On Wed, Sep 10, 2014 at 10:51:46AM -0600, Toshi Kani wrote: > This patch changes reserve_memtype() to handle the WT cache mode. > When PAT is not enabled, it continues to set UC- to *new_type for > any non-WB request. > > When a target range is RAM, reserve_ram_pages_type() fails for WT > for now. This function may not reserve a RAM range for WT since > reserve_ram_pages_type() uses the page flags limited to three memory > types, WB, WC and UC. > > Signed-off-by: Toshi Kani <[email protected]>
Reviewed-by: Konrad Rzeszutek Wilk <[email protected]> > --- > arch/x86/include/asm/cacheflush.h | 4 ++++ > arch/x86/mm/pat.c | 16 +++++++++++++--- > 2 files changed, 17 insertions(+), 3 deletions(-) > > diff --git a/arch/x86/include/asm/cacheflush.h > b/arch/x86/include/asm/cacheflush.h > index 157644b..c912680 100644 > --- a/arch/x86/include/asm/cacheflush.h > +++ b/arch/x86/include/asm/cacheflush.h > @@ -53,6 +53,10 @@ static inline void set_page_memtype(struct page *pg, > case _PAGE_CACHE_MODE_WB: > memtype_flags = _PGMT_WB; > break; > + case _PAGE_CACHE_MODE_WT: > + case _PAGE_CACHE_MODE_WP: > + pr_err("set_page_memtype: unsupported cachemode %d\n", memtype); > + BUG(); > default: > memtype_flags = _PGMT_DEFAULT; > break; > diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c > index 598d7c7..7644967 100644 > --- a/arch/x86/mm/pat.c > +++ b/arch/x86/mm/pat.c > @@ -268,6 +268,8 @@ static int pat_pagerange_is_ram(resource_size_t start, > resource_size_t end) > > /* > * For RAM pages, we use page flags to mark the pages with appropriate type. > + * The page flags are currently limited to three types, WB, WC and UC. Hence, > + * any request to WT or WP will fail with -EINVAL. > * Here we do two pass: > * - Find the memtype of all the pages in the range, look for any conflicts > * - In case of no conflicts, set the new memtype for pages in the range > @@ -279,6 +281,13 @@ static int reserve_ram_pages_type(u64 start, u64 end, > struct page *page; > u64 pfn; > > + if ((req_type == _PAGE_CACHE_MODE_WT) || > + (req_type == _PAGE_CACHE_MODE_WP)) { > + if (new_type) > + *new_type = _PAGE_CACHE_MODE_UC_MINUS; > + return -EINVAL; > + } > + > if (req_type == _PAGE_CACHE_MODE_UC) { > /* We do not support strong UC */ > WARN_ON_ONCE(1); > @@ -328,6 +337,7 @@ static int free_ram_pages_type(u64 start, u64 end) > * - _PAGE_CACHE_MODE_WC > * - _PAGE_CACHE_MODE_UC_MINUS > * - _PAGE_CACHE_MODE_UC > + * - _PAGE_CACHE_MODE_WT > * > * If new_type is NULL, function will return an error if it cannot reserve > the > * region with req_type. If new_type is non-NULL, function will return > @@ -347,10 +357,10 @@ int reserve_memtype(u64 start, u64 end, enum > page_cache_mode req_type, > if (!pat_enabled) { > /* This is identical to page table setting without PAT */ > if (new_type) { > - if (req_type == _PAGE_CACHE_MODE_WC) > - *new_type = _PAGE_CACHE_MODE_UC_MINUS; > + if (req_type == _PAGE_CACHE_MODE_WB) > + *new_type = _PAGE_CACHE_MODE_WB; > else > - *new_type = req_type; > + *new_type = _PAGE_CACHE_MODE_UC_MINUS; > } > return 0; > } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
