| Message ID | 7adb27a7c56dd06d782710a5f684ea6263900f98.1684949268.git.falcon@tinylab.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | tools/nolibc: riscv: Add full rv32 support | expand |
On 2023-05-25 01:50:57+0800, Zhangjin Wu wrote: > both riscv64 and riscv32 have the same ARCH value, it is riscv, the > default defconfig enables 64bit, to support riscv32, let's allow pass > "ARCH=riscv32" or "ARCH=riscv CONFIG_32BIT=1" to customize riscv32 > setting. What's the advantage of doing CONFIG_32BIT? For i386/x86_64, arm/arm64 it's not necessary either. (Let's ignore the "x86" case) If for riscv the "normal" version is riscv64 then adding a new "riscv32" that works the same as the other architectures seems nicer and easier.
Hi, Thomas > On 2023-05-25 01:50:57+0800, Zhangjin Wu wrote: > > both riscv64 and riscv32 have the same ARCH value, it is riscv, the > > default defconfig enables 64bit, to support riscv32, let's allow pass > > "ARCH=riscv32" or "ARCH=riscv CONFIG_32BIT=1" to customize riscv32 > > setting. > > What's the advantage of doing CONFIG_32BIT? For i386/x86_64, arm/arm64 > it's not necessary either. > (Let's ignore the "x86" case) > Very good question, thanks. This requirement may happen on mips, loongarch and even powerpc too, both x86 and arm are just the 'exception'. It is 'designed' as a temp flag/variable to specifiy that current arch is riscv32, not riscv64, of course, we can use something like this or even use a meaningless 't' variable: # Allow pass ARCH=riscv|riscv32|riscv64, riscv implies riscv64 ifneq ($(findstring xriscv,x$(ARCH)),) riscv32 := $(if $(findstring riscv32x,$(ARCH)x),1) override ARCH := riscv endif Using CONFIG_32BIT instead of riscv32 has some extra considerations: * Using it in command line is a 'side effect', if it is a meaningless variable, we will not use it for we can not remember it, here use it as a choice, riscv32 is enough, we can simply remove this comment from the commit message. * The architectures like riscv, mips, loongarch share the same source code tree between 32bit and 64bit and even 128bit in the future, x86 and arm just not do so. The ARCH specified here differs from the one to kernel make, we should provide a flag/variable or anther ARCH variant to show the difference, _ARCH or XARCH have been used in my local patch. CONFIG_32BIT is meaningful to reflect the difference, even for future, we can use the same thing CONFIG_64BIT, CONFIG_128BIT, so simply BITS=32, BITS=64, BITS=128, but that is hard to be used as a oneline condition statement (although we can use something like findstring). $(if $(findstring x32y,x$(BITS)y),something whatevever) v.s. $(if $(CONFIG_32BIT),something whatevever) If not use a tmp flag/variable, this works too, but duplicated :-) $(if $(findstring xriscv32y,x$(ARCH)y),something whatevever) * We are able to auto detect this config from include/config/auto.conf, there will be something like CONFIG_32BIT=y there. we did use such auto detect logic in my local patch, but it has some issues if we want a riscv64 build after we did a riscv32 config if we only pass ARCH=riscv, so, I just removed that logic but reserved the pontential for future. > If for riscv the "normal" version is riscv64 then adding a new "riscv32" that > works the same as the other architectures seems nicer and easier. > The complexity here is what just explained above: The ARCH specified here differs from the one to kernel make. It is ok to add riscv32 like the other architectures as following: ifeq ($(ARCH),riscv32) _ARCH := riscv else _ARCH := $(ARCH) endif IMAGE_riscv32 = arch/riscv/boot/Image DEFCONFIG_riscv32 = rv32_defconfig QEMU_ARCH_riscv32 = riscv32 QEMU_ARGS_riscv32 = -M virt -append "console=ttyS0 panic=-1 $(TEST:%=NOLIBC_TEST=%)" CFLAGS_riscv32 = -march=rv32im -mabi=ilp32 And all of the other 'ARCH' variables passed to kernel 'make' should be changed to $(_ARCH), include most of the core targets, like: sysroot/$(ARCH)/include: $(Q)rm -rf sysroot/$(ARCH) sysroot/sysroot $(QUIET_MKDIR)mkdir -p sysroot $(Q)$(MAKE) -C ../../../include/nolibc ARCH=$(_ARCH) OUTPUT=$(CURDIR)/sysroot/ headers_standalone $(Q)mv sysroot/sysroot sysroot/$(ARCH) defconfig: $(Q)$(MAKE) -C $(srctree) ARCH=$(_ARCH) CC=$(CC) CROSS_COMPILE=$(CROSS_COMPILE) mrproper $(DEFCONFIG) prepare kernel: initramfs $(Q)$(MAKE) -C $(srctree) ARCH=$(_ARCH) CC=$(CC) CROSS_COMPILE=$(CROSS_COMPILE) $(IMAGE_NAME) CONFIG_INITRAMFS_SOURCE=$(CURDIR)/initramfs It is not that easier, it touched more source code and make things a little complex, we must mixes the using of ARCH and _ARCH in the whole Makefile and that is not comfortable and may introduce more complexity, for example, we may be worry about if the directories should be named with the new $(_ARCH) ;-) And CONFIG_32BIT variable is better than riscv32, because, we can share this meaningful variable among mips, loongarch in the future if their maintainers want to add more variants support for such platforms, they will meet the same requirement. Thanks very much. Best regards, Zhangjin
diff --git a/tools/testing/selftests/nolibc/Makefile b/tools/testing/selftests/nolibc/Makefile index 47c3c89092e4..9adc8944dd80 100644 --- a/tools/testing/selftests/nolibc/Makefile +++ b/tools/testing/selftests/nolibc/Makefile @@ -14,6 +14,12 @@ include $(srctree)/scripts/subarch.include ARCH = $(SUBARCH) endif +# Allow pass ARCH=riscv|riscv32|riscv64, riscv implies riscv64 +ifneq ($(findstring xriscv,x$(ARCH)),) + CONFIG_32BIT := $(if $(findstring 32x,$(ARCH)x),1) + override ARCH := riscv +endif + # kernel image names by architecture IMAGE_i386 = arch/x86/boot/bzImage IMAGE_x86_64 = arch/x86/boot/bzImage @@ -34,7 +40,7 @@ DEFCONFIG_x86 = defconfig DEFCONFIG_arm64 = defconfig DEFCONFIG_arm = multi_v7_defconfig DEFCONFIG_mips = malta_defconfig -DEFCONFIG_riscv = defconfig +DEFCONFIG_riscv = $(if $(CONFIG_32BIT),rv32_defconfig,defconfig) DEFCONFIG_s390 = defconfig DEFCONFIG_loongarch = defconfig DEFCONFIG = $(DEFCONFIG_$(ARCH)) @@ -49,7 +55,7 @@ QEMU_ARCH_x86 = x86_64 QEMU_ARCH_arm64 = aarch64 QEMU_ARCH_arm = arm QEMU_ARCH_mips = mipsel # works with malta_defconfig -QEMU_ARCH_riscv = riscv64 +QEMU_ARCH_riscv = $(if $(CONFIG_32BIT),riscv32,riscv64) QEMU_ARCH_s390 = s390x QEMU_ARCH_loongarch = loongarch64 QEMU_ARCH = $(QEMU_ARCH_$(ARCH)) @@ -76,6 +82,7 @@ else Q=@ endif +CFLAGS_riscv = $(if $(CONFIG_32BIT),-march=rv32im -mabi=ilp32) CFLAGS_s390 = -m64 CFLAGS_STACKPROTECTOR ?= $(call cc-option,-mstack-protector-guard=global $(call cc-option,-fstack-protector-all)) CFLAGS ?= -Os -fno-ident -fno-asynchronous-unwind-tables -std=c89 \
both riscv64 and riscv32 have the same ARCH value, it is riscv, the default defconfig enables 64bit, to support riscv32, let's allow pass "ARCH=riscv32" or "ARCH=riscv CONFIG_32BIT=1" to customize riscv32 setting. Note: glibc >= 2.33 is required to avoid a bug of the old bits/wordsize.h. /usr/riscv64-linux-gnu/include/bits/wordsize.h:28:3: error: #error "rv32i-based targets are not supported" 28 | # error "rv32i-based targets are not supported" This can not pass compile, several time64 syscalls are still missing. Signed-off-by: Zhangjin Wu <falcon@tinylab.org> --- tools/testing/selftests/nolibc/Makefile | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-)