Messages in this thread | | | From | Thomas Gleixner <> | Subject | Re: [PATCH 1/1] x86: restore the write back cache of reserved RAM in iounmap() | Date | Thu, 19 Nov 2020 22:01:02 +0100 |
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On Thu, Nov 19 2020 at 12:59, Andrea Arcangeli wrote: > If reserved memory is mapped with ioremap_noncache() or ioremap_wc(), > the kernel correctly splits the direct mapping and marks the PAGE_SIZE > granular region uncached, so both the virtual direct mapping and the > second virtual mapping in vmap space will be both marked uncached or > write through (i.e. _PAGE_PCD/PWT set on the pagetable). > > However when iounmap is called later, nothing restores the direct > mapping write back memtype.
Darn. This was discussed in 2008 already and survived that long?
https://lore.kernel.org/lkml/20080205011357.GA14712@linux-os.sc.intel.com/
No idea how that happened to slip through...
Thanks,
tglx
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