Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Mon, 3 Apr 2023 23:05:17 -0700 (PDT)
From:   Ilkka Koskinen <ilkka@os.amperecomputing.com>
To:     Robin Murphy <robin.murphy@arm.com>
cc:     will@kernel.org, mark.rutland@arm.com,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] perf/arm-cmn: Validate cycles events fully
In-Reply-To: <3124e8c276a1f513c1a415dc839ca4181b3c8bc8.1680522545.git.robin.murphy@arm.com>
Message-ID: <1184027-2e39-2ed2-fa93-70c0a9d8e11@os.amperecomputing.com>
References: <3124e8c276a1f513c1a415dc839ca4181b3c8bc8.1680522545.git.robin.murphy@arm.com>
Content-Type: text/plain; charset=US-ASCII; format=flowed
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?sinHxvXI3FD7b4pJuPfhy9k0nWCb7h3sSyhJMyircJ+Ps+U6eycQ6OnKpAhi?=
 =?us-ascii?Q?rGkfgk3logva4e+WVHXBsdpf1+iPqfBCGKTOCjXJM8ZIUOgJ28uP9rwyd36E?=
 =?us-ascii?Q?bHYtTh+cz7NCglVseBpj66yaIQqG1JDY4f7aKp22RfcAiokFNTl72Td7/9X5?=
 =?us-ascii?Q?C3JTCoY+vvvcasSpiyiMvrmUOAj/cSfFP9k5J3OIVxlUjHgISNOan6n+NwUV?=
 =?us-ascii?Q?sTEOgwcmtfZr8sJoMYR8nDAAOqNtuvM0aglpcLqsAw+APIoC2cnmMc1f4fJH?=
 =?us-ascii?Q?hxb4DXKre5p0NHFrrPRgEWZZM+DumVJpaLbVVTmKmhnYexP9QMCkrj3Y7rfJ?=
 =?us-ascii?Q?/tB2GK0jVmxiLf8L2XG1h++4fmQL6NqgzTqmYKlEGOA0J2tNZBGJ8hGxGRhQ?=
 =?us-ascii?Q?U50LNVlzuCbTwYLg/3OHN1uYzVszrwsIDdvDacR4iZfMRBEyFvy+zxjhMw7m?=
 =?us-ascii?Q?LYPC1J/DbFr14RfDgP1tcrG88hGI/PQbcrFW/RKlh6d2FmYqtniRMu96edw3?=
 =?us-ascii?Q?IrWemE0JXVM9A+JISJhBsBDtgGriCjXHXFgS9kztZgI2mX5hDziTKMGNlQWt?=
 =?us-ascii?Q?IBFkgBLTjuHGIVlzJJxArT8WPy/w7Up2/gBdsgcdkyI5ZT2Wo9qEZl4IHdMe?=
 =?us-ascii?Q?hNR+iNZVr7AVuxNwFUYaT/WyerpSItFOSnOxqcrZipbiAciz/ydct/RTwQHh?=
 =?us-ascii?Q?64wHxj4gqXdlMPPhieamYEcToOax1ITHad0ozRe9UN6Ogec+ylYcAjot8Ks4?=
 =?us-ascii?Q?sBwkkYN6T0o9pmRdWK2zhGCjTMupr2xT96jwClEjo3dOQJzVqkaguRiLI8Lc?=
 =?us-ascii?Q?H5TTSc3hyCPIJKki17mPk9d9L9imKHH+Q/EIl7tD3GkhF49UE7JsAAgMVuMo?=
 =?us-ascii?Q?plhP4jPeEr+7IIuaL/7cXSQ8fzBgQGwCVyjIryak/JPX7iU335lh9Rnvz03v?=
 =?us-ascii?Q?U4+TZ0V+YmLx8QRTmLmG3OrRhZh90nwNDT6Ot02G9okgIABGaEvk5q8+p8QC?=
 =?us-ascii?Q?4sFcdfmot/4jXn/HHqUZAJDRB7VK2X2zerA1Z9E6fKNYI3pyRZaVaVqsi/UV?=
 =?us-ascii?Q?nlGSEUZqlJVI96KH1dkUH4ptH1ZufBcOe3ePaw2VD2BlbQhcqApwso5rJs8j?=
 =?us-ascii?Q?VBiXv41ZOm4juNqbTyDs5s8KxRo6jhJOldTBVPL1pJIRBmSg4XFy3xwzoKCR?=
 =?us-ascii?Q?KEnTKhr7YdCSjCYEVT/1mZ0+vf4kqGH9L1YLfMt4huc2KaOJ0LFhXnw/6rw+?=
 =?us-ascii?Q?1UTEPa8aa1YqoCppv4KUb8F4H+3CBom9Iaoj4M02kIGTaqEHHyBrmXPgD+Ss?=
 =?us-ascii?Q?iHAWAcy66H1q8PDLrKAP4mMgAgKPfgRHZxbGn4cS0CM+n5gXFGJe9OyzHFbn?=
 =?us-ascii?Q?FNb+AE9zg3FNAi9/dgEqhiP3joqlNDQp3w9ZErQNOU+r2VjiiwKdN7P/Wh2Q?=
 =?us-ascii?Q?b4+1yr+QBJB++jJw+tCEKpqkWXH9k2/gMGhmwwDvpz3P/RTBDhkNzY1PpUsS?=
 =?us-ascii?Q?WcVCgINoQy6RicOUrgQUF5M/8O41v8ASqb0d+CLMQztvb1VLZaeoGXL7j5Ei?=
 =?us-ascii?Q?IjNR9D1uY8fCpYemzT0rlwgMjHg5h1k6u9twxZz2uPkxAhZvtRa1FYbEYaLQ?=
 =?us-ascii?Q?4g=3D=3D?=
X-OriginatorOrg: os.amperecomputing.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 6c18895b-812a-44b0-0cea-08db34d29b2a
X-MS-Exchange-CrossTenant-AuthSource: DM5PR0102MB3590.prod.exchangelabs.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 04 Apr 2023 06:05:35.5431
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 3bc2b170-fd94-476d-b0ce-4229bdc904a7
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: p/L2Zo/k6C+fdhZQ5cXLpYQkuI3cZs54MADaF5Fb7RXZXsxLDJvrhEHVSXdQXvM2Vz7WyDPHAfZ7rmui2OTiXHFoW5qGWF1BXJc/2M2Q4BHg3wJ/0kVmWW7PiPmLH8NJ
X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH0PR01MB6472
X-Spam-Status: No, score=-0.1 required=5.0 tests=DKIM_SIGNED,DKIM_VALID,
        DKIM_VALID_AU,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2,SPF_HELO_PASS,
        SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on
        lindbergh.monkeyblade.net
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org


On Mon, 3 Apr 2023, Robin Murphy wrote:
> DTC cycle count events don't have anything to validate or initialise in
> themselves, but we should not forget to still validate their whole group
> context. Otherwise, we may fail to correctly reject a contrived group
> containing an impossible number of cycles events.
>
> Signed-off-by: Robin Murphy <robin.murphy@arm.com>

Looks good to me and works as expected.

Cheers, Ilkka

> ---
> drivers/perf/arm-cmn.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/perf/arm-cmn.c b/drivers/perf/arm-cmn.c
> index 367d41c5d983..45819528facb 100644
> --- a/drivers/perf/arm-cmn.c
> +++ b/drivers/perf/arm-cmn.c
> @@ -1558,7 +1558,7 @@ static int arm_cmn_event_init(struct perf_event *event)
> 	type = CMN_EVENT_TYPE(event);
> 	/* DTC events (i.e. cycles) already have everything they need */
> 	if (type == CMN_TYPE_DTC)
> -		return 0;
> +		return arm_cmn_validate_group(cmn, event);
>
> 	eventid = CMN_EVENT_EVENTID(event);
> 	/* For watchpoints we need the actual XP node here */
> -- 
> 2.39.2.101.g768bb238c484.dirty
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>