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/* Set current context.
Copyright (C) 2009-2021 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
<https://www.gnu.org/licenses/>. */
#include <sysdep.h>
#include "ucontext_i.h"
#include "ucontext-internal.h"
/* int __setcontext (const ucontext_t *ucp)
Restores the machine context in UCP and thereby resumes execution
in that context.
This implementation is intended to be used for *synchronous* context
switches only. Therefore, it does not have to restore anything
other than the PRESERVED state. */
.text
ENTRY (__setcontext)
PTR_ARG (0)
/* Save a copy of UCP. */
mov x9, x0
/* Set the signal mask with
rt_sigprocmask (SIG_SETMASK, mask, NULL, _NSIG/8). */
mov x0, #SIG_SETMASK
add x1, x9, #UCONTEXT_SIGMASK
mov x2, #0
mov x3, #_NSIG8
mov x8, SYS_ify (rt_sigprocmask)
svc 0
cbz x0, 1f
b C_SYMBOL_NAME (__syscall_error)
1:
/* Restore the general purpose registers. */
mov x0, x9
cfi_def_cfa (x0, 0)
cfi_offset (x18, oX0 + 18 * SZREG)
cfi_offset (x19, oX0 + 19 * SZREG)
cfi_offset (x20, oX0 + 20 * SZREG)
cfi_offset (x21, oX0 + 21 * SZREG)
cfi_offset (x22, oX0 + 22 * SZREG)
cfi_offset (x23, oX0 + 23 * SZREG)
cfi_offset (x24, oX0 + 24 * SZREG)
cfi_offset (x25, oX0 + 25 * SZREG)
cfi_offset (x26, oX0 + 26 * SZREG)
cfi_offset (x27, oX0 + 27 * SZREG)
cfi_offset (x28, oX0 + 28 * SZREG)
cfi_offset (x29, oX0 + 29 * SZREG)
cfi_offset (x30, oX0 + 30 * SZREG)
cfi_offset ( d8, oV0 + 8 * SZVREG)
cfi_offset ( d9, oV0 + 9 * SZVREG)
cfi_offset (d10, oV0 + 10 * SZVREG)
cfi_offset (d11, oV0 + 11 * SZVREG)
cfi_offset (d12, oV0 + 12 * SZVREG)
cfi_offset (d13, oV0 + 13 * SZVREG)
cfi_offset (d14, oV0 + 14 * SZVREG)
cfi_offset (d15, oV0 + 15 * SZVREG)
ldp x18, x19, [x0, oX0 + 18 * SZREG]
ldp x20, x21, [x0, oX0 + 20 * SZREG]
ldp x22, x23, [x0, oX0 + 22 * SZREG]
ldp x24, x25, [x0, oX0 + 24 * SZREG]
ldp x26, x27, [x0, oX0 + 26 * SZREG]
ldp x28, x29, [x0, oX0 + 28 * SZREG]
ldr x30, [x0, oX0 + 30 * SZREG]
ldr x2, [x0, oSP]
mov sp, x2
/* Check for FP SIMD context. We don't support restoring
contexts created by the kernel, so this context must have
been created by getcontext. Hence we can rely on the
first extension block being the FP SIMD context. */
add x2, x0, #oEXTENSION
mov w3, #(FPSIMD_MAGIC & 0xffff)
movk w3, #(FPSIMD_MAGIC >> 16), lsl #16
ldr w1, [x2, #oHEAD + oMAGIC]
cmp w1, w3
b.ne 2f
/* Restore the FP SIMD context. */
add x3, x2, #oV0 + 8 * SZVREG
ldp q8, q9, [x3], #2 * SZVREG
ldp q10, q11, [x3], #2 * SZVREG
ldp q12, q13, [x3], #2 * SZVREG
ldp q14, q15, [x3], #2 * SZVREG
add x3, x2, oFPSR
ldr w4, [x3]
msr fpsr, x4
ldr w4, [x3, oFPCR - oFPSR]
msr fpcr, x4
2:
ldr x16, [x0, oPC]
/* Restore arg registers. */
ldp x2, x3, [x0, oX0 + 2 * SZREG]
ldp x4, x5, [x0, oX0 + 4 * SZREG]
ldp x6, x7, [x0, oX0 + 6 * SZREG]
ldp x0, x1, [x0, oX0 + 0 * SZREG]
/* Jump to the new pc value. */
br x16
PSEUDO_END (__setcontext)
weak_alias (__setcontext, setcontext)
ENTRY (__startcontext)
mov x0, x19
cbnz x0, __setcontext
1: b HIDDEN_JUMPTARGET (exit)
END (__startcontext)
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