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author | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2017-07-24 14:28:03 +1000 |
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committer | Michael Ellerman <mpe@ellerman.id.au> | 2017-08-23 22:48:51 +1000 |
commit | 3a2df3798d4da2fc40052c25f0d9c687b1467d53 (patch) | |
tree | e94d918d17a1c0945adf9869c130ffd5e60f697e /arch/powerpc/mm | |
parent | a619e59c075c66e530a88e57b45bb0417e2f4fff (diff) | |
download | linux-stable-3a2df3798d4da2fc40052c25f0d9c687b1467d53.tar.gz linux-stable-3a2df3798d4da2fc40052c25f0d9c687b1467d53.tar.bz2 linux-stable-3a2df3798d4da2fc40052c25f0d9c687b1467d53.zip |
powerpc/mm: Make switch_mm_irqs_off() out of line
It's too big to be inline, there is no reason to keep it
that way.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[mpe: Rework to incorporate the comment changes via fixes branch]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/mm')
-rw-r--r-- | arch/powerpc/mm/Makefile | 2 | ||||
-rw-r--r-- | arch/powerpc/mm/mmu_context.c | 99 |
2 files changed, 100 insertions, 1 deletions
diff --git a/arch/powerpc/mm/Makefile b/arch/powerpc/mm/Makefile index fa6a6ba34355..fb844d2f266e 100644 --- a/arch/powerpc/mm/Makefile +++ b/arch/powerpc/mm/Makefile @@ -8,7 +8,7 @@ ccflags-$(CONFIG_PPC64) := $(NO_MINIMAL_TOC) obj-y := fault.o mem.o pgtable.o mmap.o \ init_$(BITS).o pgtable_$(BITS).o \ - init-common.o + init-common.o mmu_context.o obj-$(CONFIG_PPC_MMU_NOHASH) += mmu_context_nohash.o tlb_nohash.o \ tlb_nohash_low.o obj-$(CONFIG_PPC_BOOK3E) += tlb_low_$(BITS)e.o diff --git a/arch/powerpc/mm/mmu_context.c b/arch/powerpc/mm/mmu_context.c new file mode 100644 index 000000000000..0f613bc63c50 --- /dev/null +++ b/arch/powerpc/mm/mmu_context.c @@ -0,0 +1,99 @@ +/* + * Common implementation of switch_mm_irqs_off + * + * Copyright IBM Corp. 2017 + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + * + */ + +#include <linux/mm.h> +#include <linux/cpu.h> + +#include <asm/mmu_context.h> + +#if defined(CONFIG_PPC32) +static inline void switch_mm_pgdir(struct task_struct *tsk, + struct mm_struct *mm) +{ + /* 32-bit keeps track of the current PGDIR in the thread struct */ + tsk->thread.pgdir = mm->pgd; +} +#elif defined(CONFIG_PPC_BOOK3E_64) +static inline void switch_mm_pgdir(struct task_struct *tsk, + struct mm_struct *mm) +{ + /* 64-bit Book3E keeps track of current PGD in the PACA */ + get_paca()->pgd = mm->pgd; +} +#else +static inline void switch_mm_pgdir(struct task_struct *tsk, + struct mm_struct *mm) { } +#endif + +#ifdef CONFIG_PPC_BOOK3S_64 +static inline void inc_mm_active_cpus(struct mm_struct *mm) +{ + atomic_inc(&mm->context.active_cpus); +} +#else +static inline void inc_mm_active_cpus(struct mm_struct *mm) { } +#endif + +void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next, + struct task_struct *tsk) +{ + bool new_on_cpu = false; + + /* Mark this context has been used on the new CPU */ + if (!cpumask_test_cpu(smp_processor_id(), mm_cpumask(next))) { + cpumask_set_cpu(smp_processor_id(), mm_cpumask(next)); + inc_mm_active_cpus(next); + + /* + * This full barrier orders the store to the cpumask above vs + * a subsequent operation which allows this CPU to begin loading + * translations for next. + * + * When using the radix MMU that operation is the load of the + * MMU context id, which is then moved to SPRN_PID. + * + * For the hash MMU it is either the first load from slb_cache + * in switch_slb(), and/or the store of paca->mm_ctx_id in + * copy_mm_to_paca(). + * + * On the read side the barrier is in pte_xchg(), which orders + * the store to the PTE vs the load of mm_cpumask. + */ + smp_mb(); + + new_on_cpu = true; + } + + /* Some subarchs need to track the PGD elsewhere */ + switch_mm_pgdir(tsk, next); + + /* Nothing else to do if we aren't actually switching */ + if (prev == next) + return; + + /* + * We must stop all altivec streams before changing the HW + * context + */ + if (cpu_has_feature(CPU_FTR_ALTIVEC)) + asm volatile ("dssall"); + + if (new_on_cpu) + radix_kvm_prefetch_workaround(next); + + /* + * The actual HW switching method differs between the various + * sub architectures. Out of line for now + */ + switch_mmu_context(prev, next, tsk); +} + |