When making a system call, pass the return address in rbp.

3 files changed, 35 insertions, 10 deletions

diff --git a/libviengoos/viengoos/x86_64/ipc.h b/libviengoos/viengoos/x86_64/ipc.h
index 5ae6ee4..0eadeca 100644
--- a/libviengoos/viengoos/x86_64/ipc.h
+++ b/libviengoos/viengoos/x86_64/ipc.h
@@ -33,6 +33,9 @@ vg_ipc_syscall (uintptr_t flags,
   error_t err = 0;
 
   int dummy;
+#ifndef NDEBUG
+  uint64_t ret = __builtin_return_address (0);
+#endif
   __asm__ __volatile__
     ("movq %[recv_inline_cap], %%r8\n\t"
      "movq %[send_activity], %%r9\n\t"
@@ -43,13 +46,18 @@ vg_ipc_syscall (uintptr_t flags,
      "movq %[send_inline_cap], %%r15\n\t"
      "movq %[target_messenger], %%rax\n\t"
      "pushq %%rbp\n\t"
+     "mov %%rcx, %%rbp\n\t"
      "syscall\n\t"
      "popq %%rbp\n\t"
-     : "=a" (err), "=D"(dummy), "=S"(dummy), "=d"(dummy), "=b"(dummy)
+     : "=a" (err), "=D"(dummy), "=S"(dummy), "=d"(dummy), "=b"(dummy),
+       "=c"(dummy)
      : "D" (flags),
        "S" (recv_activity),
        "d" (recv_messenger),
        "b" (recv_buf),
+#ifndef NDEBUG
+       "c" (ret),
+#endif
        [recv_inline_cap] "m" (recv_inline_cap),
        [send_activity] "m" (send_activity),
        [target_messenger] "m" (target_messenger),
@@ -58,7 +66,7 @@ vg_ipc_syscall (uintptr_t flags,
        [send_inline_word1] "m" (send_inline_word1),
        [send_inline_word2] "m" (send_inline_word2),
        [send_inline_cap] "m" (send_inline_cap)
-     : "rcx", "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15",
+     : "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15",
        "memory");
 
   return err;
diff --git a/viengoos/server.c b/viengoos/server.c
index 33ac0d9..a45933a 100644
--- a/viengoos/server.c
+++ b/viengoos/server.c
@@ -87,21 +87,22 @@ static struct debug_command trace_buffer_debug =
     {									\
       if (level <= 4)							\
 	trace_buffer_add (&rpc_trace,					\
-			  "("OBJECT_NAME_FMT" %s %"PRIdPTR") " format, \
+			  "("OBJECT_NAME_FMT"@%"PRIxPTR			\
+			  " %s %"PRIdPTR") " format,			\
 			  OBJECT_NAME_PRINTF ((struct vg_object *) thread), \
-			  METHOD, METHOD_ID,				\
+			  user_ret, METHOD, METHOD_ID,			\
 			  ##args);					\
-      debug (level, "("OBJECT_NAME_FMT" %s:%"PRIdPTR") " format,	\
+      debug (level, "("OBJECT_NAME_FMT"@%"PRIxPTR" %s:%"PRIdPTR") " format, \
 	     OBJECT_NAME_PRINTF ((struct vg_object *) thread),		\
-	     METHOD, METHOD_ID, ##args);				\
+	     user_ret, METHOD, METHOD_ID, ##args);			\
     }									\
   while (0)
 
 #else
 # define DEBUG(level, format, args...)					\
-  debug (level, "("OBJECT_NAME_FMT" %s:%"PRIdPTR") " format,	\
-	 OBJECT_NAME_PRINTF ((struct vg_object *) thread),	\
-	 METHOD, METHOD_ID, ##args)
+  debug (level, "("OBJECT_NAME_FMT"@%"PRIxPTR" %s:%"PRIdPTR") " format,	\
+	 OBJECT_NAME_PRINTF ((struct vg_object *) thread),		\
+	 user_ret, METHOD, METHOD_ID, ##args)
 #endif
 
 void
@@ -115,6 +116,8 @@ server_bootstrap (void)
 bool
 page_fault_handler (struct thread *thread, uintptr_t fault, int access)
 {
+  uintptr_t user_ret = thread_ip (thread);
+
 #define METHOD "pagefault"
 #define METHOD_ID ((uintptr_t) (0))
 
@@ -301,6 +304,12 @@ page_fault_handler (struct thread *thread, uintptr_t fault, int access)
   return true;
 }
 
+#ifndef NDEBUG
+extern uintptr_t user_ret;
+#else
+# define user_ret ((uintptr_t) 0)
+#endif
+
 void
 dispatcher (uintptr_t flags,
 	    vg_addr_t recv_activity, vg_addr_t recv_messenger,
diff --git a/viengoos/sysdeps/x86_64/syscall.c b/viengoos/sysdeps/x86_64/syscall.c
index 6481538..e43ac19 100644
--- a/viengoos/sysdeps/x86_64/syscall.c
+++ b/viengoos/sysdeps/x86_64/syscall.c
@@ -42,16 +42,24 @@ returner (void)
   panic ("Failed to schedule something!!!");
 }
 
+#ifndef NDEBUG
+uintptr_t user_ret;
+#endif
+
 static void __attribute__ ((used))
 dummy (void)
 {
 #define S_(x) #x
 #define S(x) S_(x)
-  /* On entry, RCX contains the old RIP.  */
+  /* On entry, RCX contains the user's RIP and R11 the user's flags.  */
   asm volatile
     (".global syscall_entry\n\t"
      "syscall_entry:\n\t"
 
+#ifndef NDEBUG
+     "mov %%rbp, user_ret\n\t"
+#endif
+
      /* Save the user's RSP in RBP and switch to the kernel stack.  */
      "mov %%rsp, %%rbp\n\t"
      "leaq stack_end, %%rsp\n\t"