path: root/sbin/bsdlabel
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authorJung-uk Kim <jkim@FreeBSD.org>2010-11-22 19:52:44 +0000
committerJung-uk Kim <jkim@FreeBSD.org>2010-11-22 19:52:44 +0000
commit7dd052c1d9375f47c9143d93eabeb86483e98213 (patch)
tree93846e3185d960e68c051176e8750b1cd5aaab8a /sbin/bsdlabel
parent59b956cba0f2c87c5dd328448e717a00ebe43bee (diff)
- Disable caches and flush caches/TLBs when we update PAT as we do for MTRR.
Flushing TLBs is required to ensure cache coherency according to the AMD64 architecture manual. Flushing caches is only required when changing from a cacheable memory type (WB, WP, or WT) to an uncacheable type (WC, UC, or UC-). Since this function is only used once per processor during startup, there is no need to take any shortcuts. - Leave PAT indices 0-3 at the default of WB, WT, UC-, and UC. Program 5 as WP (from default WT) and 6 as WC (from default UC-). Leave 4 and 7 at the default of WB and UC. This is to avoid transition from a cacheable memory type to an uncacheable type to minimize possible cache incoherency. Since we perform flushing caches and TLBs now, this change may not be necessary any more but we do not want to take any chances. - Remove Apple hardware specific quirks. With the above changes, it seems this hack is no longer needed. - Improve pmap_cache_bits() with an array to map PAT memory type to index. This array is initialized early from pmap_init_pat(), so that we do not need to handle special cases in the function any more. Now this function is identical on both amd64 and i386. Reviewed by: jhb Tested by: RM (reuf_m at hotmail dot com) Ryszard Czekaj (rychoo at freeshell dot net) army.of.root (army dot of dot root at googlemail dot com) MFC after: 3 days
Notes: svn path=/head/; revision=215703
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