sysdeps/unix/sysv/linux/nios2/swapcontext.S

   1 /* Modify saved context.
   2    Copyright (C) 2015-2023 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <sysdep.h>
  20 #include "ucontext_i.h"
  21
  22 /* int swapcontext (ucontext_t *oucp, const ucontext_t *ucp) */
  23         .text
  24 ENTRY(__swapcontext)
  25
  26         /* Same as getcontext().  */
  27         stw     r16, (UCONTEXT_MCONTEXT + 16*4)(r4)
  28         stw     r17, (UCONTEXT_MCONTEXT + 17*4)(r4)
  29         stw     r18, (UCONTEXT_MCONTEXT + 18*4)(r4)
  30         stw     r19, (UCONTEXT_MCONTEXT + 19*4)(r4)
  31         stw     r20, (UCONTEXT_MCONTEXT + 20*4)(r4)
  32         stw     r21, (UCONTEXT_MCONTEXT + 21*4)(r4)
  33         stw     r22, (UCONTEXT_MCONTEXT + 22*4)(r4)
  34         stw     ra,  (UCONTEXT_MCONTEXT + 24*4)(r4)
  35         stw     fp,  (UCONTEXT_MCONTEXT + 25*4)(r4)
  36         stw     gp,  (UCONTEXT_MCONTEXT + 26*4)(r4)
  37         /* Store return address at place for EA.  */
  38         stw     ra,  (UCONTEXT_MCONTEXT + 28*4)(r4)
  39         stw     sp,  (UCONTEXT_MCONTEXT + 29*4)(r4)
  40         /* Store zero for return success.  */
  41         stw     zero, (UCONTEXT_MCONTEXT + 2*4)(r4)
  42
  43         /* Store value "1" at uc_flags to recognize as getcontext created.  */
  44         movi    r2, 1
  45         stw     r2, UCONTEXT_FLAGS(r4)
  46
  47         /* Store MCONTEXT_VERSION at first word of mcontext_t.  */
  48         movi    r2, MCONTEXT_VERSION
  49         stw     r2, UCONTEXT_MCONTEXT(r4)
  50
  51         /* Save ucp to non-argument syscall preserved register.  */
  52         mov     r10, r5
  53
  54         /* Get signal mask.  */
  55         /* rt_sigprocmask (SIG_BLOCK, NULL, &ucp->uc_sigmask, _NSIG8) */
  56         movi    r7, _NSIG8
  57         addi    r6, r4, UCONTEXT_SIGMASK
  58         mov     r5, zero
  59         movi    r4, SIG_BLOCK
  60         movi    r2, SYS_ify (rt_sigprocmask)
  61         trap
  62         bne     r7, zero, SYSCALL_ERROR_LABEL
  63
  64
  65         /* Same as setcontext().  */
  66         ldw     r5, UCONTEXT_FLAGS(r10)
  67         movi    r6, 1
  68         bne     r5, r6, .Lsigreturn
  69
  70         /* Restore signal mask.  */
  71         /* rt_sigprocmask (SIG_SETMASK, &ucp->uc_sigmask, NULL, _NSIG8) */
  72         movi    r7, _NSIG8
  73         addi    r5, r10, UCONTEXT_SIGMASK
  74         mov     r6, zero
  75         movi    r4, SIG_SETMASK
  76         movi    r2, SYS_ify (rt_sigprocmask)
  77         trap
  78         bne     r7, zero, SYSCALL_ERROR_LABEL
  79
  80         /* Restore argument registers, for the makecontext() case.  */
  81         ldw     r4,   (UCONTEXT_MCONTEXT + 4*4)(r10)
  82         ldw     r5,   (UCONTEXT_MCONTEXT + 5*4)(r10)
  83         ldw     r6,   (UCONTEXT_MCONTEXT + 6*4)(r10)
  84         ldw     r7,   (UCONTEXT_MCONTEXT + 7*4)(r10)
  85
  86         ldw     r16, (UCONTEXT_MCONTEXT + 16*4)(r10)
  87         ldw     r17, (UCONTEXT_MCONTEXT + 17*4)(r10)
  88         ldw     r18, (UCONTEXT_MCONTEXT + 18*4)(r10)
  89         ldw     r19, (UCONTEXT_MCONTEXT + 19*4)(r10)
  90         ldw     r20, (UCONTEXT_MCONTEXT + 20*4)(r10)
  91         ldw     r21, (UCONTEXT_MCONTEXT + 21*4)(r10)
  92         ldw     r22, (UCONTEXT_MCONTEXT + 22*4)(r10)
  93         ldw     ra,  (UCONTEXT_MCONTEXT + 24*4)(r10)
  94         ldw     fp,  (UCONTEXT_MCONTEXT + 25*4)(r10)
  95         ldw     gp,  (UCONTEXT_MCONTEXT + 26*4)(r10)
  96         /* Load address to continue execution.  */
  97         ldw     r3,  (UCONTEXT_MCONTEXT + 28*4)(r10)
  98         ldw     sp,  (UCONTEXT_MCONTEXT + 29*4)(r10)
  99
 100         mov     r2, zero
 101         jmp     r3
 102
 103 .Lsigreturn:
 104         addi    sp, sp, -RT_SIGFRAME_SIZE
 105         cfi_adjust_cfa_offset (RT_SIGFRAME_SIZE)
 106
 107         addi    r2, sp, RT_SIGFRAME_UCONTEXT
 108         movi    r3, UCONTEXT_SIZE-4
 109 1:
 110         add     r6, r4, r3
 111         ldw     r5, 0(r6)
 112         add     r7, r2, r3
 113         addi    r3, r3, -4
 114         stw     r5, 0(r7)
 115         bgt     r3, zero, 1b
 116
 117         movi    r2, SYS_ify (rt_sigreturn)
 118         trap
 119
 120         addi    sp, sp, RT_SIGFRAME_SIZE
 121         cfi_adjust_cfa_offset (-RT_SIGFRAME_SIZE)
 122         br      SYSCALL_ERROR_LABEL
 123
 124 PSEUDO_END (__swapcontext)
 125 weak_alias (__swapcontext, swapcontext)