diff options
Diffstat (limited to 'ports/sysdeps/unix/sysv/linux/arm/sysdep.h')
| -rw-r--r-- | ports/sysdeps/unix/sysv/linux/arm/sysdep.h | 208 |
1 files changed, 146 insertions, 62 deletions
diff --git a/ports/sysdeps/unix/sysv/linux/arm/sysdep.h b/ports/sysdeps/unix/sysv/linux/arm/sysdep.h index 4d08ea9e4..be67c211d 100644 --- a/ports/sysdeps/unix/sysv/linux/arm/sysdep.h +++ b/ports/sysdeps/unix/sysv/linux/arm/sysdep.h @@ -1,5 +1,4 @@ -/* Copyright (C) 1992, 93, 1995-2000, 2002, 2003, 2005, 2006, 2009 - Free Software Foundation, Inc. +/* Copyright (C) 1992-2012 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. @@ -29,6 +28,16 @@ #include <tls.h> +#if __NR_SYSCALL_BASE != 0 +# error Kernel headers are too old +#endif + +/* Don't use stime, even if the kernel headers define it. We have + settimeofday, and some EABI kernels have removed stime. Similarly + use setitimer to implement alarm. */ +#undef __NR_stime +#undef __NR_alarm + /* In order to get __set_errno() definition in INLINE_SYSCALL. */ #ifndef __ASSEMBLER__ #include <errno.h> @@ -163,8 +172,14 @@ __local_syscall_error: \ # define SYSCALL_ERROR __syscall_error #endif +/* The ARM EABI user interface passes the syscall number in r7, instead + of in the swi. This is more efficient, because the kernel does not need + to fetch the swi from memory to find out the number; which can be painful + with separate I-cache and D-cache. Make sure to use 0 for the SWI + argument; otherwise the (optional) compatibility code for APCS binaries + may be invoked. */ + /* Linux takes system call args in registers: - syscall number in the SWI instruction arg 1 r0 arg 2 r1 arg 3 r2 @@ -190,58 +205,111 @@ __local_syscall_error: \ */ +/* We must save and restore r7 (call-saved) for the syscall number. + We never make function calls from inside here (only potentially + signal handlers), so we do not bother with doubleword alignment. + + Just like the APCS syscall convention, the EABI syscall convention uses + r0 through r6 for up to seven syscall arguments. None are ever passed to + the kernel on the stack, although incoming arguments are on the stack for + syscalls with five or more arguments. + + The assembler will convert the literal pool load to a move for most + syscalls. */ + #undef DO_CALL #define DO_CALL(syscall_name, args) \ DOARGS_##args; \ - swi SYS_ify (syscall_name); \ + ldr r7, =SYS_ify (syscall_name); \ + swi 0x0; \ 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]!; \ +#undef DOARGS_0 +#define DOARGS_0 \ + .fnstart; \ + str r7, [sp, #-4]!; \ cfi_adjust_cfa_offset (4); \ + cfi_rel_offset (r7, 0); \ + .save { r7 } +#undef DOARGS_1 +#define DOARGS_1 DOARGS_0 +#undef DOARGS_2 +#define DOARGS_2 DOARGS_0 +#undef DOARGS_3 +#define DOARGS_3 DOARGS_0 +#undef DOARGS_4 +#define DOARGS_4 DOARGS_0 +#undef DOARGS_5 +#define DOARGS_5 \ + .fnstart; \ + stmfd sp!, {r4, r7}; \ + cfi_adjust_cfa_offset (8); \ cfi_rel_offset (r4, 0); \ - ldr r4, [sp, $4] + cfi_rel_offset (r7, 4); \ + .save { r4, r7 }; \ + ldr r4, [sp, #8] +#undef DOARGS_6 #define DOARGS_6 \ + .fnstart; \ mov ip, sp; \ - stmfd sp!, {r4, r5}; \ - cfi_adjust_cfa_offset (8); \ + stmfd sp!, {r4, r5, r7}; \ + cfi_adjust_cfa_offset (12); \ cfi_rel_offset (r4, 0); \ cfi_rel_offset (r5, 4); \ + cfi_rel_offset (r7, 8); \ + .save { r4, r5, r7 }; \ ldmia ip, {r4, r5} +#undef DOARGS_7 #define DOARGS_7 \ + .fnstart; \ mov ip, sp; \ - stmfd sp!, {r4, r5, r6}; \ - cfi_adjust_cfa_offset (12); \ + stmfd sp!, {r4, r5, r6, r7}; \ + cfi_adjust_cfa_offset (16); \ cfi_rel_offset (r4, 0); \ cfi_rel_offset (r5, 4); \ cfi_rel_offset (r6, 8); \ + cfi_rel_offset (r7, 12); \ + .save { r4, r5, r6, r7 }; \ 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; \ +#undef UNDOARGS_0 +#define UNDOARGS_0 \ + ldr r7, [sp], #4; \ cfi_adjust_cfa_offset (-4); \ - cfi_restore (r4) -#define UNDOARGS_6 \ - ldmfd sp!, {r4, r5}; \ + cfi_restore (r7); \ + .fnend +#undef UNDOARGS_1 +#define UNDOARGS_1 UNDOARGS_0 +#undef UNDOARGS_2 +#define UNDOARGS_2 UNDOARGS_0 +#undef UNDOARGS_3 +#define UNDOARGS_3 UNDOARGS_0 +#undef UNDOARGS_4 +#define UNDOARGS_4 UNDOARGS_0 +#undef UNDOARGS_5 +#define UNDOARGS_5 \ + ldmfd sp!, {r4, r7}; \ cfi_adjust_cfa_offset (-8); \ cfi_restore (r4); \ - cfi_restore (r5) -#define UNDOARGS_7 \ - ldmfd sp!, {r4, r5, r6}; \ + cfi_restore (r7); \ + .fnend +#undef UNDOARGS_6 +#define UNDOARGS_6 \ + ldmfd sp!, {r4, r5, r7}; \ cfi_adjust_cfa_offset (-12); \ cfi_restore (r4); \ cfi_restore (r5); \ - cfi_restore (r6) + cfi_restore (r7); \ + .fnend +#undef UNDOARGS_7 +#define UNDOARGS_7 \ + ldmfd sp!, {r4, r5, r6, r7}; \ + cfi_adjust_cfa_offset (-16); \ + cfi_restore (r4); \ + cfi_restore (r5); \ + cfi_restore (r6); \ + cfi_restore (r7); \ + .fnend #else /* not __ASSEMBLER__ */ @@ -260,19 +328,46 @@ __local_syscall_error: \ #undef INTERNAL_SYSCALL_DECL #define INTERNAL_SYSCALL_DECL(err) do { } while (0) -#undef INTERNAL_SYSCALL_RAW -#define INTERNAL_SYSCALL_RAW(name, err, nr, args...) \ - ({ unsigned int _sys_result; \ - { \ - register int _a1 asm ("a1"); \ +#if defined(__thumb__) +/* We can not expose the use of r7 to the compiler. GCC (as + of 4.5) uses r7 as the hard frame pointer for Thumb - although + for Thumb-2 it isn't obviously a better choice than r11. + And GCC does not support asms that conflict with the frame + pointer. + + This would be easier if syscall numbers never exceeded 255, + but they do. For the moment the LOAD_ARGS_7 is sacrificed. + We can't use push/pop inside the asm because that breaks + unwinding (i.e. thread cancellation) for this frame. We can't + locally save and restore r7, because we do not know if this + function uses r7 or if it is our caller's r7; if it is our caller's, + then unwinding will fail higher up the stack. So we move the + syscall out of line and provide its own unwind information. */ +# undef INTERNAL_SYSCALL_RAW +# define INTERNAL_SYSCALL_RAW(name, err, nr, args...) \ + ({ \ + register int _a1 asm ("a1"); \ + int _nametmp = name; \ + LOAD_ARGS_##nr (args) \ + register int _name asm ("ip") = _nametmp; \ + asm volatile ("bl __libc_do_syscall" \ + : "=r" (_a1) \ + : "r" (_name) ASM_ARGS_##nr \ + : "memory", "lr"); \ + _a1; }) +#else /* ARM */ +# undef INTERNAL_SYSCALL_RAW +# define INTERNAL_SYSCALL_RAW(name, err, nr, args...) \ + ({ \ + register int _a1 asm ("r0"), _nr asm ("r7"); \ LOAD_ARGS_##nr (args) \ - asm volatile ("swi %1 @ syscall " #name \ + _nr = name; \ + asm volatile ("swi 0x0 @ syscall " #name \ : "=r" (_a1) \ - : "i" (name) ASM_ARGS_##nr \ + : "r" (_nr) ASM_ARGS_##nr \ : "memory"); \ - _sys_result = _a1; \ - } \ - (int) _sys_result; }) + _a1; }) +#endif #undef INTERNAL_SYSCALL #define INTERNAL_SYSCALL(name, err, nr, args...) \ @@ -321,29 +416,18 @@ __local_syscall_error: \ LOAD_ARGS_5 (a1, a2, a3, a4, a5) \ register int _v2 asm ("v2") = _v2tmp; #define ASM_ARGS_6 ASM_ARGS_5, "r" (_v2) -#define LOAD_ARGS_7(a1, a2, a3, a4, a5, a6, a7) \ - int _v3tmp = (int) (a7); \ - LOAD_ARGS_6 (a1, a2, a3, a4, a5, a6) \ +#ifndef __thumb__ +# define LOAD_ARGS_7(a1, a2, a3, a4, a5, a6, a7) \ + int _v3tmp = (int) (a7); \ + LOAD_ARGS_6 (a1, a2, a3, a4, a5, a6) \ register int _v3 asm ("v3") = _v3tmp; -#define ASM_ARGS_7 ASM_ARGS_6, "r" (_v3) - -/* We can't implement non-constant syscalls directly since the syscall - number is normally encoded in the instruction. So use SYS_syscall. */ -#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) +# define ASM_ARGS_7 ASM_ARGS_6, "r" (_v3) +#endif + +/* For EABI, non-constant syscalls are actually pretty easy... */ +#undef INTERNAL_SYSCALL_NCS +#define INTERNAL_SYSCALL_NCS(number, err, nr, args...) \ + INTERNAL_SYSCALL_RAW (number, err, nr, args) #endif /* __ASSEMBLER__ */ |