linux/tools/objtool
Peter Zijlstra ba08abca66 objtool,x86: Fix uaccess PUSHF/POPF validation
Commit ab234a260b ("x86/pv: Rework arch_local_irq_restore() to not
use popf") replaced "push %reg; popf" with something like: "test
$0x200, %reg; jz 1f; sti; 1:", which breaks the pushf/popf symmetry
that commit ea24213d80 ("objtool: Add UACCESS validation") relies
on.

The result is:

  drivers/gpu/drm/amd/amdgpu/si.o: warning: objtool: si_common_hw_init()+0xf36: PUSHF stack exhausted

Meanwhile, commit c9c324dc22 ("objtool: Support stack layout changes
in alternatives") makes that we can actually use stack-ops in
alternatives, which means we can revert 1ff865e343 ("x86,smap: Fix
smap_{save,restore}() alternatives").

That in turn means we can limit the PUSHF/POPF handling of
ea24213d80 to those instructions that are in alternatives.

Fixes: ab234a260b ("x86/pv: Rework arch_local_irq_restore() to not use popf")
Reported-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lkml.kernel.org/r/YEY4rIbQYa5fnnEp@hirez.programming.kicks-ass.net
2021-03-12 09:15:49 +01:00
..
arch/x86 objtool,x86: Additionally decode: mov %rsp, (%reg) 2021-02-10 20:53:52 +01:00
Documentation objtool: Support stack layout changes in alternatives 2021-01-14 09:53:54 -06:00
include/objtool clang-lto for v5.12-rc1 (part2) 2021-02-23 15:13:45 -08:00
.gitignore objtool: Rework header include paths 2021-01-13 18:13:14 -06:00
Build objtool: Enable compilation of objtool for all architectures 2020-05-20 09:17:28 -05:00
builtin-check.c clang-lto for v5.12-rc1 (part2) 2021-02-23 15:13:45 -08:00
builtin-orc.c objtool: Refactor ORC section generation 2021-01-14 09:53:42 -06:00
check.c objtool,x86: Fix uaccess PUSHF/POPF validation 2021-03-12 09:15:49 +01:00
elf.c objtool updates: 2021-02-23 09:56:13 -08:00
Makefile objtool: Refactor ORC section generation 2021-01-14 09:53:42 -06:00
objtool.c clang-lto for v5.12-rc1 (part2) 2021-02-23 15:13:45 -08:00
orc_dump.c x86/unwind/orc: Change REG_SP_INDIRECT 2021-02-10 20:53:51 +01:00
orc_gen.c objtool: Support stack layout changes in alternatives 2021-01-14 09:53:54 -06:00
special.c objtool: Rework header include paths 2021-01-13 18:13:14 -06:00
sync-check.sh objtool: Make unwind hint definitions available to other architectures 2020-09-10 10:43:13 -05:00
weak.c objtool: Refactor ORC section generation 2021-01-14 09:53:42 -06:00