[PATCH] aarch64: Remove RNG and MTE from -mcpu=neoverse-v2

[Kyrylo Tkachov <ktkachov@nvidia.com>]

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Hi all,

According to the TRM for Neoverse V2 the Memory Tagging and RNG features
are optional configurations of the core and may not always be present.
Therefore -mcpu=neoverse-v2 shouldn't enable them, similar to how the crypto extensions aren’t enabled by default.

Bootstrapped and tested on aarch64-none-linux-gnu.
Does this reasoning make sense?
Thanks,
Kyrill


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From 690b500ef2bb5b84eb09ed9841b3e3c033715103 Mon Sep 17 00:00:00 2001
From: Kyrylo Tkachov <ktkachov@nvidia.com>
Date: Sun, 23 Jun 2024 11:01:41 -0700
Subject: [PATCH] [aarch64] Remove RNG and MTE from -mcpu=neoverse-v2

According to the TRM for Neoverse V2 the Memory Tagging and RNG features
are optional configurations of the core and may not always be present.
Therefore -mcpu=neoverse-v2 shouldn't enable them.

Bootstrapped and tested on aarch64-none-linux-gnu

	* config/aarch64/aarch64-cores.def (neoverse-v2): Remove MEMTAG and
	RNG from features.
	(demeter): Likewise.

Signed-off-by: Kyrylo Tkachov <ktkachov@nvidia.com>
---
 gcc/config/aarch64/aarch64-cores.def | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/gcc/config/aarch64/aarch64-cores.def b/gcc/config/aarch64/aarch64-cores.def
index e58bc0f27de..0c6150e407f 100644
--- a/gcc/config/aarch64/aarch64-cores.def
+++ b/gcc/config/aarch64/aarch64-cores.def
@@ -193,10 +193,10 @@ AARCH64_CORE("cortex-x4",  cortexx4, cortexa57, V9_2A,  (SVE2_BITPERM, MEMTAG, P
 AARCH64_CORE("neoverse-n2", neoversen2, cortexa57, V9A, (I8MM, BF16, SVE2_BITPERM, RNG, MEMTAG, PROFILE), neoversen2, 0x41, 0xd49, -1)
 AARCH64_CORE("cobalt-100",   cobalt100, cortexa57, V9A, (I8MM, BF16, SVE2_BITPERM, RNG, MEMTAG, PROFILE), neoversen2, 0x6d, 0xd49, -1)
 
-AARCH64_CORE("neoverse-v2", neoversev2, cortexa57, V9A, (I8MM, BF16, SVE2_BITPERM, RNG, MEMTAG, PROFILE), neoversev2, 0x41, 0xd4f, -1)
+AARCH64_CORE("neoverse-v2", neoversev2, cortexa57, V9A, (I8MM, BF16, SVE2_BITPERM, PROFILE), neoversev2, 0x41, 0xd4f, -1)
 AARCH64_CORE("grace", grace, cortexa57, V9A, (I8MM, BF16, SVE2_BITPERM, SVE2_AES, SVE2_SHA3, SVE2_SM4, PROFILE), neoversev2, 0x41, 0xd4f, -1)
 
-AARCH64_CORE("demeter", demeter, cortexa57, V9A, (I8MM, BF16, SVE2_BITPERM, RNG, MEMTAG, PROFILE), neoversev2, 0x41, 0xd4f, -1)
+AARCH64_CORE("demeter", demeter, cortexa57, V9A, (I8MM, BF16, SVE2_BITPERM, PROFILE), neoversev2, 0x41, 0xd4f, -1)
 
 /* Generic Architecture Processors.  */
 AARCH64_CORE("generic",  generic, cortexa53, V8A,  (), generic, 0x0, 0x0, -1)
-- 
2.34.1