From 27e23b5f5f6f22292347901303aab2a1d458bcb5 Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Fri, 29 Mar 2019 10:00:02 +0000 Subject: powerpc/mm: Move nohash specifics in subdirectory mm/nohash Many files in arch/powerpc/mm are only for nohash. This patch creates a subdirectory for them. Signed-off-by: Christophe Leroy [mpe: Shorten new filenames] Signed-off-by: Michael Ellerman --- arch/powerpc/mm/mmu_context_nohash.c | 497 ----------------------------------- 1 file changed, 497 deletions(-) delete mode 100644 arch/powerpc/mm/mmu_context_nohash.c (limited to 'arch/powerpc/mm/mmu_context_nohash.c') diff --git a/arch/powerpc/mm/mmu_context_nohash.c b/arch/powerpc/mm/mmu_context_nohash.c deleted file mode 100644 index ae4505d5b4b8..000000000000 --- a/arch/powerpc/mm/mmu_context_nohash.c +++ /dev/null @@ -1,497 +0,0 @@ -/* - * This file contains the routines for handling the MMU on those - * PowerPC implementations where the MMU is not using the hash - * table, such as 8xx, 4xx, BookE's etc... - * - * Copyright 2008 Ben Herrenschmidt - * IBM Corp. - * - * Derived from previous arch/powerpc/mm/mmu_context.c - * and arch/powerpc/include/asm/mmu_context.h - * - * 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. - * - * TODO: - * - * - The global context lock will not scale very well - * - The maps should be dynamically allocated to allow for processors - * that support more PID bits at runtime - * - Implement flush_tlb_mm() by making the context stale and picking - * a new one - * - More aggressively clear stale map bits and maybe find some way to - * also clear mm->cpu_vm_mask bits when processes are migrated - */ - -//#define DEBUG_MAP_CONSISTENCY -//#define DEBUG_CLAMP_LAST_CONTEXT 31 -//#define DEBUG_HARDER - -/* We don't use DEBUG because it tends to be compiled in always nowadays - * and this would generate way too much output - */ -#ifdef DEBUG_HARDER -#define pr_hard(args...) printk(KERN_DEBUG args) -#define pr_hardcont(args...) printk(KERN_CONT args) -#else -#define pr_hard(args...) do { } while(0) -#define pr_hardcont(args...) do { } while(0) -#endif - -#include -#include -#include -#include -#include -#include -#include -#include - -#include -#include - -#include - -/* - * The MPC8xx has only 16 contexts. We rotate through them on each task switch. - * A better way would be to keep track of tasks that own contexts, and implement - * an LRU usage. That way very active tasks don't always have to pay the TLB - * reload overhead. The kernel pages are mapped shared, so the kernel can run on - * behalf of any task that makes a kernel entry. Shared does not mean they are - * not protected, just that the ASID comparison is not performed. -- Dan - * - * The IBM4xx has 256 contexts, so we can just rotate through these as a way of - * "switching" contexts. If the TID of the TLB is zero, the PID/TID comparison - * is disabled, so we can use a TID of zero to represent all kernel pages as - * shared among all contexts. -- Dan - * - * The IBM 47x core supports 16-bit PIDs, thus 65535 contexts. We should - * normally never have to steal though the facility is present if needed. - * -- BenH - */ -#define FIRST_CONTEXT 1 -#ifdef DEBUG_CLAMP_LAST_CONTEXT -#define LAST_CONTEXT DEBUG_CLAMP_LAST_CONTEXT -#elif defined(CONFIG_PPC_8xx) -#define LAST_CONTEXT 16 -#elif defined(CONFIG_PPC_47x) -#define LAST_CONTEXT 65535 -#else -#define LAST_CONTEXT 255 -#endif - -static unsigned int next_context, nr_free_contexts; -static unsigned long *context_map; -#ifdef CONFIG_SMP -static unsigned long *stale_map[NR_CPUS]; -#endif -static struct mm_struct **context_mm; -static DEFINE_RAW_SPINLOCK(context_lock); - -#define CTX_MAP_SIZE \ - (sizeof(unsigned long) * (LAST_CONTEXT / BITS_PER_LONG + 1)) - - -/* Steal a context from a task that has one at the moment. - * - * This is used when we are running out of available PID numbers - * on the processors. - * - * This isn't an LRU system, it just frees up each context in - * turn (sort-of pseudo-random replacement :). This would be the - * place to implement an LRU scheme if anyone was motivated to do it. - * -- paulus - * - * For context stealing, we use a slightly different approach for - * SMP and UP. Basically, the UP one is simpler and doesn't use - * the stale map as we can just flush the local CPU - * -- benh - */ -#ifdef CONFIG_SMP -static unsigned int steal_context_smp(unsigned int id) -{ - struct mm_struct *mm; - unsigned int cpu, max, i; - - max = LAST_CONTEXT - FIRST_CONTEXT; - - /* Attempt to free next_context first and then loop until we manage */ - while (max--) { - /* Pick up the victim mm */ - mm = context_mm[id]; - - /* We have a candidate victim, check if it's active, on SMP - * we cannot steal active contexts - */ - if (mm->context.active) { - id++; - if (id > LAST_CONTEXT) - id = FIRST_CONTEXT; - continue; - } - pr_hardcont(" | steal %d from 0x%p", id, mm); - - /* Mark this mm has having no context anymore */ - mm->context.id = MMU_NO_CONTEXT; - - /* Mark it stale on all CPUs that used this mm. For threaded - * implementations, we set it on all threads on each core - * represented in the mask. A future implementation will use - * a core map instead but this will do for now. - */ - for_each_cpu(cpu, mm_cpumask(mm)) { - for (i = cpu_first_thread_sibling(cpu); - i <= cpu_last_thread_sibling(cpu); i++) { - if (stale_map[i]) - __set_bit(id, stale_map[i]); - } - cpu = i - 1; - } - return id; - } - - /* This will happen if you have more CPUs than available contexts, - * all we can do here is wait a bit and try again - */ - raw_spin_unlock(&context_lock); - cpu_relax(); - raw_spin_lock(&context_lock); - - /* This will cause the caller to try again */ - return MMU_NO_CONTEXT; -} -#endif /* CONFIG_SMP */ - -static unsigned int steal_all_contexts(void) -{ - struct mm_struct *mm; -#ifdef CONFIG_SMP - int cpu = smp_processor_id(); -#endif - unsigned int id; - - for (id = FIRST_CONTEXT; id <= LAST_CONTEXT; id++) { - /* Pick up the victim mm */ - mm = context_mm[id]; - - pr_hardcont(" | steal %d from 0x%p", id, mm); - - /* Mark this mm as having no context anymore */ - mm->context.id = MMU_NO_CONTEXT; - if (id != FIRST_CONTEXT) { - context_mm[id] = NULL; - __clear_bit(id, context_map); -#ifdef DEBUG_MAP_CONSISTENCY - mm->context.active = 0; -#endif - } -#ifdef CONFIG_SMP - __clear_bit(id, stale_map[cpu]); -#endif - } - - /* Flush the TLB for all contexts (not to be used on SMP) */ - _tlbil_all(); - - nr_free_contexts = LAST_CONTEXT - FIRST_CONTEXT; - - return FIRST_CONTEXT; -} - -/* Note that this will also be called on SMP if all other CPUs are - * offlined, which means that it may be called for cpu != 0. For - * this to work, we somewhat assume that CPUs that are onlined - * come up with a fully clean TLB (or are cleaned when offlined) - */ -static unsigned int steal_context_up(unsigned int id) -{ - struct mm_struct *mm; -#ifdef CONFIG_SMP - int cpu = smp_processor_id(); -#endif - - /* Pick up the victim mm */ - mm = context_mm[id]; - - pr_hardcont(" | steal %d from 0x%p", id, mm); - - /* Flush the TLB for that context */ - local_flush_tlb_mm(mm); - - /* Mark this mm has having no context anymore */ - mm->context.id = MMU_NO_CONTEXT; - - /* XXX This clear should ultimately be part of local_flush_tlb_mm */ -#ifdef CONFIG_SMP - __clear_bit(id, stale_map[cpu]); -#endif - - return id; -} - -#ifdef DEBUG_MAP_CONSISTENCY -static void context_check_map(void) -{ - unsigned int id, nrf, nact; - - nrf = nact = 0; - for (id = FIRST_CONTEXT; id <= LAST_CONTEXT; id++) { - int used = test_bit(id, context_map); - if (!used) - nrf++; - if (used != (context_mm[id] != NULL)) - pr_err("MMU: Context %d is %s and MM is %p !\n", - id, used ? "used" : "free", context_mm[id]); - if (context_mm[id] != NULL) - nact += context_mm[id]->context.active; - } - if (nrf != nr_free_contexts) { - pr_err("MMU: Free context count out of sync ! (%d vs %d)\n", - nr_free_contexts, nrf); - nr_free_contexts = nrf; - } - if (nact > num_online_cpus()) - pr_err("MMU: More active contexts than CPUs ! (%d vs %d)\n", - nact, num_online_cpus()); - if (FIRST_CONTEXT > 0 && !test_bit(0, context_map)) - pr_err("MMU: Context 0 has been freed !!!\n"); -} -#else -static void context_check_map(void) { } -#endif - -void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next, - struct task_struct *tsk) -{ - unsigned int id; -#ifdef CONFIG_SMP - unsigned int i, cpu = smp_processor_id(); -#endif - unsigned long *map; - - /* No lockless fast path .. yet */ - raw_spin_lock(&context_lock); - - pr_hard("[%d] activating context for mm @%p, active=%d, id=%d", - cpu, next, next->context.active, next->context.id); - -#ifdef CONFIG_SMP - /* Mark us active and the previous one not anymore */ - next->context.active++; - if (prev) { - pr_hardcont(" (old=0x%p a=%d)", prev, prev->context.active); - WARN_ON(prev->context.active < 1); - prev->context.active--; - } - - again: -#endif /* CONFIG_SMP */ - - /* If we already have a valid assigned context, skip all that */ - id = next->context.id; - if (likely(id != MMU_NO_CONTEXT)) { -#ifdef DEBUG_MAP_CONSISTENCY - if (context_mm[id] != next) - pr_err("MMU: mm 0x%p has id %d but context_mm[%d] says 0x%p\n", - next, id, id, context_mm[id]); -#endif - goto ctxt_ok; - } - - /* We really don't have a context, let's try to acquire one */ - id = next_context; - if (id > LAST_CONTEXT) - id = FIRST_CONTEXT; - map = context_map; - - /* No more free contexts, let's try to steal one */ - if (nr_free_contexts == 0) { -#ifdef CONFIG_SMP - if (num_online_cpus() > 1) { - id = steal_context_smp(id); - if (id == MMU_NO_CONTEXT) - goto again; - goto stolen; - } -#endif /* CONFIG_SMP */ - if (IS_ENABLED(CONFIG_PPC_8xx)) - id = steal_all_contexts(); - else - id = steal_context_up(id); - goto stolen; - } - nr_free_contexts--; - - /* We know there's at least one free context, try to find it */ - while (__test_and_set_bit(id, map)) { - id = find_next_zero_bit(map, LAST_CONTEXT+1, id); - if (id > LAST_CONTEXT) - id = FIRST_CONTEXT; - } - stolen: - next_context = id + 1; - context_mm[id] = next; - next->context.id = id; - pr_hardcont(" | new id=%d,nrf=%d", id, nr_free_contexts); - - context_check_map(); - ctxt_ok: - - /* If that context got marked stale on this CPU, then flush the - * local TLB for it and unmark it before we use it - */ -#ifdef CONFIG_SMP - if (test_bit(id, stale_map[cpu])) { - pr_hardcont(" | stale flush %d [%d..%d]", - id, cpu_first_thread_sibling(cpu), - cpu_last_thread_sibling(cpu)); - - local_flush_tlb_mm(next); - - /* XXX This clear should ultimately be part of local_flush_tlb_mm */ - for (i = cpu_first_thread_sibling(cpu); - i <= cpu_last_thread_sibling(cpu); i++) { - if (stale_map[i]) - __clear_bit(id, stale_map[i]); - } - } -#endif - - /* Flick the MMU and release lock */ - pr_hardcont(" -> %d\n", id); - set_context(id, next->pgd); - raw_spin_unlock(&context_lock); -} - -/* - * Set up the context for a new address space. - */ -int init_new_context(struct task_struct *t, struct mm_struct *mm) -{ - pr_hard("initing context for mm @%p\n", mm); - - /* - * We have MMU_NO_CONTEXT set to be ~0. Hence check - * explicitly against context.id == 0. This ensures that we properly - * initialize context slice details for newly allocated mm's (which will - * have id == 0) and don't alter context slice inherited via fork (which - * will have id != 0). - */ - if (mm->context.id == 0) - slice_init_new_context_exec(mm); - mm->context.id = MMU_NO_CONTEXT; - mm->context.active = 0; - pte_frag_set(&mm->context, NULL); - return 0; -} - -/* - * We're finished using the context for an address space. - */ -void destroy_context(struct mm_struct *mm) -{ - unsigned long flags; - unsigned int id; - - if (mm->context.id == MMU_NO_CONTEXT) - return; - - WARN_ON(mm->context.active != 0); - - raw_spin_lock_irqsave(&context_lock, flags); - id = mm->context.id; - if (id != MMU_NO_CONTEXT) { - __clear_bit(id, context_map); - mm->context.id = MMU_NO_CONTEXT; -#ifdef DEBUG_MAP_CONSISTENCY - mm->context.active = 0; -#endif - context_mm[id] = NULL; - nr_free_contexts++; - } - raw_spin_unlock_irqrestore(&context_lock, flags); -} - -#ifdef CONFIG_SMP -static int mmu_ctx_cpu_prepare(unsigned int cpu) -{ - /* We don't touch CPU 0 map, it's allocated at aboot and kept - * around forever - */ - if (cpu == boot_cpuid) - return 0; - - pr_devel("MMU: Allocating stale context map for CPU %d\n", cpu); - stale_map[cpu] = kzalloc(CTX_MAP_SIZE, GFP_KERNEL); - return 0; -} - -static int mmu_ctx_cpu_dead(unsigned int cpu) -{ -#ifdef CONFIG_HOTPLUG_CPU - if (cpu == boot_cpuid) - return 0; - - pr_devel("MMU: Freeing stale context map for CPU %d\n", cpu); - kfree(stale_map[cpu]); - stale_map[cpu] = NULL; - - /* We also clear the cpu_vm_mask bits of CPUs going away */ - clear_tasks_mm_cpumask(cpu); -#endif - return 0; -} - -#endif /* CONFIG_SMP */ - -/* - * Initialize the context management stuff. - */ -void __init mmu_context_init(void) -{ - /* Mark init_mm as being active on all possible CPUs since - * we'll get called with prev == init_mm the first time - * we schedule on a given CPU - */ - init_mm.context.active = NR_CPUS; - - /* - * Allocate the maps used by context management - */ - context_map = memblock_alloc(CTX_MAP_SIZE, SMP_CACHE_BYTES); - if (!context_map) - panic("%s: Failed to allocate %zu bytes\n", __func__, - CTX_MAP_SIZE); - context_mm = memblock_alloc(sizeof(void *) * (LAST_CONTEXT + 1), - SMP_CACHE_BYTES); - if (!context_mm) - panic("%s: Failed to allocate %zu bytes\n", __func__, - sizeof(void *) * (LAST_CONTEXT + 1)); -#ifdef CONFIG_SMP - stale_map[boot_cpuid] = memblock_alloc(CTX_MAP_SIZE, SMP_CACHE_BYTES); - if (!stale_map[boot_cpuid]) - panic("%s: Failed to allocate %zu bytes\n", __func__, - CTX_MAP_SIZE); - - cpuhp_setup_state_nocalls(CPUHP_POWERPC_MMU_CTX_PREPARE, - "powerpc/mmu/ctx:prepare", - mmu_ctx_cpu_prepare, mmu_ctx_cpu_dead); -#endif - - printk(KERN_INFO - "MMU: Allocated %zu bytes of context maps for %d contexts\n", - 2 * CTX_MAP_SIZE + (sizeof(void *) * (LAST_CONTEXT + 1)), - LAST_CONTEXT - FIRST_CONTEXT + 1); - - /* - * Some processors have too few contexts to reserve one for - * init_mm, and require using context 0 for a normal task. - * Other processors reserve the use of context zero for the kernel. - * This code assumes FIRST_CONTEXT < 32. - */ - context_map[0] = (1 << FIRST_CONTEXT) - 1; - next_context = FIRST_CONTEXT; - nr_free_contexts = LAST_CONTEXT - FIRST_CONTEXT + 1; -} -- cgit v1.2.3