From 4102b53392d6397d80b6e09b516517efacf7ea77 Mon Sep 17 00:00:00 2001 From: Vineet Gupta Date: Thu, 9 May 2013 21:54:51 +0530 Subject: ARC: [mm] Aliasing VIPT dcache support 2/4 This is the meat of the series which prevents any dcache alias creation by always keeping the U and K mapping of a page congruent. If a mapping already exists, and other tries to access the page, prev one is flushed to physical page (wback+inv) Essentially flush_dcache_page()/copy_user_highpage() create K-mapping of a page, but try to defer flushing, unless U-mapping exist. When page is actually mapped to userspace, update_mmu_cache() flushes the K-mapping (in certain cases this can be optimised out) Additonally flush_cache_mm(), flush_cache_range(), flush_cache_page() handle the puring of stale userspace mappings on exit/munmap... flush_anon_page() handles the existing U-mapping for anon page before kernel reads it via the GUP path. Note that while not complete, this is enough to boot a simple dynamically linked Busybox based rootfs Signed-off-by: Vineet Gupta --- arch/arc/Kconfig | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'arch/arc/Kconfig') diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig index 491ae7923b1..5917099470e 100644 --- a/arch/arc/Kconfig +++ b/arch/arc/Kconfig @@ -182,6 +182,10 @@ config ARC_CACHE_PAGES Note that Global I/D ENABLE + Per Page DISABLE works but corollary Global DISABLE + Per Page ENABLE won't work +config ARC_CACHE_VIPT_ALIASING + bool "Support VIPT Aliasing D$" + default n + endif #ARC_CACHE config ARC_HAS_ICCM -- cgit v1.2.3