• Nicholas Piggin's avatar
    powerpc/64s/hash: Convert SLB miss handlers to C · 48e7b769
    Nicholas Piggin authored
    This patch moves SLB miss handlers completely to C, using the standard
    exception handler macros to set up the stack and branch to C.
    
    This can be done because the segment containing the kernel stack is
    always bolted, so accessing it with relocation on will not cause an
    SLB exception.
    
    Arbitrary kernel memory must not be accessed when handling kernel
    space SLB misses, so care should be taken there. However user SLB
    misses can access any kernel memory, which can be used to move some
    fields out of the paca (in later patches).
    
    User SLB misses could quite easily reconcile IRQs and set up a first
    class kernel environment and exit via ret_from_except, however that
    doesn't seem to be necessary at the moment, so we only do that if a
    bad fault is encountered.
    
    [ Credit to Aneesh for bug fixes, error checks, and improvements to
      bad address handling, etc ]
    Signed-off-by: default avatarNicholas Piggin <npiggin@gmail.com>
    [mpe: Disallow tracing for all of slb.c for now.]
    Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
    48e7b769
exception-64s.h 22.5 KB