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/* Assembler macros for ARM.
Copyright (C) 1997, 1998, 2003 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, see
<http://www.gnu.org/licenses/>. */
#ifndef _LINUX_ARM_SYSDEP_H
#define _LINUX_ARM_SYSDEP_H 1
#include <common/sysdep.h>
#include <bits/arm_bx.h>
#include <sys/syscall.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__
/* Syntactic details of assembler. */
#define ALIGNARG(log2) log2
/* For ELF we need the `.type' directive to make shared libs work right. */
#define ASM_TYPE_DIRECTIVE(name,typearg) .type name,%##typearg;
#define ASM_SIZE_DIRECTIVE(name) .size name,.-name
/* In ELF C symbols are asm symbols. */
#undef NO_UNDERSCORES
#define NO_UNDERSCORES
#define PLTJMP(_x) _x##(PLT)
/* APCS-32 doesn't preserve the condition codes across function call. */
#ifdef __APCS_32__
#define LOADREGS(cond, base, reglist...)\
ldm##cond base,reglist
#define RETINSTR(cond, reg) \
BXC(cond, reg)
#define DO_RET(_reg) \
BX(_reg)
#else /* APCS-26 */
#define LOADREGS(cond, base, reglist...) \
ldm##cond base,reglist^
#define RETINSTR(cond, reg) \
mov##cond##s pc, reg
#define DO_RET(_reg) \
movs pc, _reg
#endif
/* Define an entry point visible from C. */
#define ENTRY(name) \
.globl C_SYMBOL_NAME(name); \
ASM_TYPE_DIRECTIVE (C_SYMBOL_NAME(name),function) \
.align ALIGNARG(4); \
name##:
#undef END
#define END(name) \
ASM_SIZE_DIRECTIVE(name)
#ifdef NO_UNDERSCORES
/* Since C identifiers are not normally prefixed with an underscore
on this system, the asm identifier `syscall_error' intrudes on the
C name space. Make sure we use an innocuous name. */
#define syscall_error __syscall_error
#define mcount _mcount
#endif
/* 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 safely
test with -4095. */
#undef PSEUDO
#define PSEUDO(name, syscall_name, args) \
.text; \
ENTRY (name); \
DO_CALL (syscall_name, args); \
cmn r0, $4096;
#define PSEUDO_RET \
RETINSTR(cc, lr); \
b PLTJMP(SYSCALL_ERROR)
#undef ret
#define ret PSEUDO_RET
#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);
#define PSEUDO_RET_NOERRNO \
DO_RET (lr);
#undef ret_NOERRNO
#define ret_NOERRNO PSEUDO_RET_NOERRNO
#undef PSEUDO_END_NOERRNO
#define PSEUDO_END_NOERRNO(name) \
END (name)
/* The function has to return the error code. */
#undef PSEUDO_ERRVAL
#define PSEUDO_ERRVAL(name, syscall_name, args) \
.text; \
ENTRY (name) \
DO_CALL (syscall_name, args); \
rsb r0, r0, #0
#undef PSEUDO_END_ERRVAL
#define PSEUDO_END_ERRVAL(name) \
END (name)
#undef ret_ERRVAL
#define ret_ERRVAL PSEUDO_RET_NOERRNO
#if defined NOT_IN_libc
# define SYSCALL_ERROR __local_syscall_error
# define SYSCALL_ERROR_HANDLER \
__local_syscall_error: \
str lr, [sp, #-4]!; \
str r0, [sp, #-4]!; \
bl PLTJMP(C_SYMBOL_NAME(__errno_location)); \
ldr r1, [sp], #4; \
rsb r1, r1, #0; \
str r1, [r0]; \
mvn r0, #0; \
ldr pc, [sp], #4;
#else
# define SYSCALL_ERROR_HANDLER /* Nothing here; code in sysdep.S is used. */
# define SYSCALL_ERROR __syscall_error
#endif
/* 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.
*/
#if __ARM_ARCH > 6 || defined (__ARM_ARCH_6K__) || defined (__ARM_ARCH_6ZK__)
# define ARCH_HAS_HARD_TP
#endif
# ifdef __thumb2__
# define NEGOFF_ADJ_BASE(R, OFF) add R, R, $OFF
# define NEGOFF_ADJ_BASE2(D, S, OFF) add D, S, $OFF
# define NEGOFF_OFF1(R, OFF) [R]
# define NEGOFF_OFF2(R, OFFA, OFFB) [R, $((OFFA) - (OFFB))]
# else
# define NEGOFF_ADJ_BASE(R, OFF)
# define NEGOFF_ADJ_BASE2(D, S, OFF) mov D, S
# define NEGOFF_OFF1(R, OFF) [R, $OFF]
# define NEGOFF_OFF2(R, OFFA, OFFB) [R, $OFFA]
# endif
# ifdef ARCH_HAS_HARD_TP
/* If the cpu has cp15 available, use it. */
# define GET_TLS(TMP) mrc p15, 0, r0, c13, c0, 3
# else
/* At this generic level we have no tricks to pull. Call the ABI routine. */
# define GET_TLS(TMP) \
push { r1, r2, r3, lr }; \
cfi_remember_state; \
cfi_adjust_cfa_offset (16); \
cfi_rel_offset (r1, 0); \
cfi_rel_offset (r2, 4); \
cfi_rel_offset (r3, 8); \
cfi_rel_offset (lr, 12); \
bl __aeabi_read_tp; \
pop { r1, r2, r3, lr }; \
cfi_restore_state
# endif /* ARCH_HAS_HARD_TP */
#undef DO_CALL
#if defined(__ARM_EABI__)
#define DO_CALL(syscall_name, args) \
DOARGS_##args \
mov ip, r7; \
ldr r7, =SYS_ify (syscall_name); \
swi 0x0; \
mov r7, ip; \
UNDOARGS_##args
#else
#define DO_CALL(syscall_name, args) \
DOARGS_##args \
swi SYS_ify (syscall_name); \
UNDOARGS_##args
#endif
#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};
#endif /* __ASSEMBLER__ */
#endif /* linux/arm/sysdep.h */
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