Re: [PATCH] ppc64: Fix possible race with set_pte on a present PTE

[Benjamin Herrenschmidt]

> 	static inline void ptep_update_dirty_accessed(pte_t *ptep, pte_t entry, int dirty)
> 	{
> 		unsigned long bits = pte_value(entry) & (_PAGE_DIRTY | _PAGE_ACCESSED);
> 		unsigned long tmp;
> 
> 		__asm__ __volatile__(
> 	"1:	lwarx	%0,0,%3\n\
> 		or	%0,%2,%0\n\
> 		stwcx.	%0,0,%3\n\
> 		bne-	1b"
> 		:"=&r" (tmp), "=m" (*ptep)
> 		:"r" (bits), "r" (ptep)
> 		:"cc");
> 	}
> 
> 	/* Make asm-generic/pgtable.h know about it.. */
> 	#define ptep_update_dirty_accessed ptep_update_dirty_accessed

That looks good on a first look, I need to re-read the whole discussion since
yesterday through to make sure I didn't miss anything. Note that I'd rather
call the function ptep_set_* than ptep_update_* to make clear that it can
only ever be used to _set_ those bits.

Ben.


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