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SubjectRe: [PATCH] riscv: fix build with binutils 2.38
On 31.03.2022 12:32:47, Marc Kleine-Budde wrote:
> On 26.01.2022 18:14:42, Aurelien Jarno 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@vger.kernel.org # 4.15+
> > Cc: Kito Cheng <kito.cheng@gmail.com>
> > Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
> > ---
> > 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)
>
> I'm on current linus/master, this change breaks on current Debian
> testing with:
>
> | make: Leaving directory 'linux'
> | SYNC include/config/auto.conf.cmd
> | GEN Makefile
> | GEN Makefile
> | CC scripts/mod/empty.o
> | CHECK linux/scripts/mod/empty.c
^^^^^
It's actually "sparse" that breaks

> | invalid argument to '-march': '_zicsr_zifencei'

| $ sparse --version
| 0.6.4 (Debian: 0.6.4-2)

Compiling without "C=1" for now.

regards,
Marc

--
Pengutronix e.K. | Marc Kleine-Budde |
Embedded Linux | https://www.pengutronix.de |
Vertretung West/Dortmund | Phone: +49-231-2826-924 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
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