Re: [PATCH v2 22/25] powerpc32: move xxxxx_dcache_range() functions inline
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From: Christophe Leroy <hidden>
Date: 2015-10-08 01:03:38
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Le 29/09/2015 02:29, Scott Wood a écrit :
On Tue, Sep 22, 2015 at 06:51:13PM +0200, Christophe Leroy wrote:quoted
flush/clean/invalidate _dcache_range() functions are all very similar and are quite short. They are mainly used in __dma_sync() perf_event locate them in the top 3 consumming functions during heavy ethernet activity They are good candidate for inlining, as __dma_sync() does almost nothing but calling them Signed-off-by: Christophe Leroy <redacted> --- New in v2 arch/powerpc/include/asm/cacheflush.h | 55 +++++++++++++++++++++++++++-- arch/powerpc/kernel/misc_32.S | 65 ----------------------------------- arch/powerpc/kernel/ppc_ksyms.c | 2 ++ 3 files changed, 54 insertions(+), 68 deletions(-)diff --git a/arch/powerpc/include/asm/cacheflush.h b/arch/powerpc/include/asm/cacheflush.h index 6229e6b..6169604 100644 --- a/arch/powerpc/include/asm/cacheflush.h +++ b/arch/powerpc/include/asm/cacheflush.h@@ -47,12 +47,61 @@ static inline void __flush_dcache_icache_phys(unsigned long physaddr) } #endif -extern void flush_dcache_range(unsigned long start, unsigned long stop); #ifdef CONFIG_PPC32 -extern void clean_dcache_range(unsigned long start, unsigned long stop); -extern void invalidate_dcache_range(unsigned long start, unsigned long stop); +/* + * Write any modified data cache blocks out to memory and invalidate them. + * Does not invalidate the corresponding instruction cache blocks. + */ +static inline void flush_dcache_range(unsigned long start, unsigned long stop) +{ + void *addr = (void *)(start & ~(L1_CACHE_BYTES - 1)); + unsigned int size = stop - (unsigned long)addr + (L1_CACHE_BYTES - 1); + unsigned int i; + + for (i = 0; i < size >> L1_CACHE_SHIFT; i++, addr += L1_CACHE_BYTES) + dcbf(addr); + if (i) + mb(); /* sync */ +}I know this is 32-bit-specific code, but it's still bad practice to use "unsigned int" for addresses or sizes thereof.
Ok, I can fix size, but what about start and stop ? If I change that, it means I also have to fix all caller. Do you expect me to do that ? And it is very unlykely, but what if for some reason someone wants to invalidate the entire user address space which is 3Gbytes size ? A signed size would be negative here. Christophe