linux/tools/objtool
Peter Zijlstra a149180fbc x86: Add magic AMD return-thunk
Note: needs to be in a section distinct from Retpolines such that the
Retpoline RET substitution cannot possibly use immediate jumps.

ORC unwinding for zen_untrain_ret() and __x86_return_thunk() is a
little tricky but works due to the fact that zen_untrain_ret() doesn't
have any stack ops and as such will emit a single ORC entry at the
start (+0x3f).

Meanwhile, unwinding an IP, including the __x86_return_thunk() one
(+0x40) will search for the largest ORC entry smaller or equal to the
IP, these will find the one ORC entry (+0x3f) and all works.

  [ Alexandre: SVM part. ]
  [ bp: Build fix, massages. ]

Suggested-by: Andrew Cooper <Andrew.Cooper3@citrix.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
2022-06-27 10:33:59 +02:00
..
arch/x86 x86,objtool: Create .return_sites 2022-06-27 10:33:58 +02:00
Documentation objtool: Update documentation 2022-04-22 12:32:05 +02:00
include/objtool x86,objtool: Create .return_sites 2022-06-27 10:33:58 +02:00
.gitignore objtool: Rework header include paths 2021-01-13 18:13:14 -06:00
Build objtool: Ditch subcommands 2022-04-22 12:32:01 +02:00
builtin-check.c objtool: Remove --lto and --vmlinux in favor of --link 2022-04-22 12:32:05 +02:00
check.c x86: Add magic AMD return-thunk 2022-06-27 10:33:59 +02:00
elf.c objtool: Fix objtool regression on x32 systems 2022-05-20 12:45:30 +02:00
Makefile Kbuild updates for v5.19 2022-05-26 12:09:50 -07:00
objtool.c x86,objtool: Create .return_sites 2022-06-27 10:33:58 +02:00
orc_dump.c x86/unwind/orc: Change REG_SP_INDIRECT 2021-02-10 20:53:51 +01:00
orc_gen.c Merge branch 'objtool/urgent' 2021-10-07 00:40:17 +02:00
special.c objtool,x86: Replace alternatives with .retpoline_sites 2021-10-28 23:25:25 +02:00
sync-check.sh Merge branch 'x86/cpu' into WIP.x86/core, to merge the NOP changes & resolve a semantic conflict 2021-04-02 12:36:30 +02:00
weak.c objtool: Ditch subcommands 2022-04-22 12:32:01 +02:00