[PULL 13/26] linux-user/microblaze: Implement setup_sigtramp

[Laurent Vivier <laurent@vivier.eu>]

From: Richard Henderson <richard.henderson@linaro.org>

Create and record the rt signal trampoline.

Cc: Edgar E. Iglesias <edgar.iglesias@gmail.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20210929130553.121567-14-richard.henderson@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
---
 linux-user/microblaze/signal.c        | 24 +++++++++++++++++-------
 linux-user/microblaze/target_signal.h |  2 ++
 2 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/linux-user/microblaze/signal.c b/linux-user/microblaze/signal.c
index b822679d1805..8ebb6a1b7dfe 100644
--- a/linux-user/microblaze/signal.c
+++ b/linux-user/microblaze/signal.c
@@ -161,17 +161,11 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
 
     /* Kernel does not use SA_RESTORER. */
 
-    /* addi r12, r0, __NR_sigreturn */
-    __put_user(0x31800000U | TARGET_NR_rt_sigreturn, frame->tramp + 0);
-    /* brki r14, 0x8 */
-    __put_user(0xb9cc0008U, frame->tramp + 1);
-
     /*
      * Return from sighandler will jump to the tramp.
      * Negative 8 offset because return is rtsd r15, 8
      */
-    env->regs[15] =
-        frame_addr + offsetof(struct target_rt_sigframe, tramp) - 8;
+    env->regs[15] = default_rt_sigreturn - 8;
 
     /* Set up registers for signal handler */
     env->regs[1] = frame_addr;
@@ -220,3 +214,19 @@ long do_rt_sigreturn(CPUMBState *env)
     force_sig(TARGET_SIGSEGV);
     return -TARGET_QEMU_ESIGRETURN;
 }
+
+void setup_sigtramp(abi_ulong sigtramp_page)
+{
+    uint32_t *tramp = lock_user(VERIFY_WRITE, sigtramp_page, 8, 0);
+    assert(tramp != NULL);
+
+    /*
+     * addi r12, r0, __NR_rt_sigreturn
+     * brki r14, 0x8
+     */
+    __put_user(0x31800000U | TARGET_NR_rt_sigreturn, tramp);
+    __put_user(0xb9cc0008U, tramp + 1);
+
+    default_rt_sigreturn = sigtramp_page;
+    unlock_user(tramp, sigtramp_page, 8);
+}
diff --git a/linux-user/microblaze/target_signal.h b/linux-user/microblaze/target_signal.h
index 1c326296de42..e8b510f6b182 100644
--- a/linux-user/microblaze/target_signal.h
+++ b/linux-user/microblaze/target_signal.h
@@ -21,4 +21,6 @@ typedef struct target_sigaltstack {
 
 #include "../generic/signal.h"
 
+#define TARGET_ARCH_HAS_SIGTRAMP_PAGE 1
+
 #endif /* MICROBLAZE_TARGET_SIGNAL_H */
-- 
2.31.1