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d702b0811d
The following is the cleanup sequence in arch/arm/cpu/armv7/cpu.c int cleanup_before_linux(void) { ... ... dcache_disable(); v7_outer_cache_disable(); invalidate_dcache_all(); } 1) invalidate_dcache_all call expects that all the caches has been flushed, invalidated and there are no dirty entries prior to its execution. In the above sequence dcache_disable() flushes, invalidates the caches and turns off the mmu. But after it cleanups the cache and before the mmu is disabled there is a cp_delay() function which has STR instruction. On certain cores like the cortex-a15, cache hit and a write can happen to a cache line even when the dcache is disabled. So the above mentioned STR instruction creates a dirty entry after cleaning. The mmu gets disabled after this. 2) invalidate_dcache_all invalidates the cache lines. Again on cores like cortex-a15, invalidate instruction flushes the dirty line as well. So some times the dirty line from sequence 1 can corrupt the memory resulting in a crash. Fixing this by moving the get_cr() and cp_delay() calls before cleaning up the cache, thus avoiding the dirty entry. Signed-off-by: R Sricharan <r.sricharan@ti.com> |
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