summaryrefslogtreecommitdiff
path: root/arch/sparc/mm/tsb.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/sparc/mm/tsb.c')
-rw-r--r--arch/sparc/mm/tsb.c503
1 files changed, 503 insertions, 0 deletions
diff --git a/arch/sparc/mm/tsb.c b/arch/sparc/mm/tsb.c
new file mode 100644
index 0000000..36a0813
--- /dev/null
+++ b/arch/sparc/mm/tsb.c
@@ -0,0 +1,503 @@
+/* arch/sparc64/mm/tsb.c
+ *
+ * Copyright (C) 2006, 2008 David S. Miller <davem@davemloft.net>
+ */
+
+#include <linux/kernel.h>
+#include <linux/preempt.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);
+ }
+}
+
+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
+#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:
+ printk(KERN_ERR "TSB[%s:%d]: Impossible TSB size %lu, killing process.\n",
+ current->comm, current->pid, tsb_bytes);
+ do_exit(SIGSEGV);
+ };
+ 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 struct kmem_cache *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 pgtable_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,
+ 0, NULL);
+ if (!tsb_caches[i]) {
+ prom_printf("Could not create %s cache\n", name);
+ prom_halt();
+ }
+ }
+}
+
+int sysctl_tsb_ratio = -2;
+
+static unsigned long tsb_size_to_rss_limit(unsigned long new_size)
+{
+ unsigned long num_ents = (new_size / sizeof(struct tsb));
+
+ if (sysctl_tsb_ratio < 0)
+ return num_ents - (num_ents >> -sysctl_tsb_ratio);
+ else
+ return num_ents + (num_ents >> sysctl_tsb_ratio);
+}
+
+/* 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) {
+ new_rss_limit = tsb_size_to_rss_limit(new_size);
+ if (new_rss_limit > rss)
+ break;
+ new_cache_index++;
+ }
+
+ if (new_size == max_tsb_size)
+ new_rss_limit = ~0UL;
+
+retry_tsb_alloc:
+ gfp_flags = GFP_KERNEL;
+ if (new_size > (PAGE_SIZE * 2))
+ gfp_flags = __GFP_NOWARN | __GFP_NORETRY;
+
+ new_tsb = kmem_cache_alloc_node(tsb_caches[new_cache_index],
+ gfp_flags, numa_node_id());
+ 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. */
+ preempt_disable();
+ smp_tsb_sync(mm);
+ preempt_enable();
+
+ /* 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);
+}
generated by cgit v0.10.2 at 2024-11-15 10:17:58 (GMT)