[PATCH 1/2] lib/mpi: avoid assembler warning

[PATCH 1/2] lib/mpi: avoid assembler warning

[Arnd Bergmann]

A wrapper around the umull assembly instruction might reuse
the input register as an output, which is undefined on
some ARM machines, as pointed out by this assembler warning:

  CC      lib/mpi/generic_mpih-mul1.o
/tmp/ccxJuxIy.s: Assembler messages:
/tmp/ccxJuxIy.s:53: rdhi, rdlo and rm must all be different
  CC      lib/mpi/generic_mpih-mul2.o
/tmp/ccI0scAD.s: Assembler messages:
/tmp/ccI0scAD.s:53: rdhi, rdlo and rm must all be different
  CC      lib/mpi/generic_mpih-mul3.o
/tmp/ccMvVQcp.s: Assembler messages:
/tmp/ccMvVQcp.s:53: rdhi, rdlo and rm must all be different

This changes the constraints to force different registers to
be used as output.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 lib/mpi/longlong.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/mpi/longlong.h b/lib/mpi/longlong.h
index b90e255c2a68..93336502af08 100644
--- a/lib/mpi/longlong.h
+++ b/lib/mpi/longlong.h
@@ -216,7 +216,7 @@ extern UDItype __udiv_qrnnd(UDItype *, UDItype, UDItype, UDItype);
 	__asm__ ("%@ Inlined umul_ppmm\n" \
 		"umull %r1, %r0, %r2, %r3" \
 	: "=&r" ((USItype)(xh)), \
-			"=r" ((USItype)(xl)) \
+			"=&r" ((USItype)(xl)) \
 	: "r" ((USItype)(a)), \
 			"r" ((USItype)(b)) \
 	: "r0", "r1")
-- 
2.7.0

[PATCH 2/2] lib/mpi: use "static inline" instead of "extern inline"

[Arnd Bergmann]

When we use CONFIG_PROFILE_ALL_BRANCHES, every 'if()' introduces
a static variable, but that is not allowed in 'extern inline'
functions:

mpi-inline.h:116:204: warning: '______f' is static but declared in inline function 'mpihelp_sub' which is not static
mpi-inline.h:113:184: warning: '______f' is static but declared in inline function 'mpihelp_sub' which is not static
mpi-inline.h:70:184: warning: '______f' is static but declared in inline function 'mpihelp_add' which is not static
mpi-inline.h:56:204: warning: '______f' is static but declared in inline function 'mpihelp_add_1' which is not static

This changes the MPI code to use 'static inline' instead, to get
rid of hundreds of warnings.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 lib/mpi/mpi-inline.h   | 2 +-
 lib/mpi/mpi-internal.h | 8 ++++----
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/lib/mpi/mpi-inline.h b/lib/mpi/mpi-inline.h
index e2b39852b30a..c245ea31f785 100644
--- a/lib/mpi/mpi-inline.h
+++ b/lib/mpi/mpi-inline.h
@@ -30,7 +30,7 @@
 #define G10_MPI_INLINE_H
 
 #ifndef G10_MPI_INLINE_DECL
-#define G10_MPI_INLINE_DECL  extern inline
+#define G10_MPI_INLINE_DECL  static inline
 #endif
 
 G10_MPI_INLINE_DECL mpi_limb_t
diff --git a/lib/mpi/mpi-internal.h b/lib/mpi/mpi-internal.h
index c65dd1bff45a..7eceeddb3fb8 100644
--- a/lib/mpi/mpi-internal.h
+++ b/lib/mpi/mpi-internal.h
@@ -168,19 +168,19 @@ void mpi_rshift_limbs(MPI a, unsigned int count);
 int mpi_lshift_limbs(MPI a, unsigned int count);
 
 /*-- mpihelp-add.c --*/
-mpi_limb_t mpihelp_add_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
+static inline mpi_limb_t mpihelp_add_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
 			 mpi_size_t s1_size, mpi_limb_t s2_limb);
 mpi_limb_t mpihelp_add_n(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
 			 mpi_ptr_t s2_ptr, mpi_size_t size);
-mpi_limb_t mpihelp_add(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr, mpi_size_t s1_size,
+static inline mpi_limb_t mpihelp_add(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr, mpi_size_t s1_size,
 		       mpi_ptr_t s2_ptr, mpi_size_t s2_size);
 
 /*-- mpihelp-sub.c --*/
-mpi_limb_t mpihelp_sub_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
+static inline mpi_limb_t mpihelp_sub_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
 			 mpi_size_t s1_size, mpi_limb_t s2_limb);
 mpi_limb_t mpihelp_sub_n(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
 			 mpi_ptr_t s2_ptr, mpi_size_t size);
-mpi_limb_t mpihelp_sub(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr, mpi_size_t s1_size,
+static inline mpi_limb_t mpihelp_sub(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr, mpi_size_t s1_size,
 		       mpi_ptr_t s2_ptr, mpi_size_t s2_size);
 
 /*-- mpihelp-cmp.c --*/
-- 
2.7.0

Re: [PATCH 1/2] lib/mpi: avoid assembler warning

[Herbert Xu]

On Fri, Feb 26, 2016 at 01:46:26PM +0100, Arnd Bergmann wrote:
> A wrapper around the umull assembly instruction might reuse
> the input register as an output, which is undefined on
> some ARM machines, as pointed out by this assembler warning:
> 
>   CC      lib/mpi/generic_mpih-mul1.o
> /tmp/ccxJuxIy.s: Assembler messages:
> /tmp/ccxJuxIy.s:53: rdhi, rdlo and rm must all be different
>   CC      lib/mpi/generic_mpih-mul2.o
> /tmp/ccI0scAD.s: Assembler messages:
> /tmp/ccI0scAD.s:53: rdhi, rdlo and rm must all be different
>   CC      lib/mpi/generic_mpih-mul3.o
> /tmp/ccMvVQcp.s: Assembler messages:
> /tmp/ccMvVQcp.s:53: rdhi, rdlo and rm must all be different
> 
> This changes the constraints to force different registers to
> be used as output.
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Both applied.
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt