Refactor and enhance break/watchpoint API (Jan Kiszka)

This patch prepares the QEMU cpu_watchpoint/breakpoint API to allow the
succeeding enhancements this series comes with.

First of all, it overcomes MAX_BREAKPOINTS/MAX_WATCHPOINTS by switching
to dynamically allocated data structures that are kept in linked lists.
This also allows to return a stable reference to the related objects,
required for later introduced x86 debug register support.

Breakpoints and watchpoints are stored with their full information set
and an additional flag field that makes them easily extensible for use
beyond pure guest debugging.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>



git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5738 c046a42c-6fe2-441c-8c8c-71466251a162

1 files changed, 77 insertions, 60 deletions

diff --git a/gdbstub.c b/gdbstub.c
index aff818972..a0fc62d3d 100644
--- a/gdbstub.c
+++ b/gdbstub.c
@@ -1145,10 +1145,70 @@ void gdb_register_coprocessor(CPUState * env,
     }
 }
 
+/* GDB breakpoint/watchpoint types */
+#define GDB_BREAKPOINT_SW        0
+#define GDB_BREAKPOINT_HW        1
+#define GDB_WATCHPOINT_WRITE     2
+#define GDB_WATCHPOINT_READ      3
+#define GDB_WATCHPOINT_ACCESS    4
+
+#ifndef CONFIG_USER_ONLY
+static const int xlat_gdb_type[] = {
+    [GDB_WATCHPOINT_WRITE]  = BP_GDB | BP_MEM_WRITE,
+    [GDB_WATCHPOINT_READ]   = BP_GDB | BP_MEM_READ,
+    [GDB_WATCHPOINT_ACCESS] = BP_GDB | BP_MEM_ACCESS,
+};
+#endif
+
+static int gdb_breakpoint_insert(CPUState *env, target_ulong addr,
+                                 target_ulong len, int type)
+{
+    switch (type) {
+    case GDB_BREAKPOINT_SW:
+    case GDB_BREAKPOINT_HW:
+        return cpu_breakpoint_insert(env, addr, BP_GDB, NULL);
+#ifndef CONFIG_USER_ONLY
+    case GDB_WATCHPOINT_WRITE:
+    case GDB_WATCHPOINT_READ:
+    case GDB_WATCHPOINT_ACCESS:
+        return cpu_watchpoint_insert(env, addr, len, xlat_gdb_type[type],
+                                     NULL);
+#endif
+    default:
+        return -ENOSYS;
+    }
+}
+
+static int gdb_breakpoint_remove(CPUState *env, target_ulong addr,
+                                 target_ulong len, int type)
+{
+    switch (type) {
+    case GDB_BREAKPOINT_SW:
+    case GDB_BREAKPOINT_HW:
+        return cpu_breakpoint_remove(env, addr, BP_GDB);
+#ifndef CONFIG_USER_ONLY
+    case GDB_WATCHPOINT_WRITE:
+    case GDB_WATCHPOINT_READ:
+    case GDB_WATCHPOINT_ACCESS:
+        return cpu_watchpoint_remove(env, addr, len, xlat_gdb_type[type]);
+#endif
+    default:
+        return -ENOSYS;
+    }
+}
+
+static void gdb_breakpoint_remove_all(CPUState *env)
+{
+    cpu_breakpoint_remove_all(env, BP_GDB);
+#ifndef CONFIG_USER_ONLY
+    cpu_watchpoint_remove_all(env, BP_GDB);
+#endif
+}
+
 static int gdb_handle_packet(GDBState *s, CPUState *env, const char *line_buf)
 {
     const char *p;
-    int ch, reg_size, type;
+    int ch, reg_size, type, res;
     char buf[MAX_PACKET_LENGTH];
     uint8_t mem_buf[MAX_PACKET_LENGTH];
     uint8_t *registers;
@@ -1168,8 +1228,7 @@ static int gdb_handle_packet(GDBState *s, CPUState *env, const char *line_buf)
          * because gdb is doing and initial connect and the state
          * should be cleaned up.
          */
-        cpu_breakpoint_remove_all(env);
-        cpu_watchpoint_remove_all(env);
+        gdb_breakpoint_remove_all(env);
         break;
     case 'c':
         if (*p != '\0') {
@@ -1203,8 +1262,7 @@ static int gdb_handle_packet(GDBState *s, CPUState *env, const char *line_buf)
         exit(0);
     case 'D':
         /* Detach packet */
-        cpu_breakpoint_remove_all(env);
-        cpu_watchpoint_remove_all(env);
+        gdb_breakpoint_remove_all(env);
         gdb_continue(s);
         put_packet(s, "OK");
         break;
@@ -1327,44 +1385,6 @@ static int gdb_handle_packet(GDBState *s, CPUState *env, const char *line_buf)
         put_packet(s, "OK");
         break;
     case 'Z':
-        type = strtoul(p, (char **)&p, 16);
-        if (*p == ',')
-            p++;
-        addr = strtoull(p, (char **)&p, 16);
-        if (*p == ',')
-            p++;
-        len = strtoull(p, (char **)&p, 16);
-        switch (type) {
-        case 0:
-        case 1:
-            if (cpu_breakpoint_insert(env, addr) < 0)
-                goto breakpoint_error;
-            put_packet(s, "OK");
-            break;
-#ifndef CONFIG_USER_ONLY
-        case 2:
-            type = PAGE_WRITE;
-            goto insert_watchpoint;
-        case 3:
-            type = PAGE_READ;
-            goto insert_watchpoint;
-        case 4:
-            type = PAGE_READ | PAGE_WRITE;
-        insert_watchpoint:
-            if (cpu_watchpoint_insert(env, addr, type) < 0)
-                goto breakpoint_error;
-            put_packet(s, "OK");
-            break;
-#endif
-        default:
-            put_packet(s, "");
-            break;
-        }
-        break;
-    breakpoint_error:
-        put_packet(s, "E22");
-        break;
-
     case 'z':
         type = strtoul(p, (char **)&p, 16);
         if (*p == ',')
@@ -1373,17 +1393,16 @@ static int gdb_handle_packet(GDBState *s, CPUState *env, const char *line_buf)
         if (*p == ',')
             p++;
         len = strtoull(p, (char **)&p, 16);
-        if (type == 0 || type == 1) {
-            cpu_breakpoint_remove(env, addr);
-            put_packet(s, "OK");
-#ifndef CONFIG_USER_ONLY
-        } else if (type >= 2 || type <= 4) {
-            cpu_watchpoint_remove(env, addr);
-            put_packet(s, "OK");
-#endif
-        } else {
+        if (ch == 'Z')
+            res = gdb_breakpoint_insert(env, addr, len, type);
+        else
+            res = gdb_breakpoint_remove(env, addr, len, type);
+        if (res >= 0)
+             put_packet(s, "OK");
+        else if (res == -ENOSYS)
             put_packet(s, "");
-        }
+        else
+            put_packet(s, "E22");
         break;
     case 'q':
     case 'Q':
@@ -1504,12 +1523,11 @@ static void gdb_vm_stopped(void *opaque, int reason)
 
     if (reason == EXCP_DEBUG) {
         if (s->env->watchpoint_hit) {
-            switch (s->env->watchpoint[s->env->watchpoint_hit - 1].type &
-                    (PAGE_READ | PAGE_WRITE)) {
-            case PAGE_READ:
+            switch (s->env->watchpoint_hit->flags & BP_MEM_ACCESS) {
+            case BP_MEM_READ:
                 type = "r";
                 break;
-            case PAGE_READ | PAGE_WRITE:
+            case BP_MEM_ACCESS:
                 type = "a";
                 break;
             default:
@@ -1517,10 +1535,9 @@ static void gdb_vm_stopped(void *opaque, int reason)
                 break;
             }
             snprintf(buf, sizeof(buf), "T%02x%swatch:" TARGET_FMT_lx ";",
-                     SIGTRAP, type,
-                     s->env->watchpoint[s->env->watchpoint_hit - 1].vaddr);
+                     SIGTRAP, type, s->env->watchpoint_hit->vaddr);
             put_packet(s, buf);
-            s->env->watchpoint_hit = 0;
+            s->env->watchpoint_hit = NULL;
             return;
         }
 	tb_flush(s->env);