Will Deacon | 12a0ef7 | 2013-11-06 17:20:22 +0000 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2013 ARM Ltd. |
| 3 | * |
| 4 | * This program is free software; you can redistribute it and/or modify |
| 5 | * it under the terms of the GNU General Public License version 2 as |
| 6 | * published by the Free Software Foundation. |
| 7 | * |
| 8 | * This program is distributed in the hope that it will be useful, |
| 9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 11 | * GNU General Public License for more details. |
| 12 | * |
| 13 | * You should have received a copy of the GNU General Public License |
| 14 | * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 15 | */ |
| 16 | #ifndef __ASM_WORD_AT_A_TIME_H |
| 17 | #define __ASM_WORD_AT_A_TIME_H |
| 18 | |
| 19 | #ifndef __AARCH64EB__ |
| 20 | |
| 21 | #include <linux/kernel.h> |
| 22 | |
| 23 | struct word_at_a_time { |
| 24 | const unsigned long one_bits, high_bits; |
| 25 | }; |
| 26 | |
| 27 | #define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0x01), REPEAT_BYTE(0x80) } |
| 28 | |
| 29 | static inline unsigned long has_zero(unsigned long a, unsigned long *bits, |
| 30 | const struct word_at_a_time *c) |
| 31 | { |
| 32 | unsigned long mask = ((a - c->one_bits) & ~a) & c->high_bits; |
| 33 | *bits = mask; |
| 34 | return mask; |
| 35 | } |
| 36 | |
| 37 | #define prep_zero_mask(a, bits, c) (bits) |
| 38 | |
| 39 | static inline unsigned long create_zero_mask(unsigned long bits) |
| 40 | { |
| 41 | bits = (bits - 1) & ~bits; |
| 42 | return bits >> 7; |
| 43 | } |
| 44 | |
| 45 | static inline unsigned long find_zero(unsigned long mask) |
| 46 | { |
| 47 | return fls64(mask) >> 3; |
| 48 | } |
| 49 | |
Will Deacon | 7bc13fd | 2013-11-06 19:32:13 +0000 | [diff] [blame] | 50 | #define zero_bytemask(mask) (mask) |
| 51 | |
Will Deacon | 12a0ef7 | 2013-11-06 17:20:22 +0000 | [diff] [blame] | 52 | #else /* __AARCH64EB__ */ |
| 53 | #include <asm-generic/word-at-a-time.h> |
| 54 | #endif |
| 55 | |
Will Deacon | 7bc13fd | 2013-11-06 19:32:13 +0000 | [diff] [blame] | 56 | /* |
| 57 | * Load an unaligned word from kernel space. |
| 58 | * |
| 59 | * In the (very unlikely) case of the word being a page-crosser |
| 60 | * and the next page not being mapped, take the exception and |
| 61 | * return zeroes in the non-existing part. |
| 62 | */ |
| 63 | static inline unsigned long load_unaligned_zeropad(const void *addr) |
| 64 | { |
| 65 | unsigned long ret, offset; |
| 66 | |
| 67 | /* Load word from unaligned pointer addr */ |
| 68 | asm( |
| 69 | "1: ldr %0, %3\n" |
| 70 | "2:\n" |
| 71 | " .pushsection .fixup,\"ax\"\n" |
| 72 | " .align 2\n" |
| 73 | "3: and %1, %2, #0x7\n" |
| 74 | " bic %2, %2, #0x7\n" |
| 75 | " ldr %0, [%2]\n" |
| 76 | " lsl %1, %1, #0x3\n" |
| 77 | #ifndef __AARCH64EB__ |
| 78 | " lsr %0, %0, %1\n" |
| 79 | #else |
| 80 | " lsl %0, %0, %1\n" |
| 81 | #endif |
| 82 | " b 2b\n" |
| 83 | " .popsection\n" |
| 84 | " .pushsection __ex_table,\"a\"\n" |
| 85 | " .align 3\n" |
| 86 | " .quad 1b, 3b\n" |
| 87 | " .popsection" |
| 88 | : "=&r" (ret), "=&r" (offset) |
| 89 | : "r" (addr), "Q" (*(unsigned long *)addr)); |
| 90 | |
| 91 | return ret; |
| 92 | } |
| 93 | |
Will Deacon | 12a0ef7 | 2013-11-06 17:20:22 +0000 | [diff] [blame] | 94 | #endif /* __ASM_WORD_AT_A_TIME_H */ |