Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932430AbVJYWIt (ORCPT ); Tue, 25 Oct 2005 18:08:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932436AbVJYWFf (ORCPT ); Tue, 25 Oct 2005 18:05:35 -0400 Received: from [151.97.230.9] ([151.97.230.9]:57829 "EHLO ssc.unict.it") by vger.kernel.org with ESMTP id S932429AbVJYWFc (ORCPT ); Tue, 25 Oct 2005 18:05:32 -0400 From: "Paolo 'Blaisorblade' Giarrusso" Subject: [PATCH 04/11] uml: fix SKAS0 assembly stubs - use proper constraints Date: Wed, 26 Oct 2005 00:01:27 +0200 To: Jeff Dike Cc: linux-kernel@vger.kernel.org, user-mode-linux-devel@lists.sourceforge.net Message-Id: <20051025220126.20010.28676.stgit@zion.home.lan> In-Reply-To: <20051025220053.20010.56979.stgit@zion.home.lan> References: <20051025220053.20010.56979.stgit@zion.home.lan> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6711 Lines: 212 From: Paolo 'Blaisorblade' Giarrusso 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 --- arch/um/include/sysdep-i386/stub.h | 64 +++++++++++++++++++++++----------- arch/um/include/sysdep-x86_64/stub.h | 61 ++++++++++++++++++++++++++------ 2 files changed, 92 insertions(+), 33 deletions(-) diff --git a/arch/um/include/sysdep-i386/stub.h b/arch/um/include/sysdep-i386/stub.h --- 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 --- 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) - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/