From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 737A1C021B8 for ; Thu, 27 Feb 2025 00:02:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To: Content-Transfer-Encoding:Content-Type:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=rCKtPSqaLbMiAwTZR5MaQSFBSBzSDQKA0HKE8xQS4c8=; b=XDKiMmZiwZCQ1rMc08kUygGxVB ApgFjgImOU1dmVT0jzE9DJn6viKq7pskfMQ/JWntJXfgxDuBzTdIu0NYAFkDUjItDNBu3UmlzNjIp 2lms8IjvPQnehBy93Tj0eBtb75j/D2ekRHHQo2QckI5Ao+5BxKtLEbXkLYK+lxwfYcu9BefV3Qfxc IkNw5ond2hvIHT2BtUkGr8QRjLdgd3VEIH+aeA5bzj+4JIAadsnYCw09gb2toTHM6eEQx1iEiuzsA udt13VnQ4hkn5vH9JtceyaKkNkWy4FWE1sHTEIiVyEjGVepgrpry2MtENuO8xKwgzvrzXA6WSJKAw SA7kG5wQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tnRMH-00000005l93-3Pzr; Thu, 27 Feb 2025 00:02:33 +0000 Received: from tor.source.kernel.org ([172.105.4.254]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1tnRKl-00000005l1e-1VaQ; Thu, 27 Feb 2025 00:00:59 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 743DB612B0; Thu, 27 Feb 2025 00:00:50 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id F154EC4CED6; Thu, 27 Feb 2025 00:00:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1740614458; bh=qd5L09r8BbWtp3sAdRkvQxm/boMlegFYOUTq9AxcaRA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=JJiViAXPMxyzFzf9Hv16zUQzj8/qcVzYFJj7H31yYwopnzVcgJ3IWMgfHJ+14Oawi FH/2zQ38hXIe2aBZp+k+W5gHvA14Ols6fXDb2nobInHVV9tZuM6fyRIVKnpX3rbSE/ S19H8+xhIluAVHCe3LrlHXrLWswcBkjjlrOH/VfX/SdIq/8LgFQBU7vIeh06BAMDzV /XKxRxaQP2UfjOsbZKRHTRhCx0Ozbdy0Apq0EMTCr2HEQfQpk1RSjZunhinNdVW28S /sguI1ft/UZy/3f5o7gSzvdrZJWwnBHVbnYDea42DQwCuDW4sMzAxs15CFkGwqajov yLqLq3Dn7PJJQ== Date: Wed, 26 Feb 2025 16:00:55 -0800 From: Namhyung Kim To: Ian Rogers Cc: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Adrian Hunter , Kan Liang , John Garry , Will Deacon , James Clark , Mike Leach , Leo Yan , guoren , Paul Walmsley , Palmer Dabbelt , Albert Ou , Charlie Jenkins , Bibo Mao , Huacai Chen , Catalin Marinas , Jiri Slaby , =?utf-8?B?QmrDtnJuIFTDtnBlbA==?= , Howard Chu , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-arm-kernel@lists.infradead.org, "linux-csky@vger.kernel.org" , linux-riscv@lists.infradead.org, linux-mips@vger.kernel.org, Arnd Bergmann Subject: Re: [PATCH v3 0/8] perf: Support multiple system call tables in the build Message-ID: References: <20250219185657.280286-1-irogers@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, Feb 24, 2025 at 08:22:50PM -0800, Ian Rogers wrote: > On Mon, Feb 24, 2025 at 7:20 PM Namhyung Kim wrote: > > > > On Wed, Feb 19, 2025 at 10:56:49AM -0800, Ian Rogers wrote: > > > This work builds on the clean up of system call tables and removal of > > > libaudit by Charlie Jenkins . > > > > > > The system call table in perf trace is used to map system call numbers > > > to names and vice versa. Prior to these changes, a single table > > > matching the perf binary's build was present. The table would be > > > incorrect if tracing say a 32-bit binary from a 64-bit version of > > > perf, the names and numbers wouldn't match. > > > > > > Change the build so that a single system call file is built and the > > > potentially multiple tables are identifiable from the ELF machine type > > > of the process being examined. To determine the ELF machine type, the > > > executable's header is read from /proc/pid/exe with fallbacks to using > > > the perf's binary type when unknown. > > > > Hmm.. then this is limited to live mode and potentially detect wrong > > machine type if it reads an old data, right? > > > > Also IIUC fallback to the perf binary means it cannot use cross-machine > > table. For example, it cannot process data from ARM64 on x86, no? It > > seems it should use perf_env.arch. > > The perf env arch is kind of horrid. On x86 it has the value x86 and > then there is an extra 64bit flag, who knows how x32 should be encoded > - but we barely support x32 as-is. I'd rather we added a new feature > for the e_machine/e_flags of the executable and worked with those, but > it is kind of weird with doing system wide mode. I didn't want to drag > that into this patch series anyway as there is already enough here. Right, I don't know how to handle x32 properly. Maybe we can just ignore it for now. But anyway looking at /proc/PID for recorded data doesn't seem correct. Can you please add a flag to do that only from trace__run() and just use EM_HOST for trace__replay()? Later, we may need to add a misc flag or so to PERF_RECORD_FORK (and PERF_RECORD_COMM with MISC_COMM_EXEC) to indicate non-standard ABI for a new thread. But it's not clear how to make it arch-independent. > > > One more concern is BPF. The BPF should know about the ABI of the > > current process so that it can augment the syscall arguments correctly. > > Currently it only checks the syscall number but it can be different on > > 32-bit and 64-bit. > > That's right. This change is trying to clean up > tools/perf/util/syscalltbl.c and the perf trace usage. I didn't go as > far as making BPF programs pair system call number with e_machine and > e_flags, there is enough here and the behavior after these patches > matches the behavior before - that is to assume the system call ABI > matches that of the perf binary. Right, the next step would be adding a BPF kfunc to identify the current ABI. Thanks, Namhyung From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 7BE55C021B8 for ; Thu, 27 Feb 2025 00:02:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=qLKyW88j6fb8dbr5R3Ffli5aoL64ED+JGm+M3xCS508=; b=3pLDtYPYXLpk0+ 4F82rIpltwZ3Gs0yAcsNrK8DMqIxhRs3vhpCAHXzceUhld4ivvFrt/8a0Ocs1flEXMpoUxYAuTmGX ulHhI02FH5hAnSWSgYrH3rRxEKZdA4tZGkbjsRSXFFqHLlWolsKO23FerNb+JmJK4A4vPgNHec1J5 C627F96x0Tz0WP4EaWJxv88A864qohjUB9lEpRR3OSVNtxmRdVl6v7Z21krRlYK7NQaOJPTB89LJ9 lmt43pUSD11XM5W7zH9ARBiF76JpJ2zcmgymH59aNSACPeMma41j03e2NadcDPg++/iAn0075kmoD vmWgxCdlaUlV36a8t1zg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tnRMI-00000005l99-1LHR; Thu, 27 Feb 2025 00:02:34 +0000 Received: from tor.source.kernel.org ([172.105.4.254]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1tnRKl-00000005l1e-1VaQ; Thu, 27 Feb 2025 00:00:59 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 743DB612B0; Thu, 27 Feb 2025 00:00:50 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id F154EC4CED6; Thu, 27 Feb 2025 00:00:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1740614458; bh=qd5L09r8BbWtp3sAdRkvQxm/boMlegFYOUTq9AxcaRA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=JJiViAXPMxyzFzf9Hv16zUQzj8/qcVzYFJj7H31yYwopnzVcgJ3IWMgfHJ+14Oawi FH/2zQ38hXIe2aBZp+k+W5gHvA14Ols6fXDb2nobInHVV9tZuM6fyRIVKnpX3rbSE/ S19H8+xhIluAVHCe3LrlHXrLWswcBkjjlrOH/VfX/SdIq/8LgFQBU7vIeh06BAMDzV /XKxRxaQP2UfjOsbZKRHTRhCx0Ozbdy0Apq0EMTCr2HEQfQpk1RSjZunhinNdVW28S /sguI1ft/UZy/3f5o7gSzvdrZJWwnBHVbnYDea42DQwCuDW4sMzAxs15CFkGwqajov yLqLq3Dn7PJJQ== Date: Wed, 26 Feb 2025 16:00:55 -0800 From: Namhyung Kim To: Ian Rogers Cc: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Adrian Hunter , Kan Liang , John Garry , Will Deacon , James Clark , Mike Leach , Leo Yan , guoren , Paul Walmsley , Palmer Dabbelt , Albert Ou , Charlie Jenkins , Bibo Mao , Huacai Chen , Catalin Marinas , Jiri Slaby , =?utf-8?B?QmrDtnJuIFTDtnBlbA==?= , Howard Chu , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-arm-kernel@lists.infradead.org, "linux-csky@vger.kernel.org" , linux-riscv@lists.infradead.org, linux-mips@vger.kernel.org, Arnd Bergmann Subject: Re: [PATCH v3 0/8] perf: Support multiple system call tables in the build Message-ID: References: <20250219185657.280286-1-irogers@google.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; 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