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| author | Josh Poimboeuf <jpoimboe@kernel.org> | 2025-04-09 00:47:32 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2025-04-09 13:41:30 +0300 |
| commit | b1b19cfcf4656c75088dc06b7499f493e0dec3e5 (patch) | |
| tree | 07b618cf223066705f26c761cdc18c9a2b47ec97 /lib/test_fortify/write_overflow-strncpy-src.c | |
| parent | fc9fd3f98423367c79e0bd85a9515df26dc1b3cc (diff) | |
| download | linux-b1b19cfcf4656c75088dc06b7499f493e0dec3e5.tar.xz | |
x86/bugs: Fix RSB clearing in indirect_branch_prediction_barrier()
IBPB is expected to clear the RSB. However, if X86_BUG_IBPB_NO_RET is
set, that doesn't happen. Make indirect_branch_prediction_barrier()
take that into account by calling write_ibpb() which clears RSB on
X86_BUG_IBPB_NO_RET:
/* Make sure IBPB clears return stack preductions too. */
FILL_RETURN_BUFFER %rax, RSB_CLEAR_LOOPS, X86_BUG_IBPB_NO_RET
Note that, as of the previous patch, write_ibpb() also reads
'x86_pred_cmd' in order to use SBPB when applicable:
movl _ASM_RIP(x86_pred_cmd), %eax
Therefore that existing behavior in indirect_branch_prediction_barrier()
is not lost.
Fixes: 50e4b3b94090 ("x86/entry: Have entry_ibpb() invalidate return predictions")
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Nikolay Borisov <nik.borisov@suse.com>
Link: https://lore.kernel.org/r/bba68888c511743d4cd65564d1fc41438907523f.1744148254.git.jpoimboe@kernel.org
Diffstat (limited to 'lib/test_fortify/write_overflow-strncpy-src.c')
0 files changed, 0 insertions, 0 deletions