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powerpc/mm: Update bits used to skip hash_page 

We test a number of bits from DSISR/SRR1 before deciding
to call hash_page(). If any of these is set, we go directly
to do_page_fault() as the bit indicate a fault that needs
to be handled there (no hashing needed).

This updates the current open-coded masks to use the new
DSISR definitions.

This *does* change the masks actually used in two ways:

 - We used to test various bits that were defined as "always 0"
in the architecture and could be repurposed for something
else. From now on, we just ignore such bits.

 - We were missing some new bits defined on P9

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
hifive-unleashed-5.1
Benjamin Herrenschmidt 2017-07-19 14:49:27 +10:00 committed by Michael Ellerman
parent 870cfe77a9
commit 398a719d34
2 changed files with 5 additions and 3 deletions
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6
arch/powerpc/kernel/exceptions-64s.S
View File

@ -1477,8 +1477,10 @@ USE_TEXT_SECTION()
*/
.balign IFETCH_ALIGN_BYTES
do_hash_page:
#ifdef CONFIG_PPC_STD_MMU_64
andis. r0,r4,0xa450 /* weird error? */
#ifdef CONFIG_PPC_STD_MMU_64
lis r0,DSISR_BAD_FAULT_64S@h
ori r0,r0,DSISR_BAD_FAULT_64S@l
and. r0,r4,r0 /* weird error? */
bne- handle_page_fault /* if not, try to insert a HPTE */
CURRENT_THREAD_INFO(r11, r1)
lwz r0,TI_PREEMPT(r11) /* If we're in an "NMI" */

2
arch/powerpc/kernel/head_32.S
View File

@ -388,7 +388,7 @@ DataAccess:
EXCEPTION_PROLOG
mfspr r10,SPRN_DSISR
stw r10,_DSISR(r11)
andis. r0,r10,0xa470 /* weird error? */
andis. r0,r10,DSISR_BAD_FAULT_32S@h
bne 1f /* if not, try to put a PTE */
mfspr r4,SPRN_DAR /* into the hash table */
rlwinm r3,r10,32-15,21,21 /* DSISR_STORE -> _PAGE_RW */