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/* Save current context.
Copyright (C) 2009-2025 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 getcontext (ucontext_t *ucp)
Returns 0 on success -1 and errno on failure.
*/
.text
ENTRY(__getcontext)
PTR_ARG (0)
/* The saved context will return to the getcontext() call point
with a return value of 0 */
str xzr, [x0, oX0 + 0 * SZREG]
stp x18, x19, [x0, oX0 + 18 * SZREG]
stp x20, x21, [x0, oX0 + 20 * SZREG]
stp x22, x23, [x0, oX0 + 22 * SZREG]
stp x24, x25, [x0, oX0 + 24 * SZREG]
stp x26, x27, [x0, oX0 + 26 * SZREG]
stp x28, x29, [x0, oX0 + 28 * SZREG]
str x30, [x0, oX0 + 30 * SZREG]
/* Place LR into the saved PC, this will ensure that when
switching to this saved context with setcontext() control
will pass back to the caller of getcontext(), we have
already arrange to return the appropriate return value in x0
above. */
str x30, [x0, oPC]
/* Save the current SP */
mov x2, sp
str x2, [x0, oSP]
/* Initialize the pstate. */
str xzr, [x0, oPSTATE]
/* Figure out where to place the first context extension
block. */
add x2, x0, #oEXTENSION
/* Write the context extension fpsimd header. */
mov w3, #(FPSIMD_MAGIC & 0xffff)
movk w3, #(FPSIMD_MAGIC >> 16), lsl #16
str w3, [x2, #oHEAD + oMAGIC]
mov w3, #FPSIMD_CONTEXT_SIZE
str w3, [x2, #oHEAD + oSIZE]
/* Fill in the FP SIMD context. */
add x3, x2, #oV0 + 8 * SZVREG
stp q8, q9, [x3], # 2 * SZVREG
stp q10, q11, [x3], # 2 * SZVREG
stp q12, q13, [x3], # 2 * SZVREG
stp q14, q15, [x3], # 2 * SZVREG
add x3, x2, oFPSR
mrs x4, fpsr
str w4, [x3]
mrs x4, fpcr
str w4, [x3, oFPCR - oFPSR]
add x2, x2, #FPSIMD_CONTEXT_SIZE
/* Save the GCSPR. */
mov x16, 1 /* _CHKFEAT_GCS */
CHKFEAT_X16
tbnz x16, 0, L(gcs_done)
mov w3, #(GCS_MAGIC & 0xffff)
movk w3, #(GCS_MAGIC >> 16), lsl #16
str w3, [x2, #oHEAD + oMAGIC]
mov w3, #GCS_CONTEXT_SIZE
str w3, [x2, #oHEAD + oSIZE]
MRS_GCSPR (x4)
add x4, x4, 8 /* GCS state right after getcontext returns. */
str x4, [x2, #oGCSPR]
add x2, x2, #GCS_CONTEXT_SIZE
L(gcs_done):
/* Write the termination context extension header. */
str wzr, [x2, #oHEAD + oMAGIC]
str wzr, [x2, #oHEAD + oSIZE]
/* Grab the signal mask */
/* rt_sigprocmask (SIG_BLOCK, NULL, &ucp->uc_sigmask, _NSIG8) */
add PTR_REG (2), PTR_REG (0), #UCONTEXT_SIGMASK
mov x0, SIG_BLOCK
mov x1, 0
mov x3, _NSIG8
mov x8, SYS_ify (rt_sigprocmask)
svc 0
cbnz x0, 1f
/* Return 0 for success */
mov x0, 0
RET
1:
b C_SYMBOL_NAME(__syscall_error)
PSEUDO_END (__getcontext)
weak_alias (__getcontext, getcontext)
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