glibc/sysdeps/unix/sysv/linux/arm/getcontext.S

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/* Copyright (C) 2012-2016 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 <rtld-global-offsets.h>
#include "ucontext_i.h"
.syntax unified
.text
/* int getcontext (ucontext_t *ucp) */
ENTRY(__getcontext)
/* No need to save r0-r3, d0-d7, or d16-d31. */
add r1, r0, #MCONTEXT_ARM_R4
stmia r1, {r4-r11}
/* Save R13 separately as Thumb can't STM it. */
str r13, [r0, #MCONTEXT_ARM_SP]
str r14, [r0, #MCONTEXT_ARM_LR]
/* Return to LR */
str r14, [r0, #MCONTEXT_ARM_PC]
/* Return zero */
mov r2, #0
str r2, [r0, #MCONTEXT_ARM_R0]
/* Save ucontext_t * across the next call. */
mov r4, r0
/* __sigprocmask(SIG_BLOCK, NULL, &(ucontext->uc_sigmask)) */
mov r0, #SIG_BLOCK
mov r1, #0
add r2, r4, #UCONTEXT_SIGMASK
bl PLTJMP(__sigprocmask)
/* Store FP regs. Much of the FP code is copied from arm/setjmp.S. */
#ifdef PIC
ldr r2, 1f
ldr r1, .Lrtld_global_ro
0: add r2, pc, r2
ldr r2, [r2, r1]
ldr r2, [r2, #RTLD_GLOBAL_RO_DL_HWCAP_OFFSET]
#else
ldr r2, .Lhwcap
ldr r2, [r2, #0]
#endif
add r0, r4, #UCONTEXT_REGSPACE
#ifdef __SOFTFP__
tst r2, #HWCAP_ARM_VFP
beq .Lno_vfp
#endif
/* Store the VFP registers.
Don't use VFP instructions directly because this code
is used in non-VFP multilibs. */
/* Following instruction is vstmia r0!, {d8-d15}. */
stc p11, cr8, [r0], #64
/* Store the floating-point status register. */
/* Following instruction is vmrs r1, fpscr. */
mrc p10, 7, r1, cr1, cr0, 0
str r1, [r0], #4
.Lno_vfp:
tst r2, #HWCAP_ARM_IWMMXT
beq .Lno_iwmmxt
/* Save the call-preserved iWMMXt registers. */
/* Following instructions are wstrd wr10, [r0], #8 (etc.) */
stcl p1, cr10, [r0], #8
stcl p1, cr11, [r0], #8
stcl p1, cr12, [r0], #8
stcl p1, cr13, [r0], #8
stcl p1, cr14, [r0], #8
stcl p1, cr15, [r0], #8
.Lno_iwmmxt:
/* Restore the clobbered R4 and LR. */
ldr r14, [r4, #MCONTEXT_ARM_LR]
ldr r4, [r4, #MCONTEXT_ARM_R4]
mov r0, #0
DO_RET(r14)
END(__getcontext)
#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
weak_alias(__getcontext, getcontext)