| Message ID | 1456490794-1034544-1-git-send-email-arnd@arndb.de (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Herbert Xu |
| Headers | show |
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.
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")
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(-)