powerpc: Update kernel VSID range
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]
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index 87ef8f5..b112359 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -1452,20 +1452,36 @@
_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