kernel-fxtec-pro1x/arch/sparc64/mm/tsb.c
David S. Miller 517af33237 [SPARC64]: Access TSB with physical addresses when possible.
This way we don't need to lock the TSB into the TLB.
The trick is that every TSB load/store is registered into
a special instruction patch section.  The default uses
virtual addresses, and the patch instructions use physical
address load/stores.

We can't do this on all chips because only cheetah+ and later
have the physical variant of the atomic quad load.

Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 01:11:32 -08:00

359 lines
8.6 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>
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, unsigned long context)
{
return (tag == ((vaddr >> 22) | (context << 48)));
}
/* 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, 0)) {
ent->tag = 0UL;
membar_storeload_storestore();
}
}
}
void flush_tsb_user(struct mmu_gather *mp)
{
struct mm_struct *mm = mp->mm;
struct tsb *tsb = mm->context.tsb;
unsigned long nentries = mm->context.tsb_nentries;
unsigned long ctx, base;
int i;
if (unlikely(!CTX_VALID(mm->context)))
return;
ctx = CTX_HWBITS(mm->context);
if (tlb_type == cheetah_plus)
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) | (ctx << 48UL);
tsb_flush(ent, tag);
}
}
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 = (_PAGE_VALID | _PAGE_L | _PAGE_CP |
_PAGE_CV | _PAGE_P | _PAGE_W);
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
tte |= _PAGE_SZ8K;
page_sz = 8192;
break;
case 8192 << 1:
tsb_reg = 0x1UL;
tte |= _PAGE_SZ64K;
page_sz = 64 * 1024;
break;
case 8192 << 2:
tsb_reg = 0x2UL;
tte |= _PAGE_SZ64K;
page_sz = 64 * 1024;
break;
case 8192 << 3:
tsb_reg = 0x3UL;
tte |= _PAGE_SZ64K;
page_sz = 64 * 1024;
break;
case 8192 << 4:
tsb_reg = 0x4UL;
tte |= _PAGE_SZ512K;
page_sz = 512 * 1024;
break;
case 8192 << 5:
tsb_reg = 0x5UL;
tte |= _PAGE_SZ512K;
page_sz = 512 * 1024;
break;
case 8192 << 6:
tsb_reg = 0x6UL;
tte |= _PAGE_SZ512K;
page_sz = 512 * 1024;
break;
case 8192 << 7:
tsb_reg = 0x7UL;
tte |= _PAGE_SZ4MB;
page_sz = 4 * 1024 * 1024;
break;
default:
BUG();
};
if (tlb_type == cheetah_plus) {
/* 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;
}
}
/* The page tables are locked against modifications while this
* runs.
*
* XXX do some prefetching...
*/
static void copy_tsb(struct tsb *old_tsb, unsigned long old_size,
struct tsb *new_tsb, unsigned long new_size)
{
unsigned long old_nentries = old_size / sizeof(struct tsb);
unsigned long new_nentries = new_size / sizeof(struct tsb);
unsigned long i;
for (i = 0; i < old_nentries; i++) {
register unsigned long tag asm("o4");
register unsigned long pte asm("o5");
unsigned long v, hash;
if (tlb_type == cheetah_plus) {
__asm__ __volatile__(
"ldda [%2] %3, %0"
: "=r" (tag), "=r" (pte)
: "r" (__pa(&old_tsb[i])),
"i" (ASI_QUAD_LDD_PHYS));
} else {
__asm__ __volatile__(
"ldda [%2] %3, %0"
: "=r" (tag), "=r" (pte)
: "r" (&old_tsb[i]),
"i" (ASI_NUCLEUS_QUAD_LDD));
}
if (!tag || (tag & (1UL << TSB_TAG_LOCK_BIT)))
continue;
/* We only put base page size PTEs into the TSB,
* but that might change in the future. This code
* would need to be changed if we start putting larger
* page size PTEs into there.
*/
WARN_ON((pte & _PAGE_ALL_SZ_BITS) != _PAGE_SZBITS);
/* The tag holds bits 22 to 63 of the virtual address
* and the context. Clear out the context, and shift
* up to make a virtual address.
*/
v = (tag & ((1UL << 42UL) - 1UL)) << 22UL;
/* The implied bits of the tag (bits 13 to 21) are
* determined by the TSB entry index, so fill that in.
*/
v |= (i & (512UL - 1UL)) << 13UL;
hash = tsb_hash(v, new_nentries);
if (tlb_type == cheetah_plus) {
__asm__ __volatile__(
"stxa %0, [%1] %2\n\t"
"stxa %3, [%4] %2"
: /* no outputs */
: "r" (tag),
"r" (__pa(&new_tsb[hash].tag)),
"i" (ASI_PHYS_USE_EC),
"r" (pte),
"r" (__pa(&new_tsb[hash].pte)));
} else {
new_tsb[hash].tag = tag;
new_tsb[hash].pte = pte;
}
}
}
/* When the RSS of an address space exceeds mm->context.tsb_rss_limit,
* update_mmu_cache() 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.
*
* 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, gfp_t gfp_flags)
{
unsigned long max_tsb_size = 1 * 1024 * 1024;
unsigned long size, old_size;
struct page *page;
struct tsb *old_tsb;
if (max_tsb_size > (PAGE_SIZE << MAX_ORDER))
max_tsb_size = (PAGE_SIZE << MAX_ORDER);
for (size = PAGE_SIZE; size < max_tsb_size; size <<= 1UL) {
unsigned long n_entries = size / sizeof(struct tsb);
n_entries = (n_entries * 3) / 4;
if (n_entries > rss)
break;
}
page = alloc_pages(gfp_flags | __GFP_ZERO, get_order(size));
if (unlikely(!page))
return;
if (size == max_tsb_size)
mm->context.tsb_rss_limit = ~0UL;
else
mm->context.tsb_rss_limit =
((size / sizeof(struct tsb)) * 3) / 4;
old_tsb = mm->context.tsb;
old_size = mm->context.tsb_nentries * sizeof(struct tsb);
if (old_tsb)
copy_tsb(old_tsb, old_size, page_address(page), size);
mm->context.tsb = page_address(page);
setup_tsb_params(mm, size);
/* If old_tsb is NULL, we're being invoked for the first time
* from init_new_context().
*/
if (old_tsb) {
/* Now force all other processors to reload the new
* TSB state.
*/
smp_tsb_sync(mm);
/* Finally reload it on the local cpu. No further
* references will remain to the old TSB and we can
* thus free it up.
*/
tsb_context_switch(mm);
free_pages((unsigned long) old_tsb, get_order(old_size));
}
}
int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
{
unsigned long initial_rss;
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.
*/
initial_rss = mm->context.tsb_nentries;
if (initial_rss)
initial_rss -= 1;
tsb_grow(mm, initial_rss, GFP_KERNEL);
if (unlikely(!mm->context.tsb))
return -ENOMEM;
return 0;
}
void destroy_context(struct mm_struct *mm)
{
unsigned long size = mm->context.tsb_nentries * sizeof(struct tsb);
free_pages((unsigned long) mm->context.tsb, get_order(size));
/* 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(&ctx_alloc_lock);
if (CTX_VALID(mm->context)) {
unsigned long nr = CTX_NRBITS(mm->context);
mmu_context_bmap[nr>>6] &= ~(1UL << (nr & 63));
}
spin_unlock(&ctx_alloc_lock);
}