The patch titled
Subject: include/asm-generic/5level-fixup.h: fix variable 'p4d' set but not used
has been added to the -mm tree. Its filename is
asm-generic-fix-variable-p4d-set-but-not-used.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/asm-generic-fix-variable-p4d-set-but-not-used.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/asm-generic-fix-variable-p4d-set-but-not-used.patch
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------------------------------------------------------
From: Qian Cai <cai@xxxxxx>
Subject: include/asm-generic/5level-fixup.h: fix variable 'p4d' set but not used
GCC throws a warning on an arm64 system since commit 9849a5697d3d ("arch,
mm: convert all architectures to use 5level-fixup.h"),
mm/kasan/init.c: In function 'kasan_free_p4d':
mm/kasan/init.c:344:9: warning: variable 'p4d' set but not used
[-Wunused-but-set-variable]
p4d_t *p4d;
^~~
because p4d_none() in "5level-fixup.h" is compiled away while it is a
static inline function in "pgtable-nopud.h". However, if converted
p4d_none() to a static inline there, powerpc would be unhappy as it
reads those in assembler language in
"arch/powerpc/include/asm/book3s/64/pgtable.h",
./include/asm-generic/5level-fixup.h: Assembler messages:
./include/asm-generic/5level-fixup.h:20: Error: unrecognized opcode:
`static'
./include/asm-generic/5level-fixup.h:21: Error: junk at end of line,
first unrecognized character is `{'
./include/asm-generic/5level-fixup.h:22: Error: unrecognized opcode:
`return'
./include/asm-generic/5level-fixup.h:23: Error: junk at end of line,
first unrecognized character is `}'
./include/asm-generic/5level-fixup.h:25: Error: unrecognized opcode:
`static'
./include/asm-generic/5level-fixup.h:26: Error: junk at end of line,
first unrecognized character is `{'
./include/asm-generic/5level-fixup.h:27: Error: unrecognized opcode:
`return'
./include/asm-generic/5level-fixup.h:28: Error: junk at end of line,
first unrecognized character is `}'
./include/asm-generic/5level-fixup.h:30: Error: unrecognized opcode:
`static'
./include/asm-generic/5level-fixup.h:31: Error: junk at end of line,
first unrecognized character is `{'
./include/asm-generic/5level-fixup.h:32: Error: unrecognized opcode:
`return'
./include/asm-generic/5level-fixup.h:33: Error: junk at end of line,
first unrecognized character is `}'
make[2]: *** [scripts/Makefile.build:375:
arch/powerpc/kvm/book3s_hv_rmhandlers.o] Error 1
Fix it by reference the variable in the macro instead.
Link: http://lkml.kernel.org/r/1564774882-22926-1-git-send-email-cai@xxxxxx
Signed-off-by: Qian Cai <cai@xxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/asm-generic/5level-fixup.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/include/asm-generic/5level-fixup.h~asm-generic-fix-variable-p4d-set-but-not-used
+++ a/include/asm-generic/5level-fixup.h
@@ -19,7 +19,7 @@
#define p4d_alloc(mm, pgd, address) (pgd)
#define p4d_offset(pgd, start) (pgd)
-#define p4d_none(p4d) 0
+#define p4d_none(p4d) ((void)p4d, 0)
#define p4d_bad(p4d) 0
#define p4d_present(p4d) 1
#define p4d_ERROR(p4d) do { } while (0)
_
Patches currently in -mm which might be from cai@xxxxxx are
asm-generic-fix-wtype-limits-compiler-warnings.patch
asm-generic-fix-wtype-limits-compiler-warnings-v2.patch
mm-memcontrol-fix-use-after-free-in-mem_cgroup_iter-fix.patch
asm-generic-fix-variable-p4d-set-but-not-used.patch
writeback-fix-wstringop-truncation-warnings.patch
