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| 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
|---|---|
| 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/bitops.h> |
| 12 | #include <linux/wordpart.h> |
| 13 | |
| 14 | struct word_at_a_time { |
| 15 | const unsigned long one_bits, high_bits; |
| 16 | }; |
| 17 | |
| 18 | #define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0x01), REPEAT_BYTE(0x80) } |
| 19 | |
| 20 | static inline unsigned long has_zero(unsigned long a, unsigned long *bits, |
| 21 | const struct word_at_a_time *c) |
| 22 | { |
| 23 | unsigned long mask = ((a - c->one_bits) & ~a) & c->high_bits; |
| 24 | *bits = mask; |
| 25 | return mask; |
| 26 | } |
| 27 | |
| 28 | #define prep_zero_mask(a, bits, c) (bits) |
| 29 | |
| 30 | static inline unsigned long create_zero_mask(unsigned long bits) |
| 31 | { |
| 32 | bits = (bits - 1) & ~bits; |
| 33 | return bits >> 7; |
| 34 | } |
| 35 | |
| 36 | static inline unsigned long find_zero(unsigned long mask) |
| 37 | { |
| 38 | unsigned long ret; |
| 39 | |
| 40 | #if __LINUX_ARM_ARCH__ >= 5 |
| 41 | /* We have clz available. */ |
| 42 | ret = fls(mask) >> 3; |
| 43 | #else |
| 44 | /* (000000 0000ff 00ffff ffffff) -> ( 1 1 2 3 ) */ |
| 45 | ret = (0x0ff0001 + mask) >> 23; |
| 46 | /* Fix the 1 for 00 case */ |
| 47 | ret &= mask; |
| 48 | #endif |
| 49 | |
| 50 | return ret; |
| 51 | } |
| 52 | |
| 53 | #define zero_bytemask(mask) (mask) |
| 54 | |
| 55 | #else /* __ARMEB__ */ |
| 56 | #include <asm-generic/word-at-a-time.h> |
| 57 | #endif |
| 58 | |
| 59 | #ifdef CONFIG_DCACHE_WORD_ACCESS |
| 60 | |
| 61 | /* |
| 62 | * Load an unaligned word from kernel space. |
| 63 | * |
| 64 | * In the (very unlikely) case of the word being a page-crosser |
| 65 | * and the next page not being mapped, take the exception and |
| 66 | * return zeroes in the non-existing part. |
| 67 | */ |
| 68 | static inline unsigned long load_unaligned_zeropad(const void *addr) |
| 69 | { |
| 70 | unsigned long ret, tmp; |
| 71 | |
| 72 | /* Load word from unaligned pointer addr */ |
| 73 | asm( |
| 74 | "1: ldr %0, [%2]\n" |
| 75 | "2:\n" |
| 76 | " .pushsection .text.fixup,\"ax\"\n" |
| 77 | " .align 2\n" |
| 78 | "3: bic %1, %2, #0x3\n" |
| 79 | " ldr %0, [%1]\n" |
| 80 | " and %1, %2, #0x3\n" |
| 81 | " lsl %1, %1, #0x3\n" |
| 82 | #ifndef __ARMEB__ |
| 83 | " lsr %0, %0, %1\n" |
| 84 | #else |
| 85 | " lsl %0, %0, %1\n" |
| 86 | #endif |
| 87 | " b 2b\n" |
| 88 | " .popsection\n" |
| 89 | " .pushsection __ex_table,\"a\"\n" |
| 90 | " .align 3\n" |
| 91 | " .long 1b, 3b\n" |
| 92 | " .popsection" |
| 93 | : "=&r" (ret), "=&r" (tmp) |
| 94 | : "r" (addr), "Qo" (*(unsigned long *)addr)); |
| 95 | |
| 96 | return ret; |
| 97 | } |
| 98 | |
| 99 | #endif /* DCACHE_WORD_ACCESS */ |
| 100 | #endif /* __ASM_ARM_WORD_AT_A_TIME_H */ |
| 101 |
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