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powerpc: Update kernel VSID range

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This patch change the kernel VSID range so that we limit VSID_BITS to 37.
This enables us to support 64TB with 65 bit VA (37+28). Without this patch
we have boot hangs on platforms that only support 65 bit VA.

With this patch we now have proto vsid generated as below:

We first generate a 37-bit "proto-VSID". Proto-VSIDs are generated
from mmu context id and effective segment id of the address.

For user processes max context id is limited to ((1ul << 19) - 5)
for kernel space, we use the top 4 context ids to map address as below
0x7fffc -  [ 0xc000000000000000 - 0xc0003fffffffffff ]
0x7fffd -  [ 0xd000000000000000 - 0xd0003fffffffffff ]
0x7fffe -  [ 0xe000000000000000 - 0xe0003fffffffffff ]
0x7ffff -  [ 0xf000000000000000 - 0xf0003fffffffffff ]

Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Tested-by: Geoff Levand <geoff@infradead.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: <stable@vger.kernel.org> [v3.8]
This commit is contained in:
Aneesh Kumar K.V
2013-03-13 03:34:54 +00:00
committed by Benjamin Herrenschmidt
parent e39d1a4714
commit c60ac5693c
6 changed files with 126 additions and 106 deletions
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34
arch/powerpc/kernel/exceptions-64s.S
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@@ -1452,20 +1452,36 @@ do_ste_alloc:
_GLOBAL(do_stab_bolted)
stw r9,PACA_EXSLB+EX_CCR(r13) /* save CR in exc. frame */
std r11,PACA_EXSLB+EX_SRR0(r13) /* save SRR0 in exc. frame */
mfspr r11,SPRN_DAR /* ea */
/*
* check for bad kernel/user address
* (ea & ~REGION_MASK) >= PGTABLE_RANGE
*/
rldicr. r9,r11,4,(63 - 46 - 4)
li r9,0 /* VSID = 0 for bad address */
bne- 0f
/*
* Calculate VSID:
* This is the kernel vsid, we take the top for context from
* the range. context = (MAX_USER_CONTEXT) + ((ea >> 60) - 0xc) + 1
* Here we know that (ea >> 60) == 0xc
*/
lis r9,(MAX_USER_CONTEXT + 1)@ha
addi r9,r9,(MAX_USER_CONTEXT + 1)@l
srdi r10,r11,SID_SHIFT
rldimi r10,r9,USER_ESID_BITS,0 /* proto vsid */
ASM_VSID_SCRAMBLE(r10, r9, 256M)
rldic r9,r10,12,16 /* r9 = vsid << 12 */
0:
/* Hash to the primary group */
ld r10,PACASTABVIRT(r13)
mfspr r11,SPRN_DAR
srdi r11,r11,28
srdi r11,r11,SID_SHIFT
rldimi r10,r11,7,52 /* r10 = first ste of the group */
/* Calculate VSID */
/* This is a kernel address, so protovsid = ESID | 1 << 37 */
li r9,0x1
rldimi r11,r9,(CONTEXT_BITS + USER_ESID_BITS),0
ASM_VSID_SCRAMBLE(r11, r9, 256M)
rldic r9,r11,12,16 /* r9 = vsid << 12 */
/* Search the primary group for a free entry */
1: ld r11,0(r10) /* Test valid bit of the current ste */
andi. r11,r11,0x80