From: Qian Cai cai@lca.pw
[ Upstream commit 7732d20a160c76006c7fe7bca5178aea6af1d2e8 ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- arch/arm64/include/asm/memory.h | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h index b7ba75809751e..fb04f10a78ab3 100644 --- a/arch/arm64/include/asm/memory.h +++ b/arch/arm64/include/asm/memory.h @@ -210,7 +210,11 @@ extern u64 vabits_user; #define __tag_reset(addr) untagged_addr(addr) #define __tag_get(addr) (__u8)((u64)(addr) >> 56) #else -#define __tag_set(addr, tag) (addr) +static inline const void *__tag_set(const void *addr, u8 tag) +{ + return addr; +} + #define __tag_reset(addr) (addr) #define __tag_get(addr) 0 #endif @@ -301,8 +305,8 @@ static inline void *phys_to_virt(phys_addr_t x) #define page_to_virt(page) ({ \ unsigned long __addr = \ ((__page_to_voff(page)) | PAGE_OFFSET); \ - unsigned long __addr_tag = \ - __tag_set(__addr, page_kasan_tag(page)); \ + const void *__addr_tag = \ + __tag_set((void *)__addr, page_kasan_tag(page)); \ ((void *)__addr_tag); \ })