From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from eggs.gnu.org (eggs.gnu.org [IPv6:2001:470:142:3::10]) by sourceware.org (Postfix) with ESMTPS id 781C93858413 for ; Sun, 30 Apr 2023 23:06:28 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 781C93858413 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=gnu.org Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=gnu.org Received: from fencepost.gnu.org ([2001:470:142:3::e]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ptG7f-00082V-75; Sun, 30 Apr 2023 19:06:27 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=gnu.org; s=fencepost-gnu-org; h=In-Reply-To:MIME-Version:References:Subject:To:From: Date; bh=6US/5EWEPRiGi2SuBr/Ug2OboRbSPkx9ebRwBLELuFI=; b=SRTC6QdqEFe2nd6vmgAX yuTirQsnGasfYRpPDDUyR7GXaqXDWeYZtx2HfIv0PFO9YPT2dl1gozOfao8Nz8gnunTFMYjfHwq1a S1SLK5MdM2VCNVBvSf0CIJIDpZXojqVr+r9acbyTxJwAkNII/nrD2tcoaXWg4lMSy9I+maTlIlvWU EKphpXvgP+/ION1diVKDtJJ1FsgOIobRyttCPKZfcvTQDV1zKplX42H59VJEQ91lXQQfZFGbe+zPV JijDmxYU310oMFLpGB8FYrM9Y76PDPEXxGWdPgAiUIrP0nmmRPdSVboSn4yfGXCN6sZ7ZXR37AQEe htdefg5lBSsVhQ==; Received: from [2a01:cb19:4a:a400:de41:a9ff:fe47:ec49] (helo=begin) by fencepost.gnu.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ptG7e-0006sQ-Ew; Sun, 30 Apr 2023 19:06:26 -0400 Received: from samy by begin with local (Exim 4.96) (envelope-from ) id 1ptG7c-00Ek3t-20; Mon, 01 May 2023 01:06:24 +0200 Date: Mon, 1 May 2023 01:06:24 +0200 From: Samuel Thibault To: Sergey Bugaev Cc: libc-alpha@sourceware.org, bug-hurd@gnu.org Subject: Re: [PATCH v3 1/6] hurd: Implement sigreturn for x86_64 Message-ID: <20230430230624.r4mc74yfkoyy54z7@begin> Mail-Followup-To: Sergey Bugaev , libc-alpha@sourceware.org, bug-hurd@gnu.org References: <20230429201822.2605207-1-bugaevc@gmail.com> <20230429201822.2605207-2-bugaevc@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20230429201822.2605207-2-bugaevc@gmail.com> Organization: I am not organized User-Agent: NeoMutt/20170609 (1.8.3) X-Spam-Status: No, score=-12.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,GIT_PATCH_0,KAM_NUMSUBJECT,KAM_SHORT,SPF_HELO_PASS,SPF_PASS,TXREP,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: Applied, thanks! Sergey Bugaev, le sam. 29 avril 2023 23:18:17 +0300, a ecrit: > Signed-off-by: Sergey Bugaev > --- > 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 > + . */ > + > +#include > +#include > +#include > +#include > + > +/* 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.