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: Kevin 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: 1631ba1259d6 ("riscv: Add support for non-coherent devices using zicbom extension")
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Nathan 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: Palmer Dabbelt <palmer@rivosinc.com>

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index ed66c31e465590f94c447a1fee2b590e237073e2..4c6a09f05348c39ffda999ca57be04d8f16026e8 100644 (file)
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -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

diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile
index 3fa8ef336822438570a95b613d7d89d2ed8872ce..3607d38edb4f3b9e7505501be6dd9a91886642d2 100644 (file)
--- a/arch/riscv/Makefile
+++ b/arch/riscv/Makefile
@@ -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)