From 067784f6239e08a084b4d8d597e14435331eae51 Mon Sep 17 00:00:00 2001 From: Matt Fleming Date: Tue, 6 Oct 2009 21:22:23 +0000 Subject: [PATCH] sh: Allocate PMB entry slot earlier 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 Signed-off-by: Paul Mundt --- arch/sh/mm/pmb.c | 80 +++++++++++++++++++++++------------------------- 1 file changed, 39 insertions(+), 41 deletions(-) diff --git a/arch/sh/mm/pmb.c b/arch/sh/mm/pmb.c index aade31102112..b8a33949296a 100644 --- a/arch/sh/mm/pmb.c +++ b/arch/sh/mm/pmb.c @@ -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);