On Thu, Feb 10, 2022 at 09:40:22AM -0800, Palmer Dabbelt wrote: > On Wed, 26 Jan 2022 09:14:42 PST (-0800), aurelien@xxxxxxxxxxx wrote: > > From version 2.38, binutils default to ISA spec version 20191213. This > > means that the csr read/write (csrr*/csrw*) instructions and fence.i > > instruction has separated from the `I` extension, become two standalone > > extensions: Zicsr and Zifencei. As the kernel uses those instruction, > > this causes the following build failure: > > > > CC arch/riscv/kernel/vdso/vgettimeofday.o > > <<BUILDDIR>>/arch/riscv/include/asm/vdso/gettimeofday.h: Assembler messages: > > <<BUILDDIR>>/arch/riscv/include/asm/vdso/gettimeofday.h:71: Error: unrecognized opcode `csrr a5,0xc01' > > <<BUILDDIR>>/arch/riscv/include/asm/vdso/gettimeofday.h:71: Error: unrecognized opcode `csrr a5,0xc01' > > <<BUILDDIR>>/arch/riscv/include/asm/vdso/gettimeofday.h:71: Error: unrecognized opcode `csrr a5,0xc01' > > <<BUILDDIR>>/arch/riscv/include/asm/vdso/gettimeofday.h:71: Error: unrecognized opcode `csrr a5,0xc01' > > > > The fix is to specify those extensions explicitely in -march. However as > > older binutils version do not support this, we first need to detect > > that. > > > > Cc: stable@xxxxxxxxxxxxxxx # 4.15+ > > Cc: Kito Cheng <kito.cheng@xxxxxxxxx> > > Signed-off-by: Aurelien Jarno <aurelien@xxxxxxxxxxx> > > --- > > arch/riscv/Makefile | 6 ++++++ > > 1 file changed, 6 insertions(+) > > > > diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile > > index 8a107ed18b0d..7d81102cffd4 100644 > > --- a/arch/riscv/Makefile > > +++ b/arch/riscv/Makefile > > @@ -50,6 +50,12 @@ riscv-march-$(CONFIG_ARCH_RV32I) := rv32ima > > riscv-march-$(CONFIG_ARCH_RV64I) := rv64ima > > riscv-march-$(CONFIG_FPU) := $(riscv-march-y)fd > > riscv-march-$(CONFIG_RISCV_ISA_C) := $(riscv-march-y)c > > + > > +# Newer binutils versions default to ISA spec version 20191213 which moves some > > +# instructions from the I extension to the Zicsr and Zifencei extensions. > > +toolchain-need-zicsr-zifencei := $(call cc-option-yn, -march=$(riscv-march-y)_zicsr_zifencei) > > +riscv-march-$(toolchain-need-zicsr-zifencei) := $(riscv-march-y)_zicsr_zifencei > > + > > KBUILD_CFLAGS += -march=$(subst fd,,$(riscv-march-y)) > > KBUILD_AFLAGS += -march=$(riscv-march-y) > > Thanks, this is on fixes. It's CC stable, but doesn't have a "Fixes" tag -- > I did that on purpose as this isn't really fixing a bug in Linux so I'm not > sure it's right to point at a particular patch, but I'm not sure how that > will play with the stable tree. I will backport it as far back as it easily goes to, and then forget about it :) If you have a Fixes: tag, and it doesn't properly backport that far, then you will get a "FAILED:" email notifying you about it. hope that helps explain things, greg k-h
