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    Subject[patch V3 55/66] x86/fpu: Remove PKRU handling from switch_fpu_finish()
    PKRU is already updated and the xstate is not longer the proper source of
    information.

    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
    ---
    arch/x86/include/asm/fpu/internal.h | 34 ++++------------------------------
    1 file changed, 4 insertions(+), 30 deletions(-)

    --- a/arch/x86/include/asm/fpu/internal.h
    +++ b/arch/x86/include/asm/fpu/internal.h
    @@ -549,39 +549,13 @@ static inline void switch_fpu_prepare(st
    */

    /*
    - * Load PKRU from the FPU context if available. Delay loading of the
    - * complete FPU state until the return to userland.
    + * Delay loading of the complete FPU state until the return to userland.
    + * PKRU is handled seperately.
    */
    static inline void switch_fpu_finish(struct fpu *new_fpu)
    {
    - u32 pkru_val = init_pkru_value;
    - struct pkru_state *pk;
    -
    - if (!static_cpu_has(X86_FEATURE_FPU))
    - return;
    -
    - set_thread_flag(TIF_NEED_FPU_LOAD);
    -
    - if (!cpu_feature_enabled(X86_FEATURE_OSPKE))
    - return;
    -
    - /*
    - * PKRU state is switched eagerly because it needs to be valid before we
    - * return to userland e.g. for a copy_to_user() operation.
    - */
    - if (!(current->flags & PF_KTHREAD)) {
    - /*
    - * If the PKRU bit in xsave.header.xfeatures is not set,
    - * then the PKRU component was in init state, which means
    - * XRSTOR will set PKRU to 0. If the bit is not set then
    - * get_xsave_addr() will return NULL because the PKRU value
    - * in memory is not valid. This means pkru_val has to be
    - * set to 0 and not to init_pkru_value.
    - */
    - pk = get_xsave_addr(&new_fpu->state.xsave, XFEATURE_PKRU);
    - pkru_val = pk ? pk->pkru : 0;
    - }
    - __write_pkru(pkru_val);
    + if (static_cpu_has(X86_FEATURE_FPU))
    + set_thread_flag(TIF_NEED_FPU_LOAD);
    }

    #endif /* _ASM_X86_FPU_INTERNAL_H */
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