linux/arch/sparc64/mm/tsb.c
David S. Miller dcc1e8dd88 [SPARC64]: Add a secondary TSB for hugepage mappings.
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-22 01:15:14 -08:00

501 lines
13 KiB
C

/* 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);
}