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    Subject[tip: x86/bugs] x86/srso: Improve i-cache locality for alias mitigation
    The following commit has been merged into the x86/bugs branch of tip:

    Commit-ID: da3bd8872ee00f23b58c7f62dfd403dcc83e074b
    Gitweb: https://git.kernel.org/tip/da3bd8872ee00f23b58c7f62dfd403dcc83e074b
    Author: Josh Poimboeuf <jpoimboe@kernel.org>
    AuthorDate: Mon, 04 Sep 2023 22:04:55 -07:00
    Committer: Ingo Molnar <mingo@kernel.org>
    CommitterDate: Tue, 19 Sep 2023 11:42:47 +02:00

    x86/srso: Improve i-cache locality for alias mitigation

    Move srso_alias_return_thunk() to the same section as
    srso_alias_safe_ret() so they can share a cache line.

    Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
    Signed-off-by: Ingo Molnar <mingo@kernel.org>
    Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
    Link: https://lore.kernel.org/r/eadaf5530b46a7ae8b936522da45ae555d2b3393.1693889988.git.jpoimboe@kernel.org
    ---
    arch/x86/lib/retpoline.S | 5 ++---
    1 file changed, 2 insertions(+), 3 deletions(-)

    diff --git a/arch/x86/lib/retpoline.S b/arch/x86/lib/retpoline.S
    index cd86aeb..9ab634f 100644
    --- a/arch/x86/lib/retpoline.S
    +++ b/arch/x86/lib/retpoline.S
    @@ -177,15 +177,14 @@ SYM_START(srso_alias_safe_ret, SYM_L_GLOBAL, SYM_A_NONE)
    int3
    SYM_FUNC_END(srso_alias_safe_ret)

    - .section .text..__x86.return_thunk
    -
    -SYM_CODE_START(srso_alias_return_thunk)
    +SYM_CODE_START_NOALIGN(srso_alias_return_thunk)
    UNWIND_HINT_FUNC
    ANNOTATE_NOENDBR
    call srso_alias_safe_ret
    ud2
    SYM_CODE_END(srso_alias_return_thunk)

    + .section .text..__x86.return_thunk
    /*
    * Some generic notes on the untraining sequences:
    *
    \
     
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