[PATCH 07/10] powerpc: Implement kmap_atomic_pfn on powerpc

[Dale Farnsworth]

This is needed for the ppc32 /dev/oldmem driver of crash dump.

Signed-off-by: Dale Farnsworth <dale at farnsworth.org>
---
 include/asm-powerpc/highmem.h |   18 ++++++++++++++++++
 1 files changed, 18 insertions(+), 0 deletions(-)

diff --git a/include/asm-powerpc/highmem.h b/include/asm-powerpc/highmem.h
index f7b21ee..88d9e05 100644
--- a/include/asm-powerpc/highmem.h
+++ b/include/asm-powerpc/highmem.h
@@ -117,6 +117,24 @@ static inline void kunmap_atomic(void *kvaddr, enum km_type type)
 	pagefault_enable();
 }
 
+/* This is the same as kmap_atomic() but can map memory that doesn't
+ * have a struct page associated with it.
+ */
+static inline void *kmap_atomic_pfn(unsigned long pfn, enum km_type type)
+{
+	unsigned int idx;
+	unsigned long vaddr;
+
+	pagefault_disable();
+
+	idx = type + KM_TYPE_NR * smp_processor_id();
+	vaddr = KMAP_FIX_BEGIN + idx * PAGE_SIZE;
+	set_pte_at(&init_mm, vaddr, kmap_pte+idx, pfn_pte(pfn, kmap_prot));
+	flush_tlb_page(NULL, vaddr);
+
+	return (void*) vaddr;
+}
+
 static inline struct page *kmap_atomic_to_page(void *ptr)
 {
 	unsigned long idx, vaddr = (unsigned long) ptr;
-- 
1.5.3.4