Messages in this thread | | | Date | Mon, 6 Aug 2012 14:02:19 -0400 (EDT) | From | Nicolas Pitre <> | Subject | Re: [PATCH 01/22] ARM: add mechanism for late code patching |
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On Mon, 6 Aug 2012, Russell King - ARM Linux wrote:
> On Mon, Aug 06, 2012 at 09:19:10AM -0400, Cyril Chemparathy wrote: > > With a flush_cache_all(), we could avoid having to operate a cacheline > > at a time, but that clobbers way more than necessary. > > You can't do that, because flush_cache_all() on some CPUs requires the > proper MMU mappings to be in place, and you can't get those mappings > in place because you don't have the V:P offsets fixed up in the kernel. > Welcome to the chicken and egg problem.
This problem is fixed in this case by having the p2v and v2p code sites using an out-of-line non optimized computation until those sites are runtime patched with the inlined optimized computation we have today.
Nicolas
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