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powerpc/hugetlb: Fix 8M hugepages on 8xx 

With HW assistance all page tables must be 4k aligned, the 8xx drops
the last 12 bits during the walk.

Redefine HUGEPD_SHIFT_MASK to mask last 12 bits out. HUGEPD_SHIFT_MASK
is used to for alignment of page table cache.

Fixes: 22569b881d ("powerpc/8xx: Enable 8M hugepage support with HW assistance")
Cc: stable@vger.kernel.org # v5.0+
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/778b1a248c4c7ca79640eeff7740044da6a220a0.1581264115.git.christophe.leroy@c-s.fr
alistair/sensors
Christophe Leroy 2020-02-09 16:02:41 +00:00 committed by Michael Ellerman
parent f2b67ef90b
commit 50a175dd18
1 changed files with 5 additions and 0 deletions
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5
arch/powerpc/include/asm/page.h
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@ -295,8 +295,13 @@ static inline bool pfn_valid(unsigned long pfn)
/*
* Some number of bits at the level of the page table that points to
* a hugepte are used to encode the size. This masks those bits.
* On 8xx, HW assistance requires 4k alignment for the hugepte.
*/
#ifdef CONFIG_PPC_8xx
#define HUGEPD_SHIFT_MASK 0xfff
#else
#define HUGEPD_SHIFT_MASK 0x3f
#endif
#ifndef __ASSEMBLY__