[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, 8 insertions, 5 deletions

diff --git a/arch/um/sys-i386/Makefile b/arch/um/sys-i386/Makefile
index 6dfeb70f6957..150059dbee12 100644
--- a/arch/um/sys-i386/Makefile
+++ b/arch/um/sys-i386/Makefile
@@ -5,7 +5,7 @@ obj-y = bitops.o bugs.o checksum.o delay.o fault.o ksyms.o ldt.o ptrace.o \
 obj-$(CONFIG_HIGHMEM) += highmem.o
 obj-$(CONFIG_MODULES) += module.o
 
-USER_OBJS := bugs.o ptrace_user.o sigcontext.o fault.o
+USER_OBJS := bugs.o ptrace_user.o sigcontext.o fault.o stub_segv.o
 
 SYMLINKS = bitops.c semaphore.c highmem.c module.c
 
diff --git a/arch/um/sys-i386/stub_segv.c b/arch/um/sys-i386/stub_segv.c
index 1e88b275edac..a37f672ec964 100644
--- a/arch/um/sys-i386/stub_segv.c
+++ b/arch/um/sys-i386/stub_segv.c
@@ -3,9 +3,11 @@
  * Licensed under the GPL
  */
 
-#include <asm/signal.h>
+#include <signal.h>
+#include <sys/select.h> /* The only way I can see to get sigset_t */
 #include <asm/unistd.h>
 #include "uml-config.h"
+#include "sysdep/stub.h"
 #include "sysdep/sigcontext.h"
 #include "sysdep/faultinfo.h"
 
@@ -13,13 +15,14 @@ void __attribute__ ((__section__ (".__syscall_stub")))
 stub_segv_handler(int sig)
 {
         struct sigcontext *sc = (struct sigcontext *) (&sig + 1);
+        int pid;
 
         GET_FAULTINFO_FROM_SC(*((struct faultinfo *) UML_CONFIG_STUB_DATA),
                               sc);
 
-        __asm__("movl %0, %%eax ; int $0x80": : "g" (__NR_getpid));
-        __asm__("movl %%eax, %%ebx ; movl %0, %%eax ; movl %1, %%ecx ;"
-                "int $0x80": : "g" (__NR_kill), "g" (SIGUSR1));
+        pid = stub_syscall0(__NR_getpid);
+        stub_syscall2(__NR_kill, pid, SIGUSR1);
+
         /* Load pointer to sigcontext into esp, since we need to leave
          * the stack in its original form when we do the sigreturn here, by
          * hand.