diff options
Diffstat (limited to 'arch/powerpc/mm/mmu_context_nohash.c')
-rw-r--r-- | arch/powerpc/mm/mmu_context_nohash.c | 153 |
1 files changed, 83 insertions, 70 deletions
diff --git a/arch/powerpc/mm/mmu_context_nohash.c b/arch/powerpc/mm/mmu_context_nohash.c index 4554d6527682..2faca46ad720 100644 --- a/arch/powerpc/mm/mmu_context_nohash.c +++ b/arch/powerpc/mm/mmu_context_nohash.c @@ -44,7 +44,7 @@ #include <linux/mm.h> #include <linux/init.h> #include <linux/spinlock.h> -#include <linux/bootmem.h> +#include <linux/memblock.h> #include <linux/notifier.h> #include <linux/cpu.h> #include <linux/slab.h> @@ -54,16 +54,44 @@ #include "mmu_decl.h" -static unsigned int first_context, last_context; +/* + * 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); -static bool no_selective_tlbil; #define CTX_MAP_SIZE \ - (sizeof(unsigned long) * (last_context / BITS_PER_LONG + 1)) + (sizeof(unsigned long) * (LAST_CONTEXT / BITS_PER_LONG + 1)) /* Steal a context from a task that has one at the moment. @@ -87,7 +115,7 @@ static unsigned int steal_context_smp(unsigned int id) struct mm_struct *mm; unsigned int cpu, max, i; - max = last_context - first_context; + max = LAST_CONTEXT - FIRST_CONTEXT; /* Attempt to free next_context first and then loop until we manage */ while (max--) { @@ -99,8 +127,8 @@ static unsigned int steal_context_smp(unsigned int id) */ if (mm->context.active) { id++; - if (id > last_context) - id = first_context; + if (id > LAST_CONTEXT) + id = FIRST_CONTEXT; continue; } pr_hardcont(" | steal %d from 0x%p", id, mm); @@ -139,10 +167,12 @@ static unsigned int steal_context_smp(unsigned int id) 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++) { + for (id = FIRST_CONTEXT; id <= LAST_CONTEXT; id++) { /* Pick up the victim mm */ mm = context_mm[id]; @@ -150,22 +180,24 @@ static unsigned int steal_all_contexts(void) /* Mark this mm as having no context anymore */ mm->context.id = MMU_NO_CONTEXT; - if (id != first_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; + nr_free_contexts = LAST_CONTEXT - FIRST_CONTEXT; - return first_context; + return FIRST_CONTEXT; } /* Note that this will also be called on SMP if all other CPUs are @@ -176,7 +208,9 @@ static unsigned int steal_all_contexts(void) 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]; @@ -190,7 +224,9 @@ static unsigned int steal_context_up(unsigned int id) 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; } @@ -201,7 +237,7 @@ static void context_check_map(void) unsigned int id, nrf, nact; nrf = nact = 0; - for (id = first_context; id <= last_context; id++) { + for (id = FIRST_CONTEXT; id <= LAST_CONTEXT; id++) { int used = test_bit(id, context_map); if (!used) nrf++; @@ -219,7 +255,7 @@ static void context_check_map(void) 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)) + if (FIRST_CONTEXT > 0 && !test_bit(0, context_map)) pr_err("MMU: Context 0 has been freed !!!\n"); } #else @@ -229,7 +265,10 @@ static void context_check_map(void) { } void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next, struct task_struct *tsk) { - unsigned int i, id, cpu = smp_processor_id(); + unsigned int id; +#ifdef CONFIG_SMP + unsigned int i, cpu = smp_processor_id(); +#endif unsigned long *map; /* No lockless fast path .. yet */ @@ -263,8 +302,8 @@ void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next, /* We really don't have a context, let's try to acquire one */ id = next_context; - if (id > last_context) - id = first_context; + if (id > LAST_CONTEXT) + id = FIRST_CONTEXT; map = context_map; /* No more free contexts, let's try to steal one */ @@ -277,7 +316,7 @@ void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next, goto stolen; } #endif /* CONFIG_SMP */ - if (no_selective_tlbil) + if (IS_ENABLED(CONFIG_PPC_8xx)) id = steal_all_contexts(); else id = steal_context_up(id); @@ -287,9 +326,9 @@ void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next, /* 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; + id = find_next_zero_bit(map, LAST_CONTEXT+1, id); + if (id > LAST_CONTEXT) + id = FIRST_CONTEXT; } stolen: next_context = id + 1; @@ -303,6 +342,7 @@ void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next, /* 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), @@ -317,6 +357,7 @@ void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next, __clear_bit(id, stale_map[i]); } } +#endif /* Flick the MMU and release lock */ pr_hardcont(" -> %d\n", id); @@ -331,6 +372,17 @@ int init_new_context(struct task_struct *t, struct mm_struct *mm) { pr_hard("initing context for mm @%p\n", mm); +#ifdef CONFIG_PPC_MM_SLICES + /* + * 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); +#endif mm->context.id = MMU_NO_CONTEXT; mm->context.active = 0; return 0; @@ -407,52 +459,13 @@ void __init mmu_context_init(void) init_mm.context.active = NR_CPUS; /* - * 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 - */ - if (mmu_has_feature(MMU_FTR_TYPE_8xx)) { - first_context = 0; - last_context = 15; - no_selective_tlbil = true; - } else if (mmu_has_feature(MMU_FTR_TYPE_47x)) { - first_context = 1; - last_context = 65535; - no_selective_tlbil = false; - } else { - first_context = 1; - last_context = 255; - no_selective_tlbil = false; - } - -#ifdef DEBUG_CLAMP_LAST_CONTEXT - last_context = DEBUG_CLAMP_LAST_CONTEXT; -#endif - /* * Allocate the maps used by context management */ - context_map = memblock_virt_alloc(CTX_MAP_SIZE, 0); - context_mm = memblock_virt_alloc(sizeof(void *) * (last_context + 1), 0); -#ifndef CONFIG_SMP - stale_map[0] = memblock_virt_alloc(CTX_MAP_SIZE, 0); -#else - stale_map[boot_cpuid] = memblock_virt_alloc(CTX_MAP_SIZE, 0); + context_map = memblock_alloc(CTX_MAP_SIZE, SMP_CACHE_BYTES); + context_mm = memblock_alloc(sizeof(void *) * (LAST_CONTEXT + 1), + SMP_CACHE_BYTES); +#ifdef CONFIG_SMP + stale_map[boot_cpuid] = memblock_alloc(CTX_MAP_SIZE, SMP_CACHE_BYTES); cpuhp_setup_state_nocalls(CPUHP_POWERPC_MMU_CTX_PREPARE, "powerpc/mmu/ctx:prepare", @@ -461,17 +474,17 @@ void __init mmu_context_init(void) 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); + 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. + * 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; + context_map[0] = (1 << FIRST_CONTEXT) - 1; + next_context = FIRST_CONTEXT; + nr_free_contexts = LAST_CONTEXT - FIRST_CONTEXT + 1; } |