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 23C1B3858C66 for ; Sun, 30 Apr 2023 23:16:33 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 23C1B3858C66 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 1ptGHQ-0001JF-F3; Sun, 30 Apr 2023 19:16:32 -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=47fZxwGL7b12lLxNS3Zu72fUkbFVXJlrNcwb7tYNUcU=; b=n9ihzfDxLVnnleysg9HJ c+HVuLhtMTCw6dcpvWfOwHzASEZzIny7ZV2jkKSJz/5wQPf4ALIynmBuwmgJxO836zkony2n+NikL tav74fwCoepWk8LztR3CwSlFQItQvuxBDx6zbUuuYh8A2xiyDQfBFBG1HDggoaWAQMb7V94v3m6ik ylKSPYXfBs9tdxo033wfe870doHWynKhWvhyZlX7pov2ubBZ771qYmw/r8rwiwX6YUvfSr1//KwuV 1+nMyN8Arnlil4yefusxnlSwbuB/x+QmUgjnXHLd1JbnRNFNkKq8oZRHwhLZ53PZX6YmNpz47oiCG iQRYwI2zOqBcbw==; 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 1ptGHP-0007hc-Hk; Sun, 30 Apr 2023 19:16:31 -0400 Received: from samy by begin with local (Exim 4.96) (envelope-from ) id 1ptGHM-00EkWq-1K; Mon, 01 May 2023 01:16:28 +0200 Date: Mon, 1 May 2023 01:16:28 +0200 From: Samuel Thibault To: Sergey Bugaev Cc: libc-alpha@sourceware.org, bug-hurd@gnu.org Subject: Re: [PATCH v3 2/6] hurd: Implement longjmp for x86_64 Message-ID: <20230430231628.264kw5xqnkfjqfww@begin> Mail-Followup-To: Sergey Bugaev , libc-alpha@sourceware.org, bug-hurd@gnu.org References: <20230429201822.2605207-1-bugaevc@gmail.com> <20230429201822.2605207-3-bugaevc@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20230429201822.2605207-3-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 23:18:18 +0300, a ecrit: > Checked on x86_64-gnu. > > Signed-off-by: Sergey Bugaev > --- > I have checked that setjmp/longjmp actually works sucessfully, with both > __longjmp and ____longjmp_chk. I have not been able to check w/ sigaltstack > because we don't yet have the proc server and signals. > > Changes since v1: > - drop the separate non-PIC version, we can always use %rip-relative access > on x86_64, and that's what the compiler generates anyway even with -fno-pic; > - use "cmpb $0, __libc_tls_initialized(%rip)" over > "movb __libc_tls_initialized(%rip), %r10b; testb %r10b, %r10b" -- the former > is what the compiler generates, so better be consistent. > > sysdeps/mach/hurd/x86_64/____longjmp_chk.S | 118 +++++++++++++++++++++ > sysdeps/mach/hurd/x86_64/__longjmp.S | 96 +++++++++++++++++ > 2 files changed, 214 insertions(+) > create mode 100644 sysdeps/mach/hurd/x86_64/____longjmp_chk.S > create mode 100644 sysdeps/mach/hurd/x86_64/__longjmp.S > > diff --git a/sysdeps/mach/hurd/x86_64/____longjmp_chk.S b/sysdeps/mach/hurd/x86_64/____longjmp_chk.S > new file mode 100644 > index 00000000..935b8575 > --- /dev/null > +++ b/sysdeps/mach/hurd/x86_64/____longjmp_chk.S > @@ -0,0 +1,118 @@ > +/* Checked longjmp support. x86_64 Hurd version. > + Copyright (C) 2001-2023 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 > +#include > +#include > +#include > + > +#define SS_ONSTACK 1 > + > +/* Don't restore shadow stack register if shadow stack isn't enabled. */ > +#if !SHSTK_ENABLED > +# undef SHADOW_STACK_POINTER_OFFSET > +#endif > + > + .section .rodata.str1.1,"aMS",@progbits,1 > + .type longjmp_msg,@object > +longjmp_msg: > + .string "longjmp causes uninitialized stack frame" > + .size longjmp_msg, .-longjmp_msg > + > + > +# define CALL_FAIL sub $8, %RSP_LP; \ > + cfi_remember_state; \ > + cfi_def_cfa_offset(16); \ > + lea longjmp_msg(%rip), %RDI_LP; \ > + call HIDDEN_JUMPTARGET(__fortify_fail); \ > + nop; \ > + cfi_restore_state > + > +/* Jump to the position specified by ENV, causing the > + setjmp call there to return VAL, or 1 if VAL is 0. > + void __longjmp (__jmp_buf env, int val). */ > + .text > +ENTRY(____longjmp_chk) > + /* Restore registers. */ > + mov (JB_RSP*8)(%rdi), %R8_LP > + mov (JB_RBP*8)(%rdi),%R9_LP > + mov (JB_PC*8)(%rdi), %RDX_LP > +#ifdef PTR_DEMANGLE > + PTR_DEMANGLE (%R8_LP) > + PTR_DEMANGLE (%R9_LP) > + PTR_DEMANGLE (%RDX_LP) > +#endif > + > +#if !defined (SHARED) || IS_IN (rtld) > + cmpb $0, __libc_tls_initialized(%rip) > + jz .Lok /* TLS not initialized yet */ > +#endif > + > + movq %fs:SIGSTATE_OFFSET, %R10_LP > + testq %R10_LP, %R10_LP > + jz .Lok /* sigstate not initialized yet */ > + > + testl $SS_ONSTACK, (HURD_SIGSTATE__SIGALTSTACK__OFFSET + SIGALTSTACK__SS_FLAGS__OFFSET)(%R10_LP) > + jnz .Lonstack > + > + /* We were on the main stack. Jumping to a higher-address > + frame is always allowed, otherwise it's not allowed. */ > + cmp %R8_LP, %RSP_LP > + jbe .Lok > + > +.Lfail: CALL_FAIL > + > +.Lonstack: > + cmpq (HURD_SIGSTATE__SIGALTSTACK__OFFSET + SIGALTSTACK__SS_SP__OFFSET)(%R10_LP), %R8_LP > + jb .Loks /* Jumping below the altstack, switch */ > + > + movq (HURD_SIGSTATE__SIGALTSTACK__OFFSET + SIGALTSTACK__SS_SP__OFFSET)(%R10_LP), %R11_LP > + addq (HURD_SIGSTATE__SIGALTSTACK__OFFSET + SIGALTSTACK__SS_SIZE__OFFSET)(%R10_LP), %R11_LP > + cmpq %R11_LP, %R8_LP > + jb .Lok /* Jumping inside the altstack, do not switch */ > + > + /* Jumping above the altstack, switch */ > + > +.Loks: > + andl $~(SS_ONSTACK), (HURD_SIGSTATE__SIGALTSTACK__OFFSET + SIGALTSTACK__SS_FLAGS__OFFSET)(%R10_LP) > + > +.Lok: > + /* We add unwind information for the target here. */ > + cfi_def_cfa(%rdi, 0) > + cfi_register(%rsp,%r8) > + cfi_register(%rbp,%r9) > + cfi_register(%rip,%rdx) > + cfi_offset(%rbx,JB_RBX*8) > + cfi_offset(%r12,JB_R12*8) > + cfi_offset(%r13,JB_R13*8) > + cfi_offset(%r14,JB_R14*8) > + cfi_offset(%r15,JB_R15*8) > + movq (JB_RBX*8)(%rdi), %rbx > + movq (JB_R12*8)(%rdi), %r12 > + movq (JB_R13*8)(%rdi), %r13 > + movq (JB_R14*8)(%rdi), %r14 > + movq (JB_R15*8)(%rdi), %r15 > + /* Set return value for setjmp. */ > + movl %esi, %eax > + mov %R8_LP, %RSP_LP > + movq %r9,%rbp > + jmpq *%rdx > +END (____longjmp_chk) > diff --git a/sysdeps/mach/hurd/x86_64/__longjmp.S b/sysdeps/mach/hurd/x86_64/__longjmp.S > new file mode 100644 > index 00000000..389c1d16 > --- /dev/null > +++ b/sysdeps/mach/hurd/x86_64/__longjmp.S > @@ -0,0 +1,96 @@ > +/* longjmp support. x86_64/Hurd version. > + Copyright (C) 2001-2023 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 > +#include > +#include > +#include > + > +#define SS_ONSTACK 1 > + > +/* Don't restore shadow stack register if shadow stack isn't enabled. */ > +#if !SHSTK_ENABLED > +# undef SHADOW_STACK_POINTER_OFFSET > +#endif > + > +/* Jump to the position specified by ENV, causing the > + setjmp call there to return VAL, or 1 if VAL is 0. > + void __longjmp (__jmp_buf env, int val). */ > + .text > +ENTRY(__longjmp) > + /* Restore registers. */ > + mov (JB_RSP*8)(%rdi), %R8_LP > + mov (JB_RBP*8)(%rdi),%R9_LP > + mov (JB_PC*8)(%rdi), %RDX_LP > +#ifdef PTR_DEMANGLE > + PTR_DEMANGLE (%R8_LP) > + PTR_DEMANGLE (%R9_LP) > + PTR_DEMANGLE (%RDX_LP) > +#endif > + > +#if !defined (SHARED) || IS_IN (rtld) > + cmpb $0, __libc_tls_initialized(%rip) > + jz .Lok /* TLS not initialized yet */ > +#endif > + > + movq %fs:SIGSTATE_OFFSET, %R10_LP > + testq %R10_LP, %R10_LP > + jz .Lok /* sigstate not initialized yet */ > + > + testl $SS_ONSTACK, (HURD_SIGSTATE__SIGALTSTACK__OFFSET + SIGALTSTACK__SS_FLAGS__OFFSET)(%R10_LP) > + jz .Lok > + > +.Lonstack: > + cmpq (HURD_SIGSTATE__SIGALTSTACK__OFFSET + SIGALTSTACK__SS_SP__OFFSET)(%R10_LP), %R8_LP > + jb .Loks /* Jumping below the altstack, switch */ > + > + movq (HURD_SIGSTATE__SIGALTSTACK__OFFSET + SIGALTSTACK__SS_SP__OFFSET)(%R10_LP), %R11_LP > + addq (HURD_SIGSTATE__SIGALTSTACK__OFFSET + SIGALTSTACK__SS_SIZE__OFFSET)(%R10_LP), %R11_LP > + cmpq %R11_LP, %R8_LP > + jb .Lok /* Jumping inside the altstack, do not switch */ > + > + /* Jumping above the altstack, switch */ > + > +.Loks: > + andl $~(SS_ONSTACK), (HURD_SIGSTATE__SIGALTSTACK__OFFSET + SIGALTSTACK__SS_FLAGS__OFFSET)(%R10_LP) > + > +.Lok: > + /* We add unwind information for the target here. */ > + cfi_def_cfa(%rdi, 0) > + cfi_register(%rsp,%r8) > + cfi_register(%rbp,%r9) > + cfi_register(%rip,%rdx) > + cfi_offset(%rbx,JB_RBX*8) > + cfi_offset(%r12,JB_R12*8) > + cfi_offset(%r13,JB_R13*8) > + cfi_offset(%r14,JB_R14*8) > + cfi_offset(%r15,JB_R15*8) > + movq (JB_RBX*8)(%rdi), %rbx > + movq (JB_R12*8)(%rdi), %r12 > + movq (JB_R13*8)(%rdi), %r13 > + movq (JB_R14*8)(%rdi), %r14 > + movq (JB_R15*8)(%rdi), %r15 > + /* Set return value for setjmp. */ > + movl %esi, %eax > + mov %R8_LP, %RSP_LP > + movq %r9,%rbp > + jmpq *%rdx > +END (__longjmp) > -- > 2.40.1 > -- Samuel --- Pour une évaluation indépendante, transparente et rigoureuse ! Je soutiens la Commission d'Évaluation de l'Inria.