1 files changed, 32 insertions, 17 deletions

diff --git a/linux-user/arm/signal.c b/linux-user/arm/signal.c
index cf99fd7b8a..e19b514f17 100644
--- a/linux-user/arm/signal.c
+++ b/linux-user/arm/signal.c
@@ -21,6 +21,7 @@
 #include "user-internals.h"
 #include "signal-common.h"
 #include "linux-user/trace.h"
+#include "vdso-asmoffset.h"
 
 struct target_sigcontext {
     abi_ulong trap_no;
@@ -102,6 +103,11 @@ struct rt_sigframe
     struct sigframe sig;
 };
 
+QEMU_BUILD_BUG_ON(offsetof(struct sigframe, retcode[3])
+                  != SIGFRAME_RC3_OFFSET);
+QEMU_BUILD_BUG_ON(offsetof(struct rt_sigframe, sig.retcode[3])
+                  != RT_SIGFRAME_RC3_OFFSET);
+
 static abi_ptr sigreturn_fdpic_tramp;
 
 /*
@@ -160,6 +166,9 @@ get_sigframe(struct target_sigaction *ka, CPUARMState *regs, int framesize)
     return (sp - framesize) & ~7;
 }
 
+static void write_arm_sigreturn(uint32_t *rc, int syscall);
+static void write_arm_fdpic_sigreturn(uint32_t *rc, int ofs);
+
 static int
 setup_return(CPUARMState *env, struct target_sigaction *ka, int usig,
              struct sigframe *frame, abi_ulong sp_addr)
@@ -167,9 +176,9 @@ setup_return(CPUARMState *env, struct target_sigaction *ka, int usig,
     abi_ulong handler = 0;
     abi_ulong handler_fdpic_GOT = 0;
     abi_ulong retcode;
-    int thumb, retcode_idx;
-    int is_fdpic = info_is_fdpic(((TaskState *)thread_cpu->opaque)->info);
-    bool copy_retcode;
+    bool is_fdpic = info_is_fdpic(((TaskState *)thread_cpu->opaque)->info);
+    bool is_rt = ka->sa_flags & TARGET_SA_SIGINFO;
+    bool thumb;
 
     if (is_fdpic) {
         /* In FDPIC mode, ka->_sa_handler points to a function
@@ -184,9 +193,7 @@ setup_return(CPUARMState *env, struct target_sigaction *ka, int usig,
     } else {
         handler = ka->_sa_handler;
     }
-
     thumb = handler & 1;
-    retcode_idx = thumb + (ka->sa_flags & TARGET_SA_SIGINFO ? 2 : 0);
 
     uint32_t cpsr = cpsr_read(env);
 
@@ -202,24 +209,32 @@ setup_return(CPUARMState *env, struct target_sigaction *ka, int usig,
         cpsr &= ~CPSR_E;
     }
 
+    /* Our vdso default_sigreturn label is a table of entry points. */
+    retcode = default_sigreturn + (is_fdpic * 2 + is_rt) * 8;
+
+    /*
+     * Put the sigreturn code on the stack no matter which return
+     * mechanism we use in order to remain ABI compliant.
+     * Because this is about ABI, always use the A32 instructions,
+     * despite the fact that our actual vdso trampoline is T16.
+     */
+    if (is_fdpic) {
+        write_arm_fdpic_sigreturn(frame->retcode,
+                                  is_rt ? RT_SIGFRAME_RC3_OFFSET
+                                        : SIGFRAME_RC3_OFFSET);
+    } else {
+        write_arm_sigreturn(frame->retcode,
+                            is_rt ? TARGET_NR_rt_sigreturn
+                                  : TARGET_NR_sigreturn);
+    }
+
     if (ka->sa_flags & TARGET_SA_RESTORER) {
         if (is_fdpic) {
+            /* Place the function descriptor in slot 3. */
             __put_user((abi_ulong)ka->sa_restorer, &frame->retcode[3]);
-            retcode = (sigreturn_fdpic_tramp +
-                       retcode_idx * RETCODE_BYTES + thumb);
-            copy_retcode = true;
         } else {
             retcode = ka->sa_restorer;
-            copy_retcode = false;
         }
-    } else {
-        retcode = default_sigreturn + retcode_idx * RETCODE_BYTES + thumb;
-        copy_retcode = true;
-    }
-
-    /* Copy the code to the stack slot for ABI compatibility. */
-    if (copy_retcode) {
-        memcpy(frame->retcode, g2h_untagged(retcode & ~1), RETCODE_BYTES);
     }
 
     env->regs[0] = usig;