Messages in this thread | | | Date | Mon, 13 Sep 2004 17:17:18 +0300 | From | Constantine Gavrilov <> | Subject | Re: Fwd: Calling syscalls from x86-64 kernel results in a crash on Opteron machines |
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> > >Subject: Calling syscalls from x86-64 kernel results in a crash on Opteron machines >Date: Mon, 13 Sep 2004 17:04:17 +0300 >From: Constantine Gavrilov <constg@qlusters.com> >To: bugs@x86-64.org, linux-kernel@vger.kernel.org > >Hello: > >We have a piece of kernel code that calls some system calls in kernel >context (from a process with mm and a daemonized kernel thread that does >not have mm). This works fine on IA64 and i386 architectures. > ..............
>Attached please find a test module that tries to call the umask() (JUST >TO DEMONSTRATE a problem) via the syscall machanism. Both methods (the >_syscall1() marco and GLIBC INLINE_SYCALL() were used. > >
I forgot to attach a header file with glibc version of syscall inline implementation.
-- ---------------------------------------- Constantine Gavrilov Kernel Developer Qlusters Software Ltd 1 Azrieli Center, Tel-Aviv Phone: +972-3-6081977 Fax: +972-3-6081841 ----------------------------------------
#ifndef _GSYSCALL_H_ #define _GSYSCALL_H_
#define __set_errno(Val) errno = (Val)
#undef INLINE_SYSCALL #define INLINE_SYSCALL(name, nr, args...) \ ({ \ unsigned long resultvar = INTERNAL_SYSCALL (name, , nr, args); \ if (__builtin_expect (INTERNAL_SYSCALL_ERROR_P (resultvar, ), 0)) \ { \ __set_errno (INTERNAL_SYSCALL_ERRNO (resultvar, )); \ resultvar = (unsigned long) -1; \ } \ (long) resultvar; })
#undef INTERNAL_SYSCALL_DECL #define INTERNAL_SYSCALL_DECL(err) do { } while (0)
#undef INTERNAL_SYSCALL #define INTERNAL_SYSCALL(name, err, nr, args...) \ ({ \ unsigned long resultvar; \ LOAD_ARGS_##nr (args) \ asm volatile ( \ "movq %1, %%rax\n\t" \ "syscall\n\t" \ : "=a" (resultvar) \ : "i" (__NR_##name) ASM_ARGS_##nr : "memory", "cc", "r11", "cx"); \ (long) resultvar; })
#undef INTERNAL_SYSCALL_ERROR_P #define INTERNAL_SYSCALL_ERROR_P(val, err) \ ((unsigned long) (val) >= -4095L)
#undef INTERNAL_SYSCALL_ERRNO #define INTERNAL_SYSCALL_ERRNO(val, err) (-(val))
#define LOAD_ARGS_0() #define ASM_ARGS_0
#define LOAD_ARGS_1(a1) \ register long int _a1 asm ("rdi") = (long) (a1); \ LOAD_ARGS_0 () #define ASM_ARGS_1 ASM_ARGS_0, "r" (_a1)
#define LOAD_ARGS_2(a1, a2) \ register long int _a2 asm ("rsi") = (long) (a2); \ LOAD_ARGS_1 (a1) #define ASM_ARGS_2 ASM_ARGS_1, "r" (_a2)
#define LOAD_ARGS_3(a1, a2, a3) \ register long int _a3 asm ("rdx") = (long) (a3); \ LOAD_ARGS_2 (a1, a2) #define ASM_ARGS_3 ASM_ARGS_2, "r" (_a3)
#define LOAD_ARGS_4(a1, a2, a3, a4) \ register long int _a4 asm ("r10") = (long) (a4); \ LOAD_ARGS_3 (a1, a2, a3) #define ASM_ARGS_4 ASM_ARGS_3, "r" (_a4)
#define LOAD_ARGS_5(a1, a2, a3, a4, a5) \ register long int _a5 asm ("r8") = (long) (a5); \ LOAD_ARGS_4 (a1, a2, a3, a4) #define ASM_ARGS_5 ASM_ARGS_4, "r" (_a5)
#define LOAD_ARGS_6(a1, a2, a3, a4, a5, a6) \ register long int _a6 asm ("r9") = (long) (a6); \ LOAD_ARGS_5 (a1, a2, a3, a4, a5) #define ASM_ARGS_6 ASM_ARGS_5, "r" (_a6)
#endif
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