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([2a00:1370:818c:4a57:a7ac:6f45:1787:abcc]) by smtp.gmail.com with ESMTPSA id h25-20020ac250d9000000b004eb09820adbsm3905451lfm.105.2023.04.29.13.18.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 29 Apr 2023 13:18:26 -0700 (PDT) From: Sergey Bugaev To: libc-alpha@sourceware.org Cc: bug-hurd@gnu.org, Samuel Thibault Subject: [PATCH v3 2/6] hurd: Implement longjmp for x86_64 Date: Sat, 29 Apr 2023 23:18:18 +0300 Message-Id: <20230429201822.2605207-3-bugaevc@gmail.com> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230429201822.2605207-1-bugaevc@gmail.com> References: <20230429201822.2605207-1-bugaevc@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-10.6 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FROM,GIT_PATCH_0,KAM_NUMSUBJECT,KAM_SHORT,RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,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: 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