Object *obj)
 {
     CPUState *cpu = CPU(obj);
 
+    g_array_free(cpu->gdb_regs, TRUE);
     qemu_lockcnt_destroy(&cpu->in_ioctl_lock);
     qemu_mutex_destroy(&cpu->work_mutex);
 }

include/exec/gdbstub.h

@@ -27,6 +27,12 @@ typedef struct GDBFeatureBuilder {
 typedef int (*gdb_get_reg_cb)(CPUState *cpu, GByteArray *buf, int reg);
 typedef int (*gdb_set_reg_cb)(CPUState *cpu, uint8_t *buf, int reg);
 
+/**
+ * gdb_init_cpu(): Initialize the CPU for gdbstub.
+ * @cpu: The CPU to be initialized.
+ */
+void gdb_init_cpu(CPUState *cpu);
+
 /**
  * gdb_register_coprocessor() - register a supplemental set of registers
  * @cpu - the CPU associated with registers