• Vincenzo Frascino's avatar
    arm64: compat: Add KUSER_HELPERS config option · af1b3cf2
    Vincenzo Frascino authored
    When kuser helpers are enabled the kernel maps the relative code at
    a fixed address (0xffff0000). Making configurable the option to disable
    them means that the kernel can remove this mapping and any access to
    this memory area results in a sigfault.
    
    Add a KUSER_HELPERS config option that can be used to disable the
    mapping when it is turned off.
    
    This option can be turned off if and only if the applications are
    designed specifically for the platform and they do not make use of the
    kuser helpers code.
    
    Cc: Catalin Marinas <catalin.marinas@arm.com>
    Cc: Will Deacon <will.deacon@arm.com>
    Signed-off-by: default avatarVincenzo Frascino <vincenzo.frascino@arm.com>
    Reviewed-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
    [will: Use IS_ENABLED() instead of #ifdef]
    Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
    af1b3cf2
vdso.c 7.95 KB