Hi Sergej, On 20/06/17 21:33, Sergej Proskurin wrote:
We extend the BIT macro to using values of unsigned long long as to enable setting bits of 64-bit registers on AArch32. In addition, this commit adds a define holding the register width of 64 bit double-word registers. This define simplifies using the associated constants in the following commits.Signed-off-by: Sergej Proskurin <prosku...@sec.in.tum.de> --- Cc: Stefano Stabellini <sstabell...@kernel.org> Cc: Julien Grall <julien.gr...@arm.com> --- v4: We reused the previous commit with the msg "arm/mem_access: Add defines holding the width of 32/64bit regs" from v3, as we can reuse the already existing define BITS_PER_WORD. --- xen/include/asm-arm/bitops.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/xen/include/asm-arm/bitops.h b/xen/include/asm-arm/bitops.h index bda889841b..c3486d497c 100644 --- a/xen/include/asm-arm/bitops.h +++ b/xen/include/asm-arm/bitops.h @@ -21,7 +21,8 @@ #define __clear_bit(n,p) clear_bit(n,p) #define BITS_PER_WORD 32 -#define BIT(nr) (1UL << (nr)) +#define BITS_PER_DOUBLE_WORD 64 +#define BIT(nr) (1ULL << (nr))
This macro is part of a set (BIT, BIT_MASK, BIT_WORD) that work on unsigned long. Now you are suggesting to upgrade BIT to support unsigned long long. This will confuse more than one user and break this set.
I would much prefer if you introduce BIT_ULL as Linux does. At the same time BITS_PER_DOUBLE_WORD should be renamed BITS_PER_LONG_LONG.
#define BIT_MASK(nr) (1UL << ((nr) % BITS_PER_WORD)) #define BIT_WORD(nr) ((nr) / BITS_PER_WORD) #define BITS_PER_BYTE 8
Cheers, -- Julien Grall _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel
