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2f10c4d690
The frame pointer register is rarely used for that purpose on ARM and applications that look at the contents of the jmp_buf may be relying on reading an unencrypted value. For example, Ruby uses the contents of jmp_buf to find the root set for garbage collection so relies on this pointer value being unencrypted. Without this patch the Ruby testsuite fails with a segmentation fault. ports/ChangeLog.arm: 2013-01-14 Will Newton <will.newton@linaro.org> * sysdeps/arm/__longjmp.S: Don't apply pointer encryption to fp register. * sysdeps/arm/setjmp.S: Likewise. * sysdeps/arm/include/bits/setjmp.h (JMP_BUF_REGLIST): Add fp to register list, remove a4. * sysdeps/unix/sysv/linux/arm/sysdep.h (PTR_MANGLE_LOAD): New macro.
483 lines
14 KiB
C
483 lines
14 KiB
C
/* Copyright (C) 1992-2014 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Ulrich Drepper, <drepper@gnu.ai.mit.edu>, August 1995.
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ARM changes by Philip Blundell, <pjb27@cam.ac.uk>, May 1997.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library. If not, see
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<http://www.gnu.org/licenses/>. */
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#ifndef _LINUX_ARM_SYSDEP_H
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#define _LINUX_ARM_SYSDEP_H 1
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/* There is some commonality. */
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#include <sysdeps/unix/arm/sysdep.h>
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/* Defines RTLD_PRIVATE_ERRNO and USE_DL_SYSINFO. */
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#include <dl-sysdep.h>
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#include <tls.h>
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/* In order to get __set_errno() definition in INLINE_SYSCALL. */
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#ifndef __ASSEMBLER__
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#include <errno.h>
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#endif
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/* For Linux we can use the system call table in the header file
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/usr/include/asm/unistd.h
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of the kernel. But these symbols do not follow the SYS_* syntax
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so we have to redefine the `SYS_ify' macro here. */
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#undef SYS_ify
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#define SYS_ify(syscall_name) (__NR_##syscall_name)
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#define _SYS_AUXV_H 1
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#include <bits/hwcap.h>
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#ifdef __ASSEMBLER__
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#ifndef ARCH_HAS_HARD_TP
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/* Internal macro calling the linux kernel kuser_get_tls helper.
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Note that in thumb mode, a constant pool break is often out of range, so
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we always expand the constant inline. */
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# ifdef __thumb2__
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# define GET_TLS_BODY \
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movw r0, #0x0fe0; \
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movt r0, #0xffff; \
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blx r0
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# else
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# define GET_TLS_BODY \
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mov r0, #0xffff0fff; /* Point to the high page. */ \
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mov lr, pc; /* Save our return address. */ \
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sub pc, r0, #31 /* Jump to the TLS entry. */
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# endif
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/* Helper to get the TLS base pointer. Save LR in TMP, return in R0,
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and no other registers clobbered. TMP may be LR itself to indicate
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that no save is necessary. */
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# undef GET_TLS
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# define GET_TLS(TMP) \
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.ifnc TMP, lr; \
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mov TMP, lr; \
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cfi_register (lr, TMP); \
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GET_TLS_BODY; \
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mov lr, TMP; \
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cfi_restore (lr); \
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.else; \
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GET_TLS_BODY; \
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.endif
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#endif /* ARCH_HAS_HARD_TP */
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/* Linux uses a negative return value to indicate syscall errors,
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unlike most Unices, which use the condition codes' carry flag.
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Since version 2.1 the return value of a system call might be
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negative even if the call succeeded. E.g., the `lseek' system call
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might return a large offset. Therefore we must not anymore test
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for < 0, but test for a real error by making sure the value in R0
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is a real error number. Linus said he will make sure the no syscall
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returns a value in -1 .. -4095 as a valid result so we can safely
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test with -4095. */
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#undef PSEUDO
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#define PSEUDO(name, syscall_name, args) \
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.text; \
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ENTRY (name); \
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DO_CALL (syscall_name, args); \
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cmn r0, $4096;
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#define PSEUDO_RET \
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it cc; \
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RETINSTR(cc, lr); \
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b PLTJMP(SYSCALL_ERROR)
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#undef ret
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#define ret PSEUDO_RET
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#undef PSEUDO_END
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#define PSEUDO_END(name) \
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SYSCALL_ERROR_HANDLER; \
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END (name)
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#undef PSEUDO_NOERRNO
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#define PSEUDO_NOERRNO(name, syscall_name, args) \
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.text; \
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ENTRY (name); \
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DO_CALL (syscall_name, args);
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#define PSEUDO_RET_NOERRNO \
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DO_RET (lr);
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#undef ret_NOERRNO
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#define ret_NOERRNO PSEUDO_RET_NOERRNO
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#undef PSEUDO_END_NOERRNO
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#define PSEUDO_END_NOERRNO(name) \
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END (name)
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/* The function has to return the error code. */
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#undef PSEUDO_ERRVAL
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#define PSEUDO_ERRVAL(name, syscall_name, args) \
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.text; \
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ENTRY (name) \
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DO_CALL (syscall_name, args); \
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rsb r0, r0, #0
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#undef PSEUDO_END_ERRVAL
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#define PSEUDO_END_ERRVAL(name) \
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END (name)
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#define ret_ERRVAL PSEUDO_RET_NOERRNO
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#if NOT_IN_libc
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# define SYSCALL_ERROR __local_syscall_error
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# if RTLD_PRIVATE_ERRNO
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# define SYSCALL_ERROR_HANDLER \
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__local_syscall_error: \
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rsb r0, r0, #0; \
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LDST_PCREL(str, r0, r1, C_SYMBOL_NAME(rtld_errno)); \
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mvn r0, #0; \
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DO_RET(lr)
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# else
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# if defined(__ARM_ARCH_4T__) && defined(__THUMB_INTERWORK__)
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# define POP_PC \
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pop { lr }; \
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cfi_adjust_cfa_offset (-4); \
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cfi_restore (lr); \
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bx lr
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# else
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# define POP_PC pop { pc }
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# endif
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# define SYSCALL_ERROR_HANDLER \
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__local_syscall_error: \
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push { lr }; \
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cfi_adjust_cfa_offset (4); \
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cfi_rel_offset (lr, 0); \
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push { r0 }; \
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cfi_adjust_cfa_offset (4); \
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bl PLTJMP(C_SYMBOL_NAME(__errno_location)); \
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pop { r1 }; \
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cfi_adjust_cfa_offset (-4); \
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rsb r1, r1, #0; \
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str r1, [r0]; \
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mvn r0, #0; \
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POP_PC;
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# endif
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#else
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# define SYSCALL_ERROR_HANDLER /* Nothing here; code in sysdep.S is used. */
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# define SYSCALL_ERROR __syscall_error
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#endif
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/* The ARM EABI user interface passes the syscall number in r7, instead
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of in the swi. This is more efficient, because the kernel does not need
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to fetch the swi from memory to find out the number; which can be painful
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with separate I-cache and D-cache. Make sure to use 0 for the SWI
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argument; otherwise the (optional) compatibility code for APCS binaries
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may be invoked. */
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/* Linux takes system call args in registers:
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arg 1 r0
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arg 2 r1
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arg 3 r2
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arg 4 r3
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arg 5 r4 (this is different from the APCS convention)
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arg 6 r5
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arg 7 r6
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The compiler is going to form a call by coming here, through PSEUDO, with
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arguments
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syscall number in the DO_CALL macro
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arg 1 r0
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arg 2 r1
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arg 3 r2
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arg 4 r3
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arg 5 [sp]
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arg 6 [sp+4]
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arg 7 [sp+8]
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We need to shuffle values between R4..R6 and the stack so that the
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caller's v1..v3 and stack frame are not corrupted, and the kernel
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sees the right arguments.
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*/
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/* We must save and restore r7 (call-saved) for the syscall number.
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We never make function calls from inside here (only potentially
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signal handlers), so we do not bother with doubleword alignment.
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Just like the APCS syscall convention, the EABI syscall convention uses
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r0 through r6 for up to seven syscall arguments. None are ever passed to
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the kernel on the stack, although incoming arguments are on the stack for
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syscalls with five or more arguments.
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The assembler will convert the literal pool load to a move for most
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syscalls. */
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#undef DO_CALL
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#define DO_CALL(syscall_name, args) \
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DOARGS_##args; \
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ldr r7, =SYS_ify (syscall_name); \
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swi 0x0; \
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UNDOARGS_##args
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#undef DOARGS_0
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#define DOARGS_0 \
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.fnstart; \
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push { r7 }; \
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cfi_adjust_cfa_offset (4); \
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cfi_rel_offset (r7, 0); \
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.save { r7 }
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#undef DOARGS_1
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#define DOARGS_1 DOARGS_0
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#undef DOARGS_2
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#define DOARGS_2 DOARGS_0
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#undef DOARGS_3
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#define DOARGS_3 DOARGS_0
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#undef DOARGS_4
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#define DOARGS_4 DOARGS_0
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#undef DOARGS_5
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#define DOARGS_5 \
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.fnstart; \
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push {r4, r7}; \
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cfi_adjust_cfa_offset (8); \
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cfi_rel_offset (r4, 0); \
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cfi_rel_offset (r7, 4); \
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.save { r4, r7 }; \
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ldr r4, [sp, #8]
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#undef DOARGS_6
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#define DOARGS_6 \
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.fnstart; \
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mov ip, sp; \
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push {r4, r5, r7}; \
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cfi_adjust_cfa_offset (12); \
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cfi_rel_offset (r4, 0); \
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cfi_rel_offset (r5, 4); \
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cfi_rel_offset (r7, 8); \
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.save { r4, r5, r7 }; \
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ldmia ip, {r4, r5}
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#undef DOARGS_7
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#define DOARGS_7 \
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.fnstart; \
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mov ip, sp; \
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push {r4, r5, r6, r7}; \
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cfi_adjust_cfa_offset (16); \
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cfi_rel_offset (r4, 0); \
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cfi_rel_offset (r5, 4); \
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cfi_rel_offset (r6, 8); \
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cfi_rel_offset (r7, 12); \
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.save { r4, r5, r6, r7 }; \
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ldmia ip, {r4, r5, r6}
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#undef UNDOARGS_0
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#define UNDOARGS_0 \
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pop {r7}; \
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cfi_adjust_cfa_offset (-4); \
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cfi_restore (r7); \
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.fnend
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#undef UNDOARGS_1
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#define UNDOARGS_1 UNDOARGS_0
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#undef UNDOARGS_2
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#define UNDOARGS_2 UNDOARGS_0
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#undef UNDOARGS_3
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#define UNDOARGS_3 UNDOARGS_0
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#undef UNDOARGS_4
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#define UNDOARGS_4 UNDOARGS_0
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#undef UNDOARGS_5
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#define UNDOARGS_5 \
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pop {r4, r7}; \
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cfi_adjust_cfa_offset (-8); \
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cfi_restore (r4); \
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cfi_restore (r7); \
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.fnend
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#undef UNDOARGS_6
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#define UNDOARGS_6 \
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pop {r4, r5, r7}; \
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cfi_adjust_cfa_offset (-12); \
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cfi_restore (r4); \
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cfi_restore (r5); \
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cfi_restore (r7); \
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.fnend
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#undef UNDOARGS_7
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#define UNDOARGS_7 \
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pop {r4, r5, r6, r7}; \
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cfi_adjust_cfa_offset (-16); \
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cfi_restore (r4); \
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cfi_restore (r5); \
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cfi_restore (r6); \
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cfi_restore (r7); \
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.fnend
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#else /* not __ASSEMBLER__ */
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/* Define a macro which expands into the inline wrapper code for a system
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call. */
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#undef INLINE_SYSCALL
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#define INLINE_SYSCALL(name, nr, args...) \
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({ unsigned int _sys_result = INTERNAL_SYSCALL (name, , nr, args); \
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if (__builtin_expect (INTERNAL_SYSCALL_ERROR_P (_sys_result, ), 0)) \
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{ \
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__set_errno (INTERNAL_SYSCALL_ERRNO (_sys_result, )); \
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_sys_result = (unsigned int) -1; \
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} \
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(int) _sys_result; })
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#undef INTERNAL_SYSCALL_DECL
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#define INTERNAL_SYSCALL_DECL(err) do { } while (0)
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#if defined(__thumb__)
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/* We can not expose the use of r7 to the compiler. GCC (as
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of 4.5) uses r7 as the hard frame pointer for Thumb - although
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for Thumb-2 it isn't obviously a better choice than r11.
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And GCC does not support asms that conflict with the frame
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pointer.
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This would be easier if syscall numbers never exceeded 255,
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but they do. For the moment the LOAD_ARGS_7 is sacrificed.
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We can't use push/pop inside the asm because that breaks
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unwinding (i.e. thread cancellation) for this frame. We can't
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locally save and restore r7, because we do not know if this
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function uses r7 or if it is our caller's r7; if it is our caller's,
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then unwinding will fail higher up the stack. So we move the
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syscall out of line and provide its own unwind information. */
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# undef INTERNAL_SYSCALL_RAW
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# define INTERNAL_SYSCALL_RAW(name, err, nr, args...) \
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({ \
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register int _a1 asm ("a1"); \
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int _nametmp = name; \
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LOAD_ARGS_##nr (args) \
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register int _name asm ("ip") = _nametmp; \
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asm volatile ("bl __libc_do_syscall" \
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: "=r" (_a1) \
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: "r" (_name) ASM_ARGS_##nr \
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: "memory", "lr"); \
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_a1; })
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#else /* ARM */
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# undef INTERNAL_SYSCALL_RAW
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# define INTERNAL_SYSCALL_RAW(name, err, nr, args...) \
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({ \
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register int _a1 asm ("r0"), _nr asm ("r7"); \
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LOAD_ARGS_##nr (args) \
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_nr = name; \
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asm volatile ("swi 0x0 @ syscall " #name \
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: "=r" (_a1) \
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: "r" (_nr) ASM_ARGS_##nr \
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: "memory"); \
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_a1; })
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#endif
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#undef INTERNAL_SYSCALL
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#define INTERNAL_SYSCALL(name, err, nr, args...) \
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INTERNAL_SYSCALL_RAW(SYS_ify(name), err, nr, args)
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#undef INTERNAL_SYSCALL_ARM
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#define INTERNAL_SYSCALL_ARM(name, err, nr, args...) \
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INTERNAL_SYSCALL_RAW(__ARM_NR_##name, err, nr, args)
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#undef INTERNAL_SYSCALL_ERROR_P
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#define INTERNAL_SYSCALL_ERROR_P(val, err) \
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((unsigned int) (val) >= 0xfffff001u)
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#undef INTERNAL_SYSCALL_ERRNO
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#define INTERNAL_SYSCALL_ERRNO(val, err) (-(val))
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#define LOAD_ARGS_0()
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#define ASM_ARGS_0
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#define LOAD_ARGS_1(a1) \
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int _a1tmp = (int) (a1); \
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LOAD_ARGS_0 () \
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_a1 = _a1tmp;
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#define ASM_ARGS_1 ASM_ARGS_0, "r" (_a1)
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#define LOAD_ARGS_2(a1, a2) \
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int _a2tmp = (int) (a2); \
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LOAD_ARGS_1 (a1) \
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register int _a2 asm ("a2") = _a2tmp;
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#define ASM_ARGS_2 ASM_ARGS_1, "r" (_a2)
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#define LOAD_ARGS_3(a1, a2, a3) \
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int _a3tmp = (int) (a3); \
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LOAD_ARGS_2 (a1, a2) \
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register int _a3 asm ("a3") = _a3tmp;
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#define ASM_ARGS_3 ASM_ARGS_2, "r" (_a3)
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#define LOAD_ARGS_4(a1, a2, a3, a4) \
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int _a4tmp = (int) (a4); \
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LOAD_ARGS_3 (a1, a2, a3) \
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register int _a4 asm ("a4") = _a4tmp;
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#define ASM_ARGS_4 ASM_ARGS_3, "r" (_a4)
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#define LOAD_ARGS_5(a1, a2, a3, a4, a5) \
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int _v1tmp = (int) (a5); \
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LOAD_ARGS_4 (a1, a2, a3, a4) \
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register int _v1 asm ("v1") = _v1tmp;
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#define ASM_ARGS_5 ASM_ARGS_4, "r" (_v1)
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#define LOAD_ARGS_6(a1, a2, a3, a4, a5, a6) \
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int _v2tmp = (int) (a6); \
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LOAD_ARGS_5 (a1, a2, a3, a4, a5) \
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register int _v2 asm ("v2") = _v2tmp;
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#define ASM_ARGS_6 ASM_ARGS_5, "r" (_v2)
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#ifndef __thumb__
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# define LOAD_ARGS_7(a1, a2, a3, a4, a5, a6, a7) \
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int _v3tmp = (int) (a7); \
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LOAD_ARGS_6 (a1, a2, a3, a4, a5, a6) \
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register int _v3 asm ("v3") = _v3tmp;
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# define ASM_ARGS_7 ASM_ARGS_6, "r" (_v3)
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#endif
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/* For EABI, non-constant syscalls are actually pretty easy... */
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#undef INTERNAL_SYSCALL_NCS
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#define INTERNAL_SYSCALL_NCS(number, err, nr, args...) \
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INTERNAL_SYSCALL_RAW (number, err, nr, args)
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#endif /* __ASSEMBLER__ */
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/* Pointer mangling support. */
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#if (defined NOT_IN_libc && defined IS_IN_rtld) || \
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(!defined SHARED && (!defined NOT_IN_libc || defined IS_IN_libpthread))
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# ifdef __ASSEMBLER__
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# define PTR_MANGLE_LOAD(guard, tmp) \
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LDST_PCREL(ldr, guard, tmp, C_SYMBOL_NAME(__pointer_chk_guard_local));
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# define PTR_MANGLE(dst, src, guard, tmp) \
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PTR_MANGLE_LOAD(guard, tmp); \
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PTR_MANGLE2(dst, src, guard)
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/* Use PTR_MANGLE2 for efficiency if guard is already loaded. */
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# define PTR_MANGLE2(dst, src, guard) \
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eor dst, src, guard
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# define PTR_DEMANGLE(dst, src, guard, tmp) \
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PTR_MANGLE (dst, src, guard, tmp)
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# define PTR_DEMANGLE2(dst, src, guard) \
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PTR_MANGLE2 (dst, src, guard)
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# else
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extern uintptr_t __pointer_chk_guard_local attribute_relro attribute_hidden;
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# define PTR_MANGLE(var) \
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(var) = (__typeof (var)) ((uintptr_t) (var) ^ __pointer_chk_guard_local)
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# define PTR_DEMANGLE(var) PTR_MANGLE (var)
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# endif
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#else
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# ifdef __ASSEMBLER__
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# define PTR_MANGLE_LOAD(guard, tmp) \
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LDST_GLOBAL(ldr, guard, tmp, C_SYMBOL_NAME(__pointer_chk_guard));
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# define PTR_MANGLE(dst, src, guard, tmp) \
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PTR_MANGLE_LOAD(guard, tmp); \
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PTR_MANGLE2(dst, src, guard)
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/* Use PTR_MANGLE2 for efficiency if guard is already loaded. */
|
|
# define PTR_MANGLE2(dst, src, guard) \
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|
eor dst, src, guard
|
|
# define PTR_DEMANGLE(dst, src, guard, tmp) \
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|
PTR_MANGLE (dst, src, guard, tmp)
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# define PTR_DEMANGLE2(dst, src, guard) \
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|
PTR_MANGLE2 (dst, src, guard)
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# else
|
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extern uintptr_t __pointer_chk_guard attribute_relro;
|
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# define PTR_MANGLE(var) \
|
|
(var) = (__typeof (var)) ((uintptr_t) (var) ^ __pointer_chk_guard)
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# define PTR_DEMANGLE(var) PTR_MANGLE (var)
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# endif
|
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#endif
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#endif /* linux/arm/sysdep.h */
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