Merge tag 'for-6.2/io_uring-2022-12-08' of git://git.kernel.dk/linux

[linux-2.6-microblaze.git] / include / linux / memregion.h

diff --git a/include/linux/memregion.h b/include/linux/memregion.h
index c04c4fd..bf83363 100644 (file)
--- a/include/linux/memregion.h
+++ b/include/linux/memregion.h
@@ -3,6 +3,7 @@
 #define _MEMREGION_H_
 #include <linux/types.h>
 #include <linux/errno.h>
+#include <linux/bug.h>
 
 struct memregion_info {
        int target_node;
@@ -20,4 +21,41 @@ static inline void memregion_free(int id)
 {
 }
 #endif
+
+/**
+ * cpu_cache_invalidate_memregion - drop any CPU cached data for
+ *     memregions described by @res_desc
+ * @res_desc: one of the IORES_DESC_* types
+ *
+ * Perform cache maintenance after a memory event / operation that
+ * changes the contents of physical memory in a cache-incoherent manner.
+ * For example, device memory technologies like NVDIMM and CXL have
+ * device secure erase, and dynamic region provision that can replace
+ * the memory mapped to a given physical address.
+ *
+ * Limit the functionality to architectures that have an efficient way
+ * to writeback and invalidate potentially terabytes of address space at
+ * once.  Note that this routine may or may not write back any dirty
+ * contents while performing the invalidation. It is only exported for
+ * the explicit usage of the NVDIMM and CXL modules in the 'DEVMEM'
+ * symbol namespace on bare platforms.
+ *
+ * Returns 0 on success or negative error code on a failure to perform
+ * the cache maintenance.
+ */
+#ifdef CONFIG_ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION
+int cpu_cache_invalidate_memregion(int res_desc);
+bool cpu_cache_has_invalidate_memregion(void);
+#else
+static inline bool cpu_cache_has_invalidate_memregion(void)
+{
+       return false;
+}
+
+static inline int cpu_cache_invalidate_memregion(int res_desc)
+{
+       WARN_ON_ONCE("CPU cache invalidation required");
+       return -ENXIO;
+}
+#endif
 #endif /* _MEMREGION_H_ */