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riscv: fix build with binutils 2.38

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commit 6df2a016c0c8a3d0933ef33dd192ea6606b115e3 upstream.

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.

Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Tested-by: Alexandre Ghiti <alexandre.ghiti@canonical.com>
Cc: stable@vger.kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[Conor: converted to the 4.19 style of march string generation]
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
This commit is contained in:
Aurelien Jarno 2022-01-26 18:14:42 +01:00 committed by Greg Kroah-Hartman
parent c97f6d528c
commit c00cbba504
1 changed files with 9 additions and 2 deletions
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11
arch/riscv/Makefile
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@ -49,9 +49,16 @@ ifeq ($(CONFIG_RISCV_ISA_C),y)
KBUILD_ARCH_C = c
endif
KBUILD_AFLAGS += -march=$(KBUILD_MARCH)$(KBUILD_ARCH_A)fd$(KBUILD_ARCH_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)
ifeq ($(toolchain-need-zicsr-zifencei),y)
KBUILD_ARCH_ZISCR_ZIFENCEI = _zicsr_zifencei
endif
KBUILD_CFLAGS += -march=$(KBUILD_MARCH)$(KBUILD_ARCH_A)$(KBUILD_ARCH_C)
KBUILD_AFLAGS += -march=$(KBUILD_MARCH)$(KBUILD_ARCH_A)fd$(KBUILD_ARCH_C)$(KBUILD_ARCH_ZISCR_ZIFENCEI)
KBUILD_CFLAGS += -march=$(KBUILD_MARCH)$(KBUILD_ARCH_A)$(KBUILD_ARCH_C)$(KBUILD_ARCH_ZISCR_ZIFENCEI)
KBUILD_CFLAGS += -mno-save-restore
KBUILD_CFLAGS += -DCONFIG_PAGE_OFFSET=$(CONFIG_PAGE_OFFSET)