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wordpart.h: Add REPEAT_BYTE_U32()

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In some cases it's necessary to replicate a byte across a u32 value, for
which REPEAT_BYTE() would be helpful. Currently this requires explicit
masking of the result to avoid sparse warnings, as e.g.

    (u32)REPEAT_BYTE(0xa0))

... will result in a warning:

    cast truncates bits from constant value (a0a0a0a0a0a0a0a0 becomes a0a0a0a0)

Add a new REPEAT_BYTE_U32() which does the necessary masking internally,
so that we don't need to duplicate this for every usage.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Alexandru Elisei <alexandru.elisei@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20240617111841.2529370-2-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Mark Rutland 2024-06-17 12:18:37 +01:00 committed by Catalin Marinas
parent 83a7eefedc
commit 118d777c4c
1 changed files with 8 additions and 0 deletions
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8
include/linux/wordpart.h
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@ -39,6 +39,14 @@
*/
#define REPEAT_BYTE(x) ((~0ul / 0xff) * (x))
/**
* REPEAT_BYTE_U32 - repeat the value @x multiple times as a u32 value
* @x: value to repeat
*
* NOTE: @x is not checked for > 0xff; larger values produce odd results.
*/
#define REPEAT_BYTE_U32(x) lower_32_bits(REPEAT_BYTE(x))
/* Set bits in the first 'n' bytes when loaded from memory */
#ifdef __LITTLE_ENDIAN
# define aligned_byte_mask(n) ((1UL << 8*(n))-1)