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From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
To: benh@kernel.crashing.org, paulus@samba.org
Cc: linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org,
	"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Subject: [PATCH -V1 14/24] powerpc: Fix hpte_decode to use the correct decoding for page sizes
Date: Tue, 26 Feb 2013 13:35:04 +0530	[thread overview]
Message-ID: <1361865914-13911-15-git-send-email-aneesh.kumar@linux.vnet.ibm.com> (raw)
In-Reply-To: <1361865914-13911-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com>

From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>

As per ISA doc, we encode base and actual page size in the LP bits of
PTE. The number of bit used to encode the page sizes depend on actual
page size.  ISA doc lists this as

   PTE LP     actual page size
rrrr rrrz 	≥8KB
rrrr rrzz	≥16KB
rrrr rzzz 	≥32KB
rrrr zzzz 	≥64KB
rrrz zzzz 	≥128KB
rrzz zzzz 	≥256KB
rzzz zzzz	≥512KB
zzzz zzzz 	≥1MB

ISA doc also says
"The values of the “z” bits used to specify each size, along with all possible
values of “r” bits in the LP field, must result in LP values distinct from
other LP values for other sizes."

based on the above update hpte_decode to use the correct decoding for LP bits.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/powerpc/mm/hash_native_64.c |   27 +++++++++++++++++----------
 1 file changed, 17 insertions(+), 10 deletions(-)

diff --git a/arch/powerpc/mm/hash_native_64.c b/arch/powerpc/mm/hash_native_64.c
index e800b26..2c6940f 100644
--- a/arch/powerpc/mm/hash_native_64.c
+++ b/arch/powerpc/mm/hash_native_64.c
@@ -428,19 +428,15 @@ static void hpte_decode(struct hash_pte *hpte, unsigned long slot,
 			int *psize, int *apsize, int *ssize, unsigned long *vpn)
 {
 	unsigned long avpn, pteg, vpi;
-	unsigned long hpte_r = hpte->r;
 	unsigned long hpte_v = hpte->v;
 	unsigned long vsid, seg_off;
-	int i, size, a_size = MMU_PAGE_4K, shift, penc;
+	int size, a_size = MMU_PAGE_4K, shift, mask;
+	/* Look at the 8 bit LP value */
+	unsigned int lp = (hpte->r >> LP_SHIFT) & ((1 << LP_BITS) - 1);
 
 	if (!(hpte_v & HPTE_V_LARGE))
 		size = MMU_PAGE_4K;
 	else {
-		for (i = 0; i < LP_BITS; i++) {
-			if ((hpte_r & LP_MASK(i+1)) == LP_MASK(i+1))
-				break;
-		}
-		penc = LP_MASK(i+1) >> LP_SHIFT;
 		for (size = 0; size < MMU_PAGE_COUNT; size++) {
 
 			/* 4K pages are not represented by LP */
@@ -450,12 +446,23 @@ static void hpte_decode(struct hash_pte *hpte, unsigned long slot,
 			/* valid entries have a shift value */
 			if (!mmu_psize_defs[size].shift)
 				continue;
-			for (a_size = 0; a_size < MMU_PAGE_COUNT; a_size++)
-				if (penc == mmu_psize_defs[size].penc[a_size])
+
+			for (a_size = 0; a_size < MMU_PAGE_COUNT; a_size++) {
+				/* valid entries have a shift value */
+				if (!mmu_psize_defs[a_size].shift)
+					continue;
+
+				shift = mmu_psize_defs[a_size].shift - 11;
+				if (shift > 9)
+					shift = 9;
+				mask = (1 << shift) - 1;
+				if ((lp & mask) ==
+				    mmu_psize_defs[size].penc[a_size]) {
 					goto out;
+				}
+			}
 		}
 	}
-
 out:
 	/* This works for all page sizes, and for 256M and 1T segments */
 	*ssize = hpte_v >> HPTE_V_SSIZE_SHIFT;
-- 
1.7.10

  parent reply	other threads:[~2013-02-26  8:06 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-02-26  8:04 [PATCH -V1 00/24] THP support for PPC64 Aneesh Kumar K.V
2013-02-26  8:04 ` [PATCH -V1 01/24] powerpc: Use signed formatting when printing error Aneesh Kumar K.V
2013-02-26  8:04 ` [PATCH -V1 02/24] powerpc: Save DAR and DSISR in pt_regs on MCE Aneesh Kumar K.V
2013-02-26  8:04 ` [PATCH -V1 03/24] powerpc: Don't hard code the size of pte page Aneesh Kumar K.V
2013-02-27 23:09   ` Paul Mackerras
2013-02-26  8:04 ` [PATCH -V1 04/24] powerpc: Reduce the PTE_INDEX_SIZE Aneesh Kumar K.V
2013-02-26  8:04 ` [PATCH -V1 05/24] powerpc: Move the pte free routines from common header Aneesh Kumar K.V
2013-02-28  8:36   ` Paul Mackerras
2013-02-26  8:04 ` [PATCH -V1 06/24] powerpc: Reduce PTE table memory wastage Aneesh Kumar K.V
2013-03-04  4:58   ` Paul Mackerras
2013-03-04 10:58     ` Aneesh Kumar K.V
2013-03-04 23:36       ` Benjamin Herrenschmidt
2013-03-06  4:01         ` Aneesh Kumar K.V
2013-03-05  2:12       ` Paul Mackerras
2013-03-06  4:08         ` Aneesh Kumar K.V
2013-03-06  5:03         ` Aneesh Kumar K.V
2013-02-26  8:04 ` [PATCH -V1 07/24] powerpc: Add size argument to pgtable_cache_add Aneesh Kumar K.V
2013-03-04  5:13   ` Paul Mackerras
2013-03-04 11:02     ` Aneesh Kumar K.V
2013-03-05  1:50       ` Paul Mackerras
2013-03-06  4:23         ` Aneesh Kumar K.V
2013-02-26  8:04 ` [PATCH -V1 08/24] powerpc: Use encode avpn where we need only avpn values Aneesh Kumar K.V
2013-03-04  5:15   ` Paul Mackerras
2013-02-26  8:04 ` [PATCH -V1 09/24] powerpc: Decode the pte-lp-encoding bits correctly Aneesh Kumar K.V
2013-03-04  5:48   ` Paul Mackerras
2013-03-04 11:41     ` Aneesh Kumar K.V
2013-03-05  2:02       ` Paul Mackerras
2013-03-06  4:30         ` Aneesh Kumar K.V
2013-03-04 11:52     ` Aneesh Kumar K.V
2013-03-04 18:11       ` Aneesh Kumar K.V
2013-02-26  8:05 ` [PATCH -V1 10/24] powerpc: Return all the valid pte ecndoing in KVM_PPC_GET_SMMU_INFO ioctl Aneesh Kumar K.V
2013-02-26  8:05 ` [PATCH -V1 11/24] powerpc: Update tlbie/tlbiel as per ISA doc Aneesh Kumar K.V
2013-02-26  8:05 ` [PATCH -V1 12/24] powerpc: print both base and actual page size on hash failure Aneesh Kumar K.V
2013-02-26  8:05 ` [PATCH -V1 13/24] powerpc: Print page size info during boot Aneesh Kumar K.V
2013-02-26  8:05 ` Aneesh Kumar K.V [this message]
2013-02-26  8:05 ` [PATCH -V1 15/24] mm/THP: HPAGE_SHIFT is not a #define on some arch Aneesh Kumar K.V
2013-02-26  8:05 ` [PATCH -V1 16/24] mm/THP: Add pmd args to pgtable deposit and withdraw APIs Aneesh Kumar K.V
2013-02-26  8:05 ` [PATCH -V1 17/24] mm/THP: withdraw the pgtable after pmdp related operations Aneesh Kumar K.V
2013-02-26  8:05 ` [PATCH -V1 18/24] powerpc/THP: Implement transparent huge pages for ppc64 Aneesh Kumar K.V
2013-02-26  8:05 ` [PATCH -V1 19/24] powerpc/THP: Differentiate THP PMD entries from HUGETLB PMD entries Aneesh Kumar K.V
2013-02-26  8:05 ` [PATCH -V1 20/24] powerpc/THP: Add code to handle HPTE faults for large pages Aneesh Kumar K.V
2013-02-26  8:05 ` [PATCH -V1 21/24] powerpc: Handle huge page in perf callchain Aneesh Kumar K.V
2013-02-26  8:05 ` [PATCH -V1 22/24] powerpc/THP: hypervisor require few WIMG bit set Aneesh Kumar K.V
2013-02-26  8:05 ` [PATCH -V1 23/24] powerpc/THP: get_user_pages_fast changes Aneesh Kumar K.V
2013-02-26  8:05 ` [PATCH -V1 24/24] powerpc/THP: Enable THP on PPC64 Aneesh Kumar K.V

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