x86/bugs: Do not use UNTRAIN_RET with IBPB on entry

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commit c62fa117c3 upstream.

Since X86_FEATURE_ENTRY_IBPB will invalidate all harmful predictions
with IBPB, no software-based untraining of returns is needed anymore.
Currently, this change affects retbleed and SRSO mitigations so if
either of the mitigations is doing IBPB and the other one does the
software sequence, the latter is not needed anymore.

  [ bp: Massage commit message. ]

Suggested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Johannes Wikner <kwikner@ethz.ch>
Cc: <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

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Johannes Wikner 2024-10-08 12:58:03 +02:00 • committed by Greg Kroah-Hartman

parent c42a343158

commit c04670dffb

1 changed files with 17 additions and 0 deletions

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arch/x86/kernel/cpu/bugs.c

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