Commit 17d46971 authored by Jeff Dike's avatar Jeff Dike Committed by Linus Torvalds
Browse files

[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: 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 e23181de

arch/um/include/sysdep-i386/stub.h

+9 −0
Original line number Diff line number Diff line
@@ -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;

arch/um/include/sysdep-x86_64/stub.h

+11 −1
Original line number Diff line number Diff line
@@ -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;

arch/um/sys-i386/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -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

arch/um/sys-i386/stub_segv.c

+7 −4
Original line number Diff line number Diff line
@@ -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.

arch/um/sys-x86_64/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -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

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