[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, 11 insertions, 11 deletions

diff --git a/arch/um/sys-x86_64/Makefile b/arch/um/sys-x86_64/Makefile
index ea977df395a1..00b2025427df 100644
--- a/arch/um/sys-x86_64/Makefile
+++ b/arch/um/sys-x86_64/Makefile
@@ -12,7 +12,7 @@ lib-y = bitops.o bugs.o csum-partial.o delay.o fault.o ldt.o mem.o memcpy.o \
 obj-y := ksyms.o
 obj-$(CONFIG_MODULES) += module.o um_module.o
 
-USER_OBJS := ptrace_user.o sigcontext.o
+USER_OBJS := ptrace_user.o sigcontext.o stub_segv.o
 
 SYMLINKS = bitops.c csum-copy.S csum-partial.c csum-wrappers.c ldt.c memcpy.S \
         thunk.S module.c
diff --git a/arch/um/sys-x86_64/stub_segv.c b/arch/um/sys-x86_64/stub_segv.c
index d1e53bdf2e85..a27099533198 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));
 }