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[SPARC64]: Fix ugly dependency on NR_CPUS being a power-of-2.

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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>
This commit is contained in:
David S. Miller 2005-07-27 16:08:44 -07:00
parent 40a085c41d
commit 48b0e5487f
1 changed files with 17 additions and 6 deletions
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23
arch/sparc64/mm/init.c
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@ -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