arm64/mm: fix variable 'tag' set but not used
authorQian Cai <cai@lca.pw>
Thu, 1 Aug 2019 14:47:05 +0000 (10:47 -0400)
committerWill Deacon <will@kernel.org>
Thu, 1 Aug 2019 14:53:10 +0000 (15:53 +0100)
commit7732d20a160c76006c7fe7bca5178aea6af1d2e8
treeda13a782c8a276a2e18c1e8d7a47f019e18d337b
parent7d4e2dcf311d3b98421d1f119efe5964cafa32fc
arm64/mm: fix variable 'tag' set but not used

When CONFIG_KASAN_SW_TAGS=n, set_tag() is compiled away. GCC throws a
warning,

mm/kasan/common.c: In function '__kasan_kmalloc':
mm/kasan/common.c:464:5: warning: variable 'tag' set but not used
[-Wunused-but-set-variable]
  u8 tag = 0xff;
     ^~~

Fix it by making __tag_set() a static inline function the same as
arch_kasan_set_tag() in mm/kasan/kasan.h for consistency because there
is a macro in arch/arm64/include/asm/kasan.h,

 #define arch_kasan_set_tag(addr, tag) __tag_set(addr, tag)

However, when CONFIG_DEBUG_VIRTUAL=n and CONFIG_SPARSEMEM_VMEMMAP=y,
page_to_virt() will call __tag_set() with incorrect type of a
parameter, so fix that as well. Also, still let page_to_virt() return
"void *" instead of "const void *", so will not need to add a similar
cast in lowmem_page_address().

Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Will Deacon <will@kernel.org>
arch/arm64/include/asm/memory.h