Hi Andy, On Fri, Mar 17, 2023 at 11:35:38AM +0000, Andy Chiu wrote: > From: Guo Ren <guoren@xxxxxxxxxxxxxxxxx> > > This patch adds a config which enables vector feature from the kernel > space. > > Support for RISC_V_ISA_V is limited to GNU-assembler for now, as LLVM > has not acquired the functionality to selectively change the arch option > in assembly code. This is still under review at > https://reviews.llvm.org/D123515 > > Signed-off-by: Guo Ren <guoren@xxxxxxxxxxxxxxxxx> > Co-developed-by: Greentime Hu <greentime.hu@xxxxxxxxxx> > Signed-off-by: Greentime Hu <greentime.hu@xxxxxxxxxx> > Suggested-by: Vineet Gupta <vineetg@xxxxxxxxxxxx> > Suggested-by: Atish Patra <atishp@xxxxxxxxxxxxxx> > Co-developed-by: Andy Chiu <andy.chiu@xxxxxxxxxx> > Signed-off-by: Andy Chiu <andy.chiu@xxxxxxxxxx> > --- > arch/riscv/Kconfig | 20 ++++++++++++++++++++ > arch/riscv/Makefile | 6 +++++- > 2 files changed, 25 insertions(+), 1 deletion(-) > > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig > index c736dc8e2593..bf9aba2f2811 100644 > --- a/arch/riscv/Kconfig > +++ b/arch/riscv/Kconfig > @@ -436,6 +436,26 @@ config RISCV_ISA_SVPBMT > > If you don't know what to do here, say Y. > > +config TOOLCHAIN_HAS_V > + bool > + default y > + depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64iv) > + depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32iv) > + depends on LLD_VERSION >= 140000 || LD_VERSION >= 23800 > + depends on AS_IS_GNU Consider hoisting this 'depends on AS_IS_GNU' into its own configuration option, as the same dependency is present in CONFIG_TOOLCHAIN_HAS_ZBB for the exact same reason, with no comment as to why. By having a shared dependency configuration option, we can easily update it when that change is merged into LLVM proper and gain access to the current and future options that depend on it. I imagine something like: config AS_HAS_OPTION_ARCH bool default y # https://reviews.llvm.org/D123515 depends on AS_IS_GNU config TOOLCHAIN_HAS_ZBB bool default y depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64ima_zbb) depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32ima_zbb) depends on LLD_VERSION >= 150000 || LD_VERSION >= 23900 depends on AS_HAS_OPTION_ARCH config TOOLCHAIN_HAS_V bool default y depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64iv) depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32iv) depends on LLD_VERSION >= 140000 || LD_VERSION >= 23800 depends on AS_HAS_OPTION_ARCH It would be nice if it was a hard error for LLVM like GCC so that we could just dynamically check support via as-instr but a version check is not the end of the world when we know the versions. $ cat test.s .option arch, +v $ cat test-invalid.s .option arch, +vv $ clang --target=riscv64-linux-gnu -c -o /dev/null test.s test.s:1:13: warning: unknown option, expected 'push', 'pop', 'rvc', 'norvc', 'relax' or 'norelax' .option arch, +v ^ $ clang --target=riscv64-linux-gnu -c -o /dev/null test-invalid.s test-invalid.s:1:13: warning: unknown option, expected 'push', 'pop', 'rvc', 'norvc', 'relax' or 'norelax' .option arch, +vv ^ $ riscv64-linux-gcc -c -o /dev/null test.s $ riscv64-linux-gcc -c -o /dev/null test-invalid.s test-invalid.s: Assembler messages: test-invalid.s:1: Error: unknown ISA extension `vv' in .option arch `+vv' As a side note, 'bool + default y' is the same as 'def_bool y', if you wanted to same some space. Cheers, Nathan > +config RISCV_ISA_V > + bool "VECTOR extension support" > + depends on TOOLCHAIN_HAS_V > + depends on FPU > + select DYNAMIC_SIGFRAME > + default y > + help > + Say N here if you want to disable all vector related procedure > + in the kernel. > + > + If you don't know what to do here, say Y. > + > config TOOLCHAIN_HAS_ZBB > bool > default y > diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile > index 6203c3378922..84a50cfaedf9 100644 > --- a/arch/riscv/Makefile > +++ b/arch/riscv/Makefile > @@ -56,6 +56,7 @@ 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) := $(riscv-march-y)c > +riscv-march-$(CONFIG_RISCV_ISA_V) := $(riscv-march-y)v > > # Newer binutils versions default to ISA spec version 20191213 which moves some > # instructions from the I extension to the Zicsr and Zifencei extensions. > @@ -65,7 +66,10 @@ riscv-march-$(toolchain-need-zicsr-zifencei) := $(riscv-march-y)_zicsr_zifencei > # Check if the toolchain supports Zihintpause extension > riscv-march-$(CONFIG_TOOLCHAIN_HAS_ZIHINTPAUSE) := $(riscv-march-y)_zihintpause > > -KBUILD_CFLAGS += -march=$(subst fd,,$(riscv-march-y)) > +# Remove F,D,V from isa string for all. Keep extensions between "fd" and "v" by > +# keep non-v and multi-letter extensions out with the filter ([^v_]*) > +KBUILD_CFLAGS += -march=$(shell echo $(riscv-march-y) | sed -E 's/(rv32ima|rv64ima)fd([^v_]*)v?/\1\2/') > + > KBUILD_AFLAGS += -march=$(riscv-march-y) > > KBUILD_CFLAGS += -mno-save-restore > -- > 2.17.1 >
