From d53a0d33bc3a50ea0e8dd1680a2e8435770b162a Mon Sep 17 00:00:00 2001 From: Paul Mundt Date: Wed, 17 Feb 2010 21:17:02 +0900 Subject: [PATCH] sh: PMB locking overhaul. This implements some locking for the PMB code. A high level rwlock is added for dealing with rw accesses on the entry map while a per-entry data structure spinlock is added to deal with the PMB entry changing out from underneath us. Signed-off-by: Paul Mundt --- arch/sh/include/asm/mmu.h | 18 ----- arch/sh/mm/pmb.c | 152 ++++++++++++++++++++++++++++---------- 2 files changed, 114 insertions(+), 56 deletions(-) diff --git a/arch/sh/include/asm/mmu.h b/arch/sh/include/asm/mmu.h index 5453169bf052..e42c4e2a41df 100644 --- a/arch/sh/include/asm/mmu.h +++ b/arch/sh/include/asm/mmu.h @@ -53,24 +53,6 @@ typedef struct { #endif } mm_context_t; -struct pmb_entry; - -struct pmb_entry { - unsigned long vpn; - unsigned long ppn; - unsigned long flags; - unsigned long size; - - /* - * 0 .. NR_PMB_ENTRIES for specific entry selection, or - * PMB_NO_ENTRY to search for a free one - */ - int entry; - - /* Adjacent entry link for contiguous multi-entry mappings */ - struct pmb_entry *link; -}; - #ifdef CONFIG_PMB /* arch/sh/mm/pmb.c */ long pmb_remap(unsigned long virt, unsigned long phys, diff --git a/arch/sh/mm/pmb.c b/arch/sh/mm/pmb.c index cb808a8aaffc..e65e8b8e2a5e 100644 --- a/arch/sh/mm/pmb.c +++ b/arch/sh/mm/pmb.c @@ -22,6 +22,8 @@ #include #include #include +#include +#include #include #include #include @@ -30,8 +32,29 @@ #include #include +struct pmb_entry; + +struct pmb_entry { + unsigned long vpn; + unsigned long ppn; + unsigned long flags; + unsigned long size; + + spinlock_t lock; + + /* + * 0 .. NR_PMB_ENTRIES for specific entry selection, or + * PMB_NO_ENTRY to search for a free one + */ + int entry; + + /* Adjacent entry link for contiguous multi-entry mappings */ + struct pmb_entry *link; +}; + static void pmb_unmap_entry(struct pmb_entry *); +static DEFINE_RWLOCK(pmb_rwlock); static struct pmb_entry pmb_entry_list[NR_PMB_ENTRIES]; static DECLARE_BITMAP(pmb_map, NR_PMB_ENTRIES); @@ -52,16 +75,13 @@ static __always_inline unsigned long mk_pmb_data(unsigned int entry) static int pmb_alloc_entry(void) { - unsigned int pos; + 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; + if (pos >= 0 && pos < NR_PMB_ENTRIES) + __set_bit(pos, pmb_map); + else + pos = -ENOSPC; return pos; } @@ -70,21 +90,32 @@ static struct pmb_entry *pmb_alloc(unsigned long vpn, unsigned long ppn, unsigned long flags, int entry) { struct pmb_entry *pmbe; + unsigned long irqflags; + void *ret = NULL; int pos; + write_lock_irqsave(&pmb_rwlock, irqflags); + if (entry == PMB_NO_ENTRY) { pos = pmb_alloc_entry(); - if (pos < 0) - return ERR_PTR(pos); + if (unlikely(pos < 0)) { + ret = ERR_PTR(pos); + goto out; + } } else { - if (test_and_set_bit(entry, pmb_map)) - return ERR_PTR(-ENOSPC); + if (__test_and_set_bit(entry, pmb_map)) { + ret = ERR_PTR(-ENOSPC); + goto out; + } + pos = entry; } + write_unlock_irqrestore(&pmb_rwlock, irqflags); + pmbe = &pmb_entry_list[pos]; - if (!pmbe) - return ERR_PTR(-ENOMEM); + + spin_lock_init(&pmbe->lock); pmbe->vpn = vpn; pmbe->ppn = ppn; @@ -93,11 +124,15 @@ static struct pmb_entry *pmb_alloc(unsigned long vpn, unsigned long ppn, pmbe->size = 0; return pmbe; + +out: + write_unlock_irqrestore(&pmb_rwlock, irqflags); + return ret; } static void pmb_free(struct pmb_entry *pmbe) { - clear_bit(pmbe->entry, pmb_map); + __clear_bit(pmbe->entry, pmb_map); pmbe->entry = PMB_NO_ENTRY; } @@ -124,7 +159,7 @@ static __always_inline unsigned long pmb_cache_flags(void) /* * Must be run uncached. */ -static void set_pmb_entry(struct pmb_entry *pmbe) +static void __set_pmb_entry(struct pmb_entry *pmbe) { jump_to_uncached(); @@ -137,7 +172,7 @@ static void set_pmb_entry(struct pmb_entry *pmbe) back_to_cached(); } -static void clear_pmb_entry(struct pmb_entry *pmbe) +static void __clear_pmb_entry(struct pmb_entry *pmbe) { unsigned int entry = pmbe->entry; unsigned long addr; @@ -154,6 +189,15 @@ static void clear_pmb_entry(struct pmb_entry *pmbe) back_to_cached(); } +static void set_pmb_entry(struct pmb_entry *pmbe) +{ + unsigned long flags; + + spin_lock_irqsave(&pmbe->lock, flags); + __set_pmb_entry(pmbe); + spin_unlock_irqrestore(&pmbe->lock, flags); +} + static struct { unsigned long size; int flag; @@ -190,6 +234,8 @@ long pmb_remap(unsigned long vaddr, unsigned long phys, again: for (i = 0; i < ARRAY_SIZE(pmb_sizes); i++) { + unsigned long flags; + if (size < pmb_sizes[i].size) continue; @@ -200,7 +246,9 @@ long pmb_remap(unsigned long vaddr, unsigned long phys, goto out; } - set_pmb_entry(pmbe); + spin_lock_irqsave(&pmbe->lock, flags); + + __set_pmb_entry(pmbe); phys += pmb_sizes[i].size; vaddr += pmb_sizes[i].size; @@ -212,8 +260,11 @@ long pmb_remap(unsigned long vaddr, unsigned long phys, * Link adjacent entries that span multiple PMB entries * for easier tear-down. */ - if (likely(pmbp)) + if (likely(pmbp)) { + spin_lock(&pmbp->lock); pmbp->link = pmbe; + spin_unlock(&pmbp->lock); + } pmbp = pmbe; @@ -223,9 +274,11 @@ long pmb_remap(unsigned long vaddr, unsigned long phys, * pmb_sizes[i].size again. */ i--; + + spin_unlock_irqrestore(&pmbe->lock, flags); } - if (size >= 0x1000000) + if (size >= SZ_16M) goto again; return wanted - size; @@ -238,29 +291,32 @@ long pmb_remap(unsigned long vaddr, unsigned long phys, void pmb_unmap(unsigned long addr) { - struct pmb_entry *pmbe; + struct pmb_entry *pmbe = NULL; int i; + read_lock(&pmb_rwlock); + for (i = 0; i < ARRAY_SIZE(pmb_entry_list); i++) { if (test_bit(i, pmb_map)) { pmbe = &pmb_entry_list[i]; - if (pmbe->vpn == addr) { - pmb_unmap_entry(pmbe); + if (pmbe->vpn == addr) break; - } } } + + read_unlock(&pmb_rwlock); + + pmb_unmap_entry(pmbe); } static void pmb_unmap_entry(struct pmb_entry *pmbe) { + unsigned long flags; + if (unlikely(!pmbe)) return; - if (!test_bit(pmbe->entry, pmb_map)) { - WARN_ON(1); - return; - } + write_lock_irqsave(&pmb_rwlock, flags); do { struct pmb_entry *pmblink = pmbe; @@ -272,15 +328,17 @@ static void pmb_unmap_entry(struct pmb_entry *pmbe) * this entry in pmb_alloc() (even if we haven't filled * it yet). * - * Therefore, calling clear_pmb_entry() is safe as no + * Therefore, calling __clear_pmb_entry() is safe as no * other mapping can be using that slot. */ - clear_pmb_entry(pmbe); + __clear_pmb_entry(pmbe); pmbe = pmblink->link; pmb_free(pmblink); } while (pmbe); + + write_unlock_irqrestore(&pmb_rwlock, flags); } static __always_inline unsigned int pmb_ppn_in_range(unsigned long ppn) @@ -316,6 +374,7 @@ static int pmb_synchronize_mappings(void) unsigned long addr, data; unsigned long addr_val, data_val; unsigned long ppn, vpn, flags; + unsigned long irqflags; unsigned int size; struct pmb_entry *pmbe; @@ -364,21 +423,31 @@ static int pmb_synchronize_mappings(void) continue; } + spin_lock_irqsave(&pmbe->lock, irqflags); + for (j = 0; j < ARRAY_SIZE(pmb_sizes); j++) if (pmb_sizes[j].flag == size) pmbe->size = pmb_sizes[j].size; - /* - * Compare the previous entry against the current one to - * see if the entries span a contiguous mapping. If so, - * setup the entry links accordingly. - */ - if (pmbp && ((pmbe->vpn == (pmbp->vpn + pmbp->size)) && - (pmbe->ppn == (pmbp->ppn + pmbp->size)))) - pmbp->link = pmbe; + if (pmbp) { + spin_lock(&pmbp->lock); + + /* + * Compare the previous entry against the current one to + * see if the entries span a contiguous mapping. If so, + * setup the entry links accordingly. + */ + if ((pmbe->vpn == (pmbp->vpn + pmbp->size)) && + (pmbe->ppn == (pmbp->ppn + pmbp->size))) + pmbp->link = pmbe; + + spin_unlock(&pmbp->lock); + } pmbp = pmbe; + spin_unlock_irqrestore(&pmbe->lock, irqflags); + pr_info("\t0x%08lx -> 0x%08lx [ %ldMB %scached ]\n", vpn >> PAGE_SHIFT, ppn >> PAGE_SHIFT, pmbe->size >> 20, (data_val & PMB_C) ? "" : "un"); @@ -493,14 +562,21 @@ static int pmb_sysdev_suspend(struct sys_device *dev, pm_message_t state) if (state.event == PM_EVENT_ON && prev_state.event == PM_EVENT_FREEZE) { struct pmb_entry *pmbe; + + read_lock(&pmb_rwlock); + for (i = 0; i < ARRAY_SIZE(pmb_entry_list); i++) { if (test_bit(i, pmb_map)) { pmbe = &pmb_entry_list[i]; set_pmb_entry(pmbe); } } + + read_unlock(&pmb_rwlock); } + prev_state = state; + return 0; } -- GitLab