srmmu_nocache_bitmap is cleared by bit_map_init(). But bit_map_init()
attempts to clear by memset(), so it can't clear the trailing edge of
bitmap properly on big-endian architecture if the number of bits is not
a multiple of BITS_PER_LONG.
Actually, the number of bits in srmmu_nocache_bitmap is not always
a multiple of BITS_PER_LONG. It is calculated as below:
bitmap_bits = srmmu_nocache_size >> SRMMU_NOCACHE_BITMAP_SHIFT;
srmmu_nocache_size is decided proportionally by the amount of system RAM
and it is rounded to a multiple of PAGE_SIZE. SRMMU_NOCACHE_BITMAP_SHIFT
is defined as (PAGE_SHIFT - 4). So it can only be said that bitmap_bits
is a multiple of 16.
This fixes the problem by using bitmap_clear() instead of memset()
in bit_map_init() and this also uses BITS_TO_LONGS() to calculate correct
size at bitmap allocation time.
Signed-off-by: Akinobu Mita <akinobu.mita@xxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: sparclinux@xxxxxxxxxxxxxxx
---
This patch is a combination of the patches I sent:
"sparc: clear bitmap correctly in bit_map_init()" and
"sparc/srmmu: use BITS_TO_LONGS() to calculate bitmap size", but
the patch description is rewritten.
arch/sparc/lib/bitext.c | 6 +-----
arch/sparc/mm/srmmu.c | 4 +++-
2 files changed, 4 insertions(+), 6 deletions(-)
diff --git a/arch/sparc/lib/bitext.c b/arch/sparc/lib/bitext.c
index d516fda..04d8bad 100644
--- a/arch/sparc/lib/bitext.c
+++ b/arch/sparc/lib/bitext.c
@@ -111,11 +111,7 @@ void bit_map_clear(struct bit_map *t, int offset, int len)
void bit_map_init(struct bit_map *t, unsigned long *map, int size)
{
-
- if ((size & 07) != 0)
- BUG();
- memset(map, 0, size>>3);
-
+ bitmap_zero(map, size);
memset(t, 0, sizeof *t);
spin_lock_init(&t->lock);
t->map = map;
diff --git a/arch/sparc/mm/srmmu.c b/arch/sparc/mm/srmmu.c
index c38bb72..036c279 100644
--- a/arch/sparc/mm/srmmu.c
+++ b/arch/sparc/mm/srmmu.c
@@ -280,7 +280,9 @@ static void __init srmmu_nocache_init(void)
SRMMU_NOCACHE_ALIGN_MAX, 0UL);
memset(srmmu_nocache_pool, 0, srmmu_nocache_size);
- srmmu_nocache_bitmap = __alloc_bootmem(bitmap_bits >> 3, SMP_CACHE_BYTES, 0UL);
+ srmmu_nocache_bitmap =
+ __alloc_bootmem(BITS_TO_LONGS(bitmap_bits) * sizeof(long),
+ SMP_CACHE_BYTES, 0UL);
bit_map_init(&srmmu_nocache_map, srmmu_nocache_bitmap, bitmap_bits);
srmmu_swapper_pg_dir = __srmmu_get_nocache(SRMMU_PGD_TABLE_SIZE, SRMMU_PGD_TABLE_SIZE);
--
1.8.1.4
--
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