(CC 'The REST' maintainers)
Hi,
Andre, as I mentioned already a couple of times. You should CC all the
appropriate maintainers for the code you are modifying.
On 06/04/17 00:25, Stefano Stabellini wrote:
On Thu, 6 Apr 2017, Andre Przywara wrote:
To safely handle 64-bit registers even on 32-bit systems, introduce
a GENMASK_ULL variant (lifted from Linux).
This adds a BITS_PER_LONG_LONG define as well.
Also fix a bug in the comment for the existing GENMASK variant.
Signed-off-by: Andre Przywara <andre.przyw...@arm.com>
Reviewed-by: Stefano Stabellini <sstabell...@kernel.org>
I'd like some input from Andrew here. I suggested a similar patch a year
ago (see [1]) and the final decision was to drop GENMASK_ULL.
---
xen/include/asm-arm/config.h | 2 ++
xen/include/xen/bitops.h | 5 ++++-
2 files changed, 6 insertions(+), 1 deletion(-)
diff --git a/xen/include/asm-arm/config.h b/xen/include/asm-arm/config.h
index b2edf95..1f730ce 100644
--- a/xen/include/asm-arm/config.h
+++ b/xen/include/asm-arm/config.h
@@ -19,6 +19,8 @@
#define BITS_PER_LONG (BYTES_PER_LONG << 3)
#define POINTER_ALIGN BYTES_PER_LONG
+#define BITS_PER_LONG_LONG (sizeof (long long) * BITS_PER_BYTE)
+
/* xen_ulong_t is always 64 bits */
#define BITS_PER_XEN_ULONG 64
diff --git a/xen/include/xen/bitops.h b/xen/include/xen/bitops.h
index bd0883a..9261e06 100644
--- a/xen/include/xen/bitops.h
+++ b/xen/include/xen/bitops.h
@@ -5,11 +5,14 @@
/*
* 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.
+ * GENMASK(30, 21) gives us the 32bit vector 0x7fe00000.
*/
#define GENMASK(h, l) \
(((~0UL) << (l)) & (~0UL >> (BITS_PER_LONG - 1 - (h))))
+#define GENMASK_ULL(h, l) \
+ (((~0ULL) << (l)) & (~0ULL >> (BITS_PER_LONG_LONG - 1 - (h))))
+
/*
* ffs: find first bit set. This is defined the same way as
* the libc and compiler builtin ffs routines, therefore
--
2.8.2
Cheers,
[1] https://patchwork.kernel.org/patch/8824091/
--
Julien Grall
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