Hoi Matthias! On 5 April 2017 at 17:56, Matthias Kaehlcke <mka@xxxxxxxxxxxx> wrote: > From: Greg Hackmann <ghackmann@xxxxxxxxxx> > > The current definition of ASM_EXPORT doesn't work properly with clang, > according to https://bugs.llvm.org//show_bug.cgi?id=27250#c3 it relies on > gcc specific behavior. Change the constraint from an intermediate to an > output expression which works with both gcc and clang. > > From: Greg Hackmann <ghackmann@xxxxxxxxxx> > Commit-message-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx> > Signed-off-by: Greg Hackmann <ghackmann@xxxxxxxxxx> > Signed-off-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx> > --- > arch/arm64/crypto/sha1-ce-glue.c | 2 +- > arch/arm64/crypto/sha2-ce-glue.c | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/arch/arm64/crypto/sha1-ce-glue.c b/arch/arm64/crypto/sha1-ce-glue.c > index aefda9868627..c71e94ba0e43 100644 > --- a/arch/arm64/crypto/sha1-ce-glue.c > +++ b/arch/arm64/crypto/sha1-ce-glue.c > @@ -18,7 +18,7 @@ > #include <linux/module.h> > > #define ASM_EXPORT(sym, val) \ > - asm(".globl " #sym "; .set " #sym ", %0" :: "I"(val)); > + asm(".globl " #sym "; .set " #sym ", %c0" :: "I"(val)); > > MODULE_DESCRIPTION("SHA1 secure hash using ARMv8 Crypto Extensions"); > MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>"); > diff --git a/arch/arm64/crypto/sha2-ce-glue.c b/arch/arm64/crypto/sha2-ce-glue.c > index 7cd587564a41..381b5fb2dcb2 100644 > --- a/arch/arm64/crypto/sha2-ce-glue.c > +++ b/arch/arm64/crypto/sha2-ce-glue.c > @@ -18,7 +18,7 @@ > #include <linux/module.h> > > #define ASM_EXPORT(sym, val) \ > - asm(".globl " #sym "; .set " #sym ", %0" :: "I"(val)); > + asm(".globl " #sym "; .set " #sym ", %c0" :: "I"(val)); > > MODULE_DESCRIPTION("SHA-224/SHA-256 secure hash using ARMv8 Crypto Extensions"); > MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>"); I am fine with this change, although I would really like to add a better reference to the commit log. It is *very* difficult to find any documentation regarding non-trivial uses of inline asm constraints, and if %c0 is the correct syntax, surely we can quote something better than a LLVM bugzilla entry? Also, where does the distinction between 'intermediate' vs 'output' expression come from?
