From: Jason@zx2c4.com (Jason A. Donenfeld) Date: Tue, 2 Oct 2018 15:20:26 +0200 Subject: [PATCH] ARM: makefile: use ARMv3M mode for RiscPC In-Reply-To: References: Message-ID: <20181002132026.14931-1-Jason@zx2c4.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 Cc: Ard Biesheuvel Cc: Russell King Cc: Arnd Bergmann --- 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