glibc/sysdeps/arm/__longjmp.S
Will Newton 80a56cc3ee ARM: Add SystemTap probes to longjmp and setjmp.
Now the ARM port implements pointer encryption for jmpbufs, gdb needs
a SystemTap probe point in longjmp to determine the target PC of
a call to longjmp. This patch implements the probe point in longjmp
and a similar probe point in setjmp.

In order to have all the appropriate registers available to pass to the
probe this reorders the layout of jmpbuf, putting the sp and lr registers
at the start rather than the end, allowing them to be read and
written sequentially.

Tested on armv7, no new failures in the glibc testsuite and confirmed
that this fixes the gdb.base/longjmp.exp failures in the gdb testsuite.

ChangeLog:

2014-02-25  Will Newton  <will.newton@linaro.org>

	* sysdeps/arm/__longjmp.S: Include stap-probe.h.
	(__longjmp): Restore sp and lr before restoring callee
	saved registers.  Add longjmp and longjmp_target
	SystemTap probe point.
	* sysdeps/arm/bits/setjmp.h (__jmp_buf): Update comment.
	* sysdeps/arm/include/bits/setjmp.h (__JMP_BUF_SP):
	Define to zero to match jmpbuf layout.
	* sysdeps/arm/setjmp.S: Include stap-probe.h.
	(__sigsetjmp): Save sp and lr before saving callee
	saved registers.  Add setjmp SystemTap probe point.
2014-02-25 10:07:04 +00:00

154 lines
3.5 KiB
ArmAsm

/* longjmp for ARM.
Copyright (C) 1997-2014 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, see
<http://www.gnu.org/licenses/>. */
#include <sysdep.h>
#include <stap-probe.h>
#include <bits/setjmp.h>
#include <rtld-global-offsets.h>
#include <arm-features.h>
/* __longjmp(jmpbuf, val) */
ENTRY (__longjmp)
mov ip, r0
#ifdef CHECK_SP
sfi_breg ip, \
ldr r4, [\B] /* jmpbuf's sp */
cfi_undefined (r4)
#ifdef PTR_DEMANGLE
PTR_DEMANGLE (r4, r4, a3, a4)
#endif
CHECK_SP (r4)
#endif
#ifdef PTR_DEMANGLE
ldr a4, [ip], #4
PTR_DEMANGLE (a4, a4, a3, r4)
cfi_undefined (r4)
ldr r4, [ip], #4
PTR_DEMANGLE2 (r4, r4, a3)
#else
ldr a4, [ip], #4
ldr r4, [ip], #4
cfi_undefined (r4)
#endif
/* longjmp probe expects longjmp first argument (4@r0), second
argument (-4@r1), and target address (4@r4), respectively. */
LIBC_PROBE (longjmp, 3, 4@r0, -4@r1, 4@r4)
mov sp, a4
mov lr, r4
sfi_sp sfi_breg ip, \
ldmia \B!, JMP_BUF_REGLIST
cfi_restore (v1)
cfi_restore (v2)
cfi_restore (v3)
cfi_restore (v4)
cfi_restore (v5)
cfi_restore (v6)
cfi_restore (sl)
cfi_restore (fp)
cfi_restore (sp)
cfi_restore (lr)
#if !defined ARM_ASSUME_NO_IWMMXT || defined __SOFTFP__
# define NEED_HWCAP 1
#endif
#ifdef NEED_HWCAP
# ifdef IS_IN_rtld
ldr a4, 1f
ldr a3, .Lrtld_local_ro
0: add a4, pc, a4
add a4, a4, a3
ldr a4, [a4, #RTLD_GLOBAL_RO_DL_HWCAP_OFFSET]
# else
# ifdef PIC
ldr a4, 1f
ldr a3, .Lrtld_global_ro
0: add a4, pc, a4
ldr a4, [a4, a3]
ldr a4, [a4, #RTLD_GLOBAL_RO_DL_HWCAP_OFFSET]
# else
ldr a4, .Lhwcap
ldr a4, [a4, #0]
# endif
# endif
#endif
#ifdef __SOFTFP__
tst a4, #HWCAP_ARM_VFP
beq .Lno_vfp
#endif
/* Restore the VFP registers. */
/* Following instruction is vldmia ip!, {d8-d15}. */
sfi_breg r12, \
ldc p11, cr8, [\B], #64
.Lno_vfp:
#ifndef ARM_ASSUME_NO_IWMMXT
tst a4, #HWCAP_ARM_IWMMXT
beq .Lno_iwmmxt
/* Restore the call-preserved iWMMXt registers. */
/* Following instructions are wldrd wr10, [ip], #8 (etc.) */
sfi_breg r12, \
ldcl p1, cr10, [\B], #8
sfi_breg r12, \
ldcl p1, cr11, [\B], #8
sfi_breg r12, \
ldcl p1, cr12, [\B], #8
sfi_breg r12, \
ldcl p1, cr13, [\B], #8
sfi_breg r12, \
ldcl p1, cr14, [\B], #8
sfi_breg r12, \
ldcl p1, cr15, [\B], #8
.Lno_iwmmxt:
#endif
/* longjmp_target probe expects longjmp first argument (4@r0), second
argument (-4@r1), and target address (4@r14), respectively. */
LIBC_PROBE (longjmp_target, 3, 4@r0, -4@r1, 4@r14)
movs r0, r1 /* get the return value in place */
it eq
moveq r0, #1 /* can't let setjmp() return zero! */
DO_RET(lr)
#ifdef NEED_HWCAP
# ifdef IS_IN_rtld
1: .long _GLOBAL_OFFSET_TABLE_ - 0b - PC_OFS
.Lrtld_local_ro:
.long C_SYMBOL_NAME(_rtld_local_ro)(GOTOFF)
# else
# ifdef PIC
1: .long _GLOBAL_OFFSET_TABLE_ - 0b - PC_OFS
.Lrtld_global_ro:
.long C_SYMBOL_NAME(_rtld_global_ro)(GOT)
# else
.Lhwcap:
.long C_SYMBOL_NAME(_dl_hwcap)
# endif
# endif
#endif
END (__longjmp)