From: Jeff Dike 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 Signed-off-by: Andrew Morton --- arch/um/include/sysdep-i386/stub.h | 9 +++++++++ arch/um/include/sysdep-x86_64/stub.h | 12 +++++++++++- arch/um/sys-i386/Makefile | 2 +- arch/um/sys-i386/stub_segv.c | 11 +++++++---- arch/um/sys-x86_64/Makefile | 2 +- arch/um/sys-x86_64/stub_segv.c | 20 ++++++++++---------- 6 files changed, 39 insertions(+), 17 deletions(-) diff -puN arch/um/include/sysdep-i386/stub.h~uml-properly-invoke-x86_64-system-calls arch/um/include/sysdep-i386/stub.h --- 25/arch/um/include/sysdep-i386/stub.h~uml-properly-invoke-x86_64-system-calls Thu Nov 17 15:05:27 2005 +++ 25-akpm/arch/um/include/sysdep-i386/stub.h Thu Nov 17 15:05:27 2005 @@ -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 $0x80" : "=a" (ret) : "0" (syscall)); + + return ret; +} + static inline long stub_syscall1(long syscall, long arg1) { long ret; diff -puN arch/um/include/sysdep-x86_64/stub.h~uml-properly-invoke-x86_64-system-calls arch/um/include/sysdep-x86_64/stub.h --- 25/arch/um/include/sysdep-x86_64/stub.h~uml-properly-invoke-x86_64-system-calls Thu Nov 17 15:05:27 2005 +++ 25-akpm/arch/um/include/sysdep-x86_64/stub.h Thu Nov 17 15:05:27 2005 @@ -6,7 +6,6 @@ #ifndef __SYSDEP_STUB_H #define __SYSDEP_STUB_H -#include #include #include @@ -20,6 +19,17 @@ extern void stub_clone_handler(void); #define __syscall_clobber "r11","rcx","memory" #define __syscall "syscall" +static inline long stub_syscall0(long syscall) +{ + long ret; + + __asm__ volatile (__syscall + : "=a" (ret) + : "0" (syscall) : __syscall_clobber ); + + return ret; +} + static inline long stub_syscall2(long syscall, long arg1, long arg2) { long ret; diff -puN arch/um/sys-i386/Makefile~uml-properly-invoke-x86_64-system-calls arch/um/sys-i386/Makefile --- 25/arch/um/sys-i386/Makefile~uml-properly-invoke-x86_64-system-calls Thu Nov 17 15:05:27 2005 +++ 25-akpm/arch/um/sys-i386/Makefile Thu Nov 17 15:05:27 2005 @@ -5,7 +5,7 @@ obj-y = bitops.o bugs.o checksum.o delay obj-$(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 -puN arch/um/sys-i386/stub_segv.c~uml-properly-invoke-x86_64-system-calls arch/um/sys-i386/stub_segv.c --- 25/arch/um/sys-i386/stub_segv.c~uml-properly-invoke-x86_64-system-calls Thu Nov 17 15:05:27 2005 +++ 25-akpm/arch/um/sys-i386/stub_segv.c Thu Nov 17 15:05:27 2005 @@ -3,9 +3,11 @@ * Licensed under the GPL */ -#include +#include +#include /* The only way I can see to get sigset_t */ #include #include "uml-config.h" +#include "sysdep/stub.h" #include "sysdep/sigcontext.h" #include "sysdep/faultinfo.h" @@ -13,13 +15,14 @@ void __attribute__ ((__section__ (".__sy 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 $0x80": : "g" (__NR_kill), "g" (SIGUSR1)); + pid = stub_syscall0(__NR_getpid); + stub_syscall2(__NR_kill, pid, SIGUSR1); + /* Load pointer to sigcontext into esp, since we need to leave * the stack in its original form when we do the sigreturn here, by * hand. diff -puN arch/um/sys-x86_64/Makefile~uml-properly-invoke-x86_64-system-calls arch/um/sys-x86_64/Makefile --- 25/arch/um/sys-x86_64/Makefile~uml-properly-invoke-x86_64-system-calls Thu Nov 17 15:05:27 2005 +++ 25-akpm/arch/um/sys-x86_64/Makefile Thu Nov 17 15:05:27 2005 @@ -12,7 +12,7 @@ lib-y = bitops.o bugs.o csum-partial.o d obj-y := ksyms.o obj-$(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 -puN arch/um/sys-x86_64/stub_segv.c~uml-properly-invoke-x86_64-system-calls arch/um/sys-x86_64/stub_segv.c --- 25/arch/um/sys-x86_64/stub_segv.c~uml-properly-invoke-x86_64-system-calls Thu Nov 17 15:05:27 2005 +++ 25-akpm/arch/um/sys-x86_64/stub_segv.c Thu Nov 17 15:05:27 2005 @@ -3,14 +3,14 @@ * Licensed under the GPL */ -#include +#include +#include #include #include -#include #include "uml-config.h" #include "sysdep/sigcontext.h" #include "sysdep/faultinfo.h" -#include +#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__ (".__sy 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)); } _