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    SubjectRe: [PATCH 2/2] x86/mm/KASLR: Correct the upper boundary of KALSR mm regions if adjacent to EFI
    On 03/08/17 at 03:47pm, Baoquan He wrote:
    > EFI allocates runtime services regions top-down, starting from EFI_VA_START
    > to EFI_VA_END. So EFI_VA_START is bigger than EFI_VA_END and is the end of
    > EFI region. The upper boundary of memory regions randomized by KASLR should
    > be EFI_VA_END if it's adjacent to EFI region, but not EFI_VA_START.
    >
    > Correct it in this patch.
    >
    > Signed-off-by: Baoquan He <bhe@redhat.com>
    > ---
    > arch/x86/mm/kaslr.c | 4 ++--
    > 1 file changed, 2 insertions(+), 2 deletions(-)
    >
    > diff --git a/arch/x86/mm/kaslr.c b/arch/x86/mm/kaslr.c
    > index 887e571..aed2064 100644
    > --- a/arch/x86/mm/kaslr.c
    > +++ b/arch/x86/mm/kaslr.c
    > @@ -48,7 +48,7 @@ static const unsigned long vaddr_start = __PAGE_OFFSET_BASE;
    > #if defined(CONFIG_X86_ESPFIX64)
    > static const unsigned long vaddr_end = ESPFIX_BASE_ADDR;
    > #elif defined(CONFIG_EFI)
    > -static const unsigned long vaddr_end = EFI_VA_START;
    > +static const unsigned long vaddr_end = EFI_VA_END;
    > #else
    > static const unsigned long vaddr_end = __START_KERNEL_map;
    > #endif
    > @@ -105,7 +105,7 @@ void __init kernel_randomize_memory(void)
    > */
    > BUILD_BUG_ON(vaddr_start >= vaddr_end);
    > BUILD_BUG_ON(IS_ENABLED(CONFIG_X86_ESPFIX64) &&
    > - vaddr_end >= EFI_VA_START);
    > + vaddr_end >= EFI_VA_END);
    > BUILD_BUG_ON((IS_ENABLED(CONFIG_X86_ESPFIX64) ||
    > IS_ENABLED(CONFIG_EFI)) &&
    > vaddr_end >= __START_KERNEL_map);
    > --
    > 2.5.5
    >

    Acked-by: Dave Young <dyoung@redhat.com>

    Thanks
    Dave

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