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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>
66 lines
1.5 KiB
C
66 lines
1.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_WORD_AT_A_TIME_H
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#define _ASM_WORD_AT_A_TIME_H
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#include <linux/bitops.h>
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#include <linux/wordpart.h>
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#include <asm/asm-extable.h>
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#include <asm/bitsperlong.h>
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struct word_at_a_time {
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const unsigned long bits;
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};
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#define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0x7f) }
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static inline unsigned long prep_zero_mask(unsigned long val, unsigned long data, const struct word_at_a_time *c)
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{
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return data;
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}
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static inline unsigned long create_zero_mask(unsigned long data)
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{
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return __fls(data);
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}
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static inline unsigned long find_zero(unsigned long data)
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{
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return (data ^ (BITS_PER_LONG - 1)) >> 3;
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}
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static inline unsigned long has_zero(unsigned long val, unsigned long *data, const struct word_at_a_time *c)
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{
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unsigned long mask = (val & c->bits) + c->bits;
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*data = ~(mask | val | c->bits);
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return *data;
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}
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static inline unsigned long zero_bytemask(unsigned long data)
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{
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return ~1UL << data;
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}
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/*
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* Load an unaligned word from kernel space.
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*
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* In the (very unlikely) case of the word being a page-crosser
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* and the next page not being mapped, take the exception and
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* return zeroes in the non-existing part.
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*/
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static inline unsigned long load_unaligned_zeropad(const void *addr)
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{
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unsigned long data;
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asm volatile(
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"0: lg %[data],0(%[addr])\n"
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"1: nopr %%r7\n"
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EX_TABLE_ZEROPAD(0b, 1b, %[data], %[addr])
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EX_TABLE_ZEROPAD(1b, 1b, %[data], %[addr])
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: [data] "=d" (data)
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: [addr] "a" (addr), "m" (*(unsigned long *)addr));
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return data;
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}
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#endif /* _ASM_WORD_AT_A_TIME_H */
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