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Subject[PATCH v5 15/17] 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 | 31 +++++++++++++++++--------------
1 file changed, 17 insertions(+), 14 deletions(-)

diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S
index 449625b4ff03..7ec780858299 100644
--- a/arch/powerpc/kernel/head_32.S
+++ b/arch/powerpc/kernel/head_32.S
@@ -295,24 +295,20 @@ __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_2 /* 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)
-
+ b handle_page_fault_tramp_1
+FTR_SECTION_ELSE
+ b handle_page_fault_tramp_2
+ALT_MMU_FTR_SECTION_END_IFSET(MMU_FTR_HPTE_TABLE)

/* Instruction access exception. */
. = 0x400
@@ -642,6 +638,13 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_NEED_DTLB_SW_LRU)

. = 0x3000

+handle_page_fault_tramp_1:
+ lwz r4, _DAR(r11)
+ lwz r5, _DSISR(r11)
+ /* fall through */
+handle_page_fault_tramp_2:
+ EXC_XFER_LITE(0x300, handle_page_fault)
+
AltiVecUnavailable:
EXCEPTION_PROLOG
#ifdef CONFIG_ALTIVEC
--
2.13.3
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