target-arm: Implement checking of fired watchpoint

ARM stops before access to a location covered by watchpoint. Also, QEMU
watchpoint fire is not necessarily an architectural watchpoint match.
Unfortunately, that is hardly possible to ignore a fired watchpoint in
debug exception handler. So move watchpoint check from debug exception
handler to the dedicated watchpoint checking callback.

Backports commit 3826121d9298cde1d29ead05910e1f40125ee9b0 from qemu

qemu/aarch64.h

@@ -144,6 +144,7 @@
 #define arm_cp_write_ignore arm_cp_write_ignore_aarch64
 #define arm_current_el arm_current_el_aarch64
 #define arm_dc_feature arm_dc_feature_aarch64
+#define arm_debug_check_watchpoint arm_debug_check_watchpoint_aarch64
 #define arm_debug_excp_handler arm_debug_excp_handler_aarch64
 #define arm_debug_target_el arm_debug_target_el_aarch64
 #define arm_el_is_aa64 arm_el_is_aa64_aarch64

qemu/aarch64eb.h

@@ -144,6 +144,7 @@
 #define arm_cp_write_ignore arm_cp_write_ignore_aarch64eb
 #define arm_current_el arm_current_el_aarch64eb
 #define arm_dc_feature arm_dc_feature_aarch64eb
+#define arm_debug_check_watchpoint arm_debug_check_watchpoint_aarch64eb
 #define arm_debug_excp_handler arm_debug_excp_handler_aarch64eb
 #define arm_debug_target_el arm_debug_target_el_aarch64eb
 #define arm_el_is_aa64 arm_el_is_aa64_aarch64eb

qemu/arm.h

@@ -144,6 +144,7 @@
 #define arm_cp_write_ignore arm_cp_write_ignore_arm
 #define arm_current_el arm_current_el_arm
 #define arm_dc_feature arm_dc_feature_arm
+#define arm_debug_check_watchpoint arm_debug_check_watchpoint_arm
 #define arm_debug_excp_handler arm_debug_excp_handler_arm
 #define arm_debug_target_el arm_debug_target_el_arm
 #define arm_el_is_aa64 arm_el_is_aa64_arm

qemu/armeb.h

@@ -144,6 +144,7 @@
 #define arm_cp_write_ignore arm_cp_write_ignore_armeb
 #define arm_current_el arm_current_el_armeb
 #define arm_dc_feature arm_dc_feature_armeb
+#define arm_debug_check_watchpoint arm_debug_check_watchpoint_armeb
 #define arm_debug_excp_handler arm_debug_excp_handler_armeb
 #define arm_debug_target_el arm_debug_target_el_armeb
 #define arm_el_is_aa64 arm_el_is_aa64_armeb

qemu/header_gen.py

@@ -150,6 +150,7 @@ symbols = (
     'arm_cp_write_ignore',
     'arm_current_el',
     'arm_dc_feature',
+    'arm_debug_check_watchpoint',
     'arm_debug_excp_handler',
     'arm_debug_target_el',
     'arm_el_is_aa64',

qemu/m68k.h

@@ -144,6 +144,7 @@
 #define arm_cp_write_ignore arm_cp_write_ignore_m68k
 #define arm_current_el arm_current_el_m68k
 #define arm_dc_feature arm_dc_feature_m68k
+#define arm_debug_check_watchpoint arm_debug_check_watchpoint_m68k
 #define arm_debug_excp_handler arm_debug_excp_handler_m68k
 #define arm_debug_target_el arm_debug_target_el_m68k
 #define arm_el_is_aa64 arm_el_is_aa64_m68k

qemu/mips.h

@@ -144,6 +144,7 @@
 #define arm_cp_write_ignore arm_cp_write_ignore_mips
 #define arm_current_el arm_current_el_mips
 #define arm_dc_feature arm_dc_feature_mips
+#define arm_debug_check_watchpoint arm_debug_check_watchpoint_mips
 #define arm_debug_excp_handler arm_debug_excp_handler_mips
 #define arm_debug_target_el arm_debug_target_el_mips
 #define arm_el_is_aa64 arm_el_is_aa64_mips

qemu/mips64.h

@@ -144,6 +144,7 @@
 #define arm_cp_write_ignore arm_cp_write_ignore_mips64
 #define arm_current_el arm_current_el_mips64
 #define arm_dc_feature arm_dc_feature_mips64
+#define arm_debug_check_watchpoint arm_debug_check_watchpoint_mips64
 #define arm_debug_excp_handler arm_debug_excp_handler_mips64
 #define arm_debug_target_el arm_debug_target_el_mips64
 #define arm_el_is_aa64 arm_el_is_aa64_mips64

qemu/mips64el.h

@@ -144,6 +144,7 @@
 #define arm_cp_write_ignore arm_cp_write_ignore_mips64el
 #define arm_current_el arm_current_el_mips64el
 #define arm_dc_feature arm_dc_feature_mips64el
+#define arm_debug_check_watchpoint arm_debug_check_watchpoint_mips64el
 #define arm_debug_excp_handler arm_debug_excp_handler_mips64el
 #define arm_debug_target_el arm_debug_target_el_mips64el
 #define arm_el_is_aa64 arm_el_is_aa64_mips64el

qemu/mipsel.h

@@ -144,6 +144,7 @@
 #define arm_cp_write_ignore arm_cp_write_ignore_mipsel
 #define arm_current_el arm_current_el_mipsel
 #define arm_dc_feature arm_dc_feature_mipsel
+#define arm_debug_check_watchpoint arm_debug_check_watchpoint_mipsel
 #define arm_debug_excp_handler arm_debug_excp_handler_mipsel
 #define arm_debug_target_el arm_debug_target_el_mipsel
 #define arm_el_is_aa64 arm_el_is_aa64_mipsel

qemu/powerpc.h

@@ -144,6 +144,7 @@
 #define arm_cp_write_ignore arm_cp_write_ignore_powerpc
 #define arm_current_el arm_current_el_powerpc
 #define arm_dc_feature arm_dc_feature_powerpc
+#define arm_debug_check_watchpoint arm_debug_check_watchpoint_powerpc
 #define arm_debug_excp_handler arm_debug_excp_handler_powerpc
 #define arm_debug_target_el arm_debug_target_el_powerpc
 #define arm_el_is_aa64 arm_el_is_aa64_powerpc

qemu/sparc.h

@@ -144,6 +144,7 @@
 #define arm_cp_write_ignore arm_cp_write_ignore_sparc
 #define arm_current_el arm_current_el_sparc
 #define arm_dc_feature arm_dc_feature_sparc
+#define arm_debug_check_watchpoint arm_debug_check_watchpoint_sparc
 #define arm_debug_excp_handler arm_debug_excp_handler_sparc
 #define arm_debug_target_el arm_debug_target_el_sparc
 #define arm_el_is_aa64 arm_el_is_aa64_sparc

qemu/sparc64.h

@@ -144,6 +144,7 @@
 #define arm_cp_write_ignore arm_cp_write_ignore_sparc64
 #define arm_current_el arm_current_el_sparc64
 #define arm_dc_feature arm_dc_feature_sparc64
+#define arm_debug_check_watchpoint arm_debug_check_watchpoint_sparc64
 #define arm_debug_excp_handler arm_debug_excp_handler_sparc64
 #define arm_debug_target_el arm_debug_target_el_sparc64
 #define arm_el_is_aa64 arm_el_is_aa64_sparc64

qemu/target-arm/cpu.c

@@ -1343,6 +1343,7 @@ static void arm_cpu_class_init(struct uc_struct *uc, ObjectClass *oc, void *data
     //cc->virtio_is_big_endian = arm_cpu_is_big_endian;
 #endif
     cc->debug_excp_handler = arm_debug_excp_handler;
+    cc->debug_check_watchpoint = arm_debug_check_watchpoint;
 }
 
 static void cpu_register(struct uc_struct *uc, const ARMCPUInfo *info)

qemu/target-arm/internals.h

@@ -411,6 +411,9 @@ void hw_breakpoint_update(ARMCPU *cpu, int n);
  */
 void hw_breakpoint_update_all(ARMCPU *cpu);
 
+/* Callback function for checking if a watchpoint should trigger. */
+bool arm_debug_check_watchpoint(CPUState *cs, CPUWatchpoint *wp);
+
 /* Callback function for when a watchpoint or breakpoint triggers. */
 void arm_debug_excp_handler(CPUState *cs);
 

qemu/target-arm/op_helper.c

@@ -973,6 +973,16 @@ void HELPER(check_breakpoints)(CPUARMState *env)
     }
 }
 
+bool arm_debug_check_watchpoint(CPUState *cs, CPUWatchpoint *wp)
+{
+    /* Called by core code when a CPU watchpoint fires; need to check if this
+     * is also an architectural watchpoint match.
+     */
+    ARMCPU *cpu = ARM_CPU(cs->uc, cs);
+
+    return check_watchpoints(cpu);
+}
+
 void arm_debug_excp_handler(CPUState *cs)
 {
     /* Called by core code when a watchpoint or breakpoint fires;
@@ -984,23 +994,19 @@ void arm_debug_excp_handler(CPUState *cs)
 
     if (wp_hit) {
         if (wp_hit->flags & BP_CPU) {
-            cs->watchpoint_hit = NULL;
-            if (check_watchpoints(cpu)) {
-                bool wnr = (wp_hit->flags & BP_WATCHPOINT_HIT_WRITE) != 0;
-                bool same_el = arm_debug_target_el(env) == arm_current_el(env);
+            bool wnr = (wp_hit->flags & BP_WATCHPOINT_HIT_WRITE) != 0;
+            bool same_el = arm_debug_target_el(env) == arm_current_el(env);
 
-                if (extended_addresses_enabled(env)) {
-                    env->exception.fsr = (1 << 9) | 0x22;
-                } else {
-                    env->exception.fsr = 0x2;
-                }
-                env->exception.vaddress = wp_hit->hitaddr;
-                raise_exception(env, EXCP_DATA_ABORT,
-                                syn_watchpoint(same_el, 0, wnr),
-                                arm_debug_target_el(env));
+            cs->watchpoint_hit = NULL;
+            if (extended_addresses_enabled(env)) {
+                env->exception.fsr = (1 << 9) | 0x22;
             } else {
-                cpu_resume_from_signal(cs, NULL);
+                env->exception.fsr = 0x2;
             }
+            env->exception.vaddress = wp_hit->hitaddr;
+            raise_exception(env, EXCP_DATA_ABORT,
+                    syn_watchpoint(same_el, 0, wnr),
+                    arm_debug_target_el(env));
         }
     } else {
         uint64_t pc = is_a64(env) ? env->pc : env->regs[15];

qemu/x86_64.h

@@ -144,6 +144,7 @@
 #define arm_cp_write_ignore arm_cp_write_ignore_x86_64
 #define arm_current_el arm_current_el_x86_64
 #define arm_dc_feature arm_dc_feature_x86_64
+#define arm_debug_check_watchpoint arm_debug_check_watchpoint_x86_64
 #define arm_debug_excp_handler arm_debug_excp_handler_x86_64
 #define arm_debug_target_el arm_debug_target_el_x86_64
 #define arm_el_is_aa64 arm_el_is_aa64_x86_64