commit 7678108b134fc14d0a94fd13c0dd1129525c12d7
author Tom Musta <tommusta@gmail.com> Mon Jun 30 08:13:37 2014 -0500
committer Alexander Graf <agraf@suse.de> Mon Sep 08 12:50:46 2014 +0200
tree df186cd85b337c6f9d1b964fa8a80282274ca128
parent fbdc200ac2d0d29e88ee6af9b77810c0f84265a6

linux-user: Split PPC Trampoline Encoding from Register Save

Split the encoding of the PowerPC sigreturn trampoline from the saving of
register state onto the signal handler stack.  This will make it easier
in subsequent patches to deal with variations in the stack frame layouts between
32 and 64 bit PowerPC.

Signed-off-by: Tom Musta <tommusta@gmail.com>
Signed-off-by: Alexander Graf <agraf@suse.de>

linux-user/signal.c

diff --git a/linux-user/signal.c b/linux-user/signal.c
index 2952956..7365d5d 100644
--- a/linux-user/signal.c
+++ b/linux-user/signal.c
@@ -4491,8 +4491,7 @@
     return newsp;
 }
 
-static void save_user_regs(CPUPPCState *env, struct target_mcontext *frame,
-                          int sigret)
+static void save_user_regs(CPUPPCState *env, struct target_mcontext *frame)
 {
     target_ulong msr = env->msr;
     int i;
@@ -4559,11 +4558,14 @@
 
     /* Store MSR.  */
     __put_user(msr, &frame->mc_gregs[TARGET_PT_MSR]);
+}
 
+static void encode_trampoline(int sigret, uint32_t *tramp)
+{
     /* Set up the sigreturn trampoline: li r0,sigret; sc.  */
     if (sigret) {
-        __put_user(0x38000000UL | sigret, &frame->tramp[0]);
-        __put_user(0x44000002UL, &frame->tramp[1]);
+        __put_user(0x38000000 | sigret, &tramp[0]);
+        __put_user(0x44000002, &tramp[1]);
     }
 }
 
@@ -4674,7 +4676,10 @@
     __put_user(sig, &sc->signal);
 
     /* Save user regs.  */
-    save_user_regs(env, &frame->mctx, TARGET_NR_sigreturn);
+    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.  */
@@ -4740,7 +4745,8 @@
     }
 
     frame = &rt_sf->uc.tuc_mcontext;
-    save_user_regs(env, frame, TARGET_NR_rt_sigreturn);
+    save_user_regs(env, frame);
+    encode_trampoline(TARGET_NR_rt_sigreturn, (uint32_t *)&frame->tramp);
 
     /* The kernel checks for the presence of a VDSO here.  We don't
        emulate a vdso, so use a sigreturn system call.  */