This is a note to let you know that I've just added the patch titled
powerpc/mm: Fix hash computation function
to the 3.7-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
powerpc-mm-fix-hash-computation-function.patch
and it can be found in the queue-3.7 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From eda8eebdd153c48a4e2a3a3ac3cd9e2e31f5c6b3 Mon Sep 17 00:00:00 2001
From: "Aneesh Kumar K.V" <[email protected]>
Date: Tue, 29 Jan 2013 19:40:42 +0000
Subject: powerpc/mm: Fix hash computation function
From: "Aneesh Kumar K.V" <[email protected]>
commit eda8eebdd153c48a4e2a3a3ac3cd9e2e31f5c6b3 upstream.
The ASM version of hash computation function was truncating the upper bit.
Make the ASM version similar to hpt_hash function. Remove masking vsid bits.
Without this patch, we observed hang during bootup due to not satisfying page
fault request correctly. The fault handler used wrong hash values to update
the HPTE. Hence we kept looping with page fault.
hash_page(ea=000001003e260008, access=203, trap=300 ip=3fff91787134 dsisr
42000000
The computed value of hash 000000000f22f390
update: avpnv=4003e46054003e00, hash=000000000722f390, f=80000006, psize: 2 ...
BenH: The over-masking has been there for ever but only hurts with the
new 64T support introduced in 3.7
Reported-by: Mike Qiu <[email protected]>
Signed-off-by: Aneesh Kumar K.V <[email protected]>
Tested-by: Mike Qiu <[email protected]>
Signed-off-by: Benjamin Herrenschmidt <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/powerpc/mm/hash_low_64.S | 62 +++++++++++++++++++++++-------------------
1 file changed, 35 insertions(+), 27 deletions(-)
--- a/arch/powerpc/mm/hash_low_64.S
+++ b/arch/powerpc/mm/hash_low_64.S
@@ -115,11 +115,13 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_1T_SEG
sldi r29,r5,SID_SHIFT - VPN_SHIFT
rldicl r28,r3,64 - VPN_SHIFT,64 - (SID_SHIFT - VPN_SHIFT)
or r29,r28,r29
-
- /* Calculate hash value for primary slot and store it in r28 */
- rldicl r5,r5,0,25 /* vsid & 0x0000007fffffffff */
- rldicl r0,r3,64-12,48 /* (ea >> 12) & 0xffff */
- xor r28,r5,r0
+ /*
+ * Calculate hash value for primary slot and store it in r28
+ * r3 = va, r5 = vsid
+ * r0 = (va >> 12) & ((1ul << (28 - 12)) -1)
+ */
+ rldicl r0,r3,64-12,48
+ xor r28,r5,r0 /* hash */
b 4f
3: /* Calc vpn and put it in r29 */
@@ -130,11 +132,12 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_1T_SEG
/*
* calculate hash value for primary slot and
* store it in r28 for 1T segment
+ * r3 = va, r5 = vsid
*/
- rldic r28,r5,25,25 /* (vsid << 25) & 0x7fffffffff */
- clrldi r5,r5,40 /* vsid & 0xffffff */
- rldicl r0,r3,64-12,36 /* (ea >> 12) & 0xfffffff */
- xor r28,r28,r5
+ sldi r28,r5,25 /* vsid << 25 */
+ /* r0 = (va >> 12) & ((1ul << (40 - 12)) -1) */
+ rldicl r0,r3,64-12,36
+ xor r28,r28,r5 /* vsid ^ ( vsid << 25) */
xor r28,r28,r0 /* hash */
/* Convert linux PTE bits into HW equivalents */
@@ -407,11 +410,13 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_1T_SEG
*/
rldicl r28,r3,64 - VPN_SHIFT,64 - (SID_SHIFT - VPN_SHIFT)
or r29,r28,r29
-
- /* Calculate hash value for primary slot and store it in r28 */
- rldicl r5,r5,0,25 /* vsid & 0x0000007fffffffff */
- rldicl r0,r3,64-12,48 /* (ea >> 12) & 0xffff */
- xor r28,r5,r0
+ /*
+ * Calculate hash value for primary slot and store it in r28
+ * r3 = va, r5 = vsid
+ * r0 = (va >> 12) & ((1ul << (28 - 12)) -1)
+ */
+ rldicl r0,r3,64-12,48
+ xor r28,r5,r0 /* hash */
b 4f
3: /* Calc vpn and put it in r29 */
@@ -426,11 +431,12 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_1T_SEG
/*
* Calculate hash value for primary slot and
* store it in r28 for 1T segment
+ * r3 = va, r5 = vsid
*/
- rldic r28,r5,25,25 /* (vsid << 25) & 0x7fffffffff */
- clrldi r5,r5,40 /* vsid & 0xffffff */
- rldicl r0,r3,64-12,36 /* (ea >> 12) & 0xfffffff */
- xor r28,r28,r5
+ sldi r28,r5,25 /* vsid << 25 */
+ /* r0 = (va >> 12) & ((1ul << (40 - 12)) -1) */
+ rldicl r0,r3,64-12,36
+ xor r28,r28,r5 /* vsid ^ ( vsid << 25) */
xor r28,r28,r0 /* hash */
/* Convert linux PTE bits into HW equivalents */
@@ -752,25 +758,27 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_1T_SEG
rldicl r28,r3,64 - VPN_SHIFT,64 - (SID_SHIFT - VPN_SHIFT)
or r29,r28,r29
- /* Calculate hash value for primary slot and store it in r28 */
- rldicl r5,r5,0,25 /* vsid & 0x0000007fffffffff */
- rldicl r0,r3,64-16,52 /* (ea >> 16) & 0xfff */
- xor r28,r5,r0
+ /* Calculate hash value for primary slot and store it in r28
+ * r3 = va, r5 = vsid
+ * r0 = (va >> 16) & ((1ul << (28 - 16)) -1)
+ */
+ rldicl r0,r3,64-16,52
+ xor r28,r5,r0 /* hash */
b 4f
3: /* Calc vpn and put it in r29 */
sldi r29,r5,SID_SHIFT_1T - VPN_SHIFT
rldicl r28,r3,64 - VPN_SHIFT,64 - (SID_SHIFT_1T - VPN_SHIFT)
or r29,r28,r29
-
/*
* calculate hash value for primary slot and
* store it in r28 for 1T segment
+ * r3 = va, r5 = vsid
*/
- rldic r28,r5,25,25 /* (vsid << 25) & 0x7fffffffff */
- clrldi r5,r5,40 /* vsid & 0xffffff */
- rldicl r0,r3,64-16,40 /* (ea >> 16) & 0xffffff */
- xor r28,r28,r5
+ sldi r28,r5,25 /* vsid << 25 */
+ /* r0 = (va >> 16) & ((1ul << (40 - 16)) -1) */
+ rldicl r0,r3,64-16,40
+ xor r28,r28,r5 /* vsid ^ ( vsid << 25) */
xor r28,r28,r0 /* hash */
/* Convert linux PTE bits into HW equivalents */
Patches currently in stable-queue which might be from
[email protected] are
queue-3.7/powerpc-mm-fix-hash-computation-function.patch
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