include/linux/memregion.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _MEMREGION_H_
   3 #define _MEMREGION_H_
   4 #include <linux/types.h>
   5 #include <linux/errno.h>
   6 #include <linux/range.h>
   7 #include <linux/bug.h>
   8
   9 struct memregion_info {
  10         int target_node;
  11         struct range range;
  12 };
  13
  14 #ifdef CONFIG_MEMREGION
  15 int memregion_alloc(gfp_t gfp);
  16 void memregion_free(int id);
  17 #else
  18 static inline int memregion_alloc(gfp_t gfp)
  19 {
  20         return -ENOMEM;
  21 }
  22 static inline void memregion_free(int id)
  23 {
  24 }
  25 #endif
  26
  27 /**
  28  * cpu_cache_invalidate_memregion - drop any CPU cached data for
  29  *     memregions described by @res_desc
  30  * @res_desc: one of the IORES_DESC_* types
  31  *
  32  * Perform cache maintenance after a memory event / operation that
  33  * changes the contents of physical memory in a cache-incoherent manner.
  34  * For example, device memory technologies like NVDIMM and CXL have
  35  * device secure erase, and dynamic region provision that can replace
  36  * the memory mapped to a given physical address.
  37  *
  38  * Limit the functionality to architectures that have an efficient way
  39  * to writeback and invalidate potentially terabytes of address space at
  40  * once.  Note that this routine may or may not write back any dirty
  41  * contents while performing the invalidation. It is only exported for
  42  * the explicit usage of the NVDIMM and CXL modules in the 'DEVMEM'
  43  * symbol namespace on bare platforms.
  44  *
  45  * Returns 0 on success or negative error code on a failure to perform
  46  * the cache maintenance.
  47  */
  48 #ifdef CONFIG_ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION
  49 int cpu_cache_invalidate_memregion(int res_desc);
  50 bool cpu_cache_has_invalidate_memregion(void);
  51 #else
  52 static inline bool cpu_cache_has_invalidate_memregion(void)
  53 {
  54         return false;
  55 }
  56
  57 static inline int cpu_cache_invalidate_memregion(int res_desc)
  58 {
  59         WARN_ON_ONCE("CPU cache invalidation required");
  60         return -ENXIO;
  61 }
  62 #endif
  63 #endif /* _MEMREGION_H_ */