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/* Copyright (C) 2001,02,03,04 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; \
xorq %rdx, %rdx; \
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;\
xorq %rdx, %rdx; \
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: \
xorq %rdx, %rdx; \
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; \
xorq %rdx, %rdx; \
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 \
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 = 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__ */
#endif /* linux/x86_64/sysdep.h */
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