[PATCH] uml: add missing __volatile__

We were missing __volatile__ on some bits of asm in the segfault handlers.
On x86_64, this was messing up the move from %rdx to uc because that was
moved to after the GET_FAULTINFO_FROM_SC, which changed %rdx.

Also changed the other bit of asm and the one in the i386 handler to
prevent any similar occurrences.

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

diff --git a/arch/um/sys-i386/stub_segv.c b/arch/um/sys-i386/stub_segv.c
index a37f672..2355dc1 100644 (file)
--- a/arch/um/sys-i386/stub_segv.c
+++ b/arch/um/sys-i386/stub_segv.c
@@ -27,6 +27,6 @@ stub_segv_handler(int sig)
         * the stack in its original form when we do the sigreturn here, by
         * hand.
         */
-       __asm__("mov %0,%%esp ; movl %1, %%eax ; "
-               "int $0x80" : : "a" (sc), "g" (__NR_sigreturn));
+       __asm__ __volatile__("mov %0,%%esp ; movl %1, %%eax ; "
+                            "int $0x80" : : "a" (sc), "g" (__NR_sigreturn));
 }

diff --git a/arch/um/sys-x86_64/stub_segv.c b/arch/um/sys-x86_64/stub_segv.c
index a270995..1c96702 100644 (file)
--- a/arch/um/sys-x86_64/stub_segv.c
+++ b/arch/um/sys-x86_64/stub_segv.c
@@ -33,7 +33,7 @@ stub_segv_handler(int sig)
        struct ucontext *uc;
         int pid;
 
-       __asm__("movq %%rdx, %0" : "=g" (uc) :);
+       __asm__ __volatile__("movq %%rdx, %0" : "=g" (uc) :);
        GET_FAULTINFO_FROM_SC(*((struct faultinfo *) UML_CONFIG_STUB_DATA),
                              &uc->uc_mcontext);
 
@@ -44,8 +44,8 @@ stub_segv_handler(int sig)
         * 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; movq %1, %%rax ; syscall": :
-               "g" ((unsigned long) container_of(uc, struct rt_sigframe, 
-                                                 uc) + 8),
-                "g" (__NR_rt_sigreturn));
+       __asm__ __volatile__("movq %0, %%rsp; movq %1, %%rax ; syscall": :
+                             "g" ((unsigned long)
+                                  container_of(uc, struct rt_sigframe, uc) + 8),
+                             "g" (__NR_rt_sigreturn));
 }