| Message ID | 20240411-dev-charlie-support_thead_vector_6_9-v1-14-4af9815ec746@rivosinc.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | riscv: Support vendor extensions and xtheadvector | expand |
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@rivosinc.com> > --- > 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. > pair->value |= RISCV_HWPROBE_IMA_V; > > /* > @@ -112,7 +112,7 @@ static void hwprobe_isa_ext0(struct riscv_hwprobe *pair, > EXT_KEY(ZACAS); > EXT_KEY(ZICOND); > > - if (has_vector()) { > + if (has_vector() && !riscv_has_vendor_extension_unlikely(RISCV_ISA_VENDOR_EXT_XTHEADVECTOR)) { > EXT_KEY(ZVBB); > EXT_KEY(ZVBC); > EXT_KEY(ZVKB); > > -- > 2.44.0 >
On Fri, Apr 12, 2024 at 4:35 AM Conor Dooley <conor.dooley@microchip.com> 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@rivosinc.com> > > --- > > 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? > > > pair->value |= RISCV_HWPROBE_IMA_V; > > > > /* > > @@ -112,7 +112,7 @@ static void hwprobe_isa_ext0(struct riscv_hwprobe *pair, > > EXT_KEY(ZACAS); > > EXT_KEY(ZICOND); > > > > - if (has_vector()) { > > + if (has_vector() && !riscv_has_vendor_extension_unlikely(RISCV_ISA_VENDOR_EXT_XTHEADVECTOR)) { > > EXT_KEY(ZVBB); > > EXT_KEY(ZVBC); > > EXT_KEY(ZVKB); > > > > -- > > 2.44.0 > >
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@microchip.com> 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@rivosinc.com> > > > --- > > > 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. - Charlie > > > > > > > pair->value |= RISCV_HWPROBE_IMA_V; > > > > > > /* > > > @@ -112,7 +112,7 @@ static void hwprobe_isa_ext0(struct riscv_hwprobe *pair, > > > EXT_KEY(ZACAS); > > > EXT_KEY(ZICOND); > > > > > > - if (has_vector()) { > > > + if (has_vector() && !riscv_has_vendor_extension_unlikely(RISCV_ISA_VENDOR_EXT_XTHEADVECTOR)) { > > > EXT_KEY(ZVBB); > > > EXT_KEY(ZVBC); > > > EXT_KEY(ZVKB); > > > > > > -- > > > 2.44.0 > > >
On Fri, Apr 12, 2024 at 11:22 AM Charlie Jenkins <charlie@rivosinc.com> 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@microchip.com> 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@rivosinc.com> > > > > --- > > > > 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
On Fri, Apr 12, 2024 at 03:08:31PM -0700, Evan Green wrote: > On Fri, Apr 12, 2024 at 11:22 AM Charlie Jenkins <charlie@rivosinc.com> 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@microchip.com> 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@rivosinc.com> > > > > > --- > > > > > 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? That's a great idea, thank you for the suggestion. - Charlie > > -Evan
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)) pair->value |= RISCV_HWPROBE_IMA_V; /* @@ -112,7 +112,7 @@ static void hwprobe_isa_ext0(struct riscv_hwprobe *pair, EXT_KEY(ZACAS); EXT_KEY(ZICOND); - if (has_vector()) { + if (has_vector() && !riscv_has_vendor_extension_unlikely(RISCV_ISA_VENDOR_EXT_XTHEADVECTOR)) { EXT_KEY(ZVBB); EXT_KEY(ZVBC); EXT_KEY(ZVKB);
Ensure that hwprobe does not flag "v" when xtheadvector is present. Signed-off-by: Charlie Jenkins <charlie@rivosinc.com> --- arch/riscv/kernel/sys_hwprobe.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)