/* 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, 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 #include <common/sysdep.h> #include <bits/arm_asm.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 #ifdef __USE_BX__ #define RETINSTR(cond, reg) \ bx##cond reg #define DO_RET(_reg) \ bx _reg #else #define RETINSTR(cond, reg) \ mov##cond pc, reg #define DO_RET(_reg) \ mov pc, _reg #endif #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) \ ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME(name); \ ASM_TYPE_DIRECTIVE (C_SYMBOL_NAME(name),function) \ .align ALIGNARG(4); \ name##: \ CALL_MCOUNT #undef END #define END(name) \ ASM_SIZE_DIRECTIVE(name) /* If compiled for profiling, call `mcount' at the start of each function. */ #ifdef PROF #define CALL_MCOUNT \ str lr,[sp, #-4]! ; \ bl PLTJMP(mcount) ; \ ldr lr, [sp], #4 ; #else #define CALL_MCOUNT /* Do nothing. */ #endif #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) #define ret_ERRVAL PSEUDO_RET_NOERRNO #if defined NOT_IN_libc # define SYSCALL_ERROR __local_syscall_error # ifdef RTLD_PRIVATE_ERRNO # define SYSCALL_ERROR_HANDLER \ __local_syscall_error: \ ldr r1, 1f; \ rsb r0, r0, #0; \ 0: str r0, [pc, r1]; \ mvn r0, #0; \ DO_RET(lr); \ 1: .word C_SYMBOL_NAME(rtld_errno) - 0b - 8; # else # 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; # endif #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. */ #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}; #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 _inline_sys_result = INTERNAL_SYSCALL (name, , nr, args); \ if (__builtin_expect (INTERNAL_SYSCALL_ERROR_P (_inline_sys_result, ), 0)) \ { \ __set_errno (INTERNAL_SYSCALL_ERRNO (_inline_sys_result, )); \ _inline_sys_result = (unsigned int) -1; \ } \ (int) _inline_sys_result; }) #undef INTERNAL_SYSCALL_DECL #define INTERNAL_SYSCALL_DECL(err) do { } while (0) #undef INTERNAL_SYSCALL_RAW #if defined(__thumb__) /* Hide the use of r7 from the compiler, this would be a lot * easier but for the fact that the syscalls can exceed 255. * For the moment the LOAD_ARG_7 is sacrificed. * We can't use push/pop inside the asm because that breaks * unwinding (ie. thread cancellation). */ #define INTERNAL_SYSCALL_RAW(name, err, nr, args...) \ ({ unsigned int _internal_sys_result; \ { \ int _sys_buf[2]; \ register int __a1 __asm__ ("a1"); \ register int *_v3 __asm__ ("v3") = _sys_buf; \ LOAD_ARGS_##nr (args) \ *_v3 = (int) (name); \ __asm__ __volatile__ ("str r7, [v3, #4]\n" \ "\tldr r7, [v3]\n" \ "\tswi 0 @ syscall " #name "\n" \ "\tldr r7, [v3, #4]" \ : "=r" (__a1) \ : "r" (_v3) ASM_ARGS_##nr \ : "memory"); \ _internal_sys_result = __a1; \ } \ (int) _internal_sys_result; }) #elif defined(__ARM_EABI__) #define INTERNAL_SYSCALL_RAW(name, err, nr, args...) \ ({unsigned int _internal_sys_result; \ { \ register int __a1 __asm__ ("r0"), _nr __asm__ ("r7"); \ LOAD_ARGS_##nr (args) \ _nr = name; \ __asm__ __volatile__ ("swi 0x0 @ syscall " #name \ : "=r" (__a1) \ : "r" (_nr) ASM_ARGS_##nr \ : "memory"); \ _internal_sys_result = __a1; \ } \ (int) _internal_sys_result; }) #else /* !defined(__ARM_EABI__) */ #define INTERNAL_SYSCALL_RAW(name, err, nr, args...) \ ({ unsigned int _internal_sys_result; \ { \ register int __a1 __asm__ ("a1"); \ LOAD_ARGS_##nr (args) \ __asm__ __volatile__ ("swi %1 @ syscall " #name \ : "=r" (__a1) \ : "i" (name) ASM_ARGS_##nr \ : "memory"); \ _internal_sys_result = __a1; \ } \ (int) _internal_sys_result; }) #endif #undef INTERNAL_SYSCALL #define INTERNAL_SYSCALL(name, err, nr, args...) \ INTERNAL_SYSCALL_RAW(SYS_ify(name), err, nr, args) #undef INTERNAL_SYSCALL_ARM #define INTERNAL_SYSCALL_ARM(name, err, nr, args...) \ INTERNAL_SYSCALL_RAW(__ARM_NR_##name, err, nr, args) #undef INTERNAL_SYSCALL_ERROR_P #define INTERNAL_SYSCALL_ERROR_P(val, err) \ ((unsigned int) (val) >= 0xfffff001u) #undef INTERNAL_SYSCALL_ERRNO #define INTERNAL_SYSCALL_ERRNO(val, err) (-(val)) #if defined(__ARM_EABI__) #undef INTERNAL_SYSCALL_NCS #define INTERNAL_SYSCALL_NCS(number, err, nr, args...) \ INTERNAL_SYSCALL_RAW(number, err, nr, args) #else /* We can't implement non-constant syscalls directly since the syscall number is normally encoded in the instruction. So use SYS_syscall. */ #undef INTERNAL_SYSCALL_NCS #define INTERNAL_SYSCALL_NCS(number, err, nr, args...) \ INTERNAL_SYSCALL_NCS_##nr (number, err, args) #define INTERNAL_SYSCALL_NCS_0(number, err, args...) \ INTERNAL_SYSCALL (syscall, err, 1, number, args) #define INTERNAL_SYSCALL_NCS_1(number, err, args...) \ INTERNAL_SYSCALL (syscall, err, 2, number, args) #define INTERNAL_SYSCALL_NCS_2(number, err, args...) \ INTERNAL_SYSCALL (syscall, err, 3, number, args) #define INTERNAL_SYSCALL_NCS_3(number, err, args...) \ INTERNAL_SYSCALL (syscall, err, 4, number, args) #define INTERNAL_SYSCALL_NCS_4(number, err, args...) \ INTERNAL_SYSCALL (syscall, err, 5, number, args) #define INTERNAL_SYSCALL_NCS_5(number, err, args...) \ INTERNAL_SYSCALL (syscall, err, 6, number, args) #endif #endif /* __ASSEMBLER__ */ /* Pointer mangling is not yet supported for ARM. */ #define PTR_MANGLE(var) (void) (var) #define PTR_DEMANGLE(var) (void) (var) #endif /* linux/arm/sysdep.h */