6 Commits

Author SHA1 Message Date
Thomas Gleixner
3461326e1a x86/extable: Rework the exception table mechanics
[ Upstream commit 46d28947d9876fc0f8f93d3c69813ef6e9852595 ]

The exception table entries contain the instruction address, the fixup
address and the handler address. All addresses are relative. Storing the
handler address has a few downsides:

 1) Most handlers need to be exported

 2) Handlers can be defined everywhere and there is no overview about the
    handler types

 3) MCE needs to check the handler type to decide whether an in kernel #MC
    can be recovered. The functionality of the handler itself is not in any
    way special, but for these checks there need to be separate functions
    which in the worst case have to be exported.

    Some of these 'recoverable' exception fixups are pretty obscure and
    just reuse some other handler to spare code. That obfuscates e.g. the
    #MC safe copy functions. Cleaning that up would require more handlers
    and exports

Rework the exception fixup mechanics by storing a fixup type number instead
of the handler address and invoke the proper handler for each fixup
type. Also teach the extable sort to leave the type field alone.

This makes most handlers static except for special cases like the MCE
MSR fixup and the BPF fixup. This allows to add more types for cleaning up
the obscure places without adding more handler code and exports.

There is a marginal code size reduction for a production config and it
removes _eight_ exported symbols.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lkml.kernel.org/r/20210908132525.211958725@linutronix.de
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-07-29 17:25:25 +02:00
Miles Chen
d09c38726c scripts/sorttable: riscv: fix undeclared identifier 'EM_RISCV' error
Fix the following build failure reported in [1] by adding a conditional
definition of EM_RISCV in order to allow cross-compilation on machines
which do not have EM_RISCV definition in their host.

   scripts/sorttable.c:352:7: error: use of undeclared identifier 'EM_RISCV'

EM_RISCV was added to <elf.h> in glibc 2.24 so builds on systems with
glibc headers < 2.24 should show this error.

[mkubecek@suse.cz: changelog addition]
Link: https://lore.kernel.org/lkml/e8965b25-f15b-c7b4-748c-d207dda9c8e8@i2se.com/ [1]
Link: https://lkml.kernel.org/r/20210913030625.4525-1-miles.chen@mediatek.com
Fixes: 54fed35fd393 ("riscv: Enable BUILDTIME_TABLE_SORT")
Signed-off-by: Miles Chen <miles.chen@mediatek.com>
Reported-by: Stefan Wahren <stefan.wahren@i2se.com>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Jisheng Zhang <jszhang@kernel.org>
Cc: Michal Kubecek <mkubecek@suse.cz>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Markus Mayer <mmayer@broadcom.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-09-24 16:13:35 -07:00
Jisheng Zhang
54fed35fd3
riscv: Enable BUILDTIME_TABLE_SORT
Enable BUILDTIME_TABLE_SORT to sort the exception table at build time
rather than during boot.

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-09-10 23:59:44 -07:00
Ilya Leoshkevich
05a68e892e s390/kernel: expand exception table logic to allow new handling options
This is a s390 port of commit 548acf19234d ("x86/mm: Expand the
exception table logic to allow new handling options"), which is needed
for implementing BPF_PROBE_MEM on s390.

The new handler field is made 64-bit in order to allow pointing from
dynamically allocated entries to handlers in kernel text. Unlike on x86,
NULL is used instead of ex_handler_default. This is because exception
tables are used by boot/text_dma.S, and it would be a pain to preserve
ex_handler_default.

The new infrastructure is ignored in early_pgm_check_handler, since
there is no pt_regs.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2020-07-20 10:55:50 +02:00
Shile Zhang
57fa189942 scripts/sorttable: Implement build-time ORC unwind table sorting
The ORC unwinder has two tables: .orc_unwind_ip and .orc_unwind, which
need to be sorted for binary search. Previously this sorting was done
during bootup.

Sort them at build time to speed up booting.

Add the ORC tables sorting in a parallel build process to speed up the build.

[ mingo: Rewrote the changelog and fixed some comments. ]

Suggested-by: Andy Lutomirski <luto@amacapital.net>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Shile Zhang <shile.zhang@linux.alibaba.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Michal Marek <michal.lkml@markovi.net>
Cc: linux-kbuild@vger.kernel.org
Link: https://lkml.kernel.org/r/20191204004633.88660-7-shile.zhang@linux.alibaba.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-12-13 10:47:58 +01:00
Shile Zhang
1091670637 scripts/sorttable: Rename 'sortextable' to 'sorttable'
Use a more generic name for additional table sorting usecases,
such as the upcoming ORC table sorting feature. This tool is
not tied to exception table sorting anymore.

No functional changes intended.

[ mingo: Rewrote the changelog. ]

Signed-off-by: Shile Zhang <shile.zhang@linux.alibaba.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Michal Marek <michal.lkml@markovi.net>
Cc: linux-kbuild@vger.kernel.org
Link: https://lkml.kernel.org/r/20191204004633.88660-6-shile.zhang@linux.alibaba.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-12-13 10:47:58 +01:00