From: Michael Ellerman <mpe@ellerman•id.au>
To: Alistair Popple <alistair@popple•id.au>, linuxppc-dev@lists•ozlabs.org
Cc: aneesh.kumar@linux•ibm.com, mikey@neuling•org, npiggin@gmail•com,
Alistair Popple <alistair@popple•id.au>
Subject: Re: [PATCH v2 1/7] powerpc: Add new HWCAP bits
Date: Wed, 20 May 2020 12:42:09 +1000 [thread overview]
Message-ID: <871rnf49a6.fsf@mpe.ellerman.id.au> (raw)
In-Reply-To: <20200519003157.31946-2-alistair@popple.id.au>
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
next prev parent reply other threads:[~2020-05-20 2:43 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-19 0:31 [PATCH v2 0/7] Base support for POWER10 Alistair Popple
2020-05-19 0:31 ` [PATCH v2 1/7] powerpc: Add new HWCAP bits Alistair Popple
2020-05-19 3:20 ` Michael Neuling
2020-05-19 17:48 ` Paul A. Clarke
2020-05-20 2:42 ` Michael Ellerman [this message]
2020-05-20 3:29 ` Alistair Popple
2020-05-19 0:31 ` [PATCH v2 2/7] powerpc: Add support for ISA v3.1 Alistair Popple
2020-05-19 4:04 ` Jordan Niethe
2020-05-19 5:45 ` Alistair Popple
2020-05-19 0:31 ` [PATCH v2 3/7] powerpc/dt_cpu_ftrs: Advertise support for ISA v3.1 if selected Alistair Popple
2020-05-19 0:31 ` [PATCH v2 4/7] powerpc/dt_cpu_ftrs: Set current thread fscr bits Alistair Popple
2020-05-19 0:31 ` [PATCH v2 5/7] powerpc/dt_cpu_ftrs: Enable Prefixed Instructions Alistair Popple
2020-05-19 0:31 ` [PATCH v2 6/7] powerpc/dt_cpu_ftrs: Add MMA feature Alistair Popple
2020-05-19 14:49 ` Paul A. Clarke
2020-05-19 15:05 ` Segher Boessenkool
2020-05-19 15:22 ` Paul A. Clarke
2020-05-19 15:28 ` Segher Boessenkool
2020-05-19 15:49 ` Paul A. Clarke
2020-05-19 17:51 ` Paul A. Clarke
2020-05-19 23:56 ` Alistair Popple
2020-05-19 0:31 ` [PATCH v2 7/7] powerpc: Add POWER10 architected mode Alistair Popple
2020-05-19 3:58 ` Jordan Niethe
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