* [PATCH] asm-generic: fix variable 'p4d' set but not used
@ 2019-08-02 19:41 Qian Cai
2019-08-06 10:45 ` Kirill A. Shutemov
2019-08-06 14:39 ` Jason Gunthorpe
0 siblings, 2 replies; 4+ messages in thread
From: Qian Cai @ 2019-08-02 19:41 UTC (permalink / raw)
To: akpm
Cc: arnd, kirill.shutemov, mhocko, linux-mm, linux-arch,
linux-kernel, Qian Cai
GCC throws a warning on an arm64 system since the 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.
Signed-off-by: Qian Cai <cai@lca.pw>
---
include/asm-generic/5level-fixup.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/asm-generic/5level-fixup.h b/include/asm-generic/5level-fixup.h
index bb6cb347018c..2c3e14c924b6 100644
--- a/include/asm-generic/5level-fixup.h
+++ b/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)
--
1.8.3.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] asm-generic: fix variable 'p4d' set but not used
2019-08-02 19:41 [PATCH] asm-generic: fix variable 'p4d' set but not used Qian Cai
@ 2019-08-06 10:45 ` Kirill A. Shutemov
2019-08-06 14:39 ` Jason Gunthorpe
1 sibling, 0 replies; 4+ messages in thread
From: Kirill A. Shutemov @ 2019-08-06 10:45 UTC (permalink / raw)
To: Qian Cai
Cc: akpm, arnd, kirill.shutemov, mhocko, linux-mm, linux-arch, linux-kernel
On Fri, Aug 02, 2019 at 03:41:22PM -0400, Qian Cai wrote:
> GCC throws a warning on an arm64 system since the 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.
>
> Signed-off-by: Qian Cai <cai@lca.pw>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
--
Kirill A. Shutemov
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] asm-generic: fix variable 'p4d' set but not used
2019-08-02 19:41 [PATCH] asm-generic: fix variable 'p4d' set but not used Qian Cai
2019-08-06 10:45 ` Kirill A. Shutemov
@ 2019-08-06 14:39 ` Jason Gunthorpe
2019-08-06 20:51 ` Andrew Morton
1 sibling, 1 reply; 4+ messages in thread
From: Jason Gunthorpe @ 2019-08-06 14:39 UTC (permalink / raw)
To: Qian Cai
Cc: akpm, arnd, kirill.shutemov, mhocko, linux-mm, linux-arch, linux-kernel
On Fri, Aug 02, 2019 at 03:41:22PM -0400, Qian Cai wrote:
> GCC throws a warning on an arm64 system since the 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.
>
> Signed-off-by: Qian Cai <cai@lca.pw>
> include/asm-generic/5level-fixup.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/asm-generic/5level-fixup.h b/include/asm-generic/5level-fixup.h
> index bb6cb347018c..2c3e14c924b6 100644
> +++ b/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)
Yuk, how about a static inline instead?
Jason
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] asm-generic: fix variable 'p4d' set but not used
2019-08-06 14:39 ` Jason Gunthorpe
@ 2019-08-06 20:51 ` Andrew Morton
0 siblings, 0 replies; 4+ messages in thread
From: Andrew Morton @ 2019-08-06 20:51 UTC (permalink / raw)
To: Jason Gunthorpe
Cc: Qian Cai, arnd, kirill.shutemov, mhocko, linux-mm, linux-arch,
linux-kernel
On Tue, 6 Aug 2019 11:39:04 -0300 Jason Gunthorpe <jgg@ziepe.ca> wrote:
> On Fri, Aug 02, 2019 at 03:41:22PM -0400, Qian Cai wrote:
> > GCC throws a warning on an arm64 system since the 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.
> >
> > Signed-off-by: Qian Cai <cai@lca.pw>
> > include/asm-generic/5level-fixup.h | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/include/asm-generic/5level-fixup.h b/include/asm-generic/5level-fixup.h
> > index bb6cb347018c..2c3e14c924b6 100644
> > +++ b/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)
>
> Yuk, how about a static inline instead?
Yes. With the appropriate `#ifndef __ASSEMBLY__' to avoid powerpc
build errors?
^ permalink raw reply [flat|nested] 4+ messages in thread
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2019-08-02 19:41 [PATCH] asm-generic: fix variable 'p4d' set but not used Qian Cai
2019-08-06 10:45 ` Kirill A. Shutemov
2019-08-06 14:39 ` Jason Gunthorpe
2019-08-06 20:51 ` Andrew Morton
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