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Subject[PATCH v3 14/15] powerpc/32s: reorganise DSI handler.
Date
The part decidated to handling hash_page() is fully unneeded for
processors not having real hash pages like the 603.

Lets enlarge the content of the feature fixup, and provide
an alternative which jumps directly instead of getting NIPs.

Also, in preparation of VMAP stacks, the end of DSI handler has moved
to later in the code as it won't fit anymore once VMAP stacks
are there.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
arch/powerpc/kernel/head_32.S | 29 +++++++++++++++--------------
1 file changed, 15 insertions(+), 14 deletions(-)

diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S
index 449625b4ff03..5bda6a092673 100644
--- a/arch/powerpc/kernel/head_32.S
+++ b/arch/powerpc/kernel/head_32.S
@@ -295,24 +295,22 @@ __secondary_hold_acknowledge:
DO_KVM 0x300
DataAccess:
EXCEPTION_PROLOG
- mfspr r10,SPRN_DSISR
- stw r10,_DSISR(r11)
+ get_and_save_dar_dsisr_on_stack r4, r5, r11
+BEGIN_MMU_FTR_SECTION
#ifdef CONFIG_PPC_KUAP
- andis. r0,r10,(DSISR_BAD_FAULT_32S | DSISR_DABRMATCH | DSISR_PROTFAULT)@h
+ andis. r0, r5, (DSISR_BAD_FAULT_32S | DSISR_DABRMATCH | DSISR_PROTFAULT)@h
#else
- andis. r0,r10,(DSISR_BAD_FAULT_32S|DSISR_DABRMATCH)@h
+ andis. r0, r5, (DSISR_BAD_FAULT_32S | DSISR_DABRMATCH)@h
#endif
- 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 */
-BEGIN_MMU_FTR_SECTION
+ bne handle_page_fault_tramp /* if not, try to put a PTE */
+ rlwinm r3, r5, 32 - 15, 21, 21 /* DSISR_STORE -> _PAGE_RW */
bl hash_page
-END_MMU_FTR_SECTION_IFSET(MMU_FTR_HPTE_TABLE)
-1: lwz r5,_DSISR(r11) /* get DSISR value */
- mfspr r4,SPRN_DAR
- stw r4, _DAR(r11)
- EXC_XFER_LITE(0x300, handle_page_fault)
-
+ lwz r5, _DSISR(r11) /* get DSISR value */
+ lwz r4, _DAR(r11)
+ b handle_page_fault_tramp
+FTR_SECTION_ELSE
+ b handle_page_fault_tramp
+ALT_MMU_FTR_SECTION_END_IFSET(MMU_FTR_HPTE_TABLE)

/* Instruction access exception. */
. = 0x400
@@ -642,6 +640,9 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_NEED_DTLB_SW_LRU)

. = 0x3000

+handle_page_fault_tramp:
+ EXC_XFER_LITE(0x300, handle_page_fault)
+
AltiVecUnavailable:
EXCEPTION_PROLOG
#ifdef CONFIG_ALTIVEC
--
2.13.3
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