When a RAM range is requested to reserve_memtype(), it calls reserve_ram_pages_type() to verify the requested type. reserve_ram_pages_type() is changed to fail WT and WP requests with -EINVAL since set_page_memtype() is limited to handle three types, WB, WC and UC-.
Signed-off-by: Toshi Kani <[email protected]> Reviewed-by: Konrad Rzeszutek Wilk <[email protected]> Reviewed-by: Thomas Gleixner <[email protected]> --- Patch 8/10 enhances set_page_memtype() to support WT. --- arch/x86/mm/pat.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c index 83af01a..56c8b4d 100644 --- a/arch/x86/mm/pat.c +++ b/arch/x86/mm/pat.c @@ -401,6 +401,8 @@ 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 limited to three types, WB, WC and UC-. + * WT and WP requests fail with -EINVAL, and UC gets redirected to UC-. * 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 @@ -412,6 +414,13 @@ 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); @@ -461,6 +470,7 @@ 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 -- 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/
