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: 22569b881d37 ("powerpc/8xx: Enable 8M hugepage support with HW assistance")
Cc: [email protected]
Signed-off-by: Christophe Leroy <[email protected]>
---
v2: Only do the fix of alignment which is the only vital fix.
---
arch/powerpc/include/asm/page.h | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/arch/powerpc/include/asm/page.h b/arch/powerpc/include/asm/page.h
index 86332080399a..080a0bf8e54b 100644
--- a/arch/powerpc/include/asm/page.h
+++ b/arch/powerpc/include/asm/page.h
@@ -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__
--
2.25.0
On Sun, 2020-02-09 at 16:02:41 UTC, Christophe Leroy wrote:
> 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: 22569b881d37 ("powerpc/8xx: Enable 8M hugepage support with HW assistance")
> Cc: [email protected]
> Signed-off-by: Christophe Leroy <[email protected]>
Applied to powerpc fixes, thanks.
https://git.kernel.org/powerpc/c/50a175dd18de7a647e72aca7daf4744e3a5a81e3
cheers