1/* Install given context. 2 Copyright (C) 2008-2022 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 <sys/trap.h> 21 22#include "ucontext_i.h" 23 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 34ENTRY(__setcontext) 35 save %sp, -112, %sp 36 37 mov SIG_SETMASK, %o0 38 add %i0, UC_SIGMASK, %o1 39 clr %o2 40 mov 8, %o3 41 mov __NR_rt_sigprocmask, %g1 42 ta 0x10 43 44 /* This is a bit on the expensive side, and we could optimize 45 the unwind similar to how the 32-bit sparc longjmp code 46 does if performance of this routine really matters. */ 47 ta ST_FLUSH_WINDOWS 48 49 ldub [%i0 + UC_MCONTEXT + MC_FPREGS + FPU_EN], %g1 50 cmp %g1, 0 51 be 1f 52 nop 53 ld [%i0 + UC_MCONTEXT + MC_FPREGS + FPU_FSR], %fsr 54 ldd [%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D0], %f0 55 ldd [%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D2], %f2 56 ldd [%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D4], %f4 57 ldd [%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D6], %f6 58 ldd [%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D8], %f8 59 ldd [%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D10], %f10 60 ldd [%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D12], %f12 61 ldd [%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D14], %f14 62 ldd [%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D16], %f16 63 ldd [%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D18], %f18 64 ldd [%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D20], %f20 65 ldd [%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D22], %f22 66 ldd [%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D24], %f24 67 ldd [%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D26], %f26 68 ldd [%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D28], %f28 69 ldd [%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D30], %f30 701: 71 ld [%i0 + UC_MCONTEXT + MC_GREGS + GREG_Y], %g1 72 wr %g1, 0x0, %y 73 74 /* We specifically do not restore %g1 since we need it here as 75 a temporary. */ 76 ld [%i0 + UC_MCONTEXT + MC_GREGS + GREG_G2], %g2 77 ld [%i0 + UC_MCONTEXT + MC_GREGS + GREG_G3], %g3 78 ld [%i0 + UC_MCONTEXT + MC_GREGS + GREG_G4], %g4 79 ld [%i0 + UC_MCONTEXT + MC_GREGS + GREG_G5], %g5 80 ld [%i0 + UC_MCONTEXT + MC_GREGS + GREG_G6], %g6 81 ld [%i0 + UC_MCONTEXT + MC_GREGS + GREG_G7], %g7 82 ld [%i0 + UC_MCONTEXT + MC_GREGS + GREG_O1], %i1 83 ld [%i0 + UC_MCONTEXT + MC_GREGS + GREG_O2], %i2 84 ld [%i0 + UC_MCONTEXT + MC_GREGS + GREG_O3], %i3 85 ld [%i0 + UC_MCONTEXT + MC_GREGS + GREG_O4], %i4 86 ld [%i0 + UC_MCONTEXT + MC_GREGS + GREG_O5], %i5 87 ld [%i0 + UC_MCONTEXT + MC_GREGS + GREG_O6], %i6 88 restore 89 ld [%o0 + UC_MCONTEXT + MC_GREGS + GREG_O7], %o7 90 ld [%o0 + UC_MCONTEXT + MC_GREGS + GREG_PC], %g1 91 jmpl %g1, %g0 92 ld [%o0 + UC_MCONTEXT + MC_GREGS + GREG_O0], %o0 93END(__setcontext) 94 95weak_alias (__setcontext, setcontext) 96 97/* We add an NOP here to separate between __setcontext/__startcontext. The 98 wanted behavior that happens is: when unwinding from a function called 99 inside a makecontext() context, FDE lookup will use '&__startcontext - 1', 100 then returns NULL for no FDE found, and immediately ends the unwind, in 101 a normal fashion. 102 103 If this NOP word does not exist, FDE lookup just repeatedly finds 104 __setcontext's FDE in an infinite loop, due to the convention of using 105 'address - 1' for FDE lookup. Modifiying/deleting the below 106 __startcontext's FDE has no help on this. */ 107 108 nop 109 110/* This is the helper code which gets called if a function which is 111 registered with 'makecontext' returns. In this case we have to 112 install the context listed in the uc_link element of the context 113 'makecontext' manipulated at the time of the 'makecontext' call. 114 If the pointer is NULL the process must terminate. */ 115 116ENTRY(__start_context) 117 ld [%sp + (16 * 4)], %g1 118 cmp %g1, 0 119 be,a 1f 120 clr %o0 121 call __setcontext 122 mov %g1, %o0 123 /* If this returns (which can happen if the syscall fails) we'll 124 exit the program with the return error value (-1). */ 1251: call HIDDEN_JUMPTARGET(exit) 126 nop 127 /* The 'exit' call should never return. In case it does cause 128 the process to terminate. */ 129 unimp 130END(__start_context) 131