linux/tools/objtool
Borislav Petkov (AMD) fb3bd914b3 x86/srso: Add a Speculative RAS Overflow mitigation
Add a mitigation for the speculative return address stack overflow
vulnerability found on AMD processors.

The mitigation works by ensuring all RET instructions speculate to
a controlled location, similar to how speculation is controlled in the
retpoline sequence.  To accomplish this, the __x86_return_thunk forces
the CPU to mispredict every function return using a 'safe return'
sequence.

To ensure the safety of this mitigation, the kernel must ensure that the
safe return sequence is itself free from attacker interference.  In Zen3
and Zen4, this is accomplished by creating a BTB alias between the
untraining function srso_untrain_ret_alias() and the safe return
function srso_safe_ret_alias() which results in evicting a potentially
poisoned BTB entry and using that safe one for all function returns.

In older Zen1 and Zen2, this is accomplished using a reinterpretation
technique similar to Retbleed one: srso_untrain_ret() and
srso_safe_ret().

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
2023-07-27 11:07:14 +02:00
..
arch x86/srso: Add a Speculative RAS Overflow mitigation 2023-07-27 11:07:14 +02:00
Documentation objtool: Move noreturn function list to separate file 2023-05-16 06:31:55 -07:00
include/objtool objtool: Get rid of reloc->rel[a] 2023-06-07 10:03:26 -07:00
.gitignore objtool: Install libsubcmd in build 2023-01-30 16:27:46 -08:00
Build objtool: Install libsubcmd in build 2023-01-30 16:27:46 -08:00
builtin-check.c objtool: Add verbose option for disassembling affected functions 2023-05-16 06:31:51 -07:00
check.c linux-kselftest-kunit-6.5-rc1 2023-06-27 11:12:55 -07:00
elf.c objtool: initialize all of struct elf 2023-07-10 09:52:28 +02:00
Makefile objtool: Fix HOSTCC flag usage 2023-02-01 09:15:18 -08:00
noreturns.h objtool: Remove btrfs_assertfail() from the noreturn exceptions list 2023-06-29 17:27:47 -07:00
objtool.c objtool: Remove instruction::list 2023-02-23 09:21:44 +01:00
orc_dump.c x86,objtool: Split UNWIND_HINT_EMPTY in two 2023-03-23 23:18:58 +01:00
orc_gen.c objtool: Add elf_create_section_pair() 2023-06-07 10:03:17 -07:00
special.c objtool: Get rid of reloc->addend 2023-06-07 10:03:23 -07:00
sync-check.sh objtool: Add objtool_types.h 2023-03-23 23:18:56 +01:00
weak.c objtool: Ditch subcommands 2022-04-22 12:32:01 +02:00