> -----Original Message----- > From: Conor Dooley <conor.dooley@xxxxxxxxxxxxx> > Sent: Wednesday, August 30, 2023 2:59 PM > To: Wang, Xiao W <xiao.w.wang@xxxxxxxxx> > Cc: Anup Patel <anup@xxxxxxxxxxxxxx>; paul.walmsley@xxxxxxxxxx; > palmer@xxxxxxxxxxx; aou@xxxxxxxxxxxxxxxxx; ardb@xxxxxxxxxx; Li, Haicheng > <haicheng.li@xxxxxxxxx>; linux-riscv@xxxxxxxxxxxxxxxxxxx; linux- > efi@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx > Subject: Re: [PATCH] RISC-V: Optimize bitops with Zbb extension > > On Wed, Aug 30, 2023 at 06:14:12AM +0000, Wang, Xiao W wrote: > > Hi, > > > > > -----Original Message----- > > > From: Anup Patel <anup@xxxxxxxxxxxxxx> > > > Sent: Tuesday, August 29, 2023 7:08 PM > > > To: Wang, Xiao W <xiao.w.wang@xxxxxxxxx> > > > Cc: paul.walmsley@xxxxxxxxxx; palmer@xxxxxxxxxxx; > > > aou@xxxxxxxxxxxxxxxxx; ardb@xxxxxxxxxx; Li, Haicheng > > > <haicheng.li@xxxxxxxxx>; linux-riscv@xxxxxxxxxxxxxxxxxxx; linux- > > > efi@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx > > > Subject: Re: [PATCH] RISC-V: Optimize bitops with Zbb extension > > > > > > On Sun, Aug 6, 2023 at 8:09 AM Xiao Wang <xiao.w.wang@xxxxxxxxx> > wrote: > > > > > > > > This patch leverages the alternative mechanism to dynamically optimize > > > > bitops (including __ffs, __fls, ffs, fls) with Zbb instructions. When > > > > Zbb ext is not supported by the runtime CPU, legacy implementation is > > > > used. If Zbb is supported, then the optimized variants will be selected > > > > via alternative patching. > > > > > > > > The legacy bitops support is taken from the generic C implementation as > > > > fallback. > > > > > > > > If the parameter is a build-time constant, we leverage compiler builtin to > > > > calculate the result directly, this approach is inspired by x86 bitops > > > > implementation. > > > > > > > > EFI stub runs before the kernel, so alternative mechanism should not be > > > > used there, this patch introduces a macro EFI_NO_ALTERNATIVE for this > > > > purpose. > > > > > > I am getting the following compile error with this patch: > > > > > > GEN Makefile > > > UPD include/config/kernel.release > > > UPD include/generated/utsrelease.h > > > CC kernel/bounds.s > > > In file included from /home/anup/Work/riscv- > > > test/linux/include/linux/bitmap.h:9, > > > from > > > /home/anup/Work/riscv- > test/linux/arch/riscv/include/asm/cpufeature.h:9, > > > from > > > /home/anup/Work/riscv-test/linux/arch/riscv/include/asm/hwcap.h:90, > > > > > > It looks there's a cyclic header including, which leads to this build error. > > I checked https://github.com/kvm-riscv/linux/tree/master and > > https://github.com/torvalds/linux/tree/master, but I don't see > > "asm/cpufeature.h" is included in asm/hwcap.h:90, maybe I miss > something, > > could you help point me to the repo/branch I should work on? > > From MAINTAINERS: > RISC-V ARCHITECTURE > ... > T: git git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux.git > > The for-next branch there is what you should be basing work on top of. > AFAICT, you've made bitops.h include hwcap.h while cpufeature.h includes > both bitops.h (indirectly) and hwcap.h. Thanks for the info, but I can't reproduce Anup's build error with this for-next branch, cpufeature.h is not included by hwcap.h there. Maybe Anup could help double check the test environment? BRs, Xiao > > Hope that helps, > Conor. > > > > from > > > /home/anup/Work/riscv-test/linux/arch/riscv/include/asm/bitops.h:26, > > > from > > > /home/anup/Work/riscv-test/linux/include/linux/bitops.h:68, > > > from /home/anup/Work/riscv-test/linux/include/linux/log2.h:12, > > > from /home/anup/Work/riscv-test/linux/kernel/bounds.c:13: > > > /home/anup/Work/riscv-test/linux/include/linux/find.h: In function > > > 'find_next_bit': > > > /home/anup/Work/riscv-test/linux/include/linux/find.h:64:30: error: > > > implicit declaration of function '__ffs' > > > [-Werror=implicit-function-declaration] > > > 64 | return val ? __ffs(val) : size; > > > > > > Regards, > > > Anup > > > > > > > > > > > > > > Signed-off-by: Xiao Wang <xiao.w.wang@xxxxxxxxx> > > > > --- > > > > arch/riscv/include/asm/bitops.h | 266 > +++++++++++++++++++++++++- > > > > drivers/firmware/efi/libstub/Makefile | 2 +- > > > > 2 files changed, 264 insertions(+), 4 deletions(-) > > > > > > > > diff --git a/arch/riscv/include/asm/bitops.h > > > b/arch/riscv/include/asm/bitops.h > > > > index 3540b690944b..f727f6489cd5 100644 > > > > --- a/arch/riscv/include/asm/bitops.h > > > > +++ b/arch/riscv/include/asm/bitops.h > > > > @@ -15,13 +15,273 @@ > > > > #include <asm/barrier.h> > > > > #include <asm/bitsperlong.h>
