diff options
Diffstat (limited to 'sysdeps/unix/sysv/linux/x86_64/sysdep.h')
| -rw-r--r-- | sysdeps/unix/sysv/linux/x86_64/sysdep.h | 205 |
1 files changed, 205 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/x86_64/sysdep.h b/sysdeps/unix/sysv/linux/x86_64/sysdep.h new file mode 100644 index 0000000000..972fa20442 --- /dev/null +++ b/sysdeps/unix/sysv/linux/x86_64/sysdep.h @@ -0,0 +1,205 @@ +/* Copyright (C) 2001 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +#ifndef _LINUX_X86_64_SYSDEP_H +#define _LINUX_X86_64_SYSDEP_H 1 + +/* There is some commonality. */ +#include <sysdeps/unix/x86_64/sysdep.h> +#include <bp-sym.h> +#include <bp-asm.h> + +/* For Linux we can use the system call table in the header file + /usr/include/asm/unistd.h + of the kernel. But these symbols do not follow the SYS_* syntax + so we have to redefine the `SYS_ify' macro here. */ +#undef SYS_ify +#define SYS_ify(syscall_name) __NR_##syscall_name + +/* ELF-like local names start with `.L'. */ +#undef L +#define L(name) .L##name + +#ifdef __ASSEMBLER__ + +/* Linux uses a negative return value to indicate syscall errors, + unlike most Unices, which use the condition codes' carry flag. + + Since version 2.1 the return value of a system call might be + negative even if the call succeeded. E.g., the `lseek' system call + might return a large offset. Therefore we must not anymore test + for < 0, but test for a real error by making sure the value in %eax + is a real error number. Linus said he will make sure the no syscall + returns a value in -1 .. -4095 as a valid result so we can savely + test with -4095. */ + +/* We don't want the label for the error handle to be global when we define + it here. */ +#ifdef PIC +# define SYSCALL_ERROR_LABEL 0f +#else +# define SYSCALL_ERROR_LABEL syscall_error +#endif + +#undef PSEUDO +#define PSEUDO(name, syscall_name, args) \ + .text; \ + ENTRY (name) \ + DO_CALL (args, syscall_name); \ + cmpq $-4095, %rax; \ + jae SYSCALL_ERROR_LABEL; \ + L(pseudo_end): + +#undef PSEUDO_END +#define PSEUDO_END(name) \ + SYSCALL_ERROR_HANDLER \ + END (name) + +#ifndef PIC +#define SYSCALL_ERROR_HANDLER /* Nothing here; code in sysdep.S is used. */ +#else +/* Store (- %rax) into errno through the GOT. */ +#ifdef _LIBC_REENTRANT +#define SYSCALL_ERROR_HANDLER \ +0: \ + xorq %rdx, %rdx; \ + subq %rax, %rdx; \ + pushq %rdx \ + PUSH_ERRNO_LOCATION_RETURN; \ + call BP_SYM (__errno_location)@PLT; \ + POP_ERRNO_LOCATION_RETURN; \ + popq %rdx; \ + movq %rdx, (%rax); \ + orq $-1, %rax; \ + jmp L(pseudo_end); + +/* A quick note: it is assumed that the call to `__errno_location' does + not modify the stack! */ +#else +#define SYSCALL_ERROR_HANDLER \ +0:movq errno@GOTPCREL(%RIP), %rcx; \ + xorq %rdx, %rdx; \ + subq %rax, %rdx; \ + movq %rdx, (%rcx); \ + orq $-1, %rax; \ + jmp L(pseudo_end); +#endif /* _LIBC_REENTRANT */ +#endif /* PIC */ + +/* Linux/x86-64 takes system call arguments in registers: + + Register setup: + system call number rax + arg 1 rdi + arg 2 rsi + arg 3 rdx + arg 4 rcx + arg 5 r8 + arg 6 r9 + + return address from + syscall rcx + additionally clobered: r12-r15,rbx,rbp + eflags from syscall r11 + + The compiler is going to form a call by coming here, through PSEUDO, with arguments: + + syscall number in the DO_CALL macro + arg 1 rdi + arg 2 rsi + arg 3 rdx + arg 4 r10 + arg 5 r8 + arg 6 r9 + + We have to take care that the stack is alignedto 16 bytes. When + called the stack is not aligned since the return address has just + been pushed. + + Syscalls of more than 6 arguments are not supported. */ + +#undef DO_CALL +#define DO_CALL(args, syscall_name) \ + DOARGS_##args \ + movq $SYS_ify (syscall_name), %rax; \ + syscall; + +#define DOARGS_0 /* nothing */ +#define DOARGS_1 /* nothing */ +#define DOARGS_2 /* nothing */ +#define DOARGS_3 /* nothing */ +#define DOARGS_4 movq %rcx, %r10; +#define DOARGS_5 DOARGS_4 +#define DOARGS_6 DOARGS_5 + +#else /* !__ASSEMBLER__ */ +/* Define a macro which expands inline into the wrapper code for a system + call. */ +#undef INLINE_SYSCALL +#define INLINE_SYSCALL(name, 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"); \ + if (resultvar >= (unsigned long) -4095) \ + { \ + __set_errno (-resultvar); \ + resultvar = (unsigned long) -1; \ + } \ + (long) resultvar; }) + +#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 /* __ASSEMBLER__ */ + +#endif /* linux/x86_64/sysdep.h */ |