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sh: Allocate PMB entry slot earlier

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Simplify set_pmb_entry() by removing the possibility of not finding a
free slot in the PMB. Instead we now allocate a slot in pmb_alloc() so
that if there are no free slots we fail at allocation time, rather than
in set_pmb_entry().

Signed-off-by: Matt Fleming <matt@console-pimps.org>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This commit is contained in:
Matt Fleming 2009-10-06 21:22:23 +00:00 committed by Paul Mundt
parent 5e3679c594
commit 067784f623
1 changed files with 39 additions and 41 deletions
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80
arch/sh/mm/pmb.c
View file

@ -99,10 +99,31 @@ static inline void pmb_list_del(struct pmb_entry *pmbe)
}
}
static int pmb_alloc_entry(void)
{
unsigned int pos;
repeat:
pos = find_first_zero_bit(&pmb_map, NR_PMB_ENTRIES);
if (unlikely(pos > NR_PMB_ENTRIES))
return -ENOSPC;
if (test_and_set_bit(pos, &pmb_map))
goto repeat;
return pos;
}
struct pmb_entry *pmb_alloc(unsigned long vpn, unsigned long ppn,
unsigned long flags)
{
struct pmb_entry *pmbe;
int pos;
pos = pmb_alloc_entry();
if (pos < 0)
return ERR_PTR(pos);
pmbe = kmem_cache_alloc(pmb_cache, GFP_KERNEL);
if (!pmbe)
@ -111,6 +132,7 @@ struct pmb_entry *pmb_alloc(unsigned long vpn, unsigned long ppn,
pmbe->vpn = vpn;
pmbe->ppn = ppn;
pmbe->flags = flags;
pmbe->entry = pos;
spin_lock_irq(&pmb_list_lock);
pmb_list_add(pmbe);
@ -131,23 +153,9 @@ void pmb_free(struct pmb_entry *pmbe)
/*
* Must be in P2 for __set_pmb_entry()
*/
int __set_pmb_entry(unsigned long vpn, unsigned long ppn,
unsigned long flags, int *entry)
void __set_pmb_entry(unsigned long vpn, unsigned long ppn,
unsigned long flags, int pos)
{
unsigned int pos = *entry;
if (unlikely(pos == PMB_NO_ENTRY))
pos = find_first_zero_bit(&pmb_map, NR_PMB_ENTRIES);
repeat:
if (unlikely(pos > NR_PMB_ENTRIES))
return -ENOSPC;
if (test_and_set_bit(pos, &pmb_map)) {
pos = find_first_zero_bit(&pmb_map, NR_PMB_ENTRIES);
goto repeat;
}
ctrl_outl(vpn | PMB_V, mk_pmb_addr(pos));
#ifdef CONFIG_CACHE_WRITETHROUGH
@ -161,21 +169,13 @@ int __set_pmb_entry(unsigned long vpn, unsigned long ppn,
#endif
ctrl_outl(ppn | flags | PMB_V, mk_pmb_data(pos));
*entry = pos;
return 0;
}
int __uses_jump_to_uncached set_pmb_entry(struct pmb_entry *pmbe)
void __uses_jump_to_uncached set_pmb_entry(struct pmb_entry *pmbe)
{
int ret;
jump_to_uncached();
ret = __set_pmb_entry(pmbe->vpn, pmbe->ppn, pmbe->flags, &pmbe->entry);
__set_pmb_entry(pmbe->vpn, pmbe->ppn, pmbe->flags, pmbe->entry);
back_to_cached();
return ret;
}
void __uses_jump_to_uncached clear_pmb_entry(struct pmb_entry *pmbe)
@ -239,8 +239,6 @@ long pmb_remap(unsigned long vaddr, unsigned long phys,
again:
for (i = 0; i < ARRAY_SIZE(pmb_sizes); i++) {
int ret;
if (size < pmb_sizes[i].size)
continue;
@ -250,12 +248,7 @@ long pmb_remap(unsigned long vaddr, unsigned long phys,
goto out;
}
ret = set_pmb_entry(pmbe);
if (ret != 0) {
pmb_free(pmbe);
err = -EBUSY;
goto out;
}
set_pmb_entry(pmbe);
phys += pmb_sizes[i].size;
vaddr += pmb_sizes[i].size;
@ -311,8 +304,17 @@ static void __pmb_unmap(struct pmb_entry *pmbe)
do {
struct pmb_entry *pmblink = pmbe;
if (pmbe->entry != PMB_NO_ENTRY)
clear_pmb_entry(pmbe);
/*
* We may be called before this pmb_entry has been
* entered into the PMB table via set_pmb_entry(), but
* that's OK because we've allocated a unique slot for
* this entry in pmb_alloc() (even if we haven't filled
* it yet).
*
* Therefore, calling clear_pmb_entry() is safe as no
* other mapping can be using that slot.
*/
clear_pmb_entry(pmbe);
pmbe = pmblink->link;
@ -322,11 +324,7 @@ static void __pmb_unmap(struct pmb_entry *pmbe)
static void pmb_cache_ctor(void *pmb)
{
struct pmb_entry *pmbe = pmb;
memset(pmb, 0, sizeof(struct pmb_entry));
pmbe->entry = PMB_NO_ENTRY;
}
static int __uses_jump_to_uncached pmb_init(void)
@ -349,7 +347,7 @@ static int __uses_jump_to_uncached pmb_init(void)
for (entry = 0; entry < nr_entries; entry++) {
struct pmb_entry *pmbe = pmb_init_map + entry;
__set_pmb_entry(pmbe->vpn, pmbe->ppn, pmbe->flags, &entry);
__set_pmb_entry(pmbe->vpn, pmbe->ppn, pmbe->flags, entry);
}
ctrl_outl(0, PMB_IRMCR);