Signed-off-by: Sergey Bugaev <buga...@gmail.com> --- sysdeps/mach/hurd/x86_64/sigreturn.c | 155 +++++++++++++++++++++++++++ 1 file changed, 155 insertions(+) create mode 100644 sysdeps/mach/hurd/x86_64/sigreturn.c
diff --git a/sysdeps/mach/hurd/x86_64/sigreturn.c b/sysdeps/mach/hurd/x86_64/sigreturn.c new file mode 100644 index 00000000..b8c62e53 --- /dev/null +++ b/sysdeps/mach/hurd/x86_64/sigreturn.c @@ -0,0 +1,155 @@ +/* Copyright (C) 1991-2023 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 <hurd.h> +#include <hurd/signal.h> +#include <hurd/msg.h> +#include <stdlib.h> + +/* This is run on the thread stack after restoring it, to be able to + unlock SS off sigstack. */ +void +__sigreturn2 (struct hurd_sigstate *ss) +{ + _hurd_sigstate_unlock (ss); + + /* We get jumped into, not called normally. The register dump starts where + our return address would normally be. */ + uintptr_t *usp = (uintptr_t *) __builtin_frame_address (0) + 1; + + asm volatile ( + /* Point the stack to the register dump. */ + "movq %0, %%rsp\n" + /* Pop off the registers. */ + "popq %%r8\n" + "popq %%r9\n" + "popq %%r10\n" + "popq %%r11\n" + "popq %%r12\n" + "popq %%r13\n" + "popq %%r14\n" + "popq %%r15\n" + "popq %%rdi\n" + "popq %%rsi\n" + "popq %%rbp\n" + "popq %%rbx\n" + "popq %%rdx\n" + "popq %%rcx\n" + "popq %%rax\n" + "popfq\n" + /* Restore %rip and %rsp with a single instruction. */ + "retq $128" : + : "rm" (usp)); + __builtin_unreachable (); +} + +int +__sigreturn (struct sigcontext *scp) +{ + struct hurd_sigstate *ss; + struct hurd_userlink *link = (void *) &scp[1]; + mach_port_t reply_port; + + if (scp == NULL || (scp->sc_mask & _SIG_CANT_MASK)) + { + errno = EINVAL; + return -1; + } + + ss = _hurd_self_sigstate (); + _hurd_sigstate_lock (ss); + + /* Remove the link on the `active resources' chain added by + _hurd_setup_sighandler. Its purpose was to make sure + that we got called; now we have, it is done. */ + _hurd_userlink_unlink (link); + + /* Restore the set of blocked signals, and the intr_port slot. */ + ss->blocked = scp->sc_mask; + ss->intr_port = scp->sc_intr_port; + + /* Check for pending signals that were blocked by the old set. */ + if (_hurd_sigstate_pending (ss) & ~ss->blocked) + { + /* There are pending signals that just became unblocked. Wake up the + signal thread to deliver them. But first, squirrel away SCP where + the signal thread will notice it if it runs another handler, and + arrange to have us called over again in the new reality. */ + ss->context = scp; + _hurd_sigstate_unlock (ss); + __msg_sig_post (_hurd_msgport, 0, 0, __mach_task_self ()); + /* If a pending signal was handled, sig_post never returned. + If it did return, the pending signal didn't run a handler; + proceed as usual. */ + _hurd_sigstate_lock (ss); + ss->context = NULL; + } + + if (scp->sc_onstack) + ss->sigaltstack.ss_flags &= ~SS_ONSTACK; + + /* Destroy the MiG reply port used by the signal handler, and restore the + reply port in use by the thread when interrupted. */ + reply_port = THREAD_GETMEM (THREAD_SELF, reply_port); + THREAD_SETMEM (THREAD_SELF, reply_port, scp->sc_reply_port); + __mach_port_mod_refs (__mach_task_self (), reply_port, + MACH_PORT_RIGHT_RECEIVE, -1); + + if (scp->sc_fpused) + /* Restore the FPU state. Mach conveniently stores the state + in the format the i387 `frstor' instruction uses to restore it. */ + asm volatile ("frstor %0" : : "m" (scp->sc_fpsave)); + + { + /* There are convenient instructions to pop state off the stack, so we + copy the registers onto the user's stack, switch there, pop and + return. */ + + uintptr_t *usp = (uintptr_t *) scp->sc_ursp - 128; + + *--usp = scp->sc_rip; + *--usp = scp->sc_rfl; + *--usp = scp->sc_rax; + *--usp = scp->sc_rcx; + *--usp = scp->sc_rdx; + *--usp = scp->sc_rbx; + *--usp = scp->sc_rbp; + *--usp = scp->sc_rsi; + *--usp = scp->sc_rdi; + *--usp = scp->sc_r15; + *--usp = scp->sc_r14; + *--usp = scp->sc_r13; + *--usp = scp->sc_r12; + *--usp = scp->sc_r11; + *--usp = scp->sc_r10; + *--usp = scp->sc_r9; + *--usp = scp->sc_r8; + + /* Switch to the user's stack that we have just prepared, and jump off to + __sigreturn2. Clobber "memory" to make sure GCC flushes the stack + setup to actual memory. XXX: This ignores stack alignment requirements; + hopefully it's not going to matter since __sigreturn2 must not use the + FPU. */ + asm volatile ("movq %0, %%rsp\n" + "jmp __sigreturn2" : + : "rm" (usp), "D" (ss) + : "memory"); + __builtin_unreachable (); + } +} + +weak_alias (__sigreturn, sigreturn) -- 2.39.2
