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Diffstat (limited to 'arch/tile/mm/homecache.c')
| -rw-r--r-- | arch/tile/mm/homecache.c | 433 |
1 files changed, 433 insertions, 0 deletions
diff --git a/arch/tile/mm/homecache.c b/arch/tile/mm/homecache.c new file mode 100644 index 00000000000..97c478e7be2 --- /dev/null +++ b/arch/tile/mm/homecache.c @@ -0,0 +1,433 @@ +/* + * Copyright 2010 Tilera Corporation. All Rights Reserved. + * + * 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, version 2. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or + * NON INFRINGEMENT. See the GNU General Public License for + * more details. + * + * This code maintains the "home" for each page in the system. + */ + +#include <linux/kernel.h> +#include <linux/mm.h> +#include <linux/spinlock.h> +#include <linux/list.h> +#include <linux/bootmem.h> +#include <linux/rmap.h> +#include <linux/pagemap.h> +#include <linux/mutex.h> +#include <linux/interrupt.h> +#include <linux/sysctl.h> +#include <linux/pagevec.h> +#include <linux/ptrace.h> +#include <linux/timex.h> +#include <linux/cache.h> +#include <linux/smp.h> + +#include <asm/page.h> +#include <asm/sections.h> +#include <asm/tlbflush.h> +#include <asm/pgalloc.h> +#include <asm/homecache.h> + +#include "migrate.h" + + +#if CHIP_HAS_COHERENT_LOCAL_CACHE() + +/* + * The noallocl2 option suppresses all use of the L2 cache to cache + * locally from a remote home. There's no point in using it if we + * don't have coherent local caching, though. + */ +static int __write_once noallocl2; +static int __init set_noallocl2(char *str) +{ + noallocl2 = 1; + return 0; +} +early_param("noallocl2", set_noallocl2); + +#else + +#define noallocl2 0 + +#endif + +/* Provide no-op versions of these routines to keep flush_remote() cleaner. */ +#define mark_caches_evicted_start() 0 +#define mark_caches_evicted_finish(mask, timestamp) do {} while (0) + + +/* + * Update the irq_stat for cpus that we are going to interrupt + * with TLB or cache flushes. Also handle removing dataplane cpus + * from the TLB flush set, and setting dataplane_tlb_state instead. + */ +static void hv_flush_update(const struct cpumask *cache_cpumask, + struct cpumask *tlb_cpumask, + unsigned long tlb_va, unsigned long tlb_length, + HV_Remote_ASID *asids, int asidcount) +{ + struct cpumask mask; + int i, cpu; + + cpumask_clear(&mask); + if (cache_cpumask) + cpumask_or(&mask, &mask, cache_cpumask); + if (tlb_cpumask && tlb_length) { + cpumask_or(&mask, &mask, tlb_cpumask); + } + + for (i = 0; i < asidcount; ++i) + cpumask_set_cpu(asids[i].y * smp_width + asids[i].x, &mask); + + /* + * Don't bother to update atomically; losing a count + * here is not that critical. + */ + for_each_cpu(cpu, &mask) + ++per_cpu(irq_stat, cpu).irq_hv_flush_count; +} + +/* + * This wrapper function around hv_flush_remote() does several things: + * + * - Provides a return value error-checking panic path, since + * there's never any good reason for hv_flush_remote() to fail. + * - Accepts a 32-bit PFN rather than a 64-bit PA, which generally + * is the type that Linux wants to pass around anyway. + * - Centralizes the mark_caches_evicted() handling. + * - Canonicalizes that lengths of zero make cpumasks NULL. + * - Handles deferring TLB flushes for dataplane tiles. + * - Tracks remote interrupts in the per-cpu irq_cpustat_t. + * + * Note that we have to wait until the cache flush completes before + * updating the per-cpu last_cache_flush word, since otherwise another + * concurrent flush can race, conclude the flush has already + * completed, and start to use the page while it's still dirty + * remotely (running concurrently with the actual evict, presumably). + */ +void flush_remote(unsigned long cache_pfn, unsigned long cache_control, + const struct cpumask *cache_cpumask_orig, + HV_VirtAddr tlb_va, unsigned long tlb_length, + unsigned long tlb_pgsize, + const struct cpumask *tlb_cpumask_orig, + HV_Remote_ASID *asids, int asidcount) +{ + int rc; + int timestamp = 0; /* happy compiler */ + struct cpumask cache_cpumask_copy, tlb_cpumask_copy; + struct cpumask *cache_cpumask, *tlb_cpumask; + HV_PhysAddr cache_pa; + char cache_buf[NR_CPUS*5], tlb_buf[NR_CPUS*5]; + + mb(); /* provided just to simplify "magic hypervisor" mode */ + + /* + * Canonicalize and copy the cpumasks. + */ + if (cache_cpumask_orig && cache_control) { + cpumask_copy(&cache_cpumask_copy, cache_cpumask_orig); + cache_cpumask = &cache_cpumask_copy; + } else { + cpumask_clear(&cache_cpumask_copy); + cache_cpumask = NULL; + } + if (cache_cpumask == NULL) + cache_control = 0; + if (tlb_cpumask_orig && tlb_length) { + cpumask_copy(&tlb_cpumask_copy, tlb_cpumask_orig); + tlb_cpumask = &tlb_cpumask_copy; + } else { + cpumask_clear(&tlb_cpumask_copy); + tlb_cpumask = NULL; + } + + hv_flush_update(cache_cpumask, tlb_cpumask, tlb_va, tlb_length, + asids, asidcount); + cache_pa = (HV_PhysAddr)cache_pfn << PAGE_SHIFT; + if (cache_control & HV_FLUSH_EVICT_L2) + timestamp = mark_caches_evicted_start(); + rc = hv_flush_remote(cache_pa, cache_control, + cpumask_bits(cache_cpumask), + tlb_va, tlb_length, tlb_pgsize, + cpumask_bits(tlb_cpumask), + asids, asidcount); + if (cache_control & HV_FLUSH_EVICT_L2) + mark_caches_evicted_finish(cache_cpumask, timestamp); + if (rc == 0) + return; + cpumask_scnprintf(cache_buf, sizeof(cache_buf), &cache_cpumask_copy); + cpumask_scnprintf(tlb_buf, sizeof(tlb_buf), &tlb_cpumask_copy); + + pr_err("hv_flush_remote(%#llx, %#lx, %p [%s]," + " %#lx, %#lx, %#lx, %p [%s], %p, %d) = %d\n", + cache_pa, cache_control, cache_cpumask, cache_buf, + (unsigned long)tlb_va, tlb_length, tlb_pgsize, + tlb_cpumask, tlb_buf, + asids, asidcount, rc); + panic("Unsafe to continue."); +} + +void homecache_evict(const struct cpumask *mask) +{ + flush_remote(0, HV_FLUSH_EVICT_L2, mask, 0, 0, 0, NULL, NULL, 0); +} + +/* Return a mask of the cpus whose caches currently own these pages. */ +static void homecache_mask(struct page *page, int pages, + struct cpumask *home_mask) +{ + int i; + cpumask_clear(home_mask); + for (i = 0; i < pages; ++i) { + int home = page_home(&page[i]); + if (home == PAGE_HOME_IMMUTABLE || + home == PAGE_HOME_INCOHERENT) { + cpumask_copy(home_mask, cpu_possible_mask); + return; + } +#if CHIP_HAS_CBOX_HOME_MAP() + if (home == PAGE_HOME_HASH) { + cpumask_or(home_mask, home_mask, &hash_for_home_map); + continue; + } +#endif + if (home == PAGE_HOME_UNCACHED) + continue; + BUG_ON(home < 0 || home >= NR_CPUS); + cpumask_set_cpu(home, home_mask); + } +} + +/* + * Return the passed length, or zero if it's long enough that we + * believe we should evict the whole L2 cache. + */ +static unsigned long cache_flush_length(unsigned long length) +{ + return (length >= CHIP_L2_CACHE_SIZE()) ? HV_FLUSH_EVICT_L2 : length; +} + +/* On the simulator, confirm lines have been evicted everywhere. */ +static void validate_lines_evicted(unsigned long pfn, size_t length) +{ + sim_syscall(SIM_SYSCALL_VALIDATE_LINES_EVICTED, + (HV_PhysAddr)pfn << PAGE_SHIFT, length); +} + +/* Flush a page out of whatever cache(s) it is in. */ +void homecache_flush_cache(struct page *page, int order) +{ + int pages = 1 << order; + int length = cache_flush_length(pages * PAGE_SIZE); + unsigned long pfn = page_to_pfn(page); + struct cpumask home_mask; + + homecache_mask(page, pages, &home_mask); + flush_remote(pfn, length, &home_mask, 0, 0, 0, NULL, NULL, 0); + validate_lines_evicted(pfn, pages * PAGE_SIZE); +} + + +/* Report the home corresponding to a given PTE. */ +static int pte_to_home(pte_t pte) +{ + if (hv_pte_get_nc(pte)) + return PAGE_HOME_IMMUTABLE; + switch (hv_pte_get_mode(pte)) { + case HV_PTE_MODE_CACHE_TILE_L3: + return get_remote_cache_cpu(pte); + case HV_PTE_MODE_CACHE_NO_L3: + return PAGE_HOME_INCOHERENT; + case HV_PTE_MODE_UNCACHED: + return PAGE_HOME_UNCACHED; +#if CHIP_HAS_CBOX_HOME_MAP() + case HV_PTE_MODE_CACHE_HASH_L3: + return PAGE_HOME_HASH; +#endif + } + panic("Bad PTE %#llx\n", pte.val); +} + +/* Update the home of a PTE if necessary (can also be used for a pgprot_t). */ +pte_t pte_set_home(pte_t pte, int home) +{ + /* Check for non-linear file mapping "PTEs" and pass them through. */ + if (pte_file(pte)) + return pte; + +#if CHIP_HAS_MMIO() + /* Check for MMIO mappings and pass them through. */ + if (hv_pte_get_mode(pte) == HV_PTE_MODE_MMIO) + return pte; +#endif + + + /* + * Only immutable pages get NC mappings. If we have a + * non-coherent PTE, but the underlying page is not + * immutable, it's likely the result of a forced + * caching setting running up against ptrace setting + * the page to be writable underneath. In this case, + * just keep the PTE coherent. + */ + if (hv_pte_get_nc(pte) && home != PAGE_HOME_IMMUTABLE) { + pte = hv_pte_clear_nc(pte); + pr_err("non-immutable page incoherently referenced: %#llx\n", + pte.val); + } + + switch (home) { + + case PAGE_HOME_UNCACHED: + pte = hv_pte_set_mode(pte, HV_PTE_MODE_UNCACHED); + break; + + case PAGE_HOME_INCOHERENT: + pte = hv_pte_set_mode(pte, HV_PTE_MODE_CACHE_NO_L3); + break; + + case PAGE_HOME_IMMUTABLE: + /* + * We could home this page anywhere, since it's immutable, + * but by default just home it to follow "hash_default". + */ + BUG_ON(hv_pte_get_writable(pte)); + if (pte_get_forcecache(pte)) { + /* Upgrade "force any cpu" to "No L3" for immutable. */ + if (hv_pte_get_mode(pte) == HV_PTE_MODE_CACHE_TILE_L3 + && pte_get_anyhome(pte)) { + pte = hv_pte_set_mode(pte, + HV_PTE_MODE_CACHE_NO_L3); + } + } else +#if CHIP_HAS_CBOX_HOME_MAP() + if (hash_default) + pte = hv_pte_set_mode(pte, HV_PTE_MODE_CACHE_HASH_L3); + else +#endif + pte = hv_pte_set_mode(pte, HV_PTE_MODE_CACHE_NO_L3); + pte = hv_pte_set_nc(pte); + break; + +#if CHIP_HAS_CBOX_HOME_MAP() + case PAGE_HOME_HASH: + pte = hv_pte_set_mode(pte, HV_PTE_MODE_CACHE_HASH_L3); + break; +#endif + + default: + BUG_ON(home < 0 || home >= NR_CPUS || + !cpu_is_valid_lotar(home)); + pte = hv_pte_set_mode(pte, HV_PTE_MODE_CACHE_TILE_L3); + pte = set_remote_cache_cpu(pte, home); + break; + } + +#if CHIP_HAS_NC_AND_NOALLOC_BITS() + if (noallocl2) + pte = hv_pte_set_no_alloc_l2(pte); + + /* Simplify "no local and no l3" to "uncached" */ + if (hv_pte_get_no_alloc_l2(pte) && hv_pte_get_no_alloc_l1(pte) && + hv_pte_get_mode(pte) == HV_PTE_MODE_CACHE_NO_L3) { + pte = hv_pte_set_mode(pte, HV_PTE_MODE_UNCACHED); + } +#endif + + /* Checking this case here gives a better panic than from the hv. */ + BUG_ON(hv_pte_get_mode(pte) == 0); + + return pte; +} + +/* + * The routines in this section are the "static" versions of the normal + * dynamic homecaching routines; they just set the home cache + * of a kernel page once, and require a full-chip cache/TLB flush, + * so they're not suitable for anything but infrequent use. + */ + +#if CHIP_HAS_CBOX_HOME_MAP() +static inline int initial_page_home(void) { return PAGE_HOME_HASH; } +#else +static inline int initial_page_home(void) { return 0; } +#endif + +int page_home(struct page *page) +{ + if (PageHighMem(page)) { + return initial_page_home(); + } else { + unsigned long kva = (unsigned long)page_address(page); + return pte_to_home(*virt_to_pte(NULL, kva)); + } +} + +void homecache_change_page_home(struct page *page, int order, int home) +{ + int i, pages = (1 << order); + unsigned long kva; + + BUG_ON(PageHighMem(page)); + BUG_ON(page_count(page) > 1); + BUG_ON(page_mapcount(page) != 0); + kva = (unsigned long) page_address(page); + flush_remote(0, HV_FLUSH_EVICT_L2, &cpu_cacheable_map, + kva, pages * PAGE_SIZE, PAGE_SIZE, cpu_online_mask, + NULL, 0); + + for (i = 0; i < pages; ++i, kva += PAGE_SIZE) { + pte_t *ptep = virt_to_pte(NULL, kva); + pte_t pteval = *ptep; + BUG_ON(!pte_present(pteval) || pte_huge(pteval)); + *ptep = pte_set_home(pteval, home); + } +} + +struct page *homecache_alloc_pages(gfp_t gfp_mask, + unsigned int order, int home) +{ + struct page *page; + BUG_ON(gfp_mask & __GFP_HIGHMEM); /* must be lowmem */ + page = alloc_pages(gfp_mask, order); + if (page) + homecache_change_page_home(page, order, home); + return page; +} + +struct page *homecache_alloc_pages_node(int nid, gfp_t gfp_mask, + unsigned int order, int home) +{ + struct page *page; + BUG_ON(gfp_mask & __GFP_HIGHMEM); /* must be lowmem */ + page = alloc_pages_node(nid, gfp_mask, order); + if (page) + homecache_change_page_home(page, order, home); + return page; +} + +void homecache_free_pages(unsigned long addr, unsigned int order) +{ + struct page *page; + + if (addr == 0) + return; + + VM_BUG_ON(!virt_addr_valid((void *)addr)); + page = virt_to_page((void *)addr); + if (put_page_testzero(page)) { + int pages = (1 << order); + homecache_change_page_home(page, order, initial_page_home()); + while (pages--) + __free_page(page++); + } +} |