diff options
Diffstat (limited to 'sysdeps/unix/sysv/linux/arm/sysdep.h')
| -rw-r--r-- | sysdeps/unix/sysv/linux/arm/sysdep.h | 482 |
1 files changed, 482 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/arm/sysdep.h b/sysdeps/unix/sysv/linux/arm/sysdep.h new file mode 100644 index 0000000000..dcd99198cc --- /dev/null +++ b/sysdeps/unix/sysv/linux/arm/sysdep.h @@ -0,0 +1,482 @@ +/* Copyright (C) 1992-2014 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. + + 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 + +/* There is some commonality. */ +#include <sysdeps/unix/arm/sysdep.h> + +/* Defines RTLD_PRIVATE_ERRNO and USE_DL_SYSINFO. */ +#include <dl-sysdep.h> + +#include <tls.h> + +/* In order to get __set_errno() definition in INLINE_SYSCALL. */ +#ifndef __ASSEMBLER__ +#include <errno.h> +#endif + +/* 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 SYS_ify(syscall_name) (__NR_##syscall_name) + +#define _SYS_AUXV_H 1 +#include <bits/hwcap.h> + +#ifdef __ASSEMBLER__ + +#ifndef ARCH_HAS_HARD_TP +/* Internal macro calling the linux kernel kuser_get_tls helper. + Note that in thumb mode, a constant pool break is often out of range, so + we always expand the constant inline. */ +# ifdef __thumb2__ +# define GET_TLS_BODY \ + movw r0, #0x0fe0; \ + movt r0, #0xffff; \ + blx r0 +# else +# define GET_TLS_BODY \ + mov r0, #0xffff0fff; /* Point to the high page. */ \ + mov lr, pc; /* Save our return address. */ \ + sub pc, r0, #31 /* Jump to the TLS entry. */ +# endif + +/* Helper to get the TLS base pointer. Save LR in TMP, return in R0, + and no other registers clobbered. TMP may be LR itself to indicate + that no save is necessary. */ +# undef GET_TLS +# define GET_TLS(TMP) \ + .ifnc TMP, lr; \ + mov TMP, lr; \ + cfi_register (lr, TMP); \ + GET_TLS_BODY; \ + mov lr, TMP; \ + cfi_restore (lr); \ + .else; \ + GET_TLS_BODY; \ + .endif +#endif /* ARCH_HAS_HARD_TP */ + +/* 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 \ + it cc; \ + 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 +# if RTLD_PRIVATE_ERRNO +# define SYSCALL_ERROR_HANDLER \ +__local_syscall_error: \ + rsb r0, r0, #0; \ + LDST_PCREL(str, r0, r1, C_SYMBOL_NAME(rtld_errno)); \ + mvn r0, #0; \ + DO_RET(lr) +# else +# if defined(__ARM_ARCH_4T__) && defined(__THUMB_INTERWORK__) +# define POP_PC \ + pop { lr }; \ + cfi_adjust_cfa_offset (-4); \ + cfi_restore (lr); \ + bx lr +# else +# define POP_PC pop { pc } +# endif +# define SYSCALL_ERROR_HANDLER \ +__local_syscall_error: \ + push { lr }; \ + cfi_adjust_cfa_offset (4); \ + cfi_rel_offset (lr, 0); \ + push { r0 }; \ + cfi_adjust_cfa_offset (4); \ + bl PLTJMP(C_SYMBOL_NAME(__errno_location)); \ + pop { r1 }; \ + cfi_adjust_cfa_offset (-4); \ + rsb r1, r1, #0; \ + str r1, [r0]; \ + mvn r0, #0; \ + POP_PC; +# endif +#else +# define SYSCALL_ERROR_HANDLER /* Nothing here; code in sysdep.S is used. */ +# 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: + 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. + +*/ + +/* 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; \ + ldr r7, =SYS_ify (syscall_name); \ + swi 0x0; \ + UNDOARGS_##args + +#undef DOARGS_0 +#define DOARGS_0 \ + .fnstart; \ + push { r7 }; \ + 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; \ + push {r4, r7}; \ + cfi_adjust_cfa_offset (8); \ + cfi_rel_offset (r4, 0); \ + cfi_rel_offset (r7, 4); \ + .save { r4, r7 }; \ + ldr r4, [sp, #8] +#undef DOARGS_6 +#define DOARGS_6 \ + .fnstart; \ + mov ip, sp; \ + push {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; \ + push {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} + +#undef UNDOARGS_0 +#define UNDOARGS_0 \ + pop {r7}; \ + cfi_adjust_cfa_offset (-4); \ + 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 \ + pop {r4, r7}; \ + cfi_adjust_cfa_offset (-8); \ + cfi_restore (r4); \ + cfi_restore (r7); \ + .fnend +#undef UNDOARGS_6 +#define UNDOARGS_6 \ + pop {r4, r5, r7}; \ + cfi_adjust_cfa_offset (-12); \ + cfi_restore (r4); \ + cfi_restore (r5); \ + cfi_restore (r7); \ + .fnend +#undef UNDOARGS_7 +#define UNDOARGS_7 \ + pop {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__ */ + +/* 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) + +#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) \ + _nr = name; \ + asm volatile ("swi 0x0 @ syscall " #name \ + : "=r" (_a1) \ + : "r" (_nr) ASM_ARGS_##nr \ + : "memory"); \ + _a1; }) +#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)) + +#define LOAD_ARGS_0() +#define ASM_ARGS_0 +#define LOAD_ARGS_1(a1) \ + int _a1tmp = (int) (a1); \ + LOAD_ARGS_0 () \ + _a1 = _a1tmp; +#define ASM_ARGS_1 ASM_ARGS_0, "r" (_a1) +#define LOAD_ARGS_2(a1, a2) \ + int _a2tmp = (int) (a2); \ + LOAD_ARGS_1 (a1) \ + register int _a2 asm ("a2") = _a2tmp; +#define ASM_ARGS_2 ASM_ARGS_1, "r" (_a2) +#define LOAD_ARGS_3(a1, a2, a3) \ + int _a3tmp = (int) (a3); \ + LOAD_ARGS_2 (a1, a2) \ + register int _a3 asm ("a3") = _a3tmp; +#define ASM_ARGS_3 ASM_ARGS_2, "r" (_a3) +#define LOAD_ARGS_4(a1, a2, a3, a4) \ + int _a4tmp = (int) (a4); \ + LOAD_ARGS_3 (a1, a2, a3) \ + register int _a4 asm ("a4") = _a4tmp; +#define ASM_ARGS_4 ASM_ARGS_3, "r" (_a4) +#define LOAD_ARGS_5(a1, a2, a3, a4, a5) \ + int _v1tmp = (int) (a5); \ + LOAD_ARGS_4 (a1, a2, a3, a4) \ + register int _v1 asm ("v1") = _v1tmp; +#define ASM_ARGS_5 ASM_ARGS_4, "r" (_v1) +#define LOAD_ARGS_6(a1, a2, a3, a4, a5, a6) \ + int _v2tmp = (int) (a6); \ + LOAD_ARGS_5 (a1, a2, a3, a4, a5) \ + register int _v2 asm ("v2") = _v2tmp; +#define ASM_ARGS_6 ASM_ARGS_5, "r" (_v2) +#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) +#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__ */ + +/* Pointer mangling support. */ +#if (defined NOT_IN_libc && defined IS_IN_rtld) || \ + (!defined SHARED && (!defined NOT_IN_libc || defined IS_IN_libpthread)) +# ifdef __ASSEMBLER__ +# define PTR_MANGLE_LOAD(guard, tmp) \ + LDST_PCREL(ldr, guard, tmp, C_SYMBOL_NAME(__pointer_chk_guard_local)); +# define PTR_MANGLE(dst, src, guard, tmp) \ + PTR_MANGLE_LOAD(guard, tmp); \ + PTR_MANGLE2(dst, src, guard) +/* Use PTR_MANGLE2 for efficiency if guard is already loaded. */ +# define PTR_MANGLE2(dst, src, guard) \ + eor dst, src, guard +# define PTR_DEMANGLE(dst, src, guard, tmp) \ + PTR_MANGLE (dst, src, guard, tmp) +# define PTR_DEMANGLE2(dst, src, guard) \ + PTR_MANGLE2 (dst, src, guard) +# else +extern uintptr_t __pointer_chk_guard_local attribute_relro attribute_hidden; +# define PTR_MANGLE(var) \ + (var) = (__typeof (var)) ((uintptr_t) (var) ^ __pointer_chk_guard_local) +# define PTR_DEMANGLE(var) PTR_MANGLE (var) +# endif +#else +# ifdef __ASSEMBLER__ +# define PTR_MANGLE_LOAD(guard, tmp) \ + LDST_GLOBAL(ldr, guard, tmp, C_SYMBOL_NAME(__pointer_chk_guard)); +# define PTR_MANGLE(dst, src, guard, tmp) \ + PTR_MANGLE_LOAD(guard, tmp); \ + PTR_MANGLE2(dst, src, guard) +/* Use PTR_MANGLE2 for efficiency if guard is already loaded. */ +# define PTR_MANGLE2(dst, src, guard) \ + eor dst, src, guard +# define PTR_DEMANGLE(dst, src, guard, tmp) \ + PTR_MANGLE (dst, src, guard, tmp) +# define PTR_DEMANGLE2(dst, src, guard) \ + PTR_MANGLE2 (dst, src, guard) +# else +extern uintptr_t __pointer_chk_guard attribute_relro; +# define PTR_MANGLE(var) \ + (var) = (__typeof (var)) ((uintptr_t) (var) ^ __pointer_chk_guard) +# define PTR_DEMANGLE(var) PTR_MANGLE (var) +# endif +#endif + +#endif /* linux/arm/sysdep.h */ |