• Tony Luck's avatar
    x86/mm, mm/hwpoison: Clear PRESENT bit for kernel 1:1 mappings of poison pages · ce0fa3e5
    Tony Luck authored
    Speculative processor accesses may reference any memory that has a
    valid page table entry.  While a speculative access won't generate
    a machine check, it will log the error in a machine check bank. That
    could cause escalation of a subsequent error since the overflow bit
    will be then set in the machine check bank status register.
    
    Code has to be double-plus-tricky to avoid mentioning the 1:1 virtual
    address of the page we want to map out otherwise we may trigger the
    very problem we are trying to avoid.  We use a non-canonical address
    that passes through the usual Linux table walking code to get to the
    same "pte".
    
    Thanks to Dave Hansen for reviewing several iterations of this.
    
    Also see:
    
      http://marc.info/?l=linux-mm&m=149860136413338&w=2Signed-off-by: 's avatarTony Luck <tony.luck@intel.com>
    Cc: Andrew Morton <akpm@linux-foundation.org>
    Cc: Andy Lutomirski <luto@kernel.org>
    Cc: Borislav Petkov <bp@alien8.de>
    Cc: Borislav Petkov <bp@suse.de>
    Cc: Brian Gerst <brgerst@gmail.com>
    Cc: Dave Hansen <dave.hansen@intel.com>
    Cc: Denys Vlasenko <dvlasenk@redhat.com>
    Cc: Elliott, Robert (Persistent Memory) <elliott@hpe.com>
    Cc: H. Peter Anvin <hpa@zytor.com>
    Cc: Josh Poimboeuf <jpoimboe@redhat.com>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: linux-mm@kvack.org
    Cc: stable@vger.kernel.org
    Link: http://lkml.kernel.org/r/20170816171803.28342-1-tony.luck@intel.comSigned-off-by: 's avatarIngo Molnar <mingo@kernel.org>
    ce0fa3e5
memory-failure.c 47.8 KB