• Christophe Leroy's avatar
    powerpc: Select ARCH_WANTS_MODULES_DATA_IN_VMALLOC on book3s/32 and 8xx · eeaec780
    Christophe Leroy authored
    book3s/32 and 8xx have a separate area for allocating modules,
    defined by MODULES_VADDR / MODULES_END.
    
    On book3s/32, it is not possible to protect against execution
    on a page basis. A full 256M segment is either Exec or NoExec.
    The module area is in an Exec segment while vmalloc area is
    in a NoExec segment.
    
    In order to protect module data against execution, select
    ARCH_WANTS_MODULES_DATA_IN_VMALLOC.
    
    For the 8xx (and possibly other 32 bits platform in the future),
    there is no such constraint on Exec/NoExec protection, however
    there is a critical distance between kernel functions and callers
    that needs to remain below 32Mbytes in order to avoid costly
    trampolines. By allocating data outside of module area, we
    increase the chance for module text to remain within acceptable
    distance from kernel core text.
    
    So select ARCH_WANTS_MODULES_DATA_IN_VMALLOC for 8xx as well.
    Signed-off-by: default avatarChristophe Leroy <christophe.leroy@csgroup.eu>
    Cc: Michael Ellerman <mpe@ellerman.id.au>
    Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
    Cc: Paul Mackerras <paulus@samba.org>
    Signed-off-by: default avatarLuis Chamberlain <mcgrof@kernel.org>
    eeaec780
Kconfig 37.6 KB