1 files changed, 428 insertions, 0 deletions

diff --git a/kernel/arch/tile/mm/homecache.c b/kernel/arch/tile/mm/homecache.c
new file mode 100644
index 000000000..40ca30a9f
--- /dev/null
+++ b/kernel/arch/tile/mm/homecache.c
@@ -0,0 +1,428 @@
+/*
+ * 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 <linux/module.h>
+#include <linux/hugetlb.h>
+
+#include <asm/page.h>
+#include <asm/sections.h>
+#include <asm/tlbflush.h>
+#include <asm/pgalloc.h>
+#include <asm/homecache.h>
+
+#include <arch/sim.h>
+
+#include "migrate.h"
+
+
+/*
+ * The noallocl2 option suppresses all use of the L2 cache to cache
+ * locally from a remote home.
+ */
+static int __write_once noallocl2;
+static int __init set_noallocl2(char *str)
+{
+	noallocl2 = 1;
+	return 0;
+}
+early_param("noallocl2", set_noallocl2);
+
+
+/*
+ * 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.
+ *  - 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;
+	struct cpumask cache_cpumask_copy, tlb_cpumask_copy;
+	struct cpumask *cache_cpumask, *tlb_cpumask;
+	HV_PhysAddr cache_pa;
+
+	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;
+	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 (rc == 0)
+		return;
+
+	pr_err("hv_flush_remote(%#llx, %#lx, %p [%*pb], %#lx, %#lx, %#lx, %p [%*pb], %p, %d) = %d\n",
+	       cache_pa, cache_control, cache_cpumask,
+	       cpumask_pr_args(&cache_cpumask_copy),
+	       (unsigned long)tlb_va, tlb_length, tlb_pgsize, tlb_cpumask,
+	       cpumask_pr_args(&tlb_cpumask_copy), asids, asidcount, rc);
+	panic("Unsafe to continue.");
+}
+
+static void homecache_finv_page_va(void* va, int home)
+{
+	int cpu = get_cpu();
+	if (home == cpu) {
+		finv_buffer_local(va, PAGE_SIZE);
+	} else if (home == PAGE_HOME_HASH) {
+		finv_buffer_remote(va, PAGE_SIZE, 1);
+	} else {
+		BUG_ON(home < 0 || home >= NR_CPUS);
+		finv_buffer_remote(va, PAGE_SIZE, 0);
+	}
+	put_cpu();
+}
+
+void homecache_finv_map_page(struct page *page, int home)
+{
+	unsigned long flags;
+	unsigned long va;
+	pte_t *ptep;
+	pte_t pte;
+
+	if (home == PAGE_HOME_UNCACHED)
+		return;
+	local_irq_save(flags);
+#ifdef CONFIG_HIGHMEM
+	va = __fix_to_virt(FIX_KMAP_BEGIN + kmap_atomic_idx_push() +
+			   (KM_TYPE_NR * smp_processor_id()));
+#else
+	va = __fix_to_virt(FIX_HOMECACHE_BEGIN + smp_processor_id());
+#endif
+	ptep = virt_to_kpte(va);
+	pte = pfn_pte(page_to_pfn(page), PAGE_KERNEL);
+	__set_pte(ptep, pte_set_home(pte, home));
+	homecache_finv_page_va((void *)va, home);
+	__pte_clear(ptep);
+	hv_flush_page(va, PAGE_SIZE);
+#ifdef CONFIG_HIGHMEM
+	kmap_atomic_idx_pop();
+#endif
+	local_irq_restore(flags);
+}
+
+static void homecache_finv_page_home(struct page *page, int home)
+{
+	if (!PageHighMem(page) && home == page_home(page))
+		homecache_finv_page_va(page_address(page), home);
+	else
+		homecache_finv_map_page(page, home);
+}
+
+static inline bool incoherent_home(int home)
+{
+	return home == PAGE_HOME_IMMUTABLE || home == PAGE_HOME_INCOHERENT;
+}
+
+static void homecache_finv_page_internal(struct page *page, int force_map)
+{
+	int home = page_home(page);
+	if (home == PAGE_HOME_UNCACHED)
+		return;
+	if (incoherent_home(home)) {
+		int cpu;
+		for_each_cpu(cpu, &cpu_cacheable_map)
+			homecache_finv_map_page(page, cpu);
+	} else if (force_map) {
+		/* Force if, e.g., the normal mapping is migrating. */
+		homecache_finv_map_page(page, home);
+	} else {
+		homecache_finv_page_home(page, home);
+	}
+	sim_validate_lines_evicted(PFN_PHYS(page_to_pfn(page)), PAGE_SIZE);
+}
+
+void homecache_finv_page(struct page *page)
+{
+	homecache_finv_page_internal(page, 0);
+}
+
+void homecache_evict(const struct cpumask *mask)
+{
+	flush_remote(0, HV_FLUSH_EVICT_L2, mask, 0, 0, 0, NULL, NULL, 0);
+}
+
+/* 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;
+	case HV_PTE_MODE_CACHE_HASH_L3:
+		return PAGE_HOME_HASH;
+	}
+	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)
+{
+#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 (hash_default)
+			pte = hv_pte_set_mode(pte, HV_PTE_MODE_CACHE_HASH_L3);
+		else
+			pte = hv_pte_set_mode(pte, HV_PTE_MODE_CACHE_NO_L3);
+		pte = hv_pte_set_nc(pte);
+		break;
+
+	case PAGE_HOME_HASH:
+		pte = hv_pte_set_mode(pte, HV_PTE_MODE_CACHE_HASH_L3);
+		break;
+
+	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 (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);
+	}
+
+	/* Checking this case here gives a better panic than from the hv. */
+	BUG_ON(hv_pte_get_mode(pte) == 0);
+
+	return pte;
+}
+EXPORT_SYMBOL(pte_set_home);
+
+/*
+ * 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.
+ */
+
+int page_home(struct page *page)
+{
+	if (PageHighMem(page)) {
+		return PAGE_HOME_HASH;
+	} else {
+		unsigned long kva = (unsigned long)page_address(page);
+		return pte_to_home(*virt_to_kpte(kva));
+	}
+}
+EXPORT_SYMBOL(page_home);
+
+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_kpte(kva);
+		pte_t pteval = *ptep;
+		BUG_ON(!pte_present(pteval) || pte_huge(pteval));
+		__set_pte(ptep, pte_set_home(pteval, home));
+	}
+}
+EXPORT_SYMBOL(homecache_change_page_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;
+}
+EXPORT_SYMBOL(homecache_alloc_pages);
+
+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(struct page *page, unsigned int order)
+{
+	if (put_page_testzero(page)) {
+		homecache_change_page_home(page, order, PAGE_HOME_HASH);
+		if (order == 0) {
+			free_hot_cold_page(page, false);
+		} else {
+			init_page_count(page);
+			__free_pages(page, order);
+		}
+	}
+}
+EXPORT_SYMBOL(__homecache_free_pages);
+
+void homecache_free_pages(unsigned long addr, unsigned int order)
+{
+	if (addr != 0) {
+		VM_BUG_ON(!virt_addr_valid((void *)addr));
+		__homecache_free_pages(virt_to_page((void *)addr), order);
+	}
+}
+EXPORT_SYMBOL(homecache_free_pages);