From 82d8f4c22f3514eface7e082750bc917193d91f9 Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Sat, 15 Sep 2018 01:30:50 +1000 Subject: [PATCH] powerpc/64s/hash: Use POWER9 SLBIA IH=3 variant in switch_slb POWER9 introduces SLBIA IH=3, which invalidates all SLB entries and associated lookaside information that have a class value of 1, which Linux assigns to user addresses. This matches what switch_slb wants, and allows a simple fast implementation that avoids the slb_cache complexity. As a side-effect, the POWER5 < DD2.1 SLB invalidation workaround is also avoided on POWER9. Process context switching rate is improved about 2.2% for a small process that hits the slb cache which is the best case for the current code. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman --- arch/powerpc/mm/slb.c | 83 +++++++++++++++++++++++----------------- arch/powerpc/xmon/xmon.c | 11 ++++-- 2 files changed, 55 insertions(+), 39 deletions(-) diff --git a/arch/powerpc/mm/slb.c b/arch/powerpc/mm/slb.c index a8f27fee6a23..513c6596140d 100644 --- a/arch/powerpc/mm/slb.c +++ b/arch/powerpc/mm/slb.c @@ -279,7 +279,6 @@ static inline int esids_match(unsigned long addr1, unsigned long addr2) /* Flush all user entries from the segment table of the current processor. */ void switch_slb(struct task_struct *tsk, struct mm_struct *mm) { - unsigned long offset; unsigned long pc = KSTK_EIP(tsk); unsigned long stack = KSTK_ESP(tsk); unsigned long exec_base; @@ -291,45 +290,56 @@ void switch_slb(struct task_struct *tsk, struct mm_struct *mm) * which would update the slb_cache/slb_cache_ptr fields in the PACA. */ hard_irq_disable(); - offset = get_paca()->slb_cache_ptr; - if (!mmu_has_feature(MMU_FTR_NO_SLBIE_B) && - offset <= SLB_CACHE_ENTRIES) { - unsigned long slbie_data = 0; - int i; + if (cpu_has_feature(CPU_FTR_ARCH_300)) { + /* + * SLBIA IH=3 invalidates all Class=1 SLBEs and their + * associated lookaside structures, which matches what + * switch_slb wants. So ARCH_300 does not use the slb + * cache. + */ + asm volatile("isync ; " PPC_SLBIA(3)" ; isync"); + } else { + unsigned long offset = get_paca()->slb_cache_ptr; - asm volatile("isync" : : : "memory"); - for (i = 0; i < offset; i++) { - slbie_data = (unsigned long)get_paca()->slb_cache[i] - << SID_SHIFT; /* EA */ - slbie_data |= user_segment_size(slbie_data) - << SLBIE_SSIZE_SHIFT; - slbie_data |= SLBIE_C; /* C set for user addresses */ - asm volatile("slbie %0" : : "r" (slbie_data)); + if (!mmu_has_feature(MMU_FTR_NO_SLBIE_B) && + offset <= SLB_CACHE_ENTRIES) { + unsigned long slbie_data = 0; + int i; + + asm volatile("isync" : : : "memory"); + for (i = 0; i < offset; i++) { + /* EA */ + slbie_data = (unsigned long) + get_paca()->slb_cache[i] << SID_SHIFT; + slbie_data |= user_segment_size(slbie_data) + << SLBIE_SSIZE_SHIFT; + slbie_data |= SLBIE_C; /* user slbs have C=1 */ + asm volatile("slbie %0" : : "r" (slbie_data)); + } + + /* Workaround POWER5 < DD2.1 issue */ + if (!cpu_has_feature(CPU_FTR_ARCH_207S) && offset == 1) + asm volatile("slbie %0" : : "r" (slbie_data)); + + asm volatile("isync" : : : "memory"); + } else { + struct slb_shadow *p = get_slb_shadow(); + unsigned long ksp_esid_data = + be64_to_cpu(p->save_area[KSTACK_INDEX].esid); + unsigned long ksp_vsid_data = + be64_to_cpu(p->save_area[KSTACK_INDEX].vsid); + + asm volatile("isync\n" + PPC_SLBIA(1) "\n" + "slbmte %0,%1\n" + "isync" + :: "r"(ksp_vsid_data), + "r"(ksp_esid_data)); } - /* Workaround POWER5 < DD2.1 issue */ - if (!cpu_has_feature(CPU_FTR_ARCH_207S) && offset == 1) - asm volatile("slbie %0" : : "r" (slbie_data)); - - asm volatile("isync" : : : "memory"); - } else { - struct slb_shadow *p = get_slb_shadow(); - unsigned long ksp_esid_data = - be64_to_cpu(p->save_area[KSTACK_INDEX].esid); - unsigned long ksp_vsid_data = - be64_to_cpu(p->save_area[KSTACK_INDEX].vsid); - - asm volatile("isync\n" - PPC_SLBIA(1) "\n" - "slbmte %0,%1\n" - "isync" - :: "r"(ksp_vsid_data), - "r"(ksp_esid_data)); - - asm volatile("isync" : : : "memory"); + get_paca()->slb_cache_ptr = 0; } - get_paca()->slb_cache_ptr = 0; copy_mm_to_paca(mm); /* @@ -455,6 +465,9 @@ static void insert_slb_entry(unsigned long vsid, unsigned long ea, enum slb_index index; int slb_cache_index; + if (cpu_has_feature(CPU_FTR_ARCH_300)) + return; /* ISAv3.0B and later does not use slb_cache */ + /* * We are irq disabled, hence should be safe to access PACA. */ diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c index 4264aedc7775..cd43c168dc1b 100644 --- a/arch/powerpc/xmon/xmon.c +++ b/arch/powerpc/xmon/xmon.c @@ -2393,10 +2393,13 @@ static void dump_one_paca(int cpu) } } DUMP(p, vmalloc_sllp, "%#-*x"); - DUMP(p, slb_cache_ptr, "%#-*x"); - for (i = 0; i < SLB_CACHE_ENTRIES; i++) - printf(" %-*s[%d] = 0x%016x\n", - 22, "slb_cache", i, p->slb_cache[i]); + + if (!early_cpu_has_feature(CPU_FTR_ARCH_300)) { + DUMP(p, slb_cache_ptr, "%#-*x"); + for (i = 0; i < SLB_CACHE_ENTRIES; i++) + printf(" %-*s[%d] = 0x%016x\n", + 22, "slb_cache", i, p->slb_cache[i]); + } DUMP(p, rfi_flush_fallback_area, "%-*px"); #endif