On Mon, Jul 8, 2019 at 1:31 PM Arnd Bergmann <a...@arndb.de> wrote: > > llvm gets confused by inline asm with .rep directives, which > can lead to miscalculating the number of instructions inside it, > and in turn lead to an overflow for relative address calculation: > > /tmp/cfi_cmdset_0002-539a47.s: Assembler messages: > /tmp/cfi_cmdset_0002-539a47.s:11288: Error: bad immediate value for offset > (4100) > /tmp/cfi_cmdset_0002-539a47.s:11289: Error: bad immediate value for offset > (4100) > > This might be fixed in future clang versions, but is not hard > to work around by just replacing the .rep with a series of > eight unrolled nop instructions.
Seems like this is fixable on the Clang side as well. For now, thanks for the patch. Acked-by: Nick Desaulniers <ndesaulni...@google.com> > > Link: https://bugs.llvm.org/show_bug.cgi?id=42539 > https://godbolt.org/z/DSM2Jy ^ prefix with Link: on both lines? also, linking to clang trunk will become stale once the issue is fixed. When possible, link to a release version of clang that's not prone to change over time. > Signed-off-by: Arnd Bergmann <a...@arndb.de> > --- > arch/arm/include/asm/mtd-xip.h | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/arch/arm/include/asm/mtd-xip.h b/arch/arm/include/asm/mtd-xip.h > index dfcef0152e3d..5ad0325604e4 100644 > --- a/arch/arm/include/asm/mtd-xip.h > +++ b/arch/arm/include/asm/mtd-xip.h > @@ -15,6 +15,8 @@ > #include <mach/mtd-xip.h> > > /* fill instruction prefetch */ > -#define xip_iprefetch() do { asm volatile (".rep 8; nop; .endr"); } > while (0) > +#define xip_iprefetch() do { > \ > + asm volatile ("nop; nop; nop; nop; nop; nop; nop; nop;"); \ > +} while (0) \ -- Thanks, ~Nick Desaulniers
