From: Julien Grall <julien.grall@arm.com>
To: xen-devel@lists.xen.org
Cc: sstabellini@kernel.org, Keir Fraser <keir@xen.org>,
George Dunlap <George.Dunlap@eu.citrix.com>,
andre.przywara@arm.com, Ian Jackson <ian.jackson@eu.citrix.com>,
Tim Deegan <tim@xen.org>, Julien Grall <julien.grall@arm.com>,
Jan Beulich <jbeulich@suse.com>,
Andrew Cooper <andrew.cooper3@citrix.com>,
Wei Liu <wei.liu2@citrix.com>
Subject: [for-4.7 v2 1/2] xen/bitops: Introduce GENMASK to generate mask
Date: Fri, 22 Apr 2016 16:58:32 +0100 [thread overview]
Message-ID: <1461340713-9587-2-git-send-email-julien.grall@arm.com> (raw)
In-Reply-To: <1461340713-9587-1-git-send-email-julien.grall@arm.com>
The code has been imported from the header include/linux/bitops.h in
Linux v4.6-rc3.
Signed-off-by: Julien Grall <julien.grall@arm.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
---
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: George Dunlap <George.Dunlap@eu.citrix.com>
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Keir Fraser <keir@xen.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Tim Deegan <tim@xen.org>
Cc: Wei Liu <wei.liu2@citrix.com>
Changes in v2:
- Remove GENMASK_ULL
- Add Stefano's acked-by
---
xen/include/xen/bitops.h | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/xen/include/xen/bitops.h b/xen/include/xen/bitops.h
index cb56f24..bd0883a 100644
--- a/xen/include/xen/bitops.h
+++ b/xen/include/xen/bitops.h
@@ -3,6 +3,14 @@
#include <asm/types.h>
/*
+ * Create a contiguous bitmask starting at bit position @l and ending at
+ * position @h. For example
+ * GENMASK(30, 21) gives us the 32bit vector 0x01fe00000.
+ */
+#define GENMASK(h, l) \
+ (((~0UL) << (l)) & (~0UL >> (BITS_PER_LONG - 1 - (h))))
+
+/*
* ffs: find first bit set. This is defined the same way as
* the libc and compiler builtin ffs routines, therefore
* differs in spirit from the above ffz (man ffs).
--
1.9.1
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next prev parent reply other threads:[~2016-04-22 15:58 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-22 15:58 [for-4.7 v2 0/2] xen/arm: traps: Correctly interpret the content of the register HPFAR_EL2 Julien Grall
2016-04-22 15:58 ` Julien Grall [this message]
2016-04-22 16:07 ` [for-4.7 v2 1/2] xen/bitops: Introduce GENMASK to generate mask Jan Beulich
2016-04-22 16:15 ` Stefano Stabellini
2016-04-22 17:18 ` Ian Jackson
2016-04-22 15:58 ` [for-4.7 v2 2/2] xen/arm: traps: Correctly interpret the content of the register HPFAR_EL2 Julien Grall
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