[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>
diff --git a/arch/sparc64/mm/init.c b/arch/sparc64/mm/init.c
index 8fc413c..3fbaf34 100644
--- a/arch/sparc64/mm/init.c
+++ b/arch/sparc64/mm/init.c
@@ -121,15 +121,24 @@
}
#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 @@
__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 @@
"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 @@
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