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 <[email protected]>
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 <[email protected]>
Reviewed-by: Heiko Stuebner <[email protected]>
Reviewed-by: Nathan Chancellor <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
[Palmer: Check for ld-2.38, not 2.39, as 2.38 no longer errors.]
Signed-off-by: Palmer Dabbelt <[email protected]>

0 files changed, 0 insertions, 0 deletions