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Commit fb30d645 authored by Jeff Dike's avatar Jeff Dike Committed by Linus Torvalds
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[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: default avatarJeff Dike <jdike@addtoit.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 966a082f

arch/um/sys-i386/stub_segv.c

+2 −2
Original line number Diff line number Diff line
@@ -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 ; "

	__asm__ __volatile__("mov %0,%%esp ; movl %1, %%eax ; "

			     "int $0x80" : : "a" (sc), "g" (__NR_sigreturn));

}

arch/um/sys-x86_64/stub_segv.c

+5 −5
Original line number Diff line number Diff line
@@ -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),

	__asm__ __volatile__("movq %0, %%rsp; movq %1, %%rax ; syscall": :

                             "g" ((unsigned long)

                                  container_of(uc, struct rt_sigframe, uc) + 8),

                             "g" (__NR_rt_sigreturn));

}