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Sun, 4 Jul 2021 23:14:19 +0000 Date: Mon, 5 Jul 2021 00:14:17 +0100 From: Gary Guo To: Matthew Wilcox Cc: Miguel Ojeda , Miguel Ojeda , Linus Torvalds , Greg Kroah-Hartman , rust-for-linux , Linux Kbuild mailing list , Linux Doc Mailing List , linux-kernel , Alex Gaynor , Geoffrey Thomas , Finn Behrens , Adam Bratschi-Kaye , Wedson Almeida Filho Subject: Re: [PATCH 01/17] kallsyms: support big kernel symbols (2-byte lengths) Message-ID: <20210705001417.00003d1f@garyguo.net> In-Reply-To: References: <20210704202756.29107-1-ojeda@kernel.org> <20210704202756.29107-2-ojeda@kernel.org> <20210704232007.0000357e@garyguo.net> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; i686-w64-mingw32) Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Originating-IP: [2001:470:6972:501:ac54:3e6d:9d2c:fe4e] X-ClientProxiedBy: LO2P265CA0090.GBRP265.PROD.OUTLOOK.COM (2603:10a6:600:8::30) To LNXP265MB0746.GBRP265.PROD.OUTLOOK.COM (2603:10a6:600:16::23) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 Received: from localhost (2001:470:6972:501:ac54:3e6d:9d2c:fe4e) by LO2P265CA0090.GBRP265.PROD.OUTLOOK.COM (2603:10a6:600:8::30) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4287.23 via Frontend Transport; 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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?F4JK62ESdZ2zFNOxEWNvKR407S9iREkcDoRHqIcUucZ07uX7v9qSEdYScZrs?= =?us-ascii?Q?HYq7CczYL5p1tBfpMS/kjVGNW++kxEUFmORSS3HiO8+0FP8UbnerT1ePGFS9?= =?us-ascii?Q?QEQQA/owYkm8EIULHjtLWpxoYRjPBXJqOz58oI1KOi7h8XOJymNgHKFXkV/o?= =?us-ascii?Q?6FKFOPVEYDdTQQ0QL2gGTSpb1uMW5hZZTsN4eaijH4lDeqJVzxZELwzpTx7k?= =?us-ascii?Q?PSLTzrW98m/rAIn3mU7HMJROjIjtLbGVnkZf/qWRBcwtcNaF9iq6B1CAfpG3?= =?us-ascii?Q?zUQRO2Oi+01BlNG2co+vXJb0HjDznlheLz7S8M6UXgtdY4C/RR9JL37t4L1S?= =?us-ascii?Q?F4rHkVL1QYrNjfFwIA0harlDEKNWRJ3CXu4vcQqg1eaJabJA4rRfNirsDjfu?= =?us-ascii?Q?vM6Kwx+788yiUGvfNmyB/PIALPUhpQopxMh7W4cKCmK0BP0Rzrm2XeTZHcIF?= =?us-ascii?Q?/SSVL7ewbpXpKPlK/sfmx6TuldbgrwaiuhU7/nHJvYt7IJqFOU6goQ5uiQ0x?= =?us-ascii?Q?HktXtK5hzt6lmCymvfotsAGNEcUKZHdjQ9ZZTQtrVu+8Sl/FI5Rkq6dl5HQ+?= =?us-ascii?Q?i9MiOCx4xHWPvKamSN/jbLbKOYi1LrwiN9WVocc4Vu2WOhLjgDI0QLVSDZt+?= =?us-ascii?Q?BRH9i9mXfMr5bO0tcez/02Hu6Lku2B9cHq87ceByRKBxu3oAiN5KTbUAVjR3?= =?us-ascii?Q?zZ0+gLZpXJrHSTChi7XtzD7625fQ139QLFcvfzk5X8vACYs3QNR4bWe0fsxQ?= =?us-ascii?Q?vLJXHSXVhrUIj5cY9IgXlU+D29MRcq5+sRezM8VYwadnv8Lhih6ufiuiF5tb?= =?us-ascii?Q?HpOc8MXKEF4kzrAub6ItLNHl3y57Xu5j7w1I9hFJhejUMdfvn7F4tUlrH36b?= =?us-ascii?Q?SyqQ6KjgwPZXQ1T67+fgrpH+Yh+1cVfJr2YbmtO0Xyk3bLzP05raLA7H3Yx8?= =?us-ascii?Q?+xEzN49+lpYtnEQRkOPeMLfMC9y+mBDzfAsRbAJ2GWZpuckQnQsKDvRn9Ekg?= =?us-ascii?Q?zMAjY6qQZxyQbabD3wtrdn7+0gMfTG3NVAvbg5A72Inp7M99erkt+9iVNeub?= =?us-ascii?Q?Job6K/2DiIpLQVTSKsg8PfbfYGBXC1qPrR7FdZrYxuKfDG2KL801og0lBY2N?= =?us-ascii?Q?8dCEO949Zn+lG4ZwtripL6rL83mu+ZZm0k1kRaH9u2zKH26VNisTEh0x3pHq?= =?us-ascii?Q?24n8EJVQ2itcxbqkCqtyMNAdtR5MhB+6lG0ikpOxQnniuoRKfZR4SQChRBpI?= =?us-ascii?Q?flEqREFRKT1YQdQKxKrMnLEZQDvH0W6h41BLmpBhKWNpnF4DFOaBHpz2sggM?= =?us-ascii?Q?9KVoSmnk9gMPcggUdTLfWJ85hZ3kble3OfGQx7YEBFB1DDJ1PDAyGOrylQRa?= =?us-ascii?Q?hSTthSTN1TIPtWE7IxrvjxA1wmEp?= X-OriginatorOrg: garyguo.net X-MS-Exchange-CrossTenant-Network-Message-Id: e8e271ad-6212-4d00-44e1-08d93f4173d2 X-MS-Exchange-CrossTenant-AuthSource: LNXP265MB0746.GBRP265.PROD.OUTLOOK.COM X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 04 Jul 2021 23:14:19.9479 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: bbc898ad-b10f-4e10-8552-d9377b823d45 X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: ++g6ymPhbMD9op1th2busZBGVGO8jNvX3UZGZUcmcVZz+CKcwH6BWm66P54wpJrtVLAcktca/dvO6yIg+BGsXA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: LO2P265MB3997 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 4 Jul 2021 23:42:03 +0100 Matthew Wilcox wrote: > On Sun, Jul 04, 2021 at 11:20:07PM +0100, Gary Guo wrote: > > This is big endian. > > Fundamentally, it doesn't matter whether it's encoded as top-7 + > bottom-8 or bottom-7 + top-8. It could just as well be: > > if (len >= 128) { > len -= 128; > len += *data * 256; Do you mean `*data * 128`? > data++; > } > > It doesn't matter whether it's compatible with some other encoding. > This encoding has one producer and one consumer. As long as they > agree, it's fine. I am aware that this is only for internal tooling so it doesn't really matter. I mentioned that it's big endian to do top-7 + bottom-8 because Linus suggests that big-endian shouldn't be used.