• Dave Hansen's avatar
    mm/core, x86/mm/pkeys: Differentiate instruction fetches · d61172b4
    Dave Hansen authored
    As discussed earlier, we attempt to enforce protection keys in
    software.
    
    However, the code checks all faults to ensure that they are not
    violating protection key permissions.  It was assumed that all
    faults are either write faults where we check PKRU[key].WD (write
    disable) or read faults where we check the AD (access disable)
    bit.
    
    But, there is a third category of faults for protection keys:
    instruction faults.  Instruction faults never run afoul of
    protection keys because they do not affect instruction fetches.
    
    So, plumb the PF_INSTR bit down in to the
    arch_vma_access_permitted() function where we do the protection
    key checks.
    
    We also add a new FAULT_FLAG_INSTRUCTION.  This is because
    handle_mm_fault() is not passed the architecture-specific
    error_code where we keep PF_INSTR, so we need to encode the
    instruction fetch information in to the arch-generic fault
    flags.
    Signed-off-by: 's avatarDave Hansen <dave.hansen@linux.intel.com>
    Reviewed-by: 's avatarThomas Gleixner <tglx@linutronix.de>
    Cc: Andrew Morton <akpm@linux-foundation.org>
    Cc: Andy Lutomirski <luto@amacapital.net>
    Cc: Borislav Petkov <bp@alien8.de>
    Cc: Brian Gerst <brgerst@gmail.com>
    Cc: Dave Hansen <dave@sr71.net>
    Cc: Denys Vlasenko <dvlasenk@redhat.com>
    Cc: H. Peter Anvin <hpa@zytor.com>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Rik van Riel <riel@redhat.com>
    Cc: linux-mm@kvack.org
    Link: http://lkml.kernel.org/r/20160212210224.96928009@viggo.jf.intel.comSigned-off-by: 's avatarIngo Molnar <mingo@kernel.org>
    d61172b4
mm_hooks.h 960 Bytes