target-arm: Fix CPU breakpoint handling

A QEMU breakpoint match is not definitely an architectural breakpoint
match. If an exception is generated unconditionally during translation,
it is hardly possible to ignore it in the debug exception handler.

Generate a call to a helper to check CPU breakpoints and raise an
exception only if any breakpoint matches architecturally.

Signed-off-by: Sergey Fedorov <serge.fdrv@gmail.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

4 files changed, 46 insertions, 21 deletions

diff --git a/target-arm/helper.h b/target-arm/helper.h
index 827b33dfec..c2a85c722a 100644
--- a/target-arm/helper.h
+++ b/target-arm/helper.h
@@ -54,6 +54,8 @@ DEF_HELPER_1(yield, void, env)
 DEF_HELPER_1(pre_hvc, void, env)
 DEF_HELPER_2(pre_smc, void, env, i32)
 
+DEF_HELPER_1(check_breakpoints, void, env)
+
 DEF_HELPER_3(cpsr_write, void, env, i32, i32)
 DEF_HELPER_1(cpsr_read, i32, env)
 
diff --git a/target-arm/op_helper.c b/target-arm/op_helper.c
index 67b18c09c3..7929c71b43 100644
--- a/target-arm/op_helper.c
+++ b/target-arm/op_helper.c
@@ -867,6 +867,15 @@ static bool check_breakpoints(ARMCPU *cpu)
     return false;
 }
 
+void HELPER(check_breakpoints)(CPUARMState *env)
+{
+    ARMCPU *cpu = arm_env_get_cpu(env);
+
+    if (check_breakpoints(cpu)) {
+        HELPER(exception_internal(env, EXCP_DEBUG));
+    }
+}
+
 void arm_debug_excp_handler(CPUState *cs)
 {
     /* Called by core code when a watchpoint or breakpoint fires;
@@ -898,23 +907,21 @@ void arm_debug_excp_handler(CPUState *cs)
         }
     } else {
         uint64_t pc = is_a64(env) ? env->pc : env->regs[15];
+        bool same_el = (arm_debug_target_el(env) == arm_current_el(env));
 
         if (cpu_breakpoint_test(cs, pc, BP_GDB)) {
             return;
         }
 
-        if (check_breakpoints(cpu)) {
-            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;
-            }
-            /* FAR is UNKNOWN, so doesn't need setting */
-            raise_exception(env, EXCP_PREFETCH_ABORT,
-                            syn_breakpoint(same_el),
-                            arm_debug_target_el(env));
+        if (extended_addresses_enabled(env)) {
+            env->exception.fsr = (1 << 9) | 0x22;
+        } else {
+            env->exception.fsr = 0x2;
         }
+        /* FAR is UNKNOWN, so doesn't need setting */
+        raise_exception(env, EXCP_PREFETCH_ABORT,
+                        syn_breakpoint(same_el),
+                        arm_debug_target_el(env));
     }
 }
 
diff --git a/target-arm/translate-a64.c b/target-arm/translate-a64.c
index a4580c07a6..19f9d8d2c8 100644
--- a/target-arm/translate-a64.c
+++ b/target-arm/translate-a64.c
@@ -11090,11 +11090,18 @@ void gen_intermediate_code_a64(ARMCPU *cpu, TranslationBlock *tb)
             CPUBreakpoint *bp;
             QTAILQ_FOREACH(bp, &cs->breakpoints, entry) {
                 if (bp->pc == dc->pc) {
-                    gen_exception_internal_insn(dc, 0, EXCP_DEBUG);
-                    /* Advance PC so that clearing the breakpoint will
-                       invalidate this TB.  */
-                    dc->pc += 2;
-                    goto done_generating;
+                    if (bp->flags & BP_CPU) {
+                        gen_helper_check_breakpoints(cpu_env);
+                        /* End the TB early; it likely won't be executed */
+                        dc->is_jmp = DISAS_UPDATE;
+                    } else {
+                        gen_exception_internal_insn(dc, 0, EXCP_DEBUG);
+                        /* Advance PC so that clearing the breakpoint will
+                           invalidate this TB.  */
+                        dc->pc += 4;
+                        goto done_generating;
+                    }
+                    break;
                 }
             }
         }
diff --git a/target-arm/translate.c b/target-arm/translate.c
index 127300007f..9f1d740b4e 100644
--- a/target-arm/translate.c
+++ b/target-arm/translate.c
@@ -11342,11 +11342,20 @@ void gen_intermediate_code(CPUARMState *env, TranslationBlock *tb)
             CPUBreakpoint *bp;
             QTAILQ_FOREACH(bp, &cs->breakpoints, entry) {
                 if (bp->pc == dc->pc) {
-                    gen_exception_internal_insn(dc, 0, EXCP_DEBUG);
-                    /* Advance PC so that clearing the breakpoint will
-                       invalidate this TB.  */
-                    dc->pc += 2;
-                    goto done_generating;
+                    if (bp->flags & BP_CPU) {
+                        gen_helper_check_breakpoints(cpu_env);
+                        /* End the TB early; it's likely not going to be executed */
+                        dc->is_jmp = DISAS_UPDATE;
+                    } else {
+                        gen_exception_internal_insn(dc, 0, EXCP_DEBUG);
+                        /* Advance PC so that clearing the breakpoint will
+                           invalidate this TB.  */
+                        /* TODO: Advance PC by correct instruction length to
+                         * avoid disassembler error messages */
+                        dc->pc += 2;
+                        goto done_generating;
+                    }
+                    break;
                 }
             }
         }