[RFC PATCH glibc 30/34] hurd: Implement longjmp for x86_64

[Sergey Bugaev]

Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
---
 sysdeps/mach/hurd/x86_64/____longjmp_chk.S | 134 +++++++++++++++++++++
 sysdeps/mach/hurd/x86_64/__longjmp.S       | 102 ++++++++++++++++
 2 files changed, 236 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..29f6c8c3
--- /dev/null
+++ b/sysdeps/mach/hurd/x86_64/____longjmp_chk.S
@@ -0,0 +1,134 @@
+/* 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
+
+
+#ifdef PIC
+# 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
+#else
+# define CALL_FAIL     sub     $8, %RSP_LP;                                  \
+                       cfi_remember_state;                                   \
+                       cfi_def_cfa_offset(16);                               \
+                       mov     $longjmp_msg, %RDI_LP;                        \
+                       call    HIDDEN_JUMPTARGET(__fortify_fail);            \
+                       nop;                                                  \
+                       cfi_restore_state
+#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_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)
+# ifdef PIC
+       movb    __libc_tls_initialized(%rip), %r10b
+# else
+       mobv    $__libc_tls_initialized, %r10b
+# endif
+       testb   %r10b, %r10b
+       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..9bbcfb2f
--- /dev/null
+++ b/sysdeps/mach/hurd/x86_64/__longjmp.S
@@ -0,0 +1,102 @@
+/* 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)
+# ifdef PIC
+       movb    __libc_tls_initialized(%rip), %r10b
+# else
+       mobv    $__libc_tls_initialized, %r10b
+# endif
+       testb   %r10b, %r10b
+       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)
-- 
2.39.2