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authorMatt Fleming <matt@console-pimps.org>2009-10-06 21:22:23 +0000
committerPaul Mundt <lethal@linux-sh.org>2009-10-10 21:49:57 +0900
commit067784f6239e08a084b4d8d597e14435331eae51 (patch)
tree0bfe60656a538d486df6bf79dc238cbf48b0ce04 /arch/sh/mm/pmb.c
parent5e3679c594e3a9bf819347bc59f70e03f2c6b272 (diff)
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 <matt@console-pimps.org> Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Diffstat (limited to 'arch/sh/mm/pmb.c')
-rw-r--r--arch/sh/mm/pmb.c80
1 files changed, 39 insertions, 41 deletions
diff --git a/arch/sh/mm/pmb.c b/arch/sh/mm/pmb.c
index aade3110211..b8a33949296 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 @@ repeat:
#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 @@ again:
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);