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66a5c40f60
This patch creates wordpart.h and includes it in asm/word-at-a-time.h for all architectures. WORD_AT_A_TIME_CONSTANTS depends on kernel.h because of REPEAT_BYTE. Moving this to another header and including it where necessary allows us to not include the bloated kernel.h. Making this implicit dependency on REPEAT_BYTE explicit allows for later improvements in the lib/string.c inclusion list. Suggested-by: Al Viro <viro@zeniv.linux.org.uk> Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Tanzir Hasan <tanzirh@google.com> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Link: https://lore.kernel.org/r/20231226-libstringheader-v6-1-80aa08c7652c@google.com Signed-off-by: Kees Cook <keescook@chromium.org>
57 lines
1.3 KiB
C
57 lines
1.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __ASM_SH_WORD_AT_A_TIME_H
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#define __ASM_SH_WORD_AT_A_TIME_H
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#ifdef CONFIG_CPU_BIG_ENDIAN
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# include <asm-generic/word-at-a-time.h>
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#else
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#include <linux/bitops.h>
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#include <linux/wordpart.h>
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/*
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* Little-endian version cribbed from x86.
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*/
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struct word_at_a_time {
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const unsigned long one_bits, high_bits;
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};
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#define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0x01), REPEAT_BYTE(0x80) }
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/* Carl Chatfield / Jan Achrenius G+ version for 32-bit */
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static inline long count_masked_bytes(long mask)
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{
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/* (000000 0000ff 00ffff ffffff) -> ( 1 1 2 3 ) */
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long a = (0x0ff0001+mask) >> 23;
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/* Fix the 1 for 00 case */
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return a & mask;
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}
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/* Return nonzero if it has a zero */
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static inline unsigned long has_zero(unsigned long a, unsigned long *bits, const struct word_at_a_time *c)
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{
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unsigned long mask = ((a - c->one_bits) & ~a) & c->high_bits;
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*bits = mask;
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return mask;
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}
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static inline unsigned long prep_zero_mask(unsigned long a, unsigned long bits, const struct word_at_a_time *c)
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{
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return bits;
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}
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static inline unsigned long create_zero_mask(unsigned long bits)
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{
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bits = (bits - 1) & ~bits;
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return bits >> 7;
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}
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/* The mask we created is directly usable as a bytemask */
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#define zero_bytemask(mask) (mask)
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static inline unsigned long find_zero(unsigned long mask)
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{
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return count_masked_bytes(mask);
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}
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#endif
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#endif
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