[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>

2 files changed, 20 insertions, 1 deletions

diff --git a/arch/um/include/sysdep-i386/stub.h b/arch/um/include/sysdep-i386/stub.h
index a49ceb199ee5..6ba8cbbe0d36 100644
--- a/arch/um/include/sysdep-i386/stub.h
+++ b/arch/um/include/sysdep-i386/stub.h
@@ -16,6 +16,15 @@ extern void stub_clone_handler(void);
 #define STUB_MMAP_NR __NR_mmap2
 #define MMAP_OFFSET(o) ((o) >> PAGE_SHIFT)
 
+static inline long stub_syscall0(long syscall)
+{
+        long ret;
+
+        __asm__ volatile ("int $0x80" : "=a" (ret) : "0" (syscall));
+
+        return ret;
+}
+
 static inline long stub_syscall1(long syscall, long arg1)
 {
         long ret;
diff --git a/arch/um/include/sysdep-x86_64/stub.h b/arch/um/include/sysdep-x86_64/stub.h
index 2bd6e7a97286..c41689c13dc9 100644
--- a/arch/um/include/sysdep-x86_64/stub.h
+++ b/arch/um/include/sysdep-x86_64/stub.h
@@ -6,7 +6,6 @@
 #ifndef __SYSDEP_STUB_H
 #define __SYSDEP_STUB_H
 
-#include <asm/ptrace.h>
 #include <asm/unistd.h>
 #include <sysdep/ptrace_user.h>
 
@@ -20,6 +19,17 @@ extern void stub_clone_handler(void);
 #define __syscall_clobber "r11","rcx","memory"
 #define __syscall "syscall"
 
+static inline long stub_syscall0(long syscall)
+{
+        long ret;
+
+        __asm__ volatile (__syscall
+                : "=a" (ret)
+                : "0" (syscall) : __syscall_clobber );
+
+        return ret;
+}
+
 static inline long stub_syscall2(long syscall, long arg1, long arg2)
 {
         long ret;