The commit c296d4dc13ae ("asm-generic: fix a compilation warning") changed
asm-generic/cachflush.h to use static inlines instead of macros and as a
result the nds32 build with CONFIG_CPU_CACHE_ALIASING=n fails:

  CC      init/main.o
In file included from arch/nds32/include/asm/cacheflush.h:43,
                 from include/linux/highmem.h:12,
                 from include/linux/pagemap.h:11,
                 from include/linux/blkdev.h:16,
                 from include/linux/blk-cgroup.h:23,
                 from include/linux/writeback.h:14,
                 from init/main.c:44:
include/asm-generic/cacheflush.h:50:20: error: static declaration of 'flush_icache_range' follows non-static declaration
 static inline void flush_icache_range(unsigned long start, unsigned long end)
                    ^~~~~~~~~~~~~~~~~~
In file included from include/linux/highmem.h:12,
                 from include/linux/pagemap.h:11,
                 from include/linux/blkdev.h:16,
                 from include/linux/blk-cgroup.h:23,
                 from include/linux/writeback.h:14,
                 from init/main.c:44:
arch/nds32/include/asm/cacheflush.h:11:6: note: previous declaration of 'flush_icache_range' was here
 void flush_icache_range(unsigned long start, unsigned long end);
      ^~~~~~~~~~~~~~~~~~

Surround the inline functions in asm-generic/cacheflush.h by ifdef's so
that architectures could override them and add the required overrides to
nds32.

Fixes: c296d4dc13ae ("asm-generic: fix a compilation warning")
Link: https://lore.kernel.org/lkml/201912212139.yptX8CsV%25lkp@intel.com/
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: Greentime Hu <green.hu@gmail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

This patch corrects the SPDX License Identifier style
in the nds32 Hardware Architecture related files.

Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Nishad Kamdar <nishadkamdar@gmail.com>
Acked-by: Greentime Hu <greentime@andestech.com>
Signed-off-by: Greentime Hu <greentime@andestech.com>

data cache.
This issue is found by Guo Ren. Based on the Documentation/core-api/cachetlb.rst
and it says:

"Any necessary cache flushing or other coherency operations
that need to occur should happen here.  If the processor's
instruction cache does not snoop cpu stores, it is very
likely that you will need to flush the instruction cache
for copy_to_user_page()."

"If the icache does not snoop stores then this
routine(flush_icache_range) will need to flush it."

Signed-off-by: Guo Ren <ren_guo@c-sky.com>
Signed-off-by: Greentime Hu <greentime@andestech.com>

It broke the 'allmodconfig' build.
fs/xfs/xfs_buf.c: In function 'xfs_buf_bio_end_io':
fs/xfs/xfs_buf.c:1242:3: error: implicit declaration of function 'invalidate_kernel_vmap_range' [-Werror=implicit-function-declaration]
   invalidate_kernel_vmap_range(bp->b_addr, xfs_buf_vmap_len(bp));
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
fs/xfs/xfs_buf.c: In function 'xfs_buf_ioapply_map':
fs/xfs/xfs_buf.c:1312:4: error: implicit declaration of function 'flush_kernel_vmap_range' [-Werror=implicit-function-declaration]
    flush_kernel_vmap_range(bp->b_addr,
    ^~~~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Greentime Hu <greentime@andestech.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>

Remove the address_space ->tree_lock and use the xa_lock newly added to
the radix_tree_root.  Rename the address_space ->page_tree to ->i_pages,
since we don't really care that it's a tree.

[willy@infradead.org: fix nds32, fs/dax.c]
  Link: http://lkml.kernel.org/r/20180406145415.GB20605@bombadil.infradead.orgLink: http://lkml.kernel.org/r/20180313132639.17387-9-willy@infradead.org
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

This patch contains cache and TLB maintenance functions.

Signed-off-by: Vincent Chen <vincentc@andestech.com>
Signed-off-by: Greentime Hu <greentime@andestech.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>