Messages in this thread | | | Date | Thu, 26 Jul 2007 17:13:52 +0200 | From | Zoltan Menyhart <> | Subject | Re: [PATCH] flush icache before set_pte on ia64 take3 |
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I do not think changing the semantics of flush_cache_page() is a good idea. Please have a look at Documentation/cachetlb.txt. This is for virtual address tagged caches.
The doc. does not say much about flush_icache_page(). It is used in:
install_page(): can release any previously existing mapping (similarly: for virtual address tagged I-cache)
On the other hand, I do not see why it is used in these two cases, I think the virtual address tagged I-cache must have been flushed when the old PTE of the page was removed:
do_no_page(): if (pte_none(*page_table)) { flush_icache_page(vma, new_page);
do_swap_page(): flush_icache_page(vma, page);
Anyway, it is a NO-OP on the machines with physical address tagged caches.
Sure, the names could have been chosen more carefully.
Unless you have a very strong reason, do not change their semantics (would require updates for the other architectures).
I can agree: - lazy_mmu_prot_update() is not the right place for a flush - to flush I-cache before inserting PTE (at least for the machines with physical address tagged caches)
Can we have a separate, specific exec_flush_phtag_icache_page() that is to be called before inserting a PTE with the exec bit on for physical address tagged I-caches) ? It is defined in asm-generic/cacheflush.h as NO-OP.
Or exec_flush_icache_page_before_set_pte() ?
Thanks,
Zoltan
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