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powerpc/mm: Fix hash computation function 

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 <qiudayu@linux.vnet.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Tested-by: Mike Qiu <qiudayu@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: <stable@vger.kernel.org> [v3.7]
This commit is contained in:
Aneesh Kumar K.V 2013-01-29 19:40:42 +00:00 committed by Benjamin Herrenschmidt
parent 689dfa894c
commit eda8eebdd1
1 changed files with 35 additions and 27 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

62
arch/powerpc/mm/hash_low_64.S
View File

@ -115,11 +115,13 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_1T_SEGMENT)
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_SEGMENT)
/*
* 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_SEGMENT)
*/
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_SEGMENT)
/*
* 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_SEGMENT)
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 */