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authorDavid S. Miller <davem@davemloft.net>2005-07-27 16:08:44 -0700
committerDavid S. Miller <davem@davemloft.net>2005-07-27 16:08:44 -0700
commit48b0e5487fcdcb3421bda67666277348b2bd2661 (patch)
tree37822b91e0ded470f4728aa7511e8d3f72d977e5
parent40a085c41dc3d5991fdf90ed2557cc06cce0590a (diff)
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[SPARC64]: Fix ugly dependency on NR_CPUS being a power-of-2.
The page->flags D-cache dirty state tracking depended upon NR_CPUS being a power-of-2 via it's "NR_CPUS - 1" masking. Fix that to use a fixed (256 - 1) mask as that is the limit imposed by thread_info->cpu which is a "u8". Finally, add a compile time check that NR_CPUS is not greater than 256. Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--arch/sparc64/mm/init.c23
1 files changed, 17 insertions, 6 deletions
diff --git a/arch/sparc64/mm/init.c b/arch/sparc64/mm/init.c
index 8fc413cb6acd..3fbaf342a452 100644
--- a/arch/sparc64/mm/init.c
+++ b/arch/sparc64/mm/init.c
@@ -121,15 +121,24 @@ __inline__ void flush_dcache_page_impl(struct page *page)
}
#define PG_dcache_dirty PG_arch_1
+#define PG_dcache_cpu_shift 24
+#define PG_dcache_cpu_mask (256 - 1)
+
+#if NR_CPUS > 256
+#error D-cache dirty tracking and thread_info->cpu need fixing for > 256 cpus
+#endif
#define dcache_dirty_cpu(page) \
- (((page)->flags >> 24) & (NR_CPUS - 1UL))
+ (((page)->flags >> PG_dcache_cpu_shift) & PG_dcache_cpu_mask)
static __inline__ void set_dcache_dirty(struct page *page, int this_cpu)
{
unsigned long mask = this_cpu;
- unsigned long non_cpu_bits = ~((NR_CPUS - 1UL) << 24UL);
- mask = (mask << 24) | (1UL << PG_dcache_dirty);
+ unsigned long non_cpu_bits;
+
+ non_cpu_bits = ~(PG_dcache_cpu_mask << PG_dcache_cpu_shift);
+ mask = (mask << PG_dcache_cpu_shift) | (1UL << PG_dcache_dirty);
+
__asm__ __volatile__("1:\n\t"
"ldx [%2], %%g7\n\t"
"and %%g7, %1, %%g1\n\t"
@@ -151,7 +160,7 @@ static __inline__ void clear_dcache_dirty_cpu(struct page *page, unsigned long c
__asm__ __volatile__("! test_and_clear_dcache_dirty\n"
"1:\n\t"
"ldx [%2], %%g7\n\t"
- "srlx %%g7, 24, %%g1\n\t"
+ "srlx %%g7, %4, %%g1\n\t"
"and %%g1, %3, %%g1\n\t"
"cmp %%g1, %0\n\t"
"bne,pn %%icc, 2f\n\t"
@@ -164,7 +173,8 @@ static __inline__ void clear_dcache_dirty_cpu(struct page *page, unsigned long c
"2:"
: /* no outputs */
: "r" (cpu), "r" (mask), "r" (&page->flags),
- "i" (NR_CPUS - 1UL)
+ "i" (PG_dcache_cpu_mask),
+ "i" (PG_dcache_cpu_shift)
: "g1", "g7");
}
@@ -180,7 +190,8 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long address, pte_t p
if (pfn_valid(pfn) &&
(page = pfn_to_page(pfn), page_mapping(page)) &&
((pg_flags = page->flags) & (1UL << PG_dcache_dirty))) {
- int cpu = ((pg_flags >> 24) & (NR_CPUS - 1UL));
+ int cpu = ((pg_flags >> PG_dcache_cpu_shift) &
+ PG_dcache_cpu_mask);
int this_cpu = get_cpu();
/* This is just to optimize away some function calls