[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[PATCH v3 2/6] hurd: Implement longjmp for x86_64
|
From: |
Sergey Bugaev |
|
Subject: |
[PATCH v3 2/6] hurd: Implement longjmp for x86_64 |
|
Date: |
Sat, 29 Apr 2023 23:18:18 +0300 |
Checked on x86_64-gnu.
Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
---
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
+ <https://www.gnu.org/licenses/>. */
+
+#include <sysdep.h>
+#include <pointer_guard.h>
+#include <jmpbuf-offsets.h>
+#include <asm-syntax.h>
+#include <tcb-offsets.h>
+#include <jmp_buf-ssp.h>
+#include <signal-defines.h>
+
+#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
+ <https://www.gnu.org/licenses/>. */
+
+#include <sysdep.h>
+#include <pointer_guard.h>
+#include <jmpbuf-offsets.h>
+#include <asm-syntax.h>
+#include <tcb-offsets.h>
+#include <jmp_buf-ssp.h>
+#include <signal-defines.h>
+
+#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
- [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
- [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 <=
- [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