Hi, On 2022-03-31 12:51, Marc Kleine-Budde wrote: > Cc += linux-sparse, Uwe, Luc Van Oostenryck > > tl;dr: > > A recent change in the kernel regarding the riscv -march handling breaks > current sparse. > > On 31.03.2022 12:39:14, Marc Kleine-Budde wrote: > > 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@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) > > > > > > 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) I confirm the issue. To make things clear, it's not a Makefile issue, sparse get passed the correct -march=rv64ima_zicsr_zifencei value, and only display the part it can't parse. On the medium/long term, sparse should get fixed to support those extensions. On the short term, we need to find a way to get different flags for sparse than for as/gcc. -- Aurelien Jarno GPG: 4096R/1DDD8C9B aurelien@xxxxxxxxxxx http://www.aurel32.net
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