diff mbox series

[17/21] linux-user/s390x: Implement setup_sigtramp

Message ID 20210616011209.1446045-18-richard.henderson@linaro.org
State New
Headers show
Series linux-user: Move signal trampolines to new page | expand

Commit Message

Richard Henderson June 16, 2021, 1:12 a.m. UTC 
Create and record the two signal trampolines.
Use them when the guest does not use SA_RESTORER.

Cc: qemu-s390x@nongnu.org
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 linux-user/s390x/target_signal.h |  2 ++
 linux-user/s390x/signal.c        | 24 ++++++++++++++++--------
 2 files changed, 18 insertions(+), 8 deletions(-)

Comments

Philippe Mathieu-Daudé June 16, 2021, 4:52 p.m. UTC | #1 
On 6/16/21 3:12 AM, Richard Henderson wrote:
> Create and record the two signal trampolines.
> Use them when the guest does not use SA_RESTORER.
> 
> Cc: qemu-s390x@nongnu.org
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>  linux-user/s390x/target_signal.h |  2 ++
>  linux-user/s390x/signal.c        | 24 ++++++++++++++++--------
>  2 files changed, 18 insertions(+), 8 deletions(-)

> +void setup_sigtramp(abi_ulong sigtramp_page)
> +{
> +    uint16_t *tramp = lock_user(VERIFY_WRITE, sigtramp_page, 4, 0);

4 -> 2 + 2 seems clearer (applies to some other targets in this series).

> +    assert(tramp != NULL);
> +
> +    default_sigreturn = sigtramp_page;
> +    __put_user(S390_SYSCALL_OPCODE | TARGET_NR_sigreturn, &tramp[0]);
> +
> +    default_rt_sigreturn = sigtramp_page + 2;
> +    __put_user(S390_SYSCALL_OPCODE | TARGET_NR_rt_sigreturn, &tramp[1]);
> +
> +    unlock_user(tramp, sigtramp_page, 4);

Ditto, otherwise:
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

> +}
>
diff mbox series

Patch

diff --git a/linux-user/s390x/target_signal.h b/linux-user/s390x/target_signal.h
index bbfc464d44..64f5f42201 100644
--- a/linux-user/s390x/target_signal.h
+++ b/linux-user/s390x/target_signal.h
@@ -19,4 +19,6 @@  typedef struct target_sigaltstack {
 #include "../generic/signal.h"
 
 #define TARGET_ARCH_HAS_SETUP_FRAME
+#define TARGET_ARCH_HAS_SIGTRAMP_PAGE 1
+
 #endif /* S390X_TARGET_SIGNAL_H */
diff --git a/linux-user/s390x/signal.c b/linux-user/s390x/signal.c
index ef136dae33..806c09f921 100644
--- a/linux-user/s390x/signal.c
+++ b/linux-user/s390x/signal.c
@@ -67,7 +67,6 @@  typedef struct {
     target_sigregs sregs;
     int signo;
     target_sigregs_ext sregs_ext;
-    uint16_t retcode;
 } sigframe;
 
 #define TARGET_UC_VXRS 2
@@ -84,7 +83,6 @@  struct target_ucontext {
 
 typedef struct {
     uint8_t callee_used_stack[__SIGNAL_FRAMESIZE];
-    uint16_t retcode;
     struct target_siginfo info;
     struct target_ucontext uc;
 } rt_sigframe;
@@ -200,9 +198,7 @@  void setup_frame(int sig, struct target_sigaction *ka,
     if (ka->sa_flags & TARGET_SA_RESTORER) {
         restorer = ka->sa_restorer;
     } else {
-        restorer = frame_addr + offsetof(sigframe, retcode);
-        __put_user(S390_SYSCALL_OPCODE | TARGET_NR_sigreturn,
-                   &frame->retcode);
+        restorer = default_sigreturn;
     }
 
     /* Set up registers for signal handler */
@@ -253,9 +249,7 @@  void setup_rt_frame(int sig, struct target_sigaction *ka,
     if (ka->sa_flags & TARGET_SA_RESTORER) {
         restorer = ka->sa_restorer;
     } else {
-        restorer = frame_addr + offsetof(typeof(*frame), retcode);
-        __put_user(S390_SYSCALL_OPCODE | TARGET_NR_rt_sigreturn,
-                   &frame->retcode);
+        restorer = default_rt_sigreturn;
     }
 
     /* Create siginfo on the signal stack. */
@@ -377,3 +371,17 @@  long do_rt_sigreturn(CPUS390XState *env)
     unlock_user_struct(frame, frame_addr, 0);
     return -TARGET_QEMU_ESIGRETURN;
 }
+
+void setup_sigtramp(abi_ulong sigtramp_page)
+{
+    uint16_t *tramp = lock_user(VERIFY_WRITE, sigtramp_page, 4, 0);
+    assert(tramp != NULL);
+
+    default_sigreturn = sigtramp_page;
+    __put_user(S390_SYSCALL_OPCODE | TARGET_NR_sigreturn, &tramp[0]);
+
+    default_rt_sigreturn = sigtramp_page + 2;
+    __put_user(S390_SYSCALL_OPCODE | TARGET_NR_rt_sigreturn, &tramp[1]);
+
+    unlock_user(tramp, sigtramp_page, 4);
+}