Unverified Commit b8c86872 authored by Conor Dooley's avatar Conor Dooley Committed by Palmer Dabbelt
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riscv: fix detection of toolchain Zicbom support 



It is not sufficient to check if a toolchain supports a particular
extension without checking if the linker supports that extension too.
For example, Clang 15 supports Zicbom but GNU bintutils 2.35.2 does
not, leading build errors like so:

riscv64-linux-gnu-ld: -march=rv64i2p0_m2p0_a2p0_c2p0_zicbom1p0_zihintpause2p0: Invalid or unknown z ISA extension: 'zicbom'

Convert CC_HAS_ZICBOM to TOOLCHAIN_HAS_ZICBOM & check if the linker
also supports Zicbom.

Reported-by: default avatarKevin Hilman <khilman@baylibre.com>
Link: https://github.com/ClangBuiltLinux/linux/issues/1714
Link: https://storage.kernelci.org/next/master/next-20220920/riscv/defconfig+CONFIG_EFI=n/clang-16/logs/kernel.log


Fixes: 1631ba12 ("riscv: Add support for non-coherent devices using zicbom extension")
Signed-off-by: default avatarConor Dooley <conor.dooley@microchip.com>
Reviewed-by: default avatarHeiko Stuebner <heiko@sntech.de>
Reviewed-by: default avatarNathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20221006173520.1785507-2-conor@kernel.org


[Palmer: Check for ld-2.38, not 2.39, as 2.38 no longer errors.]
Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent 568035b0

arch/riscv/Kconfig

+6 −4
Original line number Diff line number Diff line
@@ -401,14 +401,16 @@ config RISCV_ISA_SVPBMT 


	   If you don't know what to do here, say Y.



config CC_HAS_ZICBOM

config TOOLCHAIN_HAS_ZICBOM

	bool

	default y if 64BIT && $(cc-option,-mabi=lp64 -march=rv64ima_zicbom)

	default y if 32BIT && $(cc-option,-mabi=ilp32 -march=rv32ima_zicbom)

	default y

	depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64ima_zicbom)

	depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32ima_zicbom)

	depends on LLD_VERSION >= 150000 || LD_VERSION >= 23800



config RISCV_ISA_ZICBOM

	bool "Zicbom extension support for non-coherent DMA operation"

	depends on CC_HAS_ZICBOM

	depends on TOOLCHAIN_HAS_ZICBOM

	depends on !XIP_KERNEL && MMU

	select RISCV_DMA_NONCOHERENT

	select RISCV_ALTERNATIVE

arch/riscv/Makefile

+1 −2
Original line number Diff line number Diff line
@@ -57,8 +57,7 @@ toolchain-need-zicsr-zifencei := $(call cc-option-yn, -march=$(riscv-march-y)_zi 
riscv-march-$(toolchain-need-zicsr-zifencei) := $(riscv-march-y)_zicsr_zifencei



# Check if the toolchain supports Zicbom extension

toolchain-supports-zicbom := $(call cc-option-yn, -march=$(riscv-march-y)_zicbom)

riscv-march-$(toolchain-supports-zicbom) := $(riscv-march-y)_zicbom

riscv-march-$(CONFIG_TOOLCHAIN_HAS_ZICBOM) := $(riscv-march-y)_zicbom



# Check if the toolchain supports Zihintpause extension

toolchain-supports-zihintpause := $(call cc-option-yn, -march=$(riscv-march-y)_zihintpause)