1/* Set current context. 2 3 Copyright (C) 2009-2021 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 <https://www.gnu.org/licenses/>. */ 20 21#include <sysdep.h> 22#include "ucontext_i.h" 23#include "ucontext-internal.h" 24 25/* int __setcontext (const ucontext_t *ucp) 26 27 Restores the machine context in UCP and thereby resumes execution 28 in that context. 29 30 This implementation is intended to be used for *synchronous* context 31 switches only. Therefore, it does not have to restore anything 32 other than the PRESERVED state. */ 33 34 .text 35 36ENTRY (__setcontext) 37 PTR_ARG (0) 38 /* Save a copy of UCP. */ 39 mov x9, x0 40 41 /* Set the signal mask with 42 rt_sigprocmask (SIG_SETMASK, mask, NULL, _NSIG/8). */ 43 mov x0, #SIG_SETMASK 44 add x1, x9, #UCONTEXT_SIGMASK 45 mov x2, #0 46 mov x3, #_NSIG8 47 mov x8, SYS_ify (rt_sigprocmask) 48 svc 0 49 cbz x0, 1f 50 b C_SYMBOL_NAME (__syscall_error) 511: 52 /* Restore the general purpose registers. */ 53 mov x0, x9 54 cfi_def_cfa (x0, 0) 55 cfi_offset (x18, oX0 + 18 * SZREG) 56 cfi_offset (x19, oX0 + 19 * SZREG) 57 cfi_offset (x20, oX0 + 20 * SZREG) 58 cfi_offset (x21, oX0 + 21 * SZREG) 59 cfi_offset (x22, oX0 + 22 * SZREG) 60 cfi_offset (x23, oX0 + 23 * SZREG) 61 cfi_offset (x24, oX0 + 24 * SZREG) 62 cfi_offset (x25, oX0 + 25 * SZREG) 63 cfi_offset (x26, oX0 + 26 * SZREG) 64 cfi_offset (x27, oX0 + 27 * SZREG) 65 cfi_offset (x28, oX0 + 28 * SZREG) 66 cfi_offset (x29, oX0 + 29 * SZREG) 67 cfi_offset (x30, oX0 + 30 * SZREG) 68 69 cfi_offset ( d8, oV0 + 8 * SZVREG) 70 cfi_offset ( d9, oV0 + 9 * SZVREG) 71 cfi_offset (d10, oV0 + 10 * SZVREG) 72 cfi_offset (d11, oV0 + 11 * SZVREG) 73 cfi_offset (d12, oV0 + 12 * SZVREG) 74 cfi_offset (d13, oV0 + 13 * SZVREG) 75 cfi_offset (d14, oV0 + 14 * SZVREG) 76 cfi_offset (d15, oV0 + 15 * SZVREG) 77 ldp x18, x19, [x0, oX0 + 18 * SZREG] 78 ldp x20, x21, [x0, oX0 + 20 * SZREG] 79 ldp x22, x23, [x0, oX0 + 22 * SZREG] 80 ldp x24, x25, [x0, oX0 + 24 * SZREG] 81 ldp x26, x27, [x0, oX0 + 26 * SZREG] 82 ldp x28, x29, [x0, oX0 + 28 * SZREG] 83 ldr x30, [x0, oX0 + 30 * SZREG] 84 ldr x2, [x0, oSP] 85 mov sp, x2 86 87 /* Check for FP SIMD context. We don't support restoring 88 contexts created by the kernel, so this context must have 89 been created by getcontext. Hence we can rely on the 90 first extension block being the FP SIMD context. */ 91 add x2, x0, #oEXTENSION 92 93 mov w3, #(FPSIMD_MAGIC & 0xffff) 94 movk w3, #(FPSIMD_MAGIC >> 16), lsl #16 95 ldr w1, [x2, #oHEAD + oMAGIC] 96 cmp w1, w3 97 b.ne 2f 98 99 /* Restore the FP SIMD context. */ 100 add x3, x2, #oV0 + 8 * SZVREG 101 ldp q8, q9, [x3], #2 * SZVREG 102 ldp q10, q11, [x3], #2 * SZVREG 103 ldp q12, q13, [x3], #2 * SZVREG 104 ldp q14, q15, [x3], #2 * SZVREG 105 106 add x3, x2, oFPSR 107 108 ldr w4, [x3] 109 msr fpsr, x4 110 111 ldr w4, [x3, oFPCR - oFPSR] 112 msr fpcr, x4 113 1142: 115 ldr x16, [x0, oPC] 116 /* Restore arg registers. */ 117 ldp x2, x3, [x0, oX0 + 2 * SZREG] 118 ldp x4, x5, [x0, oX0 + 4 * SZREG] 119 ldp x6, x7, [x0, oX0 + 6 * SZREG] 120 ldp x0, x1, [x0, oX0 + 0 * SZREG] 121 /* Jump to the new pc value. */ 122 br x16 123PSEUDO_END (__setcontext) 124weak_alias (__setcontext, setcontext) 125 126ENTRY (__startcontext) 127 mov x0, x19 128 cbnz x0, __setcontext 1291: b HIDDEN_JUMPTARGET (exit) 130END (__startcontext) 131