diff options
Diffstat (limited to 'libc/sysdeps/unix/sysv/linux/x86_64/sysdep.h')
| -rw-r--r-- | libc/sysdeps/unix/sysv/linux/x86_64/sysdep.h | 341 |
1 files changed, 341 insertions, 0 deletions
diff --git a/libc/sysdeps/unix/sysv/linux/x86_64/sysdep.h b/libc/sysdeps/unix/sysv/linux/x86_64/sysdep.h new file mode 100644 index 000000000..5dfffca45 --- /dev/null +++ b/libc/sysdeps/unix/sysv/linux/x86_64/sysdep.h @@ -0,0 +1,341 @@ +/* Copyright (C) 2001, 2002, 2003, 2004, 2005 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> +#include <tls.h> + +#ifdef IS_IN_rtld +# include <dl-sysdep.h> /* Defines RTLD_PRIVATE_ERRNO. */ +#endif + +/* 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 + +/* This is a kludge to make syscalls.list find these under the names + pread and pwrite, since some kernel headers define those names + and some define the *64 names for the same system calls. */ +#if !defined __NR_pread && defined __NR_pread64 +# define __NR_pread __NR_pread64 +#endif +#if !defined __NR_pwrite && defined __NR_pwrite64 +# define __NR_pwrite __NR_pwrite64 +#endif + +/* This is to help the old kernel headers where __NR_semtimedop is not + available. */ +#ifndef __NR_semtimedop +# define __NR_semtimedop 220 +#endif + + +#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 (syscall_name, args); \ + cmpq $-4095, %rax; \ + jae SYSCALL_ERROR_LABEL; \ + L(pseudo_end): + +#undef PSEUDO_END +#define PSEUDO_END(name) \ + SYSCALL_ERROR_HANDLER \ + END (name) + +#undef PSEUDO_NOERRNO +#define PSEUDO_NOERRNO(name, syscall_name, args) \ + .text; \ + ENTRY (name) \ + DO_CALL (syscall_name, args) + +#undef PSEUDO_END_NOERRNO +#define PSEUDO_END_NOERRNO(name) \ + END (name) + +#define ret_NOERRNO ret + +#undef PSEUDO_ERRVAL +#define PSEUDO_ERRVAL(name, syscall_name, args) \ + .text; \ + ENTRY (name) \ + DO_CALL (syscall_name, args); \ + negq %rax + +#undef PSEUDO_END_ERRVAL +#define PSEUDO_END_ERRVAL(name) \ + END (name) + +#define ret_ERRVAL ret + +#ifndef PIC +#define SYSCALL_ERROR_HANDLER /* Nothing here; code in sysdep.S is used. */ +#elif RTLD_PRIVATE_ERRNO +# define SYSCALL_ERROR_HANDLER \ +0: \ + leaq rtld_errno(%rip), %rcx; \ + xorl %edx, %edx; \ + subq %rax, %rdx; \ + movl %edx, (%rcx); \ + orq $-1, %rax; \ + jmp L(pseudo_end); +#elif USE___THREAD +# ifndef NOT_IN_libc +# define SYSCALL_ERROR_ERRNO __libc_errno +# else +# define SYSCALL_ERROR_ERRNO errno +# endif +# define SYSCALL_ERROR_HANDLER \ +0: \ + movq SYSCALL_ERROR_ERRNO@GOTTPOFF(%rip), %rcx;\ + xorl %edx, %edx; \ + subq %rax, %rdx; \ + movl %edx, %fs:(%rcx); \ + orq $-1, %rax; \ + jmp L(pseudo_end); +#elif defined _LIBC_REENTRANT +/* Store (- %rax) into errno through the GOT. + Note that errno occupies only 4 bytes. */ +# define SYSCALL_ERROR_HANDLER \ +0: \ + xorl %edx, %edx; \ + subq %rax, %rdx; \ + pushq %rdx; \ + cfi_adjust_cfa_offset(8); \ + PUSH_ERRNO_LOCATION_RETURN; \ + call BP_SYM (__errno_location)@PLT; \ + POP_ERRNO_LOCATION_RETURN; \ + popq %rdx; \ + cfi_adjust_cfa_offset(-8); \ + movl %edx, (%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 /* Not _LIBC_REENTRANT. */ +# define SYSCALL_ERROR_HANDLER \ +0:movq errno@GOTPCREL(%RIP), %rcx; \ + xorl %edx, %edx; \ + subq %rax, %rdx; \ + movl %edx, (%rcx); \ + orq $-1, %rax; \ + jmp L(pseudo_end); +#endif /* PIC */ + +/* The Linux/x86-64 kernel expects the system call parameters in + registers according to the following table: + + syscall number rax + arg 1 rdi + arg 2 rsi + arg 3 rdx + arg 4 r10 + arg 5 r8 + arg 6 r9 + + The Linux kernel uses and destroys internally these registers: + return address from + syscall rcx + additionally clobered: r12-r15,rbx,rbp + eflags from syscall r11 + + Normal function call, including calls to the system call stub + functions in the libc, get the first six parameters passed in + registers and the seventh parameter and later on the stack. The + register use is as follows: + + system call number in the DO_CALL macro + arg 1 rdi + arg 2 rsi + arg 3 rdx + arg 4 rcx + arg 5 r8 + arg 6 r9 + + We have to take care that the stack is aligned to 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(syscall_name, args) \ + DOARGS_##args \ + movl $SYS_ify (syscall_name), %eax; \ + 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 = 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) + +#define INTERNAL_SYSCALL_NCS(name, err, nr, args...) \ + ({ \ + unsigned long resultvar; \ + LOAD_ARGS_##nr (args) \ + LOAD_REGS_##nr \ + asm volatile ( \ + "syscall\n\t" \ + : "=a" (resultvar) \ + : "0" (name) ASM_ARGS_##nr : "memory", "cc", "r11", "cx"); \ + (long) resultvar; }) +#undef INTERNAL_SYSCALL +#define INTERNAL_SYSCALL(name, err, nr, args...) \ + INTERNAL_SYSCALL_NCS (__NR_##name, err, nr, ##args) + +#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 LOAD_REGS_0 +#define ASM_ARGS_0 + +#define LOAD_ARGS_1(a1) \ + long int __arg1 = (long) (a1); \ + LOAD_ARGS_0 () +#define LOAD_REGS_1 \ + register long int _a1 asm ("rdi") = __arg1; \ + LOAD_REGS_0 +#define ASM_ARGS_1 ASM_ARGS_0, "r" (_a1) + +#define LOAD_ARGS_2(a1, a2) \ + long int __arg2 = (long) (a2); \ + LOAD_ARGS_1 (a1) +#define LOAD_REGS_2 \ + register long int _a2 asm ("rsi") = __arg2; \ + LOAD_REGS_1 +#define ASM_ARGS_2 ASM_ARGS_1, "r" (_a2) + +#define LOAD_ARGS_3(a1, a2, a3) \ + long int __arg3 = (long) (a3); \ + LOAD_ARGS_2 (a1, a2) +#define LOAD_REGS_3 \ + register long int _a3 asm ("rdx") = __arg3; \ + LOAD_REGS_2 +#define ASM_ARGS_3 ASM_ARGS_2, "r" (_a3) + +#define LOAD_ARGS_4(a1, a2, a3, a4) \ + long int __arg4 = (long) (a4); \ + LOAD_ARGS_3 (a1, a2, a3) +#define LOAD_REGS_4 \ + register long int _a4 asm ("r10") = __arg4; \ + LOAD_REGS_3 +#define ASM_ARGS_4 ASM_ARGS_3, "r" (_a4) + +#define LOAD_ARGS_5(a1, a2, a3, a4, a5) \ + long int __arg5 = (long) (a5); \ + LOAD_ARGS_4 (a1, a2, a3, a4) +#define LOAD_REGS_5 \ + register long int _a5 asm ("r8") = __arg5; \ + LOAD_REGS_4 +#define ASM_ARGS_5 ASM_ARGS_4, "r" (_a5) + +#define LOAD_ARGS_6(a1, a2, a3, a4, a5, a6) \ + long int __arg6 = (long) (a6); \ + LOAD_ARGS_5 (a1, a2, a3, a4, a5) +#define LOAD_REGS_6 \ + register long int _a6 asm ("r9") = __arg6; \ + LOAD_REGS_5 +#define ASM_ARGS_6 ASM_ARGS_5, "r" (_a6) + +#endif /* __ASSEMBLER__ */ + + +/* Pointer mangling support. */ +#if defined NOT_IN_libc && defined IS_IN_rtld +/* We cannot use the thread descriptor because in ld.so we use setjmp + earlier than the descriptor is initialized. */ +# ifdef __ASSEMBLER__ +# define PTR_MANGLE(reg) xorq __pointer_chk_guard_local(%rip), reg +# define PTR_DEMANGLE(reg) PTR_MANGLE (reg) +# else +# define PTR_MANGLE(reg) asm ("xorq __pointer_chk_guard_local(%%rip), %0"\ + : "=r" (reg) : "0" (reg)) +# define PTR_DEMANGLE(reg) PTR_MANGLE (reg) +# endif +#else +# ifdef __ASSEMBLER__ +# define PTR_MANGLE(reg) xorq %fs:POINTER_GUARD, reg +# define PTR_DEMANGLE(reg) PTR_MANGLE (reg) +# else +# define PTR_MANGLE(var) asm ("xorq %%fs:%c2, %0" \ + : "=r" (var) \ + : "0" (var), \ + "i" (offsetof (tcbhead_t, \ + pointer_guard))) +# define PTR_DEMANGLE(var) PTR_MANGLE (var) +# endif +#endif + +#endif /* linux/x86_64/sysdep.h */ |