commit c790e4ebfed8174f65d685f5a4f3262873c237a5
author Richard Henderson <richard.henderson@linaro.org> Wed Sep 29 09:05:46 2021 -0400
committer Laurent Vivier <laurent@vivier.eu> Fri Oct 01 12:03:48 2021 +0200
tree ad4fafd4971ab3bbe825bc3df439da8a0a090f18
parent 5d2fc70f57916abc6afbe739636dffed6a5009c7

linux-user/ppc: Implement setup_sigtramp

Create and record the two signal trampolines.

Cc: qemu-ppc@nongnu.org
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20210929130553.121567-20-richard.henderson@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>

linux-user/ppc/signal.c

diff --git a/linux-user/ppc/signal.c b/linux-user/ppc/signal.c
index 77f37b9..c37744c 100644
--- a/linux-user/ppc/signal.c
+++ b/linux-user/ppc/signal.c
@@ -203,9 +203,6 @@
 
 #endif
 
-/* We use the mc_pad field for the signal return trampoline.  */
-#define tramp mc_pad
-
 /* See arch/powerpc/kernel/signal.c.  */
 static target_ulong get_sigframe(struct target_sigaction *ka,
                                  CPUPPCState *env,
@@ -436,12 +433,7 @@
     /* Save user regs.  */
     save_user_regs(env, &frame->mctx);
 
-    /* Construct the trampoline code on the stack. */
-    encode_trampoline(TARGET_NR_sigreturn, (uint32_t *)&frame->mctx.tramp);
-
-    /* The kernel checks for the presence of a VDSO here.  We don't
-       emulate a vdso, so use a sigreturn system call.  */
-    env->lr = (target_ulong) h2g(frame->mctx.tramp);
+    env->lr = default_sigreturn;
 
     /* Turn off all fp exceptions.  */
     env->fpscr = 0;
@@ -477,7 +469,6 @@
                     target_sigset_t *set, CPUPPCState *env)
 {
     struct target_rt_sigframe *rt_sf;
-    uint32_t *trampptr = 0;
     struct target_mcontext *mctx = 0;
     target_ulong rt_sf_addr, newsp = 0;
     int i, err = 0;
@@ -507,22 +498,17 @@
 
 #if defined(TARGET_PPC64)
     mctx = &rt_sf->uc.tuc_sigcontext.mcontext;
-    trampptr = &rt_sf->trampoline[0];
 
     sc = &rt_sf->uc.tuc_sigcontext;
     __put_user(h2g(mctx), &sc->regs);
     __put_user(sig, &sc->signal);
 #else
     mctx = &rt_sf->uc.tuc_mcontext;
-    trampptr = (uint32_t *)&rt_sf->uc.tuc_mcontext.tramp;
 #endif
 
     save_user_regs(env, mctx);
-    encode_trampoline(TARGET_NR_rt_sigreturn, trampptr);
 
-    /* The kernel checks for the presence of a VDSO here.  We don't
-       emulate a vdso, so use a sigreturn system call.  */
-    env->lr = (target_ulong) h2g(trampptr);
+    env->lr = default_rt_sigreturn;
 
     /* Turn off all fp exceptions.  */
     env->fpscr = 0;
@@ -720,3 +706,19 @@
 
     return 0;
 }
+
+void setup_sigtramp(abi_ulong sigtramp_page)
+{
+    uint32_t *tramp = lock_user(VERIFY_WRITE, sigtramp_page, 2 * 8, 0);
+    assert(tramp != NULL);
+
+#ifdef TARGET_ARCH_HAS_SETUP_FRAME
+    default_sigreturn = sigtramp_page;
+    encode_trampoline(TARGET_NR_sigreturn, tramp + 0);
+#endif
+
+    default_rt_sigreturn = sigtramp_page + 8;
+    encode_trampoline(TARGET_NR_rt_sigreturn, tramp + 2);
+
+    unlock_user(tramp, sigtramp_page, 2 * 8);
+}