riscv: use asm-generic/cacheflush.h

RISC-V needs almost no cache flushing routines of its own.  Rely on
asm-generic/cacheflush.h for the defaults.

Also remove the pointless __KERNEL__ ifdef while we're at it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
Acked-by: Palmer Dabbelt <palmerdabbelt@google.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Link: http://lkml.kernel.org/r/20200515143646.3857579-18-hch@lst.deSigned-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/riscv/include/asm/cacheflush.h

@@ -8,65 +8,6 @@
 
 #include <linux/mm.h>
 
-#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 0
-
-/*
- * The cache doesn't need to be flushed when TLB entries change when
- * the cache is mapped to physical memory, not virtual memory
- */
-static inline void flush_cache_all(void)
-{
-}
-
-static inline void flush_cache_mm(struct mm_struct *mm)
-{
-}
-
-static inline void flush_cache_dup_mm(struct mm_struct *mm)
-{
-}
-
-static inline void flush_cache_range(struct vm_area_struct *vma,
-				     unsigned long start,
-				     unsigned long end)
-{
-}
-
-static inline void flush_cache_page(struct vm_area_struct *vma,
-				    unsigned long vmaddr,
-				    unsigned long pfn)
-{
-}
-
-static inline void flush_dcache_mmap_lock(struct address_space *mapping)
-{
-}
-
-static inline void flush_dcache_mmap_unlock(struct address_space *mapping)
-{
-}
-
-static inline void flush_icache_page(struct vm_area_struct *vma,
-				     struct page *page)
-{
-}
-
-static inline void flush_cache_vmap(unsigned long start, unsigned long end)
-{
-}
-
-static inline void flush_cache_vunmap(unsigned long start, unsigned long end)
-{
-}
-
-#define copy_to_user_page(vma, page, vaddr, dst, src, len) \
-	do { \
-		memcpy(dst, src, len); \
-		flush_icache_user_range(vma, page, vaddr, len); \
-	} while (0)
-#define copy_from_user_page(vma, page, vaddr, dst, src, len) \
-	memcpy(dst, src, len)
-
 static inline void local_flush_icache_all(void)
 {
 	asm volatile ("fence.i" ::: "memory");
@@ -79,6 +20,7 @@ static inline void flush_dcache_page(struct page *page)
 	if (test_bit(PG_dcache_clean, &page->flags))
 		clear_bit(PG_dcache_clean, &page->flags);
 }
+#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 1
 
 /*
  * RISC-V doesn't have an instruction to flush parts of the instruction cache,
@@ -105,4 +47,6 @@ void flush_icache_mm(struct mm_struct *mm, bool local);
 #define SYS_RISCV_FLUSH_ICACHE_LOCAL 1UL
 #define SYS_RISCV_FLUSH_ICACHE_ALL   (SYS_RISCV_FLUSH_ICACHE_LOCAL)
 
+#include <asm-generic/cacheflush.h>
+
 #endif /* _ASM_RISCV_CACHEFLUSH_H */