diff options
Diffstat (limited to 'arch/sparc64/mm/tsb.c')
| -rw-r--r-- | arch/sparc64/mm/tsb.c | 500 |
1 files changed, 500 insertions, 0 deletions
diff --git a/arch/sparc64/mm/tsb.c b/arch/sparc64/mm/tsb.c new file mode 100644 index 000000000000..beaa02810f0e --- /dev/null +++ b/arch/sparc64/mm/tsb.c @@ -0,0 +1,500 @@ +/* arch/sparc64/mm/tsb.c + * + * Copyright (C) 2006 David S. Miller <davem@davemloft.net> + */ + +#include <linux/kernel.h> +#include <asm/system.h> +#include <asm/page.h> +#include <asm/tlbflush.h> +#include <asm/tlb.h> +#include <asm/mmu_context.h> +#include <asm/pgtable.h> +#include <asm/tsb.h> +#include <asm/oplib.h> + +extern struct tsb swapper_tsb[KERNEL_TSB_NENTRIES]; + +static inline unsigned long tsb_hash(unsigned long vaddr, unsigned long hash_shift, unsigned long nentries) +{ + vaddr >>= hash_shift; + return vaddr & (nentries - 1); +} + +static inline int tag_compare(unsigned long tag, unsigned long vaddr) +{ + return (tag == (vaddr >> 22)); +} + +/* TSB flushes need only occur on the processor initiating the address + * space modification, not on each cpu the address space has run on. + * Only the TLB flush needs that treatment. + */ + +void flush_tsb_kernel_range(unsigned long start, unsigned long end) +{ + unsigned long v; + + for (v = start; v < end; v += PAGE_SIZE) { + unsigned long hash = tsb_hash(v, PAGE_SHIFT, + KERNEL_TSB_NENTRIES); + struct tsb *ent = &swapper_tsb[hash]; + + if (tag_compare(ent->tag, v)) { + ent->tag = (1UL << TSB_TAG_INVALID_BIT); + membar_storeload_storestore(); + } + } +} + +static void __flush_tsb_one(struct mmu_gather *mp, unsigned long hash_shift, unsigned long tsb, unsigned long nentries) +{ + unsigned long i; + + for (i = 0; i < mp->tlb_nr; i++) { + unsigned long v = mp->vaddrs[i]; + unsigned long tag, ent, hash; + + v &= ~0x1UL; + + hash = tsb_hash(v, hash_shift, nentries); + ent = tsb + (hash * sizeof(struct tsb)); + tag = (v >> 22UL); + + tsb_flush(ent, tag); + } +} + +void flush_tsb_user(struct mmu_gather *mp) +{ + struct mm_struct *mm = mp->mm; + unsigned long nentries, base, flags; + + spin_lock_irqsave(&mm->context.lock, flags); + + base = (unsigned long) mm->context.tsb_block[MM_TSB_BASE].tsb; + nentries = mm->context.tsb_block[MM_TSB_BASE].tsb_nentries; + if (tlb_type == cheetah_plus || tlb_type == hypervisor) + base = __pa(base); + __flush_tsb_one(mp, PAGE_SHIFT, base, nentries); + +#ifdef CONFIG_HUGETLB_PAGE + if (mm->context.tsb_block[MM_TSB_HUGE].tsb) { + base = (unsigned long) mm->context.tsb_block[MM_TSB_HUGE].tsb; + nentries = mm->context.tsb_block[MM_TSB_HUGE].tsb_nentries; + if (tlb_type == cheetah_plus || tlb_type == hypervisor) + base = __pa(base); + __flush_tsb_one(mp, HPAGE_SHIFT, base, nentries); + } +#endif + spin_unlock_irqrestore(&mm->context.lock, flags); +} + +#if defined(CONFIG_SPARC64_PAGE_SIZE_8KB) +#define HV_PGSZ_IDX_BASE HV_PGSZ_IDX_8K +#define HV_PGSZ_MASK_BASE HV_PGSZ_MASK_8K +#elif defined(CONFIG_SPARC64_PAGE_SIZE_64KB) +#define HV_PGSZ_IDX_BASE HV_PGSZ_IDX_64K +#define HV_PGSZ_MASK_BASE HV_PGSZ_MASK_64K +#elif defined(CONFIG_SPARC64_PAGE_SIZE_512KB) +#define HV_PGSZ_IDX_BASE HV_PGSZ_IDX_512K +#define HV_PGSZ_MASK_BASE HV_PGSZ_MASK_512K +#elif defined(CONFIG_SPARC64_PAGE_SIZE_4MB) +#define HV_PGSZ_IDX_BASE HV_PGSZ_IDX_4MB +#define HV_PGSZ_MASK_BASE HV_PGSZ_MASK_4MB +#else +#error Broken base page size setting... +#endif + +#ifdef CONFIG_HUGETLB_PAGE +#if defined(CONFIG_HUGETLB_PAGE_SIZE_64K) +#define HV_PGSZ_IDX_HUGE HV_PGSZ_IDX_64K +#define HV_PGSZ_MASK_HUGE HV_PGSZ_MASK_64K +#elif defined(CONFIG_HUGETLB_PAGE_SIZE_512K) +#define HV_PGSZ_IDX_HUGE HV_PGSZ_IDX_512K +#define HV_PGSZ_MASK_HUGE HV_PGSZ_MASK_512K +#elif defined(CONFIG_HUGETLB_PAGE_SIZE_4MB) +#define HV_PGSZ_IDX_HUGE HV_PGSZ_IDX_4MB +#define HV_PGSZ_MASK_HUGE HV_PGSZ_MASK_4MB +#else +#error Broken huge page size setting... +#endif +#endif + +static void setup_tsb_params(struct mm_struct *mm, unsigned long tsb_idx, unsigned long tsb_bytes) +{ + unsigned long tsb_reg, base, tsb_paddr; + unsigned long page_sz, tte; + + mm->context.tsb_block[tsb_idx].tsb_nentries = + tsb_bytes / sizeof(struct tsb); + + base = TSBMAP_BASE; + tte = pgprot_val(PAGE_KERNEL_LOCKED); + tsb_paddr = __pa(mm->context.tsb_block[tsb_idx].tsb); + BUG_ON(tsb_paddr & (tsb_bytes - 1UL)); + + /* Use the smallest page size that can map the whole TSB + * in one TLB entry. + */ + switch (tsb_bytes) { + case 8192 << 0: + tsb_reg = 0x0UL; +#ifdef DCACHE_ALIASING_POSSIBLE + base += (tsb_paddr & 8192); +#endif + page_sz = 8192; + break; + + case 8192 << 1: + tsb_reg = 0x1UL; + page_sz = 64 * 1024; + break; + + case 8192 << 2: + tsb_reg = 0x2UL; + page_sz = 64 * 1024; + break; + + case 8192 << 3: + tsb_reg = 0x3UL; + page_sz = 64 * 1024; + break; + + case 8192 << 4: + tsb_reg = 0x4UL; + page_sz = 512 * 1024; + break; + + case 8192 << 5: + tsb_reg = 0x5UL; + page_sz = 512 * 1024; + break; + + case 8192 << 6: + tsb_reg = 0x6UL; + page_sz = 512 * 1024; + break; + + case 8192 << 7: + tsb_reg = 0x7UL; + page_sz = 4 * 1024 * 1024; + break; + + default: + BUG(); + }; + tte |= pte_sz_bits(page_sz); + + if (tlb_type == cheetah_plus || tlb_type == hypervisor) { + /* Physical mapping, no locked TLB entry for TSB. */ + tsb_reg |= tsb_paddr; + + mm->context.tsb_block[tsb_idx].tsb_reg_val = tsb_reg; + mm->context.tsb_block[tsb_idx].tsb_map_vaddr = 0; + mm->context.tsb_block[tsb_idx].tsb_map_pte = 0; + } else { + tsb_reg |= base; + tsb_reg |= (tsb_paddr & (page_sz - 1UL)); + tte |= (tsb_paddr & ~(page_sz - 1UL)); + + mm->context.tsb_block[tsb_idx].tsb_reg_val = tsb_reg; + mm->context.tsb_block[tsb_idx].tsb_map_vaddr = base; + mm->context.tsb_block[tsb_idx].tsb_map_pte = tte; + } + + /* Setup the Hypervisor TSB descriptor. */ + if (tlb_type == hypervisor) { + struct hv_tsb_descr *hp = &mm->context.tsb_descr[tsb_idx]; + + switch (tsb_idx) { + case MM_TSB_BASE: + hp->pgsz_idx = HV_PGSZ_IDX_BASE; + break; +#ifdef CONFIG_HUGETLB_PAGE + case MM_TSB_HUGE: + hp->pgsz_idx = HV_PGSZ_IDX_HUGE; + break; +#endif + default: + BUG(); + }; + hp->assoc = 1; + hp->num_ttes = tsb_bytes / 16; + hp->ctx_idx = 0; + switch (tsb_idx) { + case MM_TSB_BASE: + hp->pgsz_mask = HV_PGSZ_MASK_BASE; + break; +#ifdef CONFIG_HUGETLB_PAGE + case MM_TSB_HUGE: + hp->pgsz_mask = HV_PGSZ_MASK_HUGE; + break; +#endif + default: + BUG(); + }; + hp->tsb_base = tsb_paddr; + hp->resv = 0; + } +} + +static kmem_cache_t *tsb_caches[8] __read_mostly; + +static const char *tsb_cache_names[8] = { + "tsb_8KB", + "tsb_16KB", + "tsb_32KB", + "tsb_64KB", + "tsb_128KB", + "tsb_256KB", + "tsb_512KB", + "tsb_1MB", +}; + +void __init tsb_cache_init(void) +{ + unsigned long i; + + for (i = 0; i < 8; i++) { + unsigned long size = 8192 << i; + const char *name = tsb_cache_names[i]; + + tsb_caches[i] = kmem_cache_create(name, + size, size, + SLAB_HWCACHE_ALIGN | + SLAB_MUST_HWCACHE_ALIGN, + NULL, NULL); + if (!tsb_caches[i]) { + prom_printf("Could not create %s cache\n", name); + prom_halt(); + } + } +} + +/* When the RSS of an address space exceeds tsb_rss_limit for a TSB, + * do_sparc64_fault() invokes this routine to try and grow it. + * + * When we reach the maximum TSB size supported, we stick ~0UL into + * tsb_rss_limit for that TSB so the grow checks in do_sparc64_fault() + * will not trigger any longer. + * + * The TSB can be anywhere from 8K to 1MB in size, in increasing powers + * of two. The TSB must be aligned to it's size, so f.e. a 512K TSB + * must be 512K aligned. It also must be physically contiguous, so we + * cannot use vmalloc(). + * + * The idea here is to grow the TSB when the RSS of the process approaches + * the number of entries that the current TSB can hold at once. Currently, + * we trigger when the RSS hits 3/4 of the TSB capacity. + */ +void tsb_grow(struct mm_struct *mm, unsigned long tsb_index, unsigned long rss) +{ + unsigned long max_tsb_size = 1 * 1024 * 1024; + unsigned long new_size, old_size, flags; + struct tsb *old_tsb, *new_tsb; + unsigned long new_cache_index, old_cache_index; + unsigned long new_rss_limit; + gfp_t gfp_flags; + + if (max_tsb_size > (PAGE_SIZE << MAX_ORDER)) + max_tsb_size = (PAGE_SIZE << MAX_ORDER); + + new_cache_index = 0; + for (new_size = 8192; new_size < max_tsb_size; new_size <<= 1UL) { + unsigned long n_entries = new_size / sizeof(struct tsb); + + n_entries = (n_entries * 3) / 4; + if (n_entries > rss) + break; + + new_cache_index++; + } + + if (new_size == max_tsb_size) + new_rss_limit = ~0UL; + else + new_rss_limit = ((new_size / sizeof(struct tsb)) * 3) / 4; + +retry_tsb_alloc: + gfp_flags = GFP_KERNEL; + if (new_size > (PAGE_SIZE * 2)) + gfp_flags = __GFP_NOWARN | __GFP_NORETRY; + + new_tsb = kmem_cache_alloc(tsb_caches[new_cache_index], gfp_flags); + if (unlikely(!new_tsb)) { + /* Not being able to fork due to a high-order TSB + * allocation failure is very bad behavior. Just back + * down to a 0-order allocation and force no TSB + * growing for this address space. + */ + if (mm->context.tsb_block[tsb_index].tsb == NULL && + new_cache_index > 0) { + new_cache_index = 0; + new_size = 8192; + new_rss_limit = ~0UL; + goto retry_tsb_alloc; + } + + /* If we failed on a TSB grow, we are under serious + * memory pressure so don't try to grow any more. + */ + if (mm->context.tsb_block[tsb_index].tsb != NULL) + mm->context.tsb_block[tsb_index].tsb_rss_limit = ~0UL; + return; + } + + /* Mark all tags as invalid. */ + tsb_init(new_tsb, new_size); + + /* Ok, we are about to commit the changes. If we are + * growing an existing TSB the locking is very tricky, + * so WATCH OUT! + * + * We have to hold mm->context.lock while committing to the + * new TSB, this synchronizes us with processors in + * flush_tsb_user() and switch_mm() for this address space. + * + * But even with that lock held, processors run asynchronously + * accessing the old TSB via TLB miss handling. This is OK + * because those actions are just propagating state from the + * Linux page tables into the TSB, page table mappings are not + * being changed. If a real fault occurs, the processor will + * synchronize with us when it hits flush_tsb_user(), this is + * also true for the case where vmscan is modifying the page + * tables. The only thing we need to be careful with is to + * skip any locked TSB entries during copy_tsb(). + * + * When we finish committing to the new TSB, we have to drop + * the lock and ask all other cpus running this address space + * to run tsb_context_switch() to see the new TSB table. + */ + spin_lock_irqsave(&mm->context.lock, flags); + + old_tsb = mm->context.tsb_block[tsb_index].tsb; + old_cache_index = + (mm->context.tsb_block[tsb_index].tsb_reg_val & 0x7UL); + old_size = (mm->context.tsb_block[tsb_index].tsb_nentries * + sizeof(struct tsb)); + + + /* Handle multiple threads trying to grow the TSB at the same time. + * One will get in here first, and bump the size and the RSS limit. + * The others will get in here next and hit this check. + */ + if (unlikely(old_tsb && + (rss < mm->context.tsb_block[tsb_index].tsb_rss_limit))) { + spin_unlock_irqrestore(&mm->context.lock, flags); + + kmem_cache_free(tsb_caches[new_cache_index], new_tsb); + return; + } + + mm->context.tsb_block[tsb_index].tsb_rss_limit = new_rss_limit; + + if (old_tsb) { + extern void copy_tsb(unsigned long old_tsb_base, + unsigned long old_tsb_size, + unsigned long new_tsb_base, + unsigned long new_tsb_size); + unsigned long old_tsb_base = (unsigned long) old_tsb; + unsigned long new_tsb_base = (unsigned long) new_tsb; + + if (tlb_type == cheetah_plus || tlb_type == hypervisor) { + old_tsb_base = __pa(old_tsb_base); + new_tsb_base = __pa(new_tsb_base); + } + copy_tsb(old_tsb_base, old_size, new_tsb_base, new_size); + } + + mm->context.tsb_block[tsb_index].tsb = new_tsb; + setup_tsb_params(mm, tsb_index, new_size); + + spin_unlock_irqrestore(&mm->context.lock, flags); + + /* If old_tsb is NULL, we're being invoked for the first time + * from init_new_context(). + */ + if (old_tsb) { + /* Reload it on the local cpu. */ + tsb_context_switch(mm); + + /* Now force other processors to do the same. */ + smp_tsb_sync(mm); + + /* Now it is safe to free the old tsb. */ + kmem_cache_free(tsb_caches[old_cache_index], old_tsb); + } +} + +int init_new_context(struct task_struct *tsk, struct mm_struct *mm) +{ +#ifdef CONFIG_HUGETLB_PAGE + unsigned long huge_pte_count; +#endif + unsigned int i; + + spin_lock_init(&mm->context.lock); + + mm->context.sparc64_ctx_val = 0UL; + +#ifdef CONFIG_HUGETLB_PAGE + /* We reset it to zero because the fork() page copying + * will re-increment the counters as the parent PTEs are + * copied into the child address space. + */ + huge_pte_count = mm->context.huge_pte_count; + mm->context.huge_pte_count = 0; +#endif + + /* copy_mm() copies over the parent's mm_struct before calling + * us, so we need to zero out the TSB pointer or else tsb_grow() + * will be confused and think there is an older TSB to free up. + */ + for (i = 0; i < MM_NUM_TSBS; i++) + mm->context.tsb_block[i].tsb = NULL; + + /* If this is fork, inherit the parent's TSB size. We would + * grow it to that size on the first page fault anyways. + */ + tsb_grow(mm, MM_TSB_BASE, get_mm_rss(mm)); + +#ifdef CONFIG_HUGETLB_PAGE + if (unlikely(huge_pte_count)) + tsb_grow(mm, MM_TSB_HUGE, huge_pte_count); +#endif + + if (unlikely(!mm->context.tsb_block[MM_TSB_BASE].tsb)) + return -ENOMEM; + + return 0; +} + +static void tsb_destroy_one(struct tsb_config *tp) +{ + unsigned long cache_index; + + if (!tp->tsb) + return; + cache_index = tp->tsb_reg_val & 0x7UL; + kmem_cache_free(tsb_caches[cache_index], tp->tsb); + tp->tsb = NULL; + tp->tsb_reg_val = 0UL; +} + +void destroy_context(struct mm_struct *mm) +{ + unsigned long flags, i; + + for (i = 0; i < MM_NUM_TSBS; i++) + tsb_destroy_one(&mm->context.tsb_block[i]); + + spin_lock_irqsave(&ctx_alloc_lock, flags); + + if (CTX_VALID(mm->context)) { + unsigned long nr = CTX_NRBITS(mm->context); + mmu_context_bmap[nr>>6] &= ~(1UL << (nr & 63)); + } + + spin_unlock_irqrestore(&ctx_alloc_lock, flags); +} |