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authorChen, Gong <gong.chen@linux.intel.com>2013-10-19 01:29:07 +0400
committerTony Luck <tony.luck@intel.com>2013-10-22 02:12:01 +0400
commit10ef6b0dffe404bcc54e94cb2ca1a5b18445a66b (patch)
tree6450859ffdc4494f2211442dd411b7f189cf326d /include/linux/bitops.h
parent88f074f4871a8c212b212b725e4dcdcdb09613c1 (diff)
downloadlinux-10ef6b0dffe404bcc54e94cb2ca1a5b18445a66b.tar.xz
bitops: Introduce a more generic BITMASK macro
GENMASK is used to create a contiguous bitmask([hi:lo]). It is implemented twice in current kernel. One is in EDAC driver, the other is in SiS/XGI FB driver. Move it to a more generic place for other usage. Signed-off-by: Chen, Gong <gong.chen@linux.intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Thomas Winischhofer <thomas@winischhofer.net> Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com> Cc: Tomi Valkeinen <tomi.valkeinen@ti.com> Acked-by: Borislav Petkov <bp@suse.de> Acked-by: Mauro Carvalho Chehab <m.chehab@samsung.com> Signed-off-by: Tony Luck <tony.luck@intel.com>
Diffstat (limited to 'include/linux/bitops.h')
-rw-r--r--include/linux/bitops.h8
1 files changed, 8 insertions, 0 deletions
diff --git a/include/linux/bitops.h b/include/linux/bitops.h
index a3b6b82108b9..bd0c4598d03b 100644
--- a/include/linux/bitops.h
+++ b/include/linux/bitops.h
@@ -10,6 +10,14 @@
#define BITS_TO_LONGS(nr) DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long))
#endif
+/*
+ * Create a contiguous bitmask starting at bit position @l and ending at
+ * position @h. For example
+ * GENMASK_ULL(39, 21) gives us the 64bit vector 0x000000ffffe00000.
+ */
+#define GENMASK(h, l) (((U32_C(1) << ((h) - (l) + 1)) - 1) << (l))
+#define GENMASK_ULL(h, l) (((U64_C(1) << ((h) - (l) + 1)) - 1) << (l))
+
extern unsigned int __sw_hweight8(unsigned int w);
extern unsigned int __sw_hweight16(unsigned int w);
extern unsigned int __sw_hweight32(unsigned int w);