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powerpc/mce: Fix SLB rebolting during MCE recovery path.

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The commit e7e8184747 ("powerpc/64s: move machine check SLB flushing
to mm/slb.c") introduced a bug in reloading bolted SLB entries. Unused
bolted entries are stored with .esid=0 in the slb_shadow area, and
that value is now used directly as the RB input to slbmte, which means
the RB[52:63] index field is set to 0, which causes SLB entry 0 to be
cleared.

Fix this by storing the index bits in the unused bolted entries, which
directs the slbmte to the right place.

The SLB shadow area is also used by the hypervisor, but PAPR is okay
with that, from LoPAPR v1.1, 14.11.1.3 SLB Shadow Buffer:

  Note: SLB is filled sequentially starting at index 0
  from the shadow buffer ignoring the contents of
  RB field bits 52-63

Fixes: e7e8184747 ("powerpc/64s: move machine check SLB flushing to mm/slb.c")
Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Mahesh Salgaonkar 2018-08-23 10:26:08 +05:30 committed by Michael Ellerman
parent 8cfbdbdc24
commit 0f52b3a00c
1 changed files with 1 additions and 1 deletions
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2
arch/powerpc/mm/slb.c
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@ -70,7 +70,7 @@ static inline void slb_shadow_update(unsigned long ea, int ssize,
static inline void slb_shadow_clear(enum slb_index index)
{
WRITE_ONCE(get_slb_shadow()->save_area[index].esid, 0);
WRITE_ONCE(get_slb_shadow()->save_area[index].esid, cpu_to_be64(index));
}
static inline void create_shadowed_slbe(unsigned long ea, int ssize,