From 48b0e5487fcdcb3421bda67666277348b2bd2661 Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Wed, 27 Jul 2005 16:08:44 -0700 Subject: [PATCH] [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 --- arch/sparc64/mm/init.c | 23 +++++++++++++++++------ 1 file 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 -- 2.39.2