On Fri, Apr 12, 2024 at 11:22 AM Charlie Jenkins <charlie@xxxxxxxxxxxx> wrote: > > On Fri, Apr 12, 2024 at 10:04:42AM -0700, Evan Green wrote: > > On Fri, Apr 12, 2024 at 4:35 AM Conor Dooley <conor.dooley@xxxxxxxxxxxxx> wrote: > > > > > > On Thu, Apr 11, 2024 at 09:11:20PM -0700, Charlie Jenkins wrote: > > > > Ensure that hwprobe does not flag "v" when xtheadvector is present. > > > > > > > > Signed-off-by: Charlie Jenkins <charlie@xxxxxxxxxxxx> > > > > --- > > > > arch/riscv/kernel/sys_hwprobe.c | 4 ++-- > > > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > > > > > diff --git a/arch/riscv/kernel/sys_hwprobe.c b/arch/riscv/kernel/sys_hwprobe.c > > > > index 8cae41a502dd..e0a42c851511 100644 > > > > --- a/arch/riscv/kernel/sys_hwprobe.c > > > > +++ b/arch/riscv/kernel/sys_hwprobe.c > > > > @@ -69,7 +69,7 @@ static void hwprobe_isa_ext0(struct riscv_hwprobe *pair, > > > > if (riscv_isa_extension_available(NULL, c)) > > > > pair->value |= RISCV_HWPROBE_IMA_C; > > > > > > > > - if (has_vector()) > > > > + if (has_vector() && !riscv_has_vendor_extension_unlikely(RISCV_ISA_VENDOR_EXT_XTHEADVECTOR)) > > > > > > Hmm, I think this is "dangerous". has_vector() is used across the kernel > > > now in several places for the in-kernel vector. I don't think that > > > has_vector() should return true for the T-Head stuff given that & > > > has_vector() should represent the ratified spec. I'll have to think > > > about this one and how nasty this makes any of the save/restore code > > > etc. > > > > Yeah, my nose crinkled here as well. If you're having to do a > > vendorish thing in this generic spot, then others may too, suggesting > > perhaps this isn't the cleanest way to go about it. Ideally extensions > > are all additive, rather than subtractive, I guess? > > This was the "easiest" way to support this but I agree this is not > ideal. The vector code is naturally coupled with having support for > "v" and I wanted to leverage that. The other concern is all of the > ifdefs for having V enabled. I can make all of those V or XTHEADVECTOR; > that will increase the surface area of xtheadvector but it is probably > the right(?) way to go. For the ifdefs, if you've got a Kconfig somewhere for THEAD_VECTOR, can't that just depend on the V config? We'd end up with the limitation that you can't add V 0.7 support without also dragging in V1.0 support, but that's probably fine, right? -Evan
