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| author |   Will Deacon <will.deacon@arm.com> | 2013-11-06 19:32:13 +0000 |
|---|---|---|
| committer |   Catalin Marinas <catalin.marinas@arm.com> | 2013-12-19 17:43:08 +0000 |
| commit | 7bc13fd33adb9536bd73965cd46bbf7377df097c (patch) | |
| tree | 7b394763246d3362bc40836bf31f17069f5d6ab8 | |
| parent | arm64: futex: ensure .fixup entries are sufficiently aligned (diff) | |
| download | linux-dev-7bc13fd33adb9536bd73965cd46bbf7377df097c.tar.xz linux-dev-7bc13fd33adb9536bd73965cd46bbf7377df097c.zip | |
arm64: dcache: select DCACHE_WORD_ACCESS for little-endian CPUs
DCACHE_WORD_ACCESS uses the word-at-a-time API for optimised string
comparisons in the vfs layer.
This patch implements support for load_unaligned_zeropad in much the
same way as has been done for ARM, although big-endian systems are also
supported.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
| -rw-r--r-- | arch/arm64/Kconfig | 1 | ||||
| -rw-r--r-- | arch/arm64/include/asm/word-at-a-time.h | 40 |
2 files changed, 41 insertions, 0 deletions
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 295bf2de7128..435c9bc1c86c 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -11,6 +11,7 @@ config ARM64 select BUILDTIME_EXTABLE_SORT select CLONE_BACKWARDS select COMMON_CLK + select DCACHE_WORD_ACCESS select GENERIC_CLOCKEVENTS select GENERIC_IOMAP select GENERIC_IRQ_PROBE diff --git a/arch/arm64/include/asm/word-at-a-time.h b/arch/arm64/include/asm/word-at-a-time.h index 27a167d044d9..aab5bf09e9d9 100644 --- a/arch/arm64/include/asm/word-at-a-time.h +++ b/arch/arm64/include/asm/word-at-a-time.h @@ -47,8 +47,48 @@ static inline unsigned long find_zero(unsigned long mask) return fls64(mask) >> 3; } +#define zero_bytemask(mask) (mask) + #else /* __AARCH64EB__ */ #include <asm-generic/word-at-a-time.h> #endif +/* + * 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, %3\n" + "2:\n" + " .pushsection .fixup,\"ax\"\n" + " .align 2\n" + "3: and %1, %2, #0x7\n" + " bic %2, %2, #0x7\n" + " ldr %0, [%2]\n" + " lsl %1, %1, #0x3\n" +#ifndef __AARCH64EB__ + " 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" + " .quad 1b, 3b\n" + " .popsection" + : "=&r" (ret), "=&r" (offset) + : "r" (addr), "Q" (*(unsigned long *)addr)); + + return ret; +} + #endif /* __ASM_WORD_AT_A_TIME_H */ |