[PATCH] uml: properly invoke x86_64 system calls

This patch makes stub_segv use the stub_syscall macros.  This was needed
anyway, but the bug that prompted this was the discovery that gcc was storing
stuff in RCX, which is trashed across a system call.  This is exactly the sort
of problem that the new macros fix.

There is a stub_syscall0 for getpid.  stub_segv was changed to be a libc file,
and that caused some include changes.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 10 insertions, 10 deletions

diff --git a/arch/um/sys-x86_64/stub_segv.c b/arch/um/sys-x86_64/stub_segv.c
index d1e53bdf2e8..a2709953319 100644
--- a/arch/um/sys-x86_64/stub_segv.c
+++ b/arch/um/sys-x86_64/stub_segv.c
@@ -3,14 +3,14 @@
  * Licensed under the GPL
  */
 
-#include <asm/signal.h>
+#include <stddef.h>
+#include <signal.h>
 #include <linux/compiler.h>
 #include <asm/unistd.h>
-#include <asm/ucontext.h>
 #include "uml-config.h"
 #include "sysdep/sigcontext.h"
 #include "sysdep/faultinfo.h"
-#include <stddef.h>
+#include "sysdep/stub.h"
 
 /* Copied from sys-x86_64/signal.c - Can't find an equivalent definition
  * in the libc headers anywhere.
@@ -31,21 +31,21 @@ void __attribute__ ((__section__ (".__syscall_stub")))
 stub_segv_handler(int sig)
 {
 	struct ucontext *uc;
+        int pid;
 
 	__asm__("movq %%rdx, %0" : "=g" (uc) :);
 	GET_FAULTINFO_FROM_SC(*((struct faultinfo *) UML_CONFIG_STUB_DATA),
 			      &uc->uc_mcontext);
 
-	__asm__("movq %0, %%rax ; syscall": : "g" (__NR_getpid));	
-	__asm__("movq %%rax, %%rdi ; movq %0, %%rax ; movq %1, %%rsi ;"
-		"syscall": : "g" (__NR_kill), "g" (SIGUSR1) : 
-		"%rdi", "%rax", "%rsi");
+	pid = stub_syscall0(__NR_getpid);
+	stub_syscall2(__NR_kill, pid, SIGUSR1);
+
 	/* sys_sigreturn expects that the stack pointer will be 8 bytes into
 	 * the signal frame.  So, we use the ucontext pointer, which we know
 	 * already, to get the signal frame pointer, and add 8 to that.
 	 */
-	__asm__("movq %0, %%rsp": : 
+	__asm__("movq %0, %%rsp; movq %1, %%rax ; syscall": :
 		"g" ((unsigned long) container_of(uc, struct rt_sigframe, 
-						  uc) + 8));
-	__asm__("movq %0, %%rax ; syscall" : : "g" (__NR_rt_sigreturn));
+						  uc) + 8),
+                "g" (__NR_rt_sigreturn));
 }