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    SubjectRe: [PATCH 11/11] x86/pti: leave kernel text global for !PCID
    On Fri, Apr 6, 2018 at 1:55 PM, Dave Hansen <dave.hansen@linux.intel.com> wrote:
    > +/*
    > + * For some configurations, map all of kernel text into the user page
    > + * tables. This reduces TLB misses, especially on non-PCID systems.
    > + */
    > +void pti_clone_kernel_text(void)
    > +{
    > + unsigned long start = PFN_ALIGN(_text);
    > + unsigned long end = ALIGN((unsigned long)_end, PMD_PAGE_SIZE);

    I think this is too much set global: _end is after data, bss, and brk,
    and all kinds of other stuff that could hold secrets. I think this
    should match what mark_rodata_ro() is doing and use
    __end_rodata_hpage_align. (And on i386, this should be maybe _etext.)

    -Kees

    --
    Kees Cook
    Pixel Security

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