Re: [PATCH v2 1/7] powerpc: Add new HWCAP bits
From: Michael Ellerman <mpe@ellerman.id.au>
Date: 2020-05-20 02:43:18
Alistair Popple [off-list ref] 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
quoted hunk ↗ jump to hunk
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