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authorBenjamin Herrenschmidt <benh@kernel.crashing.org>2017-07-19 14:49:24 +1000
committerMichael Ellerman <mpe@ellerman.id.au>2017-08-02 13:11:07 +1000
commitc433ec0455f921eaf8dd0262a718ce6f8ad62ea2 (patch)
tree0ebadb7e7d100f4aebeb137ad04d09e96abbaff3 /arch/powerpc/kernel/head_32.S
parentpowerpc/mm: Move exception_enter/exit to a do_page_fault wrapper (diff)
downloadlinux-dev-c433ec0455f921eaf8dd0262a718ce6f8ad62ea2.tar.xz
linux-dev-c433ec0455f921eaf8dd0262a718ce6f8ad62ea2.zip
powerpc/mm: Pre-filter SRR1 bits before do_page_fault()
By filtering the relevant SRR1 bits in the assembly rather than in do_page_fault() itself, we avoid a conditional branch (since we already come from different path for data and instruction faults). This will allow more simplifications later Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/kernel/head_32.S')
-rw-r--r--arch/powerpc/kernel/head_32.S2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S
index e22734278458..067b843a63a9 100644
--- a/arch/powerpc/kernel/head_32.S
+++ b/arch/powerpc/kernel/head_32.S
@@ -409,7 +409,7 @@ InstructionAccess:
mr r4,r12 /* SRR0 is fault address */
bl hash_page
1: mr r4,r12
- mr r5,r9
+ andis. r5,r9,0x4820 /* Filter relevant SRR1 bits */
EXC_XFER_LITE(0x400, handle_page_fault)
/* External interrupt */