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/* Copyright (C) 1992, 93, 95-99, 2000 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper, <drepper@gnu.ai.mit.edu>, August 1995.
ARM changes by Philip Blundell, <pjb27@cam.ac.uk>, May 1997.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#ifndef _LINUX_ARM_SYSDEP_H
#define _LINUX_ARM_SYSDEP_H 1
/* There is some commonality. */
#include <sysdeps/unix/arm/sysdep.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 SWI_BASE (0x900000)
#define SYS_ify(syscall_name) (__NR_##syscall_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 R0
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. */
#undef PSEUDO
#define PSEUDO(name, syscall_name, args) \
.text; \
.type syscall_error,%function; \
ENTRY (name); \
DO_CALL (args, syscall_name); \
cmn r0, $4096;
#define PSEUDO_RET \
RETINSTR(movcc, pc, lr); \
b PLTJMP(__syscall_error)
#undef ret
#define ret PSEUDO_RET
#undef PSEUDO_END
#define PSEUDO_END(name) \
SYSCALL_ERROR_HANDLER \
END (name)
#define SYSCALL_ERROR_HANDLER /* Nothing here; code in sysdep.S is used. */
/* Linux takes system call args in registers:
syscall number in the SWI instruction
arg 1 r0
arg 2 r1
arg 3 r2
arg 4 r3
arg 5 r4 (this is different from the APCS convention)
arg 6 r5
arg 7 r6
The compiler is going to form a call by coming here, through PSEUDO, with
arguments
syscall number in the DO_CALL macro
arg 1 r0
arg 2 r1
arg 3 r2
arg 4 r3
arg 5 [sp]
arg 6 [sp+4]
arg 7 [sp+8]
We need to shuffle values between R4..R6 and the stack so that the
caller's v1..v3 and stack frame are not corrupted, and the kernel
sees the right arguments.
*/
#undef DO_CALL
#define DO_CALL(args, syscall_name) \
DOARGS_##args \
swi SYS_ify (syscall_name); \
UNDOARGS_##args
#define DOARGS_0 /* nothing */
#define DOARGS_1 /* nothing */
#define DOARGS_2 /* nothing */
#define DOARGS_3 /* nothing */
#define DOARGS_4 /* nothing */
#define DOARGS_5 str r4, [sp, $-4]!; ldr r4, [sp, $4];
#define DOARGS_6 mov ip, sp; stmfd sp!, {r4, r5}; ldmia ip, {r4, r5};
#define DOARGS_7 mov ip, sp; stmfd sp!, {r4, r5, r6}; ldmia ip, {r4, r5, r6};
#define UNDOARGS_0 /* nothing */
#define UNDOARGS_1 /* nothing */
#define UNDOARGS_2 /* nothing */
#define UNDOARGS_3 /* nothing */
#define UNDOARGS_4 /* nothing */
#define UNDOARGS_5 ldr r4, [sp], $4;
#define UNDOARGS_6 ldmfd sp!, {r4, r5};
#define UNDOARGS_7 ldmfd sp!, {r4, r5, r6};
#else /* not __ASSEMBLER__ */
/* Define a macro which expands into the inline wrapper code for a system
call. */
#undef INLINE_SYSCALL
#define INLINE_SYSCALL(name, nr, args...) \
({ unsigned int _sys_result; \
{ \
register int _a1 asm ("a1"); \
LOAD_ARGS_##nr (args) \
asm volatile ("swi %1 @ syscall " #name \
: "=r" (_a1) \
: "i" (SYS_ify(name)) ASM_ARGS_##nr \
: "a1", "memory"); \
_sys_result = _a1; \
} \
if (_sys_result >= (unsigned int) -4095) \
{ \
__set_errno (-_sys_result); \
_sys_result = (unsigned int) -1; \
} \
(int) _sys_result; })
#define LOAD_ARGS_0()
#define ASM_ARGS_0
#define LOAD_ARGS_1(a1) \
_a1 = (int) (a1); \
LOAD_ARGS_0 ()
#define ASM_ARGS_1 ASM_ARGS_0, "r" (_a1)
#define LOAD_ARGS_2(a1, a2) \
register int _a2 asm ("a2") = (int) (a2); \
LOAD_ARGS_1 (a1)
#define ASM_ARGS_2 ASM_ARGS_1, "r" (_a2)
#define LOAD_ARGS_3(a1, a2, a3) \
register int _a3 asm ("a3") = (int) (a3); \
LOAD_ARGS_2 (a1, a2)
#define ASM_ARGS_3 ASM_ARGS_2, "r" (_a3)
#define LOAD_ARGS_4(a1, a2, a3, a4) \
register int _a4 asm ("a4") = (int) (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 int _v1 asm ("v1") = (int) (a5); \
LOAD_ARGS_4 (a1, a2, a3, a4)
#define ASM_ARGS_5 ASM_ARGS_4, "r" (_v1)
#define LOAD_ARGS_6(a1, a2, a3, a4, a5, a6) \
register int _v2 asm ("v2") = (int) (a6); \
LOAD_ARGS_5 (a1, a2, a3, a4, a5)
#define ASM_ARGS_6 ASM_ARGS_5, "r" (_v2)
#define LOAD_ARGS_7(a1, a2, a3, a4, a5, a6, a7) \
register int _v3 asm ("v3") = (int) (a7); \
LOAD_ARGS_6 (a1, a2, a3, a4, a5, a6)
#define ASM_ARGS_7 ASM_ARGS_6, "r" (_v3)
#endif /* __ASSEMBLER__ */
#endif /* linux/arm/sysdep.h */
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