Hoi Ard! El Wed, Apr 05, 2017 at 06:08:37PM +0100 Ard Biesheuvel ha dit: > 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? To be honest assembly is not really my area of expertise and I relayed the information from the LLVM bug. The link to the gcc doc on x86(!) operand modifiers posted by Robin Murphy (thanks!) should be helpful to provide a more accurate commit message. Thanks Matthias
