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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)
- #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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