• Nicholas Piggin's avatar
    powerpc/64s: Machine check handle ifetch from foreign real address for POWER9 · 90df4bfb
    Nicholas Piggin authored
    The i-side 0111b machine check, which is "Instruction Fetch to foreign
    address space", was missed by 7b9f71f9 ("powerpc/64s: POWER9 machine
    check handler").
    
        The POWER9 processor core considers host real addresses with a
        nonzero value in RA(8:12) as foreign address space, accessible only
        by the copy and paste instructions. The copy and paste instruction
        pair can be used to invoke the Nest accelerators via the Virtual
        Accelerator Switchboard (VAS).
    
    It is an error for any regular load/store or ifetch to go to a foreign
    addresses. When relocation is on, this causes an MMU exception. When
    relocation is off, a machine check exception. It is possible to trigger
    this machine check by branching to a foreign address with MSR[IR]=0.
    
    Fixes: 7b9f71f9 ("powerpc/64s: POWER9 machine check handler")
    Reported-by: default avatarMahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
    Signed-off-by: default avatarNicholas Piggin <npiggin@gmail.com>
    Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
    90df4bfb
mce_power.c 17.2 KB