| /* 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/bitops.h> |
| #include <linux/wordpart.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 */ |