Unwind hints are useful to provide objtool with information about stack
states in non-standard functions/code.
While the type of information being provided might be very arch
specific, the mechanism to provide the information can be useful for
other architectures.
Move the relevant unwint hint definitions for all architectures to
see.
[ jpoimboe: REGS_IRET -> REGS_PARTIAL ]
Signed-off-by: Julien Thierry <jthierry@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Objtool currently only compiles for x86 architectures. This is
fine as it presently does not support tooling for other
architectures. However, we would like to be able to convert other
kernel tools to run as objtool sub commands because they too
process ELF object files. This will allow us to convert tools
such as recordmcount to use objtool's ELF code.
Since much of recordmcount's ELF code is copy-paste code to/from
a variety of other kernel tools (look at modpost for example) this
means that if we can convert recordmcount we can convert more.
We define weak definitions for subcommand entry functions and other weak
definitions for shared functions critical to building existing
subcommands. These return 127 when the command is missing which signify
tools that do not exist on all architectures. In this case the "check"
and "orc" tools do not exist on all architectures so we only add them
for x86. Future changes adding support for "check", to arm64 for
example, can then modify the SUBCMD_CHECK variable when building for
arm64.
Objtool is not currently wired in to KConfig to be built for other
architectures because it's not needed for those architectures and
there are no commands it supports other than those for x86. As more
command support is enabled on various architectures the necessary
KConfig changes can be made (e.g. adding "STACK_VALIDATION") to
trigger building objtool.
[ jpoimboe: remove aliases, add __weak macro, add error messages ]
Cc: Julien Thierry <jthierry@redhat.com>
Signed-off-by: Matt Helsley <mhelsley@vmware.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Historically, the relocation symbols for ORC entries have only been
section symbols:
.text+0: sp:sp+8 bp:(und) type:call end:0
However, the Clang assembler is aggressive about stripping section
symbols. In that case we will need to use function symbols:
freezing_slow_path+0: sp:sp+8 bp:(und) type:call end:0
In preparation for the generation of such entries in "objtool orc
generate", add support for reading them in "objtool orc dump".
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/b811b5eb1a42602c3b523576dc5efab9ad1c174d.1585761021.git.jpoimboe@redhat.com
Based on 2 normalized pattern(s):
this program 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 2 of the license or at
your option any later version this program 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 you
should have received a copy of the gnu general public license along
with this program if not see http www gnu org licenses
this program 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 2 of the license or at
your option any later version this program 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 [based]
[from] [clk] [highbank] [c] you should have received a copy of the
gnu general public license along with this program if not see http
www gnu org licenses
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-or-later
has been chosen to replace the boilerplate/reference in 355 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Jilayne Lovejoy <opensource@jilayne.com>
Reviewed-by: Steve Winslow <swinslow@gmail.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190519154041.837383322@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The existing UNWIND_HINT_EMPTY annotations happen to be good indicators
of where entry code calls into C code for the first time. So also use
them to mark the end of the stack for the ORC unwinder.
Use that information to set unwind->error if the ORC unwinder doesn't
unwind all the way to the end. This will be needed for enabling
HAVE_RELIABLE_STACKTRACE for the ORC unwinder so we can use it with the
livepatch consistency model.
Thanks to Jiri Slaby for teaching the ORCs about the unwind hints.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/lkml/20180518064713.26440-5-jslaby@suse.cz
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The new ORC unwinder breaks the build of a 64-bit kernel on a 32-bit
host. Building the kernel on a i386 or x32 host fails with:
orc_dump.c: In function 'orc_dump':
orc_dump.c:105:26: error: passing argument 2 of 'elf_getshdrnum' from incompatible pointer type [-Werror=incompatible-pointer-types]
if (elf_getshdrnum(elf, &nr_sections)) {
^
In file included from /usr/local/include/gelf.h:32:0,
from elf.h:22,
from warn.h:26,
from orc_dump.c:20:
/usr/local/include/libelf.h:304:12: note: expected 'size_t * {aka unsigned int *}' but argument is of type 'long unsigned int *'
extern int elf_getshdrnum (Elf *__elf, size_t *__dst);
^~~~~~~~~~~~~~
orc_dump.c:190:17: error: format '%lx' expects argument of type 'long unsigned int', but argument 3 has type 'Elf64_Sxword {aka long long int}' [-Werror=format=]
printf("%s+%lx:", name, rela.r_addend);
~~^ ~~~~~~~~~~~~~
%llx
Fix the build failure.
Another problem is that if the user specifies HOSTCC or HOSTLD
variables, they are ignored in the objtool makefile. Change the
Makefile to respect these variables.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sven Joachim <svenjoac@gmx.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 627fce1480 ("objtool: Add ORC unwind table generation")
Link: http://lkml.kernel.org/r/19f0e64d8e07e30a7b307cd010eb780c404fe08d.1512252895.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Now that objtool knows the states of all registers on the stack for each
instruction, it's straightforward to generate debuginfo for an unwinder
to use.
Instead of generating DWARF, generate a new format called ORC, which is
more suitable for an in-kernel unwinder. See
Documentation/x86/orc-unwinder.txt for a more detailed description of
this new debuginfo format and why it's preferable to DWARF.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/c9b9f01ba6c5ed2bdc9bb0957b78167fdbf9632e.1499786555.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Julien Thierry