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    Subject[PATCH 4.14 099/159] x86/cpufeatures: Make CPU bugs sticky
    Date
    4.14-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Thomas Gleixner <tglx@linutronix.de>

    commit 6cbd2171e89b13377261d15e64384df60ecb530e upstream.

    There is currently no way to force CPU bug bits like CPU feature bits. That
    makes it impossible to set a bug bit once at boot and have it stick for all
    upcoming CPUs.

    Extend the force set/clear arrays to handle bug bits as well.

    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
    Reviewed-by: Borislav Petkov <bp@suse.de>
    Cc: Andy Lutomirski <luto@kernel.org>
    Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
    Cc: Borislav Petkov <bp@alien8.de>
    Cc: Borislav Petkov <bpetkov@suse.de>
    Cc: Brian Gerst <brgerst@gmail.com>
    Cc: Dave Hansen <dave.hansen@intel.com>
    Cc: Dave Hansen <dave.hansen@linux.intel.com>
    Cc: David Laight <David.Laight@aculab.com>
    Cc: Denys Vlasenko <dvlasenk@redhat.com>
    Cc: Eduardo Valentin <eduval@amazon.com>
    Cc: Greg KH <gregkh@linuxfoundation.org>
    Cc: H. Peter Anvin <hpa@zytor.com>
    Cc: Josh Poimboeuf <jpoimboe@redhat.com>
    Cc: Juergen Gross <jgross@suse.com>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Rik van Riel <riel@redhat.com>
    Cc: Will Deacon <will.deacon@arm.com>
    Cc: aliguori@amazon.com
    Cc: daniel.gruss@iaik.tugraz.at
    Cc: hughd@google.com
    Cc: keescook@google.com
    Link: https://lkml.kernel.org/r/20171204150606.992156574@linutronix.de
    Signed-off-by: Ingo Molnar <mingo@kernel.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    arch/x86/include/asm/cpufeature.h | 2 ++
    arch/x86/include/asm/processor.h | 4 ++--
    arch/x86/kernel/cpu/common.c | 6 +++---
    3 files changed, 7 insertions(+), 5 deletions(-)

    --- a/arch/x86/include/asm/cpufeature.h
    +++ b/arch/x86/include/asm/cpufeature.h
    @@ -135,6 +135,8 @@ extern void clear_cpu_cap(struct cpuinfo
    set_bit(bit, (unsigned long *)cpu_caps_set); \
    } while (0)

    +#define setup_force_cpu_bug(bit) setup_force_cpu_cap(bit)
    +
    #if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_X86_FAST_FEATURE_TESTS)
    /*
    * Static testing of CPU features. Used the same as boot_cpu_has().
    --- a/arch/x86/include/asm/processor.h
    +++ b/arch/x86/include/asm/processor.h
    @@ -163,8 +163,8 @@ extern struct cpuinfo_x86 boot_cpu_data;
    extern struct cpuinfo_x86 new_cpu_data;

    extern struct x86_hw_tss doublefault_tss;
    -extern __u32 cpu_caps_cleared[NCAPINTS];
    -extern __u32 cpu_caps_set[NCAPINTS];
    +extern __u32 cpu_caps_cleared[NCAPINTS + NBUGINTS];
    +extern __u32 cpu_caps_set[NCAPINTS + NBUGINTS];

    #ifdef CONFIG_SMP
    DECLARE_PER_CPU_READ_MOSTLY(struct cpuinfo_x86, cpu_info);
    --- a/arch/x86/kernel/cpu/common.c
    +++ b/arch/x86/kernel/cpu/common.c
    @@ -452,8 +452,8 @@ static const char *table_lookup_model(st
    return NULL; /* Not found */
    }

    -__u32 cpu_caps_cleared[NCAPINTS];
    -__u32 cpu_caps_set[NCAPINTS];
    +__u32 cpu_caps_cleared[NCAPINTS + NBUGINTS];
    +__u32 cpu_caps_set[NCAPINTS + NBUGINTS];

    void load_percpu_segment(int cpu)
    {
    @@ -812,7 +812,7 @@ static void apply_forced_caps(struct cpu
    {
    int i;

    - for (i = 0; i < NCAPINTS; i++) {
    + for (i = 0; i < NCAPINTS + NBUGINTS; i++) {
    c->x86_capability[i] &= ~cpu_caps_cleared[i];
    c->x86_capability[i] |= cpu_caps_set[i];
    }

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