From 4f0272415ad1867cea2a7ef5659769243ae50fbe Mon Sep 17 00:00:00 2001 From: Paolo 'Blaisorblade' Giarrusso Date: Mon, 7 Nov 2005 00:58:46 -0800 Subject: [PATCH] uml: fix syscall stubs Jeff Dike noted that the assembly code for syscall stubs is misassembled with GCC 3.2.3: the values copied in registers weren't preserved between one asm() and the following one. So I fixed the thing by rewriting the __asm__ constraints more like unistd.h ones. Note: in syscall6 case I had to add one more instruction (i.e. moving arg6 in eax and shuffling things around) - it's needed for the function to be valid in general (we can't load the value from the stack, relative to ebp, because we change it), but could be avoided since we actually use a constant as param 6. The only fix would be to turn stub_syscall6 to a macro and use a "i" constraint for arg6 (i.e., specify it's a constant value). Signed-off-by: Paolo 'Blaisorblade' Giarrusso Signed-off-by: Jeff Dike Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/um/include/sysdep-i386/stub.h | 64 +++++++++++++++++++++++++----------- arch/um/include/sysdep-x86_64/stub.h | 61 ++++++++++++++++++++++++++-------- 2 files changed, 92 insertions(+), 33 deletions(-) (limited to 'arch/um') diff --git a/arch/um/include/sysdep-i386/stub.h b/arch/um/include/sysdep-i386/stub.h index d3699fe1c61..a49ceb199ee 100644 --- a/arch/um/include/sysdep-i386/stub.h +++ b/arch/um/include/sysdep-i386/stub.h @@ -16,45 +16,69 @@ extern void stub_clone_handler(void); #define STUB_MMAP_NR __NR_mmap2 #define MMAP_OFFSET(o) ((o) >> PAGE_SHIFT) +static inline long stub_syscall1(long syscall, long arg1) +{ + long ret; + + __asm__ volatile ("int $0x80" : "=a" (ret) : "0" (syscall), "b" (arg1)); + + return ret; +} + static inline long stub_syscall2(long syscall, long arg1, long arg2) { long ret; - __asm__("movl %0, %%ecx; " : : "g" (arg2) : "%ecx"); - __asm__("movl %0, %%ebx; " : : "g" (arg1) : "%ebx"); - __asm__("movl %0, %%eax; " : : "g" (syscall) : "%eax"); - __asm__("int $0x80;" : : : "%eax"); - __asm__ __volatile__("movl %%eax, %0; " : "=g" (ret) :); - return(ret); + __asm__ volatile ("int $0x80" : "=a" (ret) : "0" (syscall), "b" (arg1), + "c" (arg2)); + + return ret; } static inline long stub_syscall3(long syscall, long arg1, long arg2, long arg3) { - __asm__("movl %0, %%edx; " : : "g" (arg3) : "%edx"); - return(stub_syscall2(syscall, arg1, arg2)); + long ret; + + __asm__ volatile ("int $0x80" : "=a" (ret) : "0" (syscall), "b" (arg1), + "c" (arg2), "d" (arg3)); + + return ret; } static inline long stub_syscall4(long syscall, long arg1, long arg2, long arg3, long arg4) { - __asm__("movl %0, %%esi; " : : "g" (arg4) : "%esi"); - return(stub_syscall3(syscall, arg1, arg2, arg3)); + long ret; + + __asm__ volatile ("int $0x80" : "=a" (ret) : "0" (syscall), "b" (arg1), + "c" (arg2), "d" (arg3), "S" (arg4)); + + return ret; +} + +static inline long stub_syscall5(long syscall, long arg1, long arg2, long arg3, + long arg4, long arg5) +{ + long ret; + + __asm__ volatile ("int $0x80" : "=a" (ret) : "0" (syscall), "b" (arg1), + "c" (arg2), "d" (arg3), "S" (arg4), "D" (arg5)); + + return ret; } static inline long stub_syscall6(long syscall, long arg1, long arg2, long arg3, long arg4, long arg5, long arg6) { long ret; - __asm__("movl %0, %%eax; " : : "g" (syscall) : "%eax"); - __asm__("movl %0, %%ebx; " : : "g" (arg1) : "%ebx"); - __asm__("movl %0, %%ecx; " : : "g" (arg2) : "%ecx"); - __asm__("movl %0, %%edx; " : : "g" (arg3) : "%edx"); - __asm__("movl %0, %%esi; " : : "g" (arg4) : "%esi"); - __asm__("movl %0, %%edi; " : : "g" (arg5) : "%edi"); - __asm__ __volatile__("pushl %%ebp ; movl %1, %%ebp; " - "int $0x80; popl %%ebp ; " - "movl %%eax, %0; " : "=g" (ret) : "g" (arg6) : "%eax"); - return(ret); + + __asm__ volatile ("push %%ebp ; movl %%eax,%%ebp ; movl %1,%%eax ; " + "int $0x80 ; pop %%ebp" + : "=a" (ret) + : "g" (syscall), "b" (arg1), "c" (arg2), "d" (arg3), + "S" (arg4), "D" (arg5), "0" (arg6)); + + return ret; } static inline void trap_myself(void) diff --git a/arch/um/include/sysdep-x86_64/stub.h b/arch/um/include/sysdep-x86_64/stub.h index f599058d826..2bd6e7a9728 100644 --- a/arch/um/include/sysdep-x86_64/stub.h +++ b/arch/um/include/sysdep-x86_64/stub.h @@ -17,37 +17,72 @@ extern void stub_clone_handler(void); #define STUB_MMAP_NR __NR_mmap #define MMAP_OFFSET(o) (o) +#define __syscall_clobber "r11","rcx","memory" +#define __syscall "syscall" + static inline long stub_syscall2(long syscall, long arg1, long arg2) { long ret; - __asm__("movq %0, %%rsi; " : : "g" (arg2) : "%rsi"); - __asm__("movq %0, %%rdi; " : : "g" (arg1) : "%rdi"); - __asm__("movq %0, %%rax; " : : "g" (syscall) : "%rax"); - __asm__("syscall;" : : : "%rax", "%r11", "%rcx"); - __asm__ __volatile__("movq %%rax, %0; " : "=g" (ret) :); - return(ret); + __asm__ volatile (__syscall + : "=a" (ret) + : "0" (syscall), "D" (arg1), "S" (arg2) : __syscall_clobber ); + + return ret; } static inline long stub_syscall3(long syscall, long arg1, long arg2, long arg3) { - __asm__("movq %0, %%rdx; " : : "g" (arg3) : "%rdx"); - return(stub_syscall2(syscall, arg1, arg2)); + long ret; + + __asm__ volatile (__syscall + : "=a" (ret) + : "0" (syscall), "D" (arg1), "S" (arg2), "d" (arg3) + : __syscall_clobber ); + + return ret; } static inline long stub_syscall4(long syscall, long arg1, long arg2, long arg3, long arg4) { - __asm__("movq %0, %%r10; " : : "g" (arg4) : "%r10"); - return(stub_syscall3(syscall, arg1, arg2, arg3)); + long ret; + + __asm__ volatile ("movq %5,%%r10 ; " __syscall + : "=a" (ret) + : "0" (syscall), "D" (arg1), "S" (arg2), "d" (arg3), + "g" (arg4) + : __syscall_clobber, "r10" ); + + return ret; +} + +static inline long stub_syscall5(long syscall, long arg1, long arg2, long arg3, + long arg4, long arg5) +{ + long ret; + + __asm__ volatile ("movq %5,%%r10 ; movq %6,%%r8 ; " __syscall + : "=a" (ret) + : "0" (syscall), "D" (arg1), "S" (arg2), "d" (arg3), + "g" (arg4), "g" (arg5) + : __syscall_clobber, "r10", "r8" ); + + return ret; } static inline long stub_syscall6(long syscall, long arg1, long arg2, long arg3, long arg4, long arg5, long arg6) { - __asm__("movq %0, %%r9; " : : "g" (arg6) : "%r9"); - __asm__("movq %0, %%r8; " : : "g" (arg5) : "%r8"); - return(stub_syscall4(syscall, arg1, arg2, arg3, arg4)); + long ret; + + __asm__ volatile ("movq %5,%%r10 ; movq %6,%%r8 ; " + "movq %7, %%r9; " __syscall : "=a" (ret) + : "0" (syscall), "D" (arg1), "S" (arg2), "d" (arg3), + "g" (arg4), "g" (arg5), "g" (arg6) + : __syscall_clobber, "r10", "r8", "r9" ); + + return ret; } static inline void trap_myself(void) -- cgit v1.2.3-18-g5258