[PATCH] powerpc/603: Avoid a pile of NOPs when not using SW LRU in TLB exceptions
From: Christophe Leroy <hidden>
Date: 2021-05-07 05:02:08
The SW LRU is in an MMU feature section. When not used, that's a dozen of NOPs to fetch for nothing. Define an ALT section that does the few remaining operations. That also avoids a double read on SRR1 in the SW LRU case. Signed-off-by: Christophe Leroy <redacted> --- arch/powerpc/kernel/head_book3s_32.S | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-)
diff --git a/arch/powerpc/kernel/head_book3s_32.S b/arch/powerpc/kernel/head_book3s_32.S
index 065178f19a3d..f2a5ceff52b2 100644
--- a/arch/powerpc/kernel/head_book3s_32.S
+++ b/arch/powerpc/kernel/head_book3s_32.S@@ -518,8 +518,6 @@ BEGIN_FTR_SECTION rlwinm r1,r1,0,~_PAGE_COHERENT /* clear M (coherence not required) */ END_FTR_SECTION_IFCLR(CPU_FTR_NEED_COHERENT) mtspr SPRN_RPA,r1 - mfspr r2,SPRN_SRR1 /* Need to restore CR0 */ - mtcrf 0x80,r2 BEGIN_MMU_FTR_SECTION li r0,1 mfspr r1,SPRN_SPRG_603_LRU
@@ -531,9 +529,15 @@ BEGIN_MMU_FTR_SECTION mfspr r2,SPRN_SRR1 rlwimi r2,r0,31-14,14,14 mtspr SPRN_SRR1,r2 -END_MMU_FTR_SECTION_IFSET(MMU_FTR_NEED_DTLB_SW_LRU) + mtcrf 0x80,r2 + tlbld r3 + rfi +MMU_FTR_SECTION_ELSE + mfspr r2,SPRN_SRR1 /* Need to restore CR0 */ + mtcrf 0x80,r2 tlbld r3 rfi +ALT_MMU_FTR_SECTION_END_IFSET(MMU_FTR_NEED_DTLB_SW_LRU) DataAddressInvalid: mfspr r3,SPRN_SRR1 rlwinm r1,r3,9,6,6 /* Get load/store bit */
@@ -607,9 +611,15 @@ BEGIN_MMU_FTR_SECTION mfspr r2,SPRN_SRR1 rlwimi r2,r0,31-14,14,14 mtspr SPRN_SRR1,r2 -END_MMU_FTR_SECTION_IFSET(MMU_FTR_NEED_DTLB_SW_LRU) + mtcrf 0x80,r2 + tlbld r3 + rfi +MMU_FTR_SECTION_ELSE + mfspr r2,SPRN_SRR1 /* Need to restore CR0 */ + mtcrf 0x80,r2 tlbld r3 rfi +ALT_MMU_FTR_SECTION_END_IFSET(MMU_FTR_NEED_DTLB_SW_LRU) #ifndef CONFIG_ALTIVEC #define altivec_assist_exception unknown_exception
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2.25.0