sysdeps/unix/sysv/linux/aarch64/swapcontext.S

   1 /* Modify saved context.
   2
   3    Copyright (C) 2009-2016 Free Software Foundation, Inc.
   4
   5    This file is part of the GNU C Library.
   6
   7    The GNU C Library is free software; you can redistribute it and/or
   8    modify it under the terms of the GNU Lesser General Public License as
   9    published by the Free Software Foundation; either version 2.1 of the
  10    License, or (at your option) any later version.
  11
  12    The GNU C Library is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15    Lesser General Public License for more details.
  16
  17    You should have received a copy of the GNU Lesser General Public
  18    License along with the GNU C Library; if not, see
  19    <http://www.gnu.org/licenses/>.  */
  20
  21 #include <sysdep.h>
  22
  23 #include "ucontext_i.h"
  24 #include "ucontext-internal.h"
  25
  26 /* int swapcontext (ucontext_t *oucp, const ucontext_t *ucp) */
  27
  28         .text
  29 ENTRY(__swapcontext)
  30         /* Set the value returned when swapcontext() returns in this context. */
  31         str     xzr,      [x0, oX0 +  0 * SZREG]
  32
  33         stp     x18, x19, [x0, oX0 + 18 * SZREG]
  34         stp     x20, x21, [x0, oX0 + 20 * SZREG]
  35         stp     x22, x23, [x0, oX0 + 22 * SZREG]
  36         stp     x24, x25, [x0, oX0 + 24 * SZREG]
  37         stp     x26, x27, [x0, oX0 + 26 * SZREG]
  38         stp     x28, x29, [x0, oX0 + 28 * SZREG]
  39         str     x30,      [x0, oX0 + 30 * SZREG]
  40         str     x30,      [x0, oPC]
  41         mov     x2, sp
  42         str     x2,       [x0, oSP]
  43
  44         /* Figure out where to place the first context extension
  45            block.  */
  46         add     x2, x0, #oEXTENSION
  47
  48         /* Write the context extension fpsimd header.  */
  49         mov     w3, #(FPSIMD_MAGIC & 0xffff)
  50         movk    w3, #(FPSIMD_MAGIC >> 16), lsl #16
  51         str     w3, [x2, #oHEAD + oMAGIC]
  52         mov     w3, #FPSIMD_CONTEXT_SIZE
  53         str     w3, [x2, #oHEAD + oSIZE]
  54
  55         /* Fill in the FP SIMD context.  */
  56         add     x3, x2, #oV0 + 8 * SZVREG
  57         stp      q8,  q9, [x3], #2 * SZVREG
  58         stp     q10, q11, [x3], #2 * SZVREG
  59         stp     q12, q13, [x3], #2 * SZVREG
  60         stp     q14, q15, [x3], #2 * SZVREG
  61
  62         add     x3, x2, #oFPSR
  63
  64         mrs     x4, fpsr
  65         str     w4, [x3, #oFPSR - oFPSR]
  66
  67         mrs     x4, fpcr
  68         str     w4, [x3, #oFPCR - oFPSR]
  69
  70         /* Write the termination context extension header.  */
  71         add     x2, x2, #FPSIMD_CONTEXT_SIZE
  72
  73         str     xzr, [x2, #oHEAD + oMAGIC]
  74         str     xzr, [x2, #oHEAD + oSIZE]
  75
  76         /* Preserve ucp.  */
  77         mov     x21, x1
  78
  79         /* rt_sigprocmask (SIG_SETMASK, &ucp->uc_sigmask, &oucp->uc_sigmask,
  80                            _NSIG8) */
  81         /* Grab the signal mask */
  82         /* rt_sigprocmask (SIG_BLOCK, NULL, &ucp->uc_sigmask, _NSIG8) */
  83         add     x2, x0, #UCONTEXT_SIGMASK
  84         mov     x0, SIG_BLOCK
  85         mov     x1, 0
  86         mov     x3, _NSIG8
  87         mov     x8, SYS_ify (rt_sigprocmask)
  88         svc     0
  89         cbnz    x0, 1f
  90
  91         mov     x22, x30
  92         mov     x0, x21
  93         bl      JUMPTARGET (__setcontext)
  94         mov     x30, x22
  95         RET
  96
  97 1:
  98         b       C_SYMBOL_NAME(__syscall_error)
  99 PSEUDO_END (__swapcontext)
 100 weak_alias (__swapcontext, swapcontext)