On 23.11.16 21:25:06, Ard Biesheuvel wrote: > Why? MEMREMAP_WB is used often, among other things for mapping > firmware tables, which are marked as NOMAP, so in these cases, the > linear address is not mapped. If fw tables are mapped wb, that is wrong and needs a separate fix. > > If you think pfn_valid() is wrong here, I am happy to send a patch > > that fixes this by using page_is_ram(). In any case, the worst case > > that may happen is to behave the same as v4.4, we might fix then the > > wrong use of pfn_valid() where it is not correctly used to check for > > ram. > > > > page_is_ram() uses string comparisons to look for regions called > 'System RAM'. Is that something we can tolerate for each pfn_valid() > calll? > > Perhaps the solution is to reimplement page_is_ram() for arm64 using > memblock_is_memory() instead, But that still means we need to modify > the generic memremap() code first to switch to it before changing the > arm64 implementation of pfn_valid No, that's not the solution. pfn_valid() should just check if there is a valid struct page, as other archs do. And if there is a mis-use of pfn_valid() to check for ram, only that calls should be fixed to use page_is_ram(), however this is implemented, or something appropriate. But I don't see any problematic code, and if so, I will fix that. -Robert -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
