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Re: [PATCH v3 1/6] hurd: Implement sigreturn for x86_64
From: |
Samuel Thibault |
Subject: |
Re: [PATCH v3 1/6] hurd: Implement sigreturn for x86_64 |
Date: |
Mon, 1 May 2023 01:06:24 +0200 |
User-agent: |
NeoMutt/20170609 (1.8.3) |
Applied, thanks!
Sergey Bugaev, le sam. 29 avril 2023 23:18:17 +0300, a ecrit:
> Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
> ---
> This incorporates back the fix made to the i386 version: we do need to call
> _hurd_self_sigstate () once after all.
>
> sysdeps/mach/hurd/x86_64/sigreturn.c | 162 +++++++++++++++++++++++++++
> 1 file changed, 162 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..82247e3c
> --- /dev/null
> +++ b/sysdeps/mach/hurd/x86_64/sigreturn.c
> @@ -0,0 +1,162 @@
> +/* 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, uintptr_t *usp,
> + struct sigcontext *scp)
> +{
> + mach_port_t reply_port;
> + _hurd_sigstate_unlock (ss);
> +
> + /* Destroy the MiG reply port used by the signal handler, and restore the
> + reply port in use by the thread when interrupted.
> +
> + We cannot use the original reply port for our RPCs that we do here,
> since
> + we could unexpectedly receive/consume a reply message meant for the user
> + (in particular, msg_sig_post_reply), and also since we would deallocate
> + the port if *our* RPC fails, which we don't want to do since the user
> + still has the old name. And so, temporarily set MACH_PORT_DEAD as our
> + reply name, and make sure destroying the port is the very last RPC we
> + do. */
> + reply_port = THREAD_GETMEM (THREAD_SELF, reply_port);
> + THREAD_SETMEM (THREAD_SELF, reply_port, MACH_PORT_DEAD);
> + if (__glibc_likely (MACH_PORT_VALID (reply_port)))
> + (void) __mach_port_mod_refs (__mach_task_self (), reply_port,
> + MACH_PORT_RIGHT_RECEIVE, -1);
> + THREAD_SETMEM (THREAD_SELF, reply_port, scp->sc_reply_port);
> +
> + 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];
> +
> + if (__glibc_unlikely (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;
> +
> + 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 call
> + __sigreturn2. Clobber "memory" to make sure GCC flushes the stack
> + setup to actual memory. We align the stack as per the ABI, but pass
> + the original usp to __sigreturn2 as an argument. */
> + asm volatile ("movq %1, %%rsp\n"
> + "andq $-16, %%rsp\n"
> + "call __sigreturn2" :
> + : "D" (ss), "S" (usp), "d" (scp)
> + : "memory");
> + __builtin_unreachable ();
> + }
> +}
> +
> +weak_alias (__sigreturn, sigreturn)
> --
> 2.40.1
>
--
Samuel
---
Pour une évaluation indépendante, transparente et rigoureuse !
Je soutiens la Commission d'Évaluation de l'Inria.
- [PATCH v3 0/6] The remaining x86_64-gnu patches, Sergey Bugaev, 2023/04/29
- [PATCH v3 1/6] hurd: Implement sigreturn for x86_64, Sergey Bugaev, 2023/04/29
- Re: [PATCH v3 1/6] hurd: Implement sigreturn for x86_64,
Samuel Thibault <=
- [RFC PATCH v3 3/6] hurd: Replace reply port with a dead name on failed interruption, Sergey Bugaev, 2023/04/29
- [PATCH v3 2/6] hurd: Implement longjmp for x86_64, Sergey Bugaev, 2023/04/29
- [RFC PATCH v3 5/6] hurd: Make it possible to call memcpy very early, Sergey Bugaev, 2023/04/29
- [DO NOT PUSH PATCH v3 6/6] TMP hurd: Lower BRK_START, Sergey Bugaev, 2023/04/29
- [PATCH v3 4/6] hurd: Add expected abilist files for x86_64, Sergey Bugaev, 2023/04/29