diff options
Diffstat (limited to 'libc')
| -rw-r--r-- | libc/sysdeps/linux/arm/sysdep.h | 285 |
1 files changed, 278 insertions, 7 deletions
diff --git a/libc/sysdeps/linux/arm/sysdep.h b/libc/sysdeps/linux/arm/sysdep.h index 3c7a182bb..0c39dfa31 100644 --- a/libc/sysdeps/linux/arm/sysdep.h +++ b/libc/sysdeps/linux/arm/sysdep.h @@ -17,8 +17,20 @@ 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 <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. */ @@ -50,7 +62,7 @@ mov pc, _reg #endif #else /* APCS-26 */ -#define LOADREGS(cond, base, reglist...)\ +#define LOADREGS(cond, base, reglist...) \ ldm##cond base,reglist^ #define RETINSTR(cond, reg) \ mov##cond##s pc, reg @@ -59,15 +71,15 @@ #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##: \ +#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) \ +#define END(name) \ ASM_SIZE_DIRECTIVE(name) /* If compiled for profiling, call `mcount' at the start of each function. */ @@ -87,5 +99,264 @@ #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 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 _sys_result = INTERNAL_SYSCALL (name, , nr, args); \ + if (__builtin_expect (INTERNAL_SYSCALL_ERROR_P (_sys_result, ), 0)) \ + { \ + __set_errno (INTERNAL_SYSCALL_ERRNO (_sys_result, )); \ + _sys_result = (unsigned int) -1; \ + } \ + (int) _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 _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"); \ + _sys_result = _a1; \ + } \ + (int) _sys_result; }) +#elif defined(__ARM_EABI__) +#define INTERNAL_SYSCALL_RAW(name, err, nr, args...) \ + ({unsigned int _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"); \ + _sys_result = _a1; \ + } \ + (int) _sys_result; }) +#else /* !defined(__ARM_EABI__) */ +#define INTERNAL_SYSCALL_RAW(name, err, nr, args...) \ + ({ unsigned int _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"); \ + _sys_result = _a1; \ + } \ + (int) _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__ */ +#endif /* linux/arm/sysdep.h */ |