On 2 October 2018 at 15:20, Jason A. Donenfeld <ja...@zx2c4.com> wrote: > The purpose of CONFIG_CPU_32v3 is to avoid ldrh/strh on the RiscPC, > which is pretty much an ARMv4 device, except its bus will choke on the > half-words. The way to make the C compiler not output ldrh/strh is with > -march=armv3, which doesn't support them in the ISA. However, this > prevents certain cryptography code from working that uses instructions > like umull. Fortunately there's also -march=armv3m that does support > those, making it possible to continue assembling optimized cryptography > routines for our beloved RiscPC. > > Signed-off-by: Jason A. Donenfeld <ja...@zx2c4.com> > Cc: Ard Biesheuvel <ard.biesheu...@linaro.org> > Cc: Russell King <li...@armlinux.org.uk> > Cc: Arnd Bergmann <a...@arndb.de>
Acked-by: Ard Biesheuvel <ard.biesheu...@linaro.org> > --- > arch/arm/Makefile | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/arm/Makefile b/arch/arm/Makefile > index d1516f85f25d..7fd4bcaf0721 100644 > --- a/arch/arm/Makefile > +++ b/arch/arm/Makefile > @@ -74,7 +74,7 @@ endif > arch-$(CONFIG_CPU_32v5) =-D__LINUX_ARM_ARCH__=5 $(call > cc-option,-march=armv5te,-march=armv4t) > arch-$(CONFIG_CPU_32v4T) =-D__LINUX_ARM_ARCH__=4 -march=armv4t > arch-$(CONFIG_CPU_32v4) =-D__LINUX_ARM_ARCH__=4 -march=armv4 > -arch-$(CONFIG_CPU_32v3) =-D__LINUX_ARM_ARCH__=3 -march=armv3 > +arch-$(CONFIG_CPU_32v3) =-D__LINUX_ARM_ARCH__=3 -march=armv3m > > # Evaluate arch cc-option calls now > arch-y := $(arch-y) > -- > 2.19.0 >
