linux-user: Don't call gdb_handlesig() before queue_signal()

The CPU main-loop routines for linux-user generally
call gdb_handlesig() when they're about to queue a
SIGTRAP signal. This is wrong, because queue_signal()
will cause us to pend a signal, and process_pending_signals()
will then call gdb_handlesig() itself. So the effect is that
we notify gdb of the SIGTRAP, and then if gdb says "OK,
continue with signal X" we will incorrectly notify
gdb of the signal X as well. We don't do this double-notify
for anything else, only SIGTRAP.

Remove this unnecessary and incorrect code from all
the targets except for nios2 (whose main loop is
doing something different and broken, and will be handled
in a separate patch).

This bug only manifests if the user responds to the reported
SIGTRAP using "signal SIGFOO" rather than "continue"; since
the latter is the overwhelmingly common thing to do after a
breakpoint most people won't have hit this.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20181019174958.26616-2-peter.maydell@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>

diff --git a/linux-user/aarch64/cpu_loop.c b/linux-user/aarch64/cpu_loop.c
index c97a646546449fabca8eb53d6b7890a7a8d01702..65d815f0300c81680e6b163d23534c9b62ad9a2e 100644 (file)
--- a/linux-user/aarch64/cpu_loop.c
+++ b/linux-user/aarch64/cpu_loop.c
@@ -73,7 +73,7 @@
 void cpu_loop(CPUARMState *env)
 {
     CPUState *cs = CPU(arm_env_get_cpu(env));
-    int trapnr, sig;
+    int trapnr;
     abi_long ret;
     target_siginfo_t info;
 
@@ -121,13 +121,10 @@ void cpu_loop(CPUARMState *env)
             break;
         case EXCP_DEBUG:
         case EXCP_BKPT:
-            sig = gdb_handlesig(cs, TARGET_SIGTRAP);
-            if (sig) {
-                info.si_signo = sig;
-                info.si_errno = 0;
-                info.si_code = TARGET_TRAP_BRKPT;
-                queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
-            }
+            info.si_signo = TARGET_SIGTRAP;
+            info.si_errno = 0;
+            info.si_code = TARGET_TRAP_BRKPT;
+            queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
             break;
         case EXCP_SEMIHOST:
             env->xregs[0] = do_arm_semihosting(env);

diff --git a/linux-user/alpha/cpu_loop.c b/linux-user/alpha/cpu_loop.c
index c1a98c8cbfb3be4f0c885ed0756d2ff416f21c38..824b6d665885a6cbc0a5921cd59974ac9028c82b 100644 (file)
--- a/linux-user/alpha/cpu_loop.c
+++ b/linux-user/alpha/cpu_loop.c
@@ -179,14 +179,10 @@ void cpu_loop(CPUAlphaState *env)
             }
             break;
         case EXCP_DEBUG:
-            info.si_signo = gdb_handlesig(cs, TARGET_SIGTRAP);
-            if (info.si_signo) {
-                info.si_errno = 0;
-                info.si_code = TARGET_TRAP_BRKPT;
-                queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
-            } else {
-                arch_interrupt = false;
-            }
+            info.si_signo = TARGET_SIGTRAP;
+            info.si_errno = 0;
+            info.si_code = TARGET_TRAP_BRKPT;
+            queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
             break;
         case EXCP_INTERRUPT:
             /* Just indicate that signals should be handled asap.  */

diff --git a/linux-user/arm/cpu_loop.c b/linux-user/arm/cpu_loop.c
index 26928fbbb2c3f97b3b28816752a1d98ab3155d49..ee68aa60bf3f4a76d96ae546cc00bdaaf4558bec 100644 (file)
--- a/linux-user/arm/cpu_loop.c
+++ b/linux-user/arm/cpu_loop.c
@@ -397,18 +397,10 @@ void cpu_loop(CPUARMState *env)
             break;
         case EXCP_DEBUG:
         excp_debug:
-            {
-                int sig;
-
-                sig = gdb_handlesig(cs, TARGET_SIGTRAP);
-                if (sig)
-                  {
-                    info.si_signo = sig;
-                    info.si_errno = 0;
-                    info.si_code = TARGET_TRAP_BRKPT;
-                    queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
-                  }
-            }
+            info.si_signo = TARGET_SIGTRAP;
+            info.si_errno = 0;
+            info.si_code = TARGET_TRAP_BRKPT;
+            queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
             break;
         case EXCP_KERNEL_TRAP:
             if (do_kernel_trap(env))

diff --git a/linux-user/cris/cpu_loop.c b/linux-user/cris/cpu_loop.c
index 37bdcfa8cc3357a36b469510c46afc4dec725ee0..dacf604c7df1f1e5e3d966dd219fcdbc2a452c7c 100644 (file)
--- a/linux-user/cris/cpu_loop.c
+++ b/linux-user/cris/cpu_loop.c
@@ -64,18 +64,10 @@ void cpu_loop(CPUCRISState *env)
             }
             break;
         case EXCP_DEBUG:
-            {
-                int sig;
-
-                sig = gdb_handlesig(cs, TARGET_SIGTRAP);
-                if (sig)
-                  {
-                    info.si_signo = sig;
-                    info.si_errno = 0;
-                    info.si_code = TARGET_TRAP_BRKPT;
-                    queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
-                  }
-            }
+            info.si_signo = TARGET_SIGTRAP;
+            info.si_errno = 0;
+            info.si_code = TARGET_TRAP_BRKPT;
+            queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
             break;
         case EXCP_ATOMIC:
             cpu_exec_step_atomic(cs);

diff --git a/linux-user/hppa/cpu_loop.c b/linux-user/hppa/cpu_loop.c
index 0301c766c6f14eb1469930117ea09633a8a494bf..880955fdefd557eb691b45595eb96fe8ac64dcb0 100644 (file)
--- a/linux-user/hppa/cpu_loop.c
+++ b/linux-user/hppa/cpu_loop.c
@@ -182,13 +182,10 @@ void cpu_loop(CPUHPPAState *env)
             queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
             break;
         case EXCP_DEBUG:
-            trapnr = gdb_handlesig(cs, TARGET_SIGTRAP);
-            if (trapnr) {
-                info.si_signo = trapnr;
-                info.si_errno = 0;
-                info.si_code = TARGET_TRAP_BRKPT;
-                queue_signal(env, trapnr, QEMU_SI_FAULT, &info);
-            }
+            info.si_signo = TARGET_SIGTRAP;
+            info.si_errno = 0;
+            info.si_code = TARGET_TRAP_BRKPT;
+            queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
             break;
         case EXCP_INTERRUPT:
             /* just indicate that signals should be handled asap */

diff --git a/linux-user/i386/cpu_loop.c b/linux-user/i386/cpu_loop.c
index 2374abfd0bd594c9b59301ac3a8e57ee52e8f56d..51cfa006c9767dcc282bfd7012910114f8233a2a 100644 (file)
--- a/linux-user/i386/cpu_loop.c
+++ b/linux-user/i386/cpu_loop.c
@@ -225,18 +225,10 @@ void cpu_loop(CPUX86State *env)
             /* just indicate that signals should be handled asap */
             break;
         case EXCP_DEBUG:
-            {
-                int sig;
-
-                sig = gdb_handlesig(cs, TARGET_SIGTRAP);
-                if (sig)
-                  {
-                    info.si_signo = sig;
-                    info.si_errno = 0;
-                    info.si_code = TARGET_TRAP_BRKPT;
-                    queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
-                  }
-            }
+            info.si_signo = TARGET_SIGTRAP;
+            info.si_errno = 0;
+            info.si_code = TARGET_TRAP_BRKPT;
+            queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
             break;
         case EXCP_ATOMIC:
             cpu_exec_step_atomic(cs);

diff --git a/linux-user/m68k/cpu_loop.c b/linux-user/m68k/cpu_loop.c
index 30c3332af46efc4d4f758bd2d0c6534e2b0227e3..bfb41bbcc51f673f7ae890e940adb9587ec2dd0c 100644 (file)
--- a/linux-user/m68k/cpu_loop.c
+++ b/linux-user/m68k/cpu_loop.c
@@ -112,18 +112,10 @@ void cpu_loop(CPUM68KState *env)
             }
             break;
         case EXCP_DEBUG:
-            {
-                int sig;
-
-                sig = gdb_handlesig(cs, TARGET_SIGTRAP);
-                if (sig)
-                  {
-                    info.si_signo = sig;
-                    info.si_errno = 0;
-                    info.si_code = TARGET_TRAP_BRKPT;
-                    queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
-                  }
-            }
+            info.si_signo = TARGET_SIGTRAP;
+            info.si_errno = 0;
+            info.si_code = TARGET_TRAP_BRKPT;
+            queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
             break;
         case EXCP_ATOMIC:
             cpu_exec_step_atomic(cs);

diff --git a/linux-user/microblaze/cpu_loop.c b/linux-user/microblaze/cpu_loop.c
index 2af93eb39a601a071f01b3a0c77f78611a5d9631..c2190e15fdc1276a5d2519737902f0fc8fe165b9 100644 (file)
--- a/linux-user/microblaze/cpu_loop.c
+++ b/linux-user/microblaze/cpu_loop.c
@@ -113,18 +113,10 @@ void cpu_loop(CPUMBState *env)
             }
             break;
         case EXCP_DEBUG:
-            {
-                int sig;
-
-                sig = gdb_handlesig(cs, TARGET_SIGTRAP);
-                if (sig)
-                  {
-                    info.si_signo = sig;
-                    info.si_errno = 0;
-                    info.si_code = TARGET_TRAP_BRKPT;
-                    queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
-                  }
-            }
+            info.si_signo = TARGET_SIGTRAP;
+            info.si_errno = 0;
+            info.si_code = TARGET_TRAP_BRKPT;
+            queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
             break;
         case EXCP_ATOMIC:
             cpu_exec_step_atomic(cs);

diff --git a/linux-user/mips/cpu_loop.c b/linux-user/mips/cpu_loop.c
index 97e495747f5f13a29d06126efe366692aa48394d..d0f62ec9b6cb38c9b7dc5a2ee5297937ffda860f 100644 (file)
--- a/linux-user/mips/cpu_loop.c
+++ b/linux-user/mips/cpu_loop.c
@@ -592,18 +592,10 @@ done_syscall:
             /* just indicate that signals should be handled asap */
             break;
         case EXCP_DEBUG:
-            {
-                int sig;
-
-                sig = gdb_handlesig(cs, TARGET_SIGTRAP);
-                if (sig)
-                  {
-                    info.si_signo = sig;
-                    info.si_errno = 0;
-                    info.si_code = TARGET_TRAP_BRKPT;
-                    queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
-                  }
-            }
+            info.si_signo = TARGET_SIGTRAP;
+            info.si_errno = 0;
+            info.si_code = TARGET_TRAP_BRKPT;
+            queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
             break;
         case EXCP_SC:
             if (do_store_exclusive(env)) {

diff --git a/linux-user/openrisc/cpu_loop.c b/linux-user/openrisc/cpu_loop.c
index 6c6ea871e16d2cc47fb65de83de71bc5607e586f..f496e4b48ad3dba3f68509f84e75670c6e445484 100644 (file)
--- a/linux-user/openrisc/cpu_loop.c
+++ b/linux-user/openrisc/cpu_loop.c
@@ -85,13 +85,10 @@ void cpu_loop(CPUOpenRISCState *env)
             /* We processed the pending cpu work above.  */
             break;
         case EXCP_DEBUG:
-            trapnr = gdb_handlesig(cs, TARGET_SIGTRAP);
-            if (trapnr) {
-                info.si_signo = trapnr;
-                info.si_errno = 0;
-                info.si_code = TARGET_TRAP_BRKPT;
-                queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
-            }
+            info.si_signo = TARGET_SIGTRAP;
+            info.si_errno = 0;
+            info.si_code = TARGET_TRAP_BRKPT;
+            queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
             break;
         case EXCP_ATOMIC:
             cpu_exec_step_atomic(cs);

diff --git a/linux-user/ppc/cpu_loop.c b/linux-user/ppc/cpu_loop.c
index 133a87f349ba0f0563cc7e23da73af4eee7abaae..801f5ace29fd68955a3b18176c4287a73a603f33 100644 (file)
--- a/linux-user/ppc/cpu_loop.c
+++ b/linux-user/ppc/cpu_loop.c
@@ -69,7 +69,7 @@ void cpu_loop(CPUPPCState *env)
 {
     CPUState *cs = CPU(ppc_env_get_cpu(env));
     target_siginfo_t info;
-    int trapnr, sig;
+    int trapnr;
     target_ulong ret;
 
     for(;;) {
@@ -449,15 +449,10 @@ void cpu_loop(CPUPPCState *env)
             env->gpr[3] = ret;
             break;
         case EXCP_DEBUG:
-            sig = gdb_handlesig(cs, TARGET_SIGTRAP);
-            if (sig) {
-                info.si_signo = sig;
-                info.si_errno = 0;
-                info.si_code = TARGET_TRAP_BRKPT;
-                queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
-            } else {
-                arch_interrupt = false;
-            }
+            info.si_signo = TARGET_SIGTRAP;
+            info.si_errno = 0;
+            info.si_code = TARGET_TRAP_BRKPT;
+            queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
             break;
         case EXCP_INTERRUPT:
             /* just indicate that signals should be handled asap */

diff --git a/linux-user/riscv/cpu_loop.c b/linux-user/riscv/cpu_loop.c
index f137d39d7e820932ffc1d650bd27757069bef7ea..4cf3e9463240b1a59364f72d72d37696cee186d8 100644 (file)
--- a/linux-user/riscv/cpu_loop.c
+++ b/linux-user/riscv/cpu_loop.c
@@ -88,7 +88,7 @@ void cpu_loop(CPURISCVState *env)
             break;
         case EXCP_DEBUG:
         gdbstep:
-            signum = gdb_handlesig(cs, TARGET_SIGTRAP);
+            signum = TARGET_SIGTRAP;
             sigcode = TARGET_TRAP_BRKPT;
             break;
         default:

diff --git a/linux-user/s390x/cpu_loop.c b/linux-user/s390x/cpu_loop.c
index 99f5f1594f4a0fb5778a41e3609e08826baf4cfd..51b5412ea27bd2391c7e86f798bf46c865948d6e 100644 (file)
--- a/linux-user/s390x/cpu_loop.c
+++ b/linux-user/s390x/cpu_loop.c
@@ -61,12 +61,9 @@ void cpu_loop(CPUS390XState *env)
             break;
 
         case EXCP_DEBUG:
-            sig = gdb_handlesig(cs, TARGET_SIGTRAP);
-            if (sig) {
-                n = TARGET_TRAP_BRKPT;
-                goto do_signal_pc;
-            }
-            break;
+            sig = TARGET_SIGTRAP;
+            n = TARGET_TRAP_BRKPT;
+            goto do_signal_pc;
         case EXCP_PGM:
             n = env->int_pgm_code;
             switch (n) {

diff --git a/linux-user/sh4/cpu_loop.c b/linux-user/sh4/cpu_loop.c
index fdd348170b933fc71f9b6140f050246401f8bd2f..47e54b9b61a4e6c4f13e769b7f253495b1ac3dc4 100644 (file)
--- a/linux-user/sh4/cpu_loop.c
+++ b/linux-user/sh4/cpu_loop.c
@@ -57,19 +57,10 @@ void cpu_loop(CPUSH4State *env)
             /* just indicate that signals should be handled asap */
             break;
         case EXCP_DEBUG:
-            {
-                int sig;
-
-                sig = gdb_handlesig(cs, TARGET_SIGTRAP);
-                if (sig) {
-                    info.si_signo = sig;
-                    info.si_errno = 0;
-                    info.si_code = TARGET_TRAP_BRKPT;
-                    queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
-                } else {
-                    arch_interrupt = false;
-                }
-            }
+            info.si_signo = TARGET_SIGTRAP;
+            info.si_errno = 0;
+            info.si_code = TARGET_TRAP_BRKPT;
+            queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
             break;
         case 0xa0:
         case 0xc0:

diff --git a/linux-user/sparc/cpu_loop.c b/linux-user/sparc/cpu_loop.c
index 91f714afc6cc03a64ac2d0b7e1d01ee2edb0e58a..7d5b337b97236df10cddee3bbbe1219e0e9124c0 100644 (file)
--- a/linux-user/sparc/cpu_loop.c
+++ b/linux-user/sparc/cpu_loop.c
@@ -268,18 +268,10 @@ void cpu_loop (CPUSPARCState *env)
             }
             break;
         case EXCP_DEBUG:
-            {
-                int sig;
-
-                sig = gdb_handlesig(cs, TARGET_SIGTRAP);
-                if (sig)
-                  {
-                    info.si_signo = sig;
-                    info.si_errno = 0;
-                    info.si_code = TARGET_TRAP_BRKPT;
-                    queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
-                  }
-            }
+            info.si_signo = TARGET_SIGTRAP;
+            info.si_errno = 0;
+            info.si_code = TARGET_TRAP_BRKPT;
+            queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
             break;
         case EXCP_ATOMIC:
             cpu_exec_step_atomic(cs);

diff --git a/linux-user/xtensa/cpu_loop.c b/linux-user/xtensa/cpu_loop.c
index d142988ebe1523a8a87e97dea14fb31a25f87a37..bee78edb8a90463265ea679767ed1a84f0d097cf 100644 (file)
--- a/linux-user/xtensa/cpu_loop.c
+++ b/linux-user/xtensa/cpu_loop.c
@@ -239,13 +239,10 @@ void cpu_loop(CPUXtensaState *env)
             }
             break;
         case EXCP_DEBUG:
-            trapnr = gdb_handlesig(cs, TARGET_SIGTRAP);
-            if (trapnr) {
-                info.si_signo = trapnr;
-                info.si_errno = 0;
-                info.si_code = TARGET_TRAP_BRKPT;
-                queue_signal(env, trapnr, QEMU_SI_FAULT, &info);
-            }
+            info.si_signo = TARGET_SIGTRAP;
+            info.si_errno = 0;
+            info.si_code = TARGET_TRAP_BRKPT;
+            queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
             break;
         case EXC_DEBUG:
         default: