• Balbir Singh's avatar
    powerpc/mm/radix: Fix execute permissions for interrupt_vectors · 7f6d498e
    Balbir Singh authored
    Commit 9abcc981 ("powerpc/mm/radix: Only add X for pages
    overlapping kernel text") changed the linear mapping on Radix to only
    mark the kernel text executable.
    
    However if the kernel is run relocated, for example as a kdump kernel,
    then the exception vectors are split from the kernel text, ie. they
    remain at real address 0.
    
    We tend to get away with it, because the kernel itself will usually be
    below 1G, which means the 1G page at 0-1G is marked executable and
    everything works OK. However if the kernel is loaded above 1G, or the
    system has less than 1G in total (meaning we can't use a 1G page),
    then the exception vectors will not be marked executable and the
    kernel will fail to boot.
    
    Fix it by also checking if the address range overlaps the exception
    vectors when deciding if we should add PAGE_KERNEL_X.
    
    Fixes: 9abcc981 ("powerpc/mm/radix: Only add X for pages overlapping kernel text")
    Cc: stable@vger.kernel.org # v4.7+
    Signed-off-by: default avatarBalbir Singh <bsingharora@gmail.com>
    [mpe: Combine with the existing check, rewrite change log]
    Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
    7f6d498e
pgtable-radix.c 19.2 KB