[PATCH 20/21] linux-user/xtensa: Implement setup_sigtramp

[Richard Henderson]

Create and record the rt signal trampoline.
Use it when the guest does not use SA_RESTORER.

Cc: Max Filippov <jcmvb...@gmail.com>
Signed-off-by: Richard Henderson <richard.hender...@linaro.org>
---
 linux-user/xtensa/target_signal.h |  2 ++
 linux-user/xtensa/signal.c        | 50 ++++++++++++++++++-------------
 2 files changed, 32 insertions(+), 20 deletions(-)

diff --git a/linux-user/xtensa/target_signal.h 
b/linux-user/xtensa/target_signal.h
index c60bf656f6..1c7ee73154 100644
--- a/linux-user/xtensa/target_signal.h
+++ b/linux-user/xtensa/target_signal.h
@@ -20,4 +20,6 @@ typedef struct target_sigaltstack {
 
 #include "../generic/signal.h"
 
+#define TARGET_ARCH_HAS_SIGTRAMP_PAGE 1
+
 #endif
diff --git a/linux-user/xtensa/signal.c b/linux-user/xtensa/signal.c
index 72771e1294..fd57481bf5 100644
--- a/linux-user/xtensa/signal.c
+++ b/linux-user/xtensa/signal.c
@@ -163,26 +163,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
     if (ka->sa_flags & TARGET_SA_RESTORER) {
         ra = ka->sa_restorer;
     } else {
-        ra = frame_addr + offsetof(struct target_rt_sigframe, retcode);
-#ifdef TARGET_WORDS_BIGENDIAN
-        /* Generate instruction:  MOVI a2, __NR_rt_sigreturn */
-        __put_user(0x22, &frame->retcode[0]);
-        __put_user(0x0a, &frame->retcode[1]);
-        __put_user(TARGET_NR_rt_sigreturn, &frame->retcode[2]);
-        /* Generate instruction:  SYSCALL */
-        __put_user(0x00, &frame->retcode[3]);
-        __put_user(0x05, &frame->retcode[4]);
-        __put_user(0x00, &frame->retcode[5]);
-#else
-        /* Generate instruction:  MOVI a2, __NR_rt_sigreturn */
-        __put_user(0x22, &frame->retcode[0]);
-        __put_user(0xa0, &frame->retcode[1]);
-        __put_user(TARGET_NR_rt_sigreturn, &frame->retcode[2]);
-        /* Generate instruction:  SYSCALL */
-        __put_user(0x00, &frame->retcode[3]);
-        __put_user(0x50, &frame->retcode[4]);
-        __put_user(0x00, &frame->retcode[5]);
-#endif
+        ra = default_rt_sigreturn;
     }
     memset(env->regs, 0, sizeof(env->regs));
     env->pc = ka->_sa_handler;
@@ -263,3 +244,32 @@ badframe:
     force_sig(TARGET_SIGSEGV);
     return -TARGET_QEMU_ESIGRETURN;
 }
+
+void setup_sigtramp(abi_ulong sigtramp_page)
+{
+    uint8_t *tramp = lock_user(VERIFY_WRITE, sigtramp_page, 6, 0);
+    assert(tramp != NULL);
+
+#ifdef TARGET_WORDS_BIGENDIAN
+    /* Generate instruction:  MOVI a2, __NR_rt_sigreturn */
+    __put_user(0x22, &tramp[0]);
+    __put_user(0x0a, &tramp[1]);
+    __put_user(TARGET_NR_rt_sigreturn, &tramp[2]);
+    /* Generate instruction:  SYSCALL */
+    __put_user(0x00, &tramp[3]);
+    __put_user(0x05, &tramp[4]);
+    __put_user(0x00, &tramp[5]);
+#else
+    /* Generate instruction:  MOVI a2, __NR_rt_sigreturn */
+    __put_user(0x22, &tramp[0]);
+    __put_user(0xa0, &tramp[1]);
+    __put_user(TARGET_NR_rt_sigreturn, &tramp[2]);
+    /* Generate instruction:  SYSCALL */
+    __put_user(0x00, &tramp[3]);
+    __put_user(0x50, &tramp[4]);
+    __put_user(0x00, &tramp[5]);
+#endif
+
+    default_rt_sigreturn = sigtramp_page;
+    unlock_user(tramp, sigtramp_page, 6);
+}
-- 
2.25.1