From cf4f08bed876fbc50e64da92d2e1cfdf7653ddb2 Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" Date: Wed, 26 Apr 2017 21:38:30 +1000 Subject: [PATCH] powerpc/mm/radix: Optimise Page Walk Cache flush Currently we implement flushing of the page walk cache (PWC) by calling _tlbiel_pid() with a RIC (Radix Invalidation Control) value of 1 which says to only flush the PWC. But _tlbiel_pid() loops over each set (congruence class) of the TLB, which is not necessary when we're just flushing the PWC. In fact the set argument is ignored for a PWC flush, so essentially we're just flushing the PWC 127 extra times for no benefit. Fix it by adding tlbiel_pwc() which just does a single flush of the PWC. Signed-off-by: Aneesh Kumar K.V [mpe: Split out of combined patch, drop _ in name, rewrite change log] Signed-off-by: Michael Ellerman --- arch/powerpc/mm/tlb-radix.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/mm/tlb-radix.c b/arch/powerpc/mm/tlb-radix.c index b68b5219cf45..ae2e799822bd 100644 --- a/arch/powerpc/mm/tlb-radix.c +++ b/arch/powerpc/mm/tlb-radix.c @@ -53,6 +53,17 @@ static inline void _tlbiel_pid(unsigned long pid, unsigned long ric) asm volatile(PPC_INVALIDATE_ERAT "; isync" : : :"memory"); } +static inline void tlbiel_pwc(unsigned long pid) +{ + asm volatile("ptesync": : :"memory"); + + /* For PWC flush, we don't look at set number */ + __tlbiel_pid(pid, 0, RIC_FLUSH_PWC); + + asm volatile("ptesync": : :"memory"); + asm volatile(PPC_INVALIDATE_ERAT "; isync" : : :"memory"); +} + static inline void _tlbie_pid(unsigned long pid, unsigned long ric) { unsigned long rb,rs,prs,r; @@ -140,7 +151,7 @@ void radix__local_flush_tlb_pwc(struct mmu_gather *tlb, unsigned long addr) pid = mm->context.id; if (pid != MMU_NO_CONTEXT) - _tlbiel_pid(pid, RIC_FLUSH_PWC); + tlbiel_pwc(pid); preempt_enable(); } @@ -222,7 +233,7 @@ void radix__flush_tlb_pwc(struct mmu_gather *tlb, unsigned long addr) if (lock_tlbie) raw_spin_unlock(&native_tlbie_lock); } else - _tlbiel_pid(pid, RIC_FLUSH_PWC); + tlbiel_pwc(pid); no_context: preempt_enable(); } -- 2.11.0