diff options
Diffstat (limited to 'arch/riscv/include/asm/word-at-a-time.h')
| -rw-r--r-- | arch/riscv/include/asm/word-at-a-time.h | 30 |
1 files changed, 29 insertions, 1 deletions
diff --git a/arch/riscv/include/asm/word-at-a-time.h b/arch/riscv/include/asm/word-at-a-time.h index 7c086ac6ecd4..3802cda71ab7 100644 --- a/arch/riscv/include/asm/word-at-a-time.h +++ b/arch/riscv/include/asm/word-at-a-time.h @@ -9,7 +9,9 @@ #define _ASM_RISCV_WORD_AT_A_TIME_H -#include <linux/kernel.h> +#include <asm/asm-extable.h> +#include <linux/bitops.h> +#include <linux/wordpart.h> struct word_at_a_time { const unsigned long one_bits, high_bits; @@ -45,4 +47,30 @@ static inline unsigned long find_zero(unsigned long mask) /* The mask we created is directly usable as a bytemask */ #define zero_bytemask(mask) (mask) +#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; + + /* Load word from unaligned pointer addr */ + asm( + "1: " REG_L " %0, %2\n" + "2:\n" + _ASM_EXTABLE_LOAD_UNALIGNED_ZEROPAD(1b, 2b, %0, %1) + : "=&r" (ret) + : "r" (addr), "m" (*(unsigned long *)addr)); + + return ret; +} + +#endif /* CONFIG_DCACHE_WORD_ACCESS */ + #endif /* _ASM_RISCV_WORD_AT_A_TIME_H */ |