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Re: [PATCH] hurd: libgcc unwinding support over signal trampolines
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From: |
Thomas Schwinge |
|
Subject: |
Re: [PATCH] hurd: libgcc unwinding support over signal trampolines |
|
Date: |
Thu, 18 Jun 2020 00:10:03 +0200 |
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User-agent: |
Notmuch/0.29.1+93~g67ed7df (https://notmuchmail.org) Emacs/26.3 (x86_64-pc-linux-gnu) |
Hi!
On 2020-06-08T13:49:55+0200, Samuel Thibault <samuel.thibault@gnu.org> wrote:
> Samuel Thibault, le lun. 08 juin 2020 13:36:55 +0200, a ecrit:
>> Thomas Schwinge, le lun. 08 juin 2020 12:15:12 +0200, a ecrit:
>> > Which GCC branches would you like this on?
>>
>> Ideally it's be backported to gcc 9 and 10, so that it lands naturally
>> in the Debian packages without having to bother doko.
>
> Actually only gcc 10 would be needed.
Well, it was easy enough to just put it onto all active branches, so I've
now pushed "hurd: libgcc unwinding support over signal trampolines" to
master branch in commit 5e2eebc80d6eeca24745c27a925afdb64292ed22,
releases/gcc-10 branch in commit
a2b187c13919987ca0444ab7c701f9f93ee536c2, releases/gcc-9 branch in commit
cd32b2c51b913eed517e9503009fb3f0822d9cab, releases/gcc-8 branch in commit
9c5787ea072e16f26c9950139c00ae28fddadd72, see attached.
Grüße
Thomas
-----------------
Mentor Graphics (Deutschland) GmbH, Arnulfstraße 201, 80634 München / Germany
Registergericht München HRB 106955, Geschäftsführer: Thomas Heurung, Alexander
Walter
>From 5e2eebc80d6eeca24745c27a925afdb64292ed22 Mon Sep 17 00:00:00 2001
From: Samuel Thibault <samuel.thibault@gnu.org>
Date: Fri, 29 May 2020 13:46:50 +0200
Subject: [PATCH] hurd: libgcc unwinding support over signal trampolines
libgcc/
* config.host (md_unwind_header) <i[34567]86-*-gnu*>: Set to
'i386/gnu-unwind.h'
* config/i386/gnu-unwind.h: New file.
Signed-off-by: Thomas Schwinge <thomas@codesourcery.com>
---
libgcc/config.host | 8 ++-
libgcc/config/i386/gnu-unwind.h | 107 ++++++++++++++++++++++++++++++++
2 files changed, 114 insertions(+), 1 deletion(-)
create mode 100644 libgcc/config/i386/gnu-unwind.h
diff --git a/libgcc/config.host b/libgcc/config.host
index 2cd420971675..044b34d53ccd 100644
--- a/libgcc/config.host
+++ b/libgcc/config.host
@@ -734,11 +734,17 @@ i[34567]86-*-linux*)
tm_file="${tm_file} i386/elf-lib.h"
md_unwind_header=i386/linux-unwind.h
;;
-i[34567]86-*-kfreebsd*-gnu | i[34567]86-*-gnu* |
i[34567]86-*-kopensolaris*-gnu)
+i[34567]86-*-kfreebsd*-gnu | i[34567]86-*-kopensolaris*-gnu)
extra_parts="$extra_parts crtprec32.o crtprec64.o crtprec80.o
crtfastmath.o"
tmake_file="${tmake_file} i386/t-crtpc t-crtfm i386/t-crtstuff
t-dfprules"
tm_file="${tm_file} i386/elf-lib.h"
;;
+i[34567]86-*-gnu*)
+ extra_parts="$extra_parts crtprec32.o crtprec64.o crtprec80.o
crtfastmath.o"
+ tmake_file="${tmake_file} i386/t-crtpc t-crtfm i386/t-crtstuff
t-dfprules"
+ tm_file="${tm_file} i386/elf-lib.h"
+ md_unwind_header=i386/gnu-unwind.h
+ ;;
x86_64-*-linux*)
extra_parts="$extra_parts crtprec32.o crtprec64.o crtprec80.o
crtfastmath.o"
tmake_file="${tmake_file} i386/t-crtpc t-crtfm i386/t-crtstuff
t-dfprules"
diff --git a/libgcc/config/i386/gnu-unwind.h b/libgcc/config/i386/gnu-unwind.h
new file mode 100644
index 000000000000..db47f0ac1d4b
--- /dev/null
+++ b/libgcc/config/i386/gnu-unwind.h
@@ -0,0 +1,107 @@
+/* DWARF2 EH unwinding support for GNU Hurd: x86.
+ Copyright (C) 2020 Free Software Foundation, Inc.
+ Contributed by Samuel Thibault <samuel.thibault@gnu.org>
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 3, or (at your option)
+any later version.
+
+GCC 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 General Public License for more details.
+
+Under Section 7 of GPL version 3, you are granted additional
+permissions described in the GCC Runtime Library Exception, version
+3.1, as published by the Free Software Foundation.
+
+You should have received a copy of the GNU General Public License and
+a copy of the GCC Runtime Library Exception along with this program;
+see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
+<http://www.gnu.org/licenses/>. */
+
+/* Do code reading to identify a signal frame, and set the frame
+ state data appropriately. See unwind-dw2.c for the structs. */
+
+#ifndef inhibit_libc
+
+#include <signal.h>
+
+#define MD_FALLBACK_FRAME_STATE_FOR x86_gnu_fallback_frame_state
+
+static _Unwind_Reason_Code
+x86_gnu_fallback_frame_state
+(struct _Unwind_Context *context, _Unwind_FrameState *fs)
+{
+ struct handler_args {
+ int signo;
+ int sigcode;
+ struct sigcontext *scp;
+ } *handler_args;
+ struct sigcontext *scp;
+ unsigned long usp;
+
+/*
+ * i386 sigtramp frame we are looking for follows.
+ * (see glibc/sysdeps/mach/hurd/i386/trampoline.c assembly)
+ *
+ * rpc_wait_trampoline:
+ * 0: b8 e7 ff ff ff mov $-25,%eax mach_msg_trap
+ * 5: 9a 00 00 00 00 07 00 lcall $7,$0
+ * 12: 89 01 movl %eax, (%ecx)
+ * 14: 89 dc movl %ebx, %esp switch to signal
stack
+ *
+ * trampoline:
+ * 16: ff d2 call *%edx call the handler
function
+ * RA HERE
+ * 18: 83 c4 0c addl $12, %esp pop its args
+ * 21: c3 ret return to
sigreturn
+ *
+ * firewall:
+ * 22: f4 hlt
+ */
+
+ if (!( *(unsigned int *)(context->ra ) == 0xc30cc483
+ && *(unsigned char *)(context->ra + 4) == 0xf4
+
+ && *(unsigned int *)(context->ra - 4) == 0xd2ffdc89
+ && *(unsigned int *)(context->ra - 8) == 0x01890007
+ && *(unsigned int *)(context->ra - 12) == 0x00000000
+ && *(unsigned int *)(context->ra - 16) == 0x9affffff
+ && *(unsigned short *)(context->ra - 18) == 0xe7b8))
+ return _URC_END_OF_STACK;
+
+ handler_args = context->cfa;
+ scp = handler_args->scp;
+ usp = scp->sc_uesp;
+
+ fs->regs.cfa_how = CFA_REG_OFFSET;
+ fs->regs.cfa_reg = 4;
+ fs->regs.cfa_offset = usp - (unsigned long) context->cfa;
+
+ fs->regs.reg[0].how = REG_SAVED_OFFSET;
+ fs->regs.reg[0].loc.offset = (unsigned long)&scp->sc_eax - usp;
+ fs->regs.reg[1].how = REG_SAVED_OFFSET;
+ fs->regs.reg[1].loc.offset = (unsigned long)&scp->sc_ecx - usp;
+ fs->regs.reg[2].how = REG_SAVED_OFFSET;
+ fs->regs.reg[2].loc.offset = (unsigned long)&scp->sc_edx - usp;
+ fs->regs.reg[3].how = REG_SAVED_OFFSET;
+ fs->regs.reg[3].loc.offset = (unsigned long)&scp->sc_ebx - usp;
+ fs->regs.reg[5].how = REG_SAVED_OFFSET;
+ fs->regs.reg[5].loc.offset = (unsigned long)&scp->sc_ebp - usp;
+ fs->regs.reg[6].how = REG_SAVED_OFFSET;
+ fs->regs.reg[6].loc.offset = (unsigned long)&scp->sc_esi - usp;
+ fs->regs.reg[7].how = REG_SAVED_OFFSET;
+ fs->regs.reg[7].loc.offset = (unsigned long)&scp->sc_edi - usp;
+ fs->regs.reg[8].how = REG_SAVED_OFFSET;
+ fs->regs.reg[8].loc.offset = (unsigned long)&scp->sc_eip - usp;
+ fs->retaddr_column = 8;
+ fs->signal_frame = 1;
+
+ return _URC_NO_REASON;
+}
+
+#endif /* ifndef inhibit_libc */
--
2.27.0
>From a2b187c13919987ca0444ab7c701f9f93ee536c2 Mon Sep 17 00:00:00 2001
From: Samuel Thibault <samuel.thibault@gnu.org>
Date: Fri, 29 May 2020 13:46:50 +0200
Subject: [PATCH] hurd: libgcc unwinding support over signal trampolines
libgcc/
* config.host (md_unwind_header) <i[34567]86-*-gnu*>: Set to
'i386/gnu-unwind.h'
* config/i386/gnu-unwind.h: New file.
Signed-off-by: Thomas Schwinge <thomas@codesourcery.com>
(cherry picked from commit 5e2eebc80d6eeca24745c27a925afdb64292ed22)
---
libgcc/config.host | 8 ++-
libgcc/config/i386/gnu-unwind.h | 107 ++++++++++++++++++++++++++++++++
2 files changed, 114 insertions(+), 1 deletion(-)
create mode 100644 libgcc/config/i386/gnu-unwind.h
diff --git a/libgcc/config.host b/libgcc/config.host
index 1ff41592337e..c529cc40f0c8 100644
--- a/libgcc/config.host
+++ b/libgcc/config.host
@@ -743,11 +743,17 @@ i[34567]86-*-linux*)
tm_file="${tm_file} i386/elf-lib.h"
md_unwind_header=i386/linux-unwind.h
;;
-i[34567]86-*-kfreebsd*-gnu | i[34567]86-*-gnu* |
i[34567]86-*-kopensolaris*-gnu)
+i[34567]86-*-kfreebsd*-gnu | i[34567]86-*-kopensolaris*-gnu)
extra_parts="$extra_parts crtprec32.o crtprec64.o crtprec80.o
crtfastmath.o"
tmake_file="${tmake_file} i386/t-crtpc t-crtfm i386/t-crtstuff
t-dfprules"
tm_file="${tm_file} i386/elf-lib.h"
;;
+i[34567]86-*-gnu*)
+ extra_parts="$extra_parts crtprec32.o crtprec64.o crtprec80.o
crtfastmath.o"
+ tmake_file="${tmake_file} i386/t-crtpc t-crtfm i386/t-crtstuff
t-dfprules"
+ tm_file="${tm_file} i386/elf-lib.h"
+ md_unwind_header=i386/gnu-unwind.h
+ ;;
x86_64-*-linux*)
extra_parts="$extra_parts crtprec32.o crtprec64.o crtprec80.o
crtfastmath.o"
tmake_file="${tmake_file} i386/t-crtpc t-crtfm i386/t-crtstuff
t-dfprules"
diff --git a/libgcc/config/i386/gnu-unwind.h b/libgcc/config/i386/gnu-unwind.h
new file mode 100644
index 000000000000..db47f0ac1d4b
--- /dev/null
+++ b/libgcc/config/i386/gnu-unwind.h
@@ -0,0 +1,107 @@
+/* DWARF2 EH unwinding support for GNU Hurd: x86.
+ Copyright (C) 2020 Free Software Foundation, Inc.
+ Contributed by Samuel Thibault <samuel.thibault@gnu.org>
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 3, or (at your option)
+any later version.
+
+GCC 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 General Public License for more details.
+
+Under Section 7 of GPL version 3, you are granted additional
+permissions described in the GCC Runtime Library Exception, version
+3.1, as published by the Free Software Foundation.
+
+You should have received a copy of the GNU General Public License and
+a copy of the GCC Runtime Library Exception along with this program;
+see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
+<http://www.gnu.org/licenses/>. */
+
+/* Do code reading to identify a signal frame, and set the frame
+ state data appropriately. See unwind-dw2.c for the structs. */
+
+#ifndef inhibit_libc
+
+#include <signal.h>
+
+#define MD_FALLBACK_FRAME_STATE_FOR x86_gnu_fallback_frame_state
+
+static _Unwind_Reason_Code
+x86_gnu_fallback_frame_state
+(struct _Unwind_Context *context, _Unwind_FrameState *fs)
+{
+ struct handler_args {
+ int signo;
+ int sigcode;
+ struct sigcontext *scp;
+ } *handler_args;
+ struct sigcontext *scp;
+ unsigned long usp;
+
+/*
+ * i386 sigtramp frame we are looking for follows.
+ * (see glibc/sysdeps/mach/hurd/i386/trampoline.c assembly)
+ *
+ * rpc_wait_trampoline:
+ * 0: b8 e7 ff ff ff mov $-25,%eax mach_msg_trap
+ * 5: 9a 00 00 00 00 07 00 lcall $7,$0
+ * 12: 89 01 movl %eax, (%ecx)
+ * 14: 89 dc movl %ebx, %esp switch to signal
stack
+ *
+ * trampoline:
+ * 16: ff d2 call *%edx call the handler
function
+ * RA HERE
+ * 18: 83 c4 0c addl $12, %esp pop its args
+ * 21: c3 ret return to
sigreturn
+ *
+ * firewall:
+ * 22: f4 hlt
+ */
+
+ if (!( *(unsigned int *)(context->ra ) == 0xc30cc483
+ && *(unsigned char *)(context->ra + 4) == 0xf4
+
+ && *(unsigned int *)(context->ra - 4) == 0xd2ffdc89
+ && *(unsigned int *)(context->ra - 8) == 0x01890007
+ && *(unsigned int *)(context->ra - 12) == 0x00000000
+ && *(unsigned int *)(context->ra - 16) == 0x9affffff
+ && *(unsigned short *)(context->ra - 18) == 0xe7b8))
+ return _URC_END_OF_STACK;
+
+ handler_args = context->cfa;
+ scp = handler_args->scp;
+ usp = scp->sc_uesp;
+
+ fs->regs.cfa_how = CFA_REG_OFFSET;
+ fs->regs.cfa_reg = 4;
+ fs->regs.cfa_offset = usp - (unsigned long) context->cfa;
+
+ fs->regs.reg[0].how = REG_SAVED_OFFSET;
+ fs->regs.reg[0].loc.offset = (unsigned long)&scp->sc_eax - usp;
+ fs->regs.reg[1].how = REG_SAVED_OFFSET;
+ fs->regs.reg[1].loc.offset = (unsigned long)&scp->sc_ecx - usp;
+ fs->regs.reg[2].how = REG_SAVED_OFFSET;
+ fs->regs.reg[2].loc.offset = (unsigned long)&scp->sc_edx - usp;
+ fs->regs.reg[3].how = REG_SAVED_OFFSET;
+ fs->regs.reg[3].loc.offset = (unsigned long)&scp->sc_ebx - usp;
+ fs->regs.reg[5].how = REG_SAVED_OFFSET;
+ fs->regs.reg[5].loc.offset = (unsigned long)&scp->sc_ebp - usp;
+ fs->regs.reg[6].how = REG_SAVED_OFFSET;
+ fs->regs.reg[6].loc.offset = (unsigned long)&scp->sc_esi - usp;
+ fs->regs.reg[7].how = REG_SAVED_OFFSET;
+ fs->regs.reg[7].loc.offset = (unsigned long)&scp->sc_edi - usp;
+ fs->regs.reg[8].how = REG_SAVED_OFFSET;
+ fs->regs.reg[8].loc.offset = (unsigned long)&scp->sc_eip - usp;
+ fs->retaddr_column = 8;
+ fs->signal_frame = 1;
+
+ return _URC_NO_REASON;
+}
+
+#endif /* ifndef inhibit_libc */
--
2.27.0
>From cd32b2c51b913eed517e9503009fb3f0822d9cab Mon Sep 17 00:00:00 2001
From: Samuel Thibault <samuel.thibault@gnu.org>
Date: Fri, 29 May 2020 13:46:50 +0200
Subject: [PATCH] hurd: libgcc unwinding support over signal trampolines
libgcc/
* config.host (md_unwind_header) <i[34567]86-*-gnu*>: Set to
'i386/gnu-unwind.h'
* config/i386/gnu-unwind.h: New file.
Signed-off-by: Thomas Schwinge <thomas@codesourcery.com>
(cherry picked from commit 5e2eebc80d6eeca24745c27a925afdb64292ed22)
---
libgcc/config.host | 8 ++-
libgcc/config/i386/gnu-unwind.h | 107 ++++++++++++++++++++++++++++++++
2 files changed, 114 insertions(+), 1 deletion(-)
create mode 100644 libgcc/config/i386/gnu-unwind.h
diff --git a/libgcc/config.host b/libgcc/config.host
index 18e306b48a52..bdbf77a3e629 100644
--- a/libgcc/config.host
+++ b/libgcc/config.host
@@ -679,11 +679,17 @@ i[34567]86-*-linux*)
tm_file="${tm_file} i386/elf-lib.h"
md_unwind_header=i386/linux-unwind.h
;;
-i[34567]86-*-kfreebsd*-gnu | i[34567]86-*-gnu* |
i[34567]86-*-kopensolaris*-gnu)
+i[34567]86-*-kfreebsd*-gnu | i[34567]86-*-kopensolaris*-gnu)
extra_parts="$extra_parts crtprec32.o crtprec64.o crtprec80.o
crtfastmath.o"
tmake_file="${tmake_file} i386/t-crtpc t-crtfm i386/t-crtstuff
t-dfprules"
tm_file="${tm_file} i386/elf-lib.h"
;;
+i[34567]86-*-gnu*)
+ extra_parts="$extra_parts crtprec32.o crtprec64.o crtprec80.o
crtfastmath.o"
+ tmake_file="${tmake_file} i386/t-crtpc t-crtfm i386/t-crtstuff
t-dfprules"
+ tm_file="${tm_file} i386/elf-lib.h"
+ md_unwind_header=i386/gnu-unwind.h
+ ;;
x86_64-*-linux*)
extra_parts="$extra_parts crtprec32.o crtprec64.o crtprec80.o
crtfastmath.o"
tmake_file="${tmake_file} i386/t-crtpc t-crtfm i386/t-crtstuff
t-dfprules"
diff --git a/libgcc/config/i386/gnu-unwind.h b/libgcc/config/i386/gnu-unwind.h
new file mode 100644
index 000000000000..db47f0ac1d4b
--- /dev/null
+++ b/libgcc/config/i386/gnu-unwind.h
@@ -0,0 +1,107 @@
+/* DWARF2 EH unwinding support for GNU Hurd: x86.
+ Copyright (C) 2020 Free Software Foundation, Inc.
+ Contributed by Samuel Thibault <samuel.thibault@gnu.org>
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 3, or (at your option)
+any later version.
+
+GCC 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 General Public License for more details.
+
+Under Section 7 of GPL version 3, you are granted additional
+permissions described in the GCC Runtime Library Exception, version
+3.1, as published by the Free Software Foundation.
+
+You should have received a copy of the GNU General Public License and
+a copy of the GCC Runtime Library Exception along with this program;
+see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
+<http://www.gnu.org/licenses/>. */
+
+/* Do code reading to identify a signal frame, and set the frame
+ state data appropriately. See unwind-dw2.c for the structs. */
+
+#ifndef inhibit_libc
+
+#include <signal.h>
+
+#define MD_FALLBACK_FRAME_STATE_FOR x86_gnu_fallback_frame_state
+
+static _Unwind_Reason_Code
+x86_gnu_fallback_frame_state
+(struct _Unwind_Context *context, _Unwind_FrameState *fs)
+{
+ struct handler_args {
+ int signo;
+ int sigcode;
+ struct sigcontext *scp;
+ } *handler_args;
+ struct sigcontext *scp;
+ unsigned long usp;
+
+/*
+ * i386 sigtramp frame we are looking for follows.
+ * (see glibc/sysdeps/mach/hurd/i386/trampoline.c assembly)
+ *
+ * rpc_wait_trampoline:
+ * 0: b8 e7 ff ff ff mov $-25,%eax mach_msg_trap
+ * 5: 9a 00 00 00 00 07 00 lcall $7,$0
+ * 12: 89 01 movl %eax, (%ecx)
+ * 14: 89 dc movl %ebx, %esp switch to signal
stack
+ *
+ * trampoline:
+ * 16: ff d2 call *%edx call the handler
function
+ * RA HERE
+ * 18: 83 c4 0c addl $12, %esp pop its args
+ * 21: c3 ret return to
sigreturn
+ *
+ * firewall:
+ * 22: f4 hlt
+ */
+
+ if (!( *(unsigned int *)(context->ra ) == 0xc30cc483
+ && *(unsigned char *)(context->ra + 4) == 0xf4
+
+ && *(unsigned int *)(context->ra - 4) == 0xd2ffdc89
+ && *(unsigned int *)(context->ra - 8) == 0x01890007
+ && *(unsigned int *)(context->ra - 12) == 0x00000000
+ && *(unsigned int *)(context->ra - 16) == 0x9affffff
+ && *(unsigned short *)(context->ra - 18) == 0xe7b8))
+ return _URC_END_OF_STACK;
+
+ handler_args = context->cfa;
+ scp = handler_args->scp;
+ usp = scp->sc_uesp;
+
+ fs->regs.cfa_how = CFA_REG_OFFSET;
+ fs->regs.cfa_reg = 4;
+ fs->regs.cfa_offset = usp - (unsigned long) context->cfa;
+
+ fs->regs.reg[0].how = REG_SAVED_OFFSET;
+ fs->regs.reg[0].loc.offset = (unsigned long)&scp->sc_eax - usp;
+ fs->regs.reg[1].how = REG_SAVED_OFFSET;
+ fs->regs.reg[1].loc.offset = (unsigned long)&scp->sc_ecx - usp;
+ fs->regs.reg[2].how = REG_SAVED_OFFSET;
+ fs->regs.reg[2].loc.offset = (unsigned long)&scp->sc_edx - usp;
+ fs->regs.reg[3].how = REG_SAVED_OFFSET;
+ fs->regs.reg[3].loc.offset = (unsigned long)&scp->sc_ebx - usp;
+ fs->regs.reg[5].how = REG_SAVED_OFFSET;
+ fs->regs.reg[5].loc.offset = (unsigned long)&scp->sc_ebp - usp;
+ fs->regs.reg[6].how = REG_SAVED_OFFSET;
+ fs->regs.reg[6].loc.offset = (unsigned long)&scp->sc_esi - usp;
+ fs->regs.reg[7].how = REG_SAVED_OFFSET;
+ fs->regs.reg[7].loc.offset = (unsigned long)&scp->sc_edi - usp;
+ fs->regs.reg[8].how = REG_SAVED_OFFSET;
+ fs->regs.reg[8].loc.offset = (unsigned long)&scp->sc_eip - usp;
+ fs->retaddr_column = 8;
+ fs->signal_frame = 1;
+
+ return _URC_NO_REASON;
+}
+
+#endif /* ifndef inhibit_libc */
--
2.27.0
>From 9c5787ea072e16f26c9950139c00ae28fddadd72 Mon Sep 17 00:00:00 2001
From: Samuel Thibault <samuel.thibault@gnu.org>
Date: Fri, 29 May 2020 13:46:50 +0200
Subject: [PATCH] hurd: libgcc unwinding support over signal trampolines
libgcc/
* config.host (md_unwind_header) <i[34567]86-*-gnu*>: Set to
'i386/gnu-unwind.h'
* config/i386/gnu-unwind.h: New file.
Signed-off-by: Thomas Schwinge <thomas@codesourcery.com>
(cherry picked from commit 5e2eebc80d6eeca24745c27a925afdb64292ed22)
---
libgcc/config.host | 8 ++-
libgcc/config/i386/gnu-unwind.h | 107 ++++++++++++++++++++++++++++++++
2 files changed, 114 insertions(+), 1 deletion(-)
create mode 100644 libgcc/config/i386/gnu-unwind.h
diff --git a/libgcc/config.host b/libgcc/config.host
index e436ade1a68c..677173eee432 100644
--- a/libgcc/config.host
+++ b/libgcc/config.host
@@ -651,11 +651,17 @@ i[34567]86-*-linux*)
tm_file="${tm_file} i386/elf-lib.h"
md_unwind_header=i386/linux-unwind.h
;;
-i[34567]86-*-kfreebsd*-gnu | i[34567]86-*-gnu* |
i[34567]86-*-kopensolaris*-gnu)
+i[34567]86-*-kfreebsd*-gnu | i[34567]86-*-kopensolaris*-gnu)
extra_parts="$extra_parts crtprec32.o crtprec64.o crtprec80.o
crtfastmath.o"
tmake_file="${tmake_file} i386/t-crtpc t-crtfm i386/t-crtstuff
t-dfprules"
tm_file="${tm_file} i386/elf-lib.h"
;;
+i[34567]86-*-gnu*)
+ extra_parts="$extra_parts crtprec32.o crtprec64.o crtprec80.o
crtfastmath.o"
+ tmake_file="${tmake_file} i386/t-crtpc t-crtfm i386/t-crtstuff
t-dfprules"
+ tm_file="${tm_file} i386/elf-lib.h"
+ md_unwind_header=i386/gnu-unwind.h
+ ;;
x86_64-*-linux*)
extra_parts="$extra_parts crtprec32.o crtprec64.o crtprec80.o
crtfastmath.o"
tmake_file="${tmake_file} i386/t-crtpc t-crtfm i386/t-crtstuff
t-dfprules"
diff --git a/libgcc/config/i386/gnu-unwind.h b/libgcc/config/i386/gnu-unwind.h
new file mode 100644
index 000000000000..db47f0ac1d4b
--- /dev/null
+++ b/libgcc/config/i386/gnu-unwind.h
@@ -0,0 +1,107 @@
+/* DWARF2 EH unwinding support for GNU Hurd: x86.
+ Copyright (C) 2020 Free Software Foundation, Inc.
+ Contributed by Samuel Thibault <samuel.thibault@gnu.org>
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 3, or (at your option)
+any later version.
+
+GCC 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 General Public License for more details.
+
+Under Section 7 of GPL version 3, you are granted additional
+permissions described in the GCC Runtime Library Exception, version
+3.1, as published by the Free Software Foundation.
+
+You should have received a copy of the GNU General Public License and
+a copy of the GCC Runtime Library Exception along with this program;
+see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
+<http://www.gnu.org/licenses/>. */
+
+/* Do code reading to identify a signal frame, and set the frame
+ state data appropriately. See unwind-dw2.c for the structs. */
+
+#ifndef inhibit_libc
+
+#include <signal.h>
+
+#define MD_FALLBACK_FRAME_STATE_FOR x86_gnu_fallback_frame_state
+
+static _Unwind_Reason_Code
+x86_gnu_fallback_frame_state
+(struct _Unwind_Context *context, _Unwind_FrameState *fs)
+{
+ struct handler_args {
+ int signo;
+ int sigcode;
+ struct sigcontext *scp;
+ } *handler_args;
+ struct sigcontext *scp;
+ unsigned long usp;
+
+/*
+ * i386 sigtramp frame we are looking for follows.
+ * (see glibc/sysdeps/mach/hurd/i386/trampoline.c assembly)
+ *
+ * rpc_wait_trampoline:
+ * 0: b8 e7 ff ff ff mov $-25,%eax mach_msg_trap
+ * 5: 9a 00 00 00 00 07 00 lcall $7,$0
+ * 12: 89 01 movl %eax, (%ecx)
+ * 14: 89 dc movl %ebx, %esp switch to signal
stack
+ *
+ * trampoline:
+ * 16: ff d2 call *%edx call the handler
function
+ * RA HERE
+ * 18: 83 c4 0c addl $12, %esp pop its args
+ * 21: c3 ret return to
sigreturn
+ *
+ * firewall:
+ * 22: f4 hlt
+ */
+
+ if (!( *(unsigned int *)(context->ra ) == 0xc30cc483
+ && *(unsigned char *)(context->ra + 4) == 0xf4
+
+ && *(unsigned int *)(context->ra - 4) == 0xd2ffdc89
+ && *(unsigned int *)(context->ra - 8) == 0x01890007
+ && *(unsigned int *)(context->ra - 12) == 0x00000000
+ && *(unsigned int *)(context->ra - 16) == 0x9affffff
+ && *(unsigned short *)(context->ra - 18) == 0xe7b8))
+ return _URC_END_OF_STACK;
+
+ handler_args = context->cfa;
+ scp = handler_args->scp;
+ usp = scp->sc_uesp;
+
+ fs->regs.cfa_how = CFA_REG_OFFSET;
+ fs->regs.cfa_reg = 4;
+ fs->regs.cfa_offset = usp - (unsigned long) context->cfa;
+
+ fs->regs.reg[0].how = REG_SAVED_OFFSET;
+ fs->regs.reg[0].loc.offset = (unsigned long)&scp->sc_eax - usp;
+ fs->regs.reg[1].how = REG_SAVED_OFFSET;
+ fs->regs.reg[1].loc.offset = (unsigned long)&scp->sc_ecx - usp;
+ fs->regs.reg[2].how = REG_SAVED_OFFSET;
+ fs->regs.reg[2].loc.offset = (unsigned long)&scp->sc_edx - usp;
+ fs->regs.reg[3].how = REG_SAVED_OFFSET;
+ fs->regs.reg[3].loc.offset = (unsigned long)&scp->sc_ebx - usp;
+ fs->regs.reg[5].how = REG_SAVED_OFFSET;
+ fs->regs.reg[5].loc.offset = (unsigned long)&scp->sc_ebp - usp;
+ fs->regs.reg[6].how = REG_SAVED_OFFSET;
+ fs->regs.reg[6].loc.offset = (unsigned long)&scp->sc_esi - usp;
+ fs->regs.reg[7].how = REG_SAVED_OFFSET;
+ fs->regs.reg[7].loc.offset = (unsigned long)&scp->sc_edi - usp;
+ fs->regs.reg[8].how = REG_SAVED_OFFSET;
+ fs->regs.reg[8].loc.offset = (unsigned long)&scp->sc_eip - usp;
+ fs->retaddr_column = 8;
+ fs->signal_frame = 1;
+
+ return _URC_NO_REASON;
+}
+
+#endif /* ifndef inhibit_libc */
--
2.27.0