[mirror_ubuntu-focal-kernel.git] / arch / arm / include / asm / word-at-a-time.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __ASM_ARM_WORD_AT_A_TIME_H
#define __ASM_ARM_WORD_AT_A_TIME_H

#ifndef __ARMEB__

/*
 * Little-endian word-at-a-time zero byte handling.
 * Heavily based on the x86 algorithm.
 */
#include <linux/kernel.h>

struct word_at_a_time {
	const unsigned long one_bits, high_bits;
};

#define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0x01), REPEAT_BYTE(0x80) }

static inline unsigned long has_zero(unsigned long a, unsigned long *bits,
				     const struct word_at_a_time *c)
{
	unsigned long mask = ((a - c->one_bits) & ~a) & c->high_bits;
	*bits = mask;
	return mask;
}

#define prep_zero_mask(a, bits, c) (bits)

static inline unsigned long create_zero_mask(unsigned long bits)
{
	bits = (bits - 1) & ~bits;
	return bits >> 7;
}

static inline unsigned long find_zero(unsigned long mask)
{
	unsigned long ret;

#if __LINUX_ARM_ARCH__ >= 5
	/* We have clz available. */
	ret = fls(mask) >> 3;
#else
	/* (000000 0000ff 00ffff ffffff) -> ( 1 1 2 3 ) */
	ret = (0x0ff0001 + mask) >> 23;
	/* Fix the 1 for 00 case */
	ret &= mask;
#endif

	return ret;
}

#define zero_bytemask(mask) (mask)

#else	/* __ARMEB__ */
#include <asm-generic/word-at-a-time.h>
#endif

#ifdef CONFIG_DCACHE_WORD_ACCESS

/*
 * Load an unaligned word from kernel space.
 *
 * In the (very unlikely) case of the word being a page-crosser
 * and the next page not being mapped, take the exception and
 * return zeroes in the non-existing part.
 */
static inline unsigned long load_unaligned_zeropad(const void *addr)
{
	unsigned long ret, offset;

	/* Load word from unaligned pointer addr */
	asm(
	"1:	ldr	%0, [%2]\n"
	"2:\n"
	"	.pushsection .text.fixup,\"ax\"\n"
	"	.align 2\n"
	"3:	and	%1, %2, #0x3\n"
	"	bic	%2, %2, #0x3\n"
	"	ldr	%0, [%2]\n"
	"	lsl	%1, %1, #0x3\n"
#ifndef __ARMEB__
	"	lsr	%0, %0, %1\n"
#else
	"	lsl	%0, %0, %1\n"
#endif
	"	b	2b\n"
	"	.popsection\n"
	"	.pushsection __ex_table,\"a\"\n"
	"	.align	3\n"
	"	.long	1b, 3b\n"
	"	.popsection"
	: "=&r" (ret), "=&r" (offset)
	: "r" (addr), "Qo" (*(unsigned long *)addr));

	return ret;
}

#endif	/* DCACHE_WORD_ACCESS */
#endif /* __ASM_ARM_WORD_AT_A_TIME_H */
Commit	Line	Data
b2441318	1	/* SPDX-License-Identifier: GPL-2.0 */
8c56cc8b WD	2	#ifndef __ASM_ARM_WORD_AT_A_TIME_H
	3	#define __ASM_ARM_WORD_AT_A_TIME_H
	4
	5	#ifndef __ARMEB__
	6
	7	/*
	8	* Little-endian word-at-a-time zero byte handling.
	9	* Heavily based on the x86 algorithm.
	10	*/
	11	#include <linux/kernel.h>
	12
	13	struct word_at_a_time {
	14	const unsigned long one_bits, high_bits;
	15	};
	16
	17	#define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0x01), REPEAT_BYTE(0x80) }
	18
	19	static inline unsigned long has_zero(unsigned long a, unsigned long *bits,
	20	const struct word_at_a_time *c)
	21	{
	22	unsigned long mask = ((a - c->one_bits) & ~a) & c->high_bits;
	23	*bits = mask;
	24	return mask;
	25	}
	26
	27	#define prep_zero_mask(a, bits, c) (bits)
	28
	29	static inline unsigned long create_zero_mask(unsigned long bits)
	30	{
	31	bits = (bits - 1) & ~bits;
	32	return bits >> 7;
	33	}
	34
	35	static inline unsigned long find_zero(unsigned long mask)
	36	{
	37	unsigned long ret;
	38
	39	#if __LINUX_ARM_ARCH__ >= 5
	40	/* We have clz available. */
	41	ret = fls(mask) >> 3;
	42	#else
	43	/* (000000 0000ff 00ffff ffffff) -> ( 1 1 2 3 ) */
	44	ret = (0x0ff0001 + mask) >> 23;
	45	/* Fix the 1 for 00 case */
	46	ret &= mask;
	47	#endif
	48
	49	return ret;
	50	}
	51
b9a50f74 WD	52	#define zero_bytemask(mask) (mask)
b9a50f74 WD	53
cb601185 WD	54	#else /* __ARMEB__ */
	55	#include <asm-generic/word-at-a-time.h>
	56	#endif
	57
	58	#ifdef CONFIG_DCACHE_WORD_ACCESS
	59
b9a50f74 WD	60	/*
	61	* Load an unaligned word from kernel space.
	62	*
	63	* In the (very unlikely) case of the word being a page-crosser
	64	* and the next page not being mapped, take the exception and
	65	* return zeroes in the non-existing part.
	66	*/
	67	static inline unsigned long load_unaligned_zeropad(const void *addr)
	68	{
	69	unsigned long ret, offset;
	70
	71	/* Load word from unaligned pointer addr */
	72	asm(
	73	"1: ldr %0, [%2]\n"
	74	"2:\n"
c4a84ae3	75	" .pushsection .text.fixup,\"ax\"\n"
b9a50f74 WD	76	" .align 2\n"
	77	"3: and %1, %2, #0x3\n"
	78	" bic %2, %2, #0x3\n"
	79	" ldr %0, [%2]\n"
	80	" lsl %1, %1, #0x3\n"
cb601185	81	#ifndef __ARMEB__
b9a50f74	82	" lsr %0, %0, %1\n"
cb601185 WD	83	#else
	84	" lsl %0, %0, %1\n"
	85	#endif
b9a50f74 WD	86	" b 2b\n"
	87	" .popsection\n"
	88	" .pushsection __ex_table,\"a\"\n"
	89	" .align 3\n"
	90	" .long 1b, 3b\n"
	91	" .popsection"
	92	: "=&r" (ret), "=&r" (offset)
	93	: "r" (addr), "Qo" ((unsigned long )addr));
	94
	95	return ret;
	96	}
	97
b9a50f74	98	#endif /* DCACHE_WORD_ACCESS */
8c56cc8b	99	#endif /* __ASM_ARM_WORD_AT_A_TIME_H */