This patch changes reserve_memtype() to handle the new WT type.
When (!pat_enabled && new_type), it continues to set either WB
or UC- to *new_type. When pat_enabled, it can reserve a given
non-RAM range for WT. At this point, it 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 <toshi.k...@hp.com>
---
arch/x86/include/asm/cacheflush.h | 2 ++
arch/x86/mm/pat.c | 12 +++++++++---
arch/x86/mm/pat_internal.h | 1 +
3 files changed, 12 insertions(+), 3 deletions(-)
diff --git a/arch/x86/include/asm/cacheflush.h
b/arch/x86/include/asm/cacheflush.h
index 9863ee3..c80a3a1 100644
--- a/arch/x86/include/asm/cacheflush.h
+++ b/arch/x86/include/asm/cacheflush.h
@@ -42,6 +42,8 @@ static inline void set_page_memtype(struct page *pg, unsigned
long memtype)
unsigned long old_flags;
unsigned long new_flags;
+ BUG_ON(memtype == _PAGE_CACHE_WT);
+
switch (memtype) {
case _PAGE_CACHE_WC:
memtype_flags = _PGMT_WC;
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index 176d4d6..8a8be17 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -203,6 +203,8 @@ 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 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
@@ -213,6 +215,9 @@ static int reserve_ram_pages_type(u64 start, u64 end,
unsigned long req_type,
struct page *page;
u64 pfn;
+ if (req_type == _PAGE_CACHE_WT)
+ return -EINVAL;
+
for (pfn = (start >> PAGE_SHIFT); pfn < (end >> PAGE_SHIFT); ++pfn) {
unsigned long type;
@@ -254,6 +259,7 @@ static int free_ram_pages_type(u64 start, u64 end)
* req_type typically has one of the:
* - _PAGE_CACHE_WB
* - _PAGE_CACHE_WC
+ * - _PAGE_CACHE_WT
* - _PAGE_CACHE_UC_MINUS
*
* If new_type is NULL, function will return an error if it cannot reserve the
@@ -274,10 +280,10 @@ int reserve_memtype(u64 start, u64 end, unsigned long
req_type,
if (!pat_enabled) {
/* This is identical to page table setting without PAT */
if (new_type) {
- if (req_type == _PAGE_CACHE_WC)
- *new_type = _PAGE_CACHE_UC_MINUS;
+ if (req_type == _PAGE_CACHE_WB)
+ *new_type = _PAGE_CACHE_WB;
else
- *new_type = req_type & _PAGE_CACHE_MASK;
+ *new_type = _PAGE_CACHE_UC_MINUS;
}
return 0;
}
diff --git a/arch/x86/mm/pat_internal.h b/arch/x86/mm/pat_internal.h
index 2593d40..7ae6b37 100644
--- a/arch/x86/mm/pat_internal.h
+++ b/arch/x86/mm/pat_internal.h
@@ -20,6 +20,7 @@ static inline char *cattr_name(unsigned long flags)
case _PAGE_CACHE_UC_MINUS: return "uncached-minus";
case _PAGE_CACHE_WB: return "write-back";
case _PAGE_CACHE_WC: return "write-combining";
+ case _PAGE_CACHE_WT: return "write-through";
default: return "broken";
}
}
--
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