Messages in this thread | | | Date | Tue, 22 Feb 2005 02:03:09 -0800 | From | Andrew Morton <> | Subject | Re: [patch -mm series] ia64 specific /dev/mem handlers |
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jes@trained-monkey.org (Jes Sorensen) wrote: > > Hi, > > This patch introduces ia64 specific read/write handlers for /dev/mem > access which is needed to avoid uncached pages to be accessed through > the cached kernel window which can lead to random corruption. It also > introduces a new page-flag PG_uncached which will be used to mark the > uncached pages. I assume this may be useful to other architectures as > well where the CPU may use speculative reads which conflict with > uncached access. In addition I moved do_write_mem to be under > ARCH_HAS_DEV_MEM as it's only ever used if that is defined. > > The patch is needed for the new ia64 special memory driver (mspec - > former fetchop). > > Patch is relative to 2.6.11-rc3-mm2 and relies on the ARCH_HAS_DEV_MEM > flag which isn't in Linus' nor Tony's trees yet.
Is it possible to avoid consuming a page flag?
If this is an ia64-only (or 64-bit-only) thing I guess we could use bit 32.
> + if (page->flags & PG_uncached)
dude. That ain't gonna work ;) - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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