1 files changed, 440 insertions, 0 deletions

diff --git a/arch/sparc64/mm/tsb.c b/arch/sparc64/mm/tsb.c
new file mode 100644
index 000000000000..b2064e2a44d6
--- /dev/null
+++ b/arch/sparc64/mm/tsb.c
@@ -0,0 +1,440 @@
+/* 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 nentries)
+{
+	vaddr >>= PAGE_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, 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();
+		}
+	}
+}
+
+void flush_tsb_user(struct mmu_gather *mp)
+{
+	struct mm_struct *mm = mp->mm;
+	unsigned long nentries, base, flags;
+	struct tsb *tsb;
+	int i;
+
+	spin_lock_irqsave(&mm->context.lock, flags);
+
+	tsb = mm->context.tsb;
+	nentries = mm->context.tsb_nentries;
+
+	if (tlb_type == cheetah_plus || tlb_type == hypervisor)
+		base = __pa(tsb);
+	else
+		base = (unsigned long) tsb;
+	
+	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, nentries);
+		ent = base + (hash * sizeof(struct tsb));
+		tag = (v >> 22UL);
+
+		tsb_flush(ent, tag);
+	}
+
+	spin_unlock_irqrestore(&mm->context.lock, flags);
+}
+
+static void setup_tsb_params(struct mm_struct *mm, unsigned long tsb_bytes)
+{
+	unsigned long tsb_reg, base, tsb_paddr;
+	unsigned long page_sz, tte;
+
+	mm->context.tsb_nentries = tsb_bytes / sizeof(struct tsb);
+
+	base = TSBMAP_BASE;
+	tte = pgprot_val(PAGE_KERNEL_LOCKED);
+	tsb_paddr = __pa(mm->context.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_reg_val = tsb_reg;
+		mm->context.tsb_map_vaddr = 0;
+		mm->context.tsb_map_pte = 0;
+	} else {
+		tsb_reg |= base;
+		tsb_reg |= (tsb_paddr & (page_sz - 1UL));
+		tte |= (tsb_paddr & ~(page_sz - 1UL));
+
+		mm->context.tsb_reg_val = tsb_reg;
+		mm->context.tsb_map_vaddr = base;
+		mm->context.tsb_map_pte = tte;
+	}
+
+	/* Setup the Hypervisor TSB descriptor.  */
+	if (tlb_type == hypervisor) {
+		struct hv_tsb_descr *hp = &mm->context.tsb_descr;
+
+		switch (PAGE_SIZE) {
+		case 8192:
+		default:
+			hp->pgsz_idx = HV_PGSZ_IDX_8K;
+			break;
+
+		case 64 * 1024:
+			hp->pgsz_idx = HV_PGSZ_IDX_64K;
+			break;
+
+		case 512 * 1024:
+			hp->pgsz_idx = HV_PGSZ_IDX_512K;
+			break;
+
+		case 4 * 1024 * 1024:
+			hp->pgsz_idx = HV_PGSZ_IDX_4MB;
+			break;
+		};
+		hp->assoc = 1;
+		hp->num_ttes = tsb_bytes / 16;
+		hp->ctx_idx = 0;
+		switch (PAGE_SIZE) {
+		case 8192:
+		default:
+			hp->pgsz_mask = HV_PGSZ_MASK_8K;
+			break;
+
+		case 64 * 1024:
+			hp->pgsz_mask = HV_PGSZ_MASK_64K;
+			break;
+
+		case 512 * 1024:
+			hp->pgsz_mask = HV_PGSZ_MASK_512K;
+			break;
+
+		case 4 * 1024 * 1024:
+			hp->pgsz_mask = HV_PGSZ_MASK_4MB;
+			break;
+		};
+		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 mm->context.tsb_rss_limit,
+ * do_sparc64_fault() invokes this routine to try and grow the TSB.
+ *
+ * When we reach the maximum TSB size supported, we stick ~0UL into
+ * mm->context.tsb_rss_limit so the grow checks in update_mmu_cache()
+ * 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 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 == 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 != NULL)
+			mm->context.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;
+	old_cache_index = (mm->context.tsb_reg_val & 0x7UL);
+	old_size = mm->context.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_rss_limit))) {
+		spin_unlock_irqrestore(&mm->context.lock, flags);
+
+		kmem_cache_free(tsb_caches[new_cache_index], new_tsb);
+		return;
+	}
+
+	mm->context.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 = new_tsb;
+	setup_tsb_params(mm, 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)
+{
+	spin_lock_init(&mm->context.lock);
+
+	mm->context.sparc64_ctx_val = 0UL;
+
+	/* 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.
+	 */
+	mm->context.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, get_mm_rss(mm));
+
+	if (unlikely(!mm->context.tsb))
+		return -ENOMEM;
+
+	return 0;
+}
+
+void destroy_context(struct mm_struct *mm)
+{
+	unsigned long flags, cache_index;
+
+	cache_index = (mm->context.tsb_reg_val & 0x7UL);
+	kmem_cache_free(tsb_caches[cache_index], mm->context.tsb);
+
+	/* We can remove these later, but for now it's useful
+	 * to catch any bogus post-destroy_context() references
+	 * to the TSB.
+	 */
+	mm->context.tsb = NULL;
+	mm->context.tsb_reg_val = 0UL;
+
+	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);
+}