| Message ID | 20200519003157.31946-2-alistair@popple.id.au (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Base support for POWER10 | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | success | Successfully applied on branch powerpc/merge (7b06fb8795ffea9d12be45a172197c3307955479) |
| snowpatch_ozlabs/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 8 lines checked |
| snowpatch_ozlabs/needsstable | success | Patch has no Fixes tags |
On Tue, 2020-05-19 at 10:31 +1000, Alistair Popple wrote: > POWER10 introduces two new architectural features - ISAv3.1 and matrix > multiply accumulate (MMA) instructions. Userspace detects the presence > of these features via two HWCAP bits introduced in this patch. These > bits have been agreed to by the compiler and binutils team. > > Signed-off-by: Alistair Popple <alistair@popple.id.au> I've test booted this series + powerpc/next (30df74d67d) on top of powervm and OPAL on a P10 simulator. In both cases, it enables MMA and prefix instructions and advertises them via HWCAP2 MMA + ISA 3.1. Hence: Tested-by: Michael Neuling <mikey@neuling.org> > --- > arch/powerpc/include/uapi/asm/cputable.h | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/arch/powerpc/include/uapi/asm/cputable.h > b/arch/powerpc/include/uapi/asm/cputable.h > index 540592034740..2692a56bf20b 100644 > --- a/arch/powerpc/include/uapi/asm/cputable.h > +++ b/arch/powerpc/include/uapi/asm/cputable.h > @@ -50,6 +50,8 @@ > #define PPC_FEATURE2_DARN 0x00200000 /* darn random number insn */ > #define PPC_FEATURE2_SCV 0x00100000 /* scv syscall */ > #define PPC_FEATURE2_HTM_NO_SUSPEND 0x00080000 /* TM w/out suspended state > */ > +#define PPC_FEATURE2_ARCH_3_1 0x00040000 /* ISA 3.1 */ > +#define PPC_FEATURE2_MMA 0x00020000 /* Matrix Multiply Accumulate > */ > > /* > * IMPORTANT!
On Tue, May 19, 2020 at 10:31:51AM +1000, Alistair Popple wrote: > POWER10 introduces two new architectural features - ISAv3.1 and matrix > multiply accumulate (MMA) instructions. Userspace detects the presence > of these features via two HWCAP bits introduced in this patch. These > bits have been agreed to by the compiler and binutils team. > > Signed-off-by: Alistair Popple <alistair@popple.id.au> > --- > arch/powerpc/include/uapi/asm/cputable.h | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/arch/powerpc/include/uapi/asm/cputable.h b/arch/powerpc/include/uapi/asm/cputable.h > index 540592034740..2692a56bf20b 100644 > --- a/arch/powerpc/include/uapi/asm/cputable.h > +++ b/arch/powerpc/include/uapi/asm/cputable.h > @@ -50,6 +50,8 @@ > #define PPC_FEATURE2_DARN 0x00200000 /* darn random number insn */ > #define PPC_FEATURE2_SCV 0x00100000 /* scv syscall */ > #define PPC_FEATURE2_HTM_NO_SUSPEND 0x00080000 /* TM w/out suspended state */ > +#define PPC_FEATURE2_ARCH_3_1 0x00040000 /* ISA 3.1 */ > +#define PPC_FEATURE2_MMA 0x00020000 /* Matrix Multiply Accumulate */ Carrying the conclusion of the recent discussion further, this should also be "Matrix-Multiply Assist". PC
Alistair Popple <alistair@popple.id.au> writes: > POWER10 introduces two new architectural features - ISAv3.1 and matrix > multiply accumulate (MMA) instructions. Userspace detects the presence > of these features via two HWCAP bits introduced in this patch. These > bits have been agreed to by the compiler and binutils team. Do we have an explanation of why we're exposing MMA separately. I believe it's because ISA v3.1 says that MMA is optional, in the table on page ix? cheers > diff --git a/arch/powerpc/include/uapi/asm/cputable.h b/arch/powerpc/include/uapi/asm/cputable.h > index 540592034740..2692a56bf20b 100644 > --- a/arch/powerpc/include/uapi/asm/cputable.h > +++ b/arch/powerpc/include/uapi/asm/cputable.h > @@ -50,6 +50,8 @@ > #define PPC_FEATURE2_DARN 0x00200000 /* darn random number insn */ > #define PPC_FEATURE2_SCV 0x00100000 /* scv syscall */ > #define PPC_FEATURE2_HTM_NO_SUSPEND 0x00080000 /* TM w/out suspended state */ > +#define PPC_FEATURE2_ARCH_3_1 0x00040000 /* ISA 3.1 */ > +#define PPC_FEATURE2_MMA 0x00020000 /* Matrix Multiply Accumulate */ > > /* > * IMPORTANT! > -- > 2.20.1
On Wednesday, 20 May 2020 12:42:09 PM AEST Michael Ellerman wrote: > Alistair Popple <alistair@popple.id.au> writes: > > POWER10 introduces two new architectural features - ISAv3.1 and matrix > > multiply accumulate (MMA) instructions. Userspace detects the presence > > of these features via two HWCAP bits introduced in this patch. These > > bits have been agreed to by the compiler and binutils team. > > Do we have an explanation of why we're exposing MMA separately. > > I believe it's because ISA v3.1 says that MMA is optional, in the table > on page ix? Right, MMA is an optional feature and software should check for its presence prior to use. This is explicitly stated in the ISA on pg. 574: 7.6.1.12 VSX Matrix-Multiply Assist (MMA) Instructions The MMA facility is optional. Software that uses this facility should test for its availability and provide an alternate execution path. The HWCAP bit is the mechanism for that. I can add the description to the commit message. - Alistair > cheers > > > diff --git a/arch/powerpc/include/uapi/asm/cputable.h > > b/arch/powerpc/include/uapi/asm/cputable.h index > > 540592034740..2692a56bf20b 100644 > > --- a/arch/powerpc/include/uapi/asm/cputable.h > > +++ b/arch/powerpc/include/uapi/asm/cputable.h > > @@ -50,6 +50,8 @@ > > > > #define PPC_FEATURE2_DARN 0x00200000 /* darn random number insn */ > > #define PPC_FEATURE2_SCV 0x00100000 /* scv syscall */ > > #define PPC_FEATURE2_HTM_NO_SUSPEND 0x00080000 /* TM w/out suspended > > state */> > > +#define PPC_FEATURE2_ARCH_3_1 0x00040000 /* ISA 3.1 */ > > +#define PPC_FEATURE2_MMA 0x00020000 /* Matrix Multiply Accumulate */ > > > > /* > > > > * IMPORTANT!
diff --git a/arch/powerpc/include/uapi/asm/cputable.h b/arch/powerpc/include/uapi/asm/cputable.h index 540592034740..2692a56bf20b 100644 --- a/arch/powerpc/include/uapi/asm/cputable.h +++ b/arch/powerpc/include/uapi/asm/cputable.h @@ -50,6 +50,8 @@ #define PPC_FEATURE2_DARN 0x00200000 /* darn random number insn */ #define PPC_FEATURE2_SCV 0x00100000 /* scv syscall */ #define PPC_FEATURE2_HTM_NO_SUSPEND 0x00080000 /* TM w/out suspended state */ +#define PPC_FEATURE2_ARCH_3_1 0x00040000 /* ISA 3.1 */ +#define PPC_FEATURE2_MMA 0x00020000 /* Matrix Multiply Accumulate */ /* * IMPORTANT!
POWER10 introduces two new architectural features - ISAv3.1 and matrix multiply accumulate (MMA) instructions. Userspace detects the presence of these features via two HWCAP bits introduced in this patch. These bits have been agreed to by the compiler and binutils team. Signed-off-by: Alistair Popple <alistair@popple.id.au> --- arch/powerpc/include/uapi/asm/cputable.h | 2 ++ 1 file changed, 2 insertions(+)