From patchwork Tue Oct 16 16:24:44 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lorenzo Pieralisi X-Patchwork-Id: 1601501 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) by patchwork1.kernel.org (Postfix) with ESMTP id 543AD40ABA for ; Tue, 16 Oct 2012 16:26:48 +0000 (UTC) Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1TO9x3-0001nc-6m; Tue, 16 Oct 2012 16:25:05 +0000 Received: from service87.mimecast.com ([91.220.42.44]) by merlin.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1TO9wy-0001mn-9G for linux-arm-kernel@lists.infradead.org; Tue, 16 Oct 2012 16:25:01 +0000 Received: from cam-owa1.Emea.Arm.com (fw-tnat.cambridge.arm.com [217.140.96.21]) by service87.mimecast.com; Tue, 16 Oct 2012 17:24:57 +0100 Received: from e102568-lin.cambridge.arm.com ([10.1.255.212]) by cam-owa1.Emea.Arm.com with Microsoft SMTPSVC(6.0.3790.0); Tue, 16 Oct 2012 17:24:55 +0100 From: Lorenzo Pieralisi To: linux-arm-kernel@lists.infradead.org Subject: [RFC PATCH] ARM: kernel: update cpuinfo to print all online CPUs features Date: Tue, 16 Oct 2012 17:24:44 +0100 Message-Id: <1350404684-6883-1-git-send-email-lorenzo.pieralisi@arm.com> X-Mailer: git-send-email 1.7.12 X-OriginalArrivalTime: 16 Oct 2012 16:24:55.0309 (UTC) FILETIME=[C6E9CBD0:01CDABBA] X-MC-Unique: 112101617245711201 X-Spam-Note: CRM114 invocation failed X-Spam-Score: -2.6 (--) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-2.6 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at http://www.dnswl.org/, low trust [91.220.42.44 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Cc: Nicolas Pitre , Catalin Marinas , Lorenzo Pieralisi , Russell King X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org Currently, reading /proc/cpuinfo provides userspace with CPU ID of the CPU carrying out the read from the file. This is fine as long as all CPUs in the system are the same. With the advent of big.LITTLE and heterogenous ARM systems this approach provides user space with incorrect bits of information since CPU ids in the system might differ from the one provided by the CPU reading the file. This patch updates the cpuinfo show function and some internal data structures so that a read from /proc/cpuinfo prints HW information for all online CPUs at once, mirroring x86 behaviour. Signed-off-by: Lorenzo Pieralisi --- Posting it as a way to get advice on the best way to improve /proc/cpuinfo for heterogenous multi-cluster systems and to provide proper information to userspace without breaking existing semantics, no more than that. Comments more than welcome. Thanks, Lorenzo arch/arm/include/asm/cpu.h | 1 + arch/arm/kernel/setup.c | 66 +++++++++++++++++++++++----------------------- arch/arm/kernel/smp.c | 1 + 3 files changed, 35 insertions(+), 33 deletions(-) diff --git a/arch/arm/include/asm/cpu.h b/arch/arm/include/asm/cpu.h index d797223..2744f06 100644 --- a/arch/arm/include/asm/cpu.h +++ b/arch/arm/include/asm/cpu.h @@ -15,6 +15,7 @@ struct cpuinfo_arm { struct cpu cpu; + u32 cpuid; #ifdef CONFIG_SMP unsigned int loops_per_jiffy; #endif diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c index 8707cff..bf7839d08 100644 --- a/arch/arm/kernel/setup.c +++ b/arch/arm/kernel/setup.c @@ -1054,13 +1054,15 @@ static const char *hwcap_str[] = { static int c_show(struct seq_file *m, void *v) { - int i; + int i, j; + u32 cpuid; - seq_printf(m, "Processor\t: %s rev %d (%s)\n", - cpu_name, read_cpuid_id() & 15, elf_platform); + for_each_online_cpu(i) { + cpuid = is_smp() ? per_cpu(cpu_data, i).cpuid : read_cpuid_id(); + seq_printf(m, "Processor\t: %s rev %d (%s)\n", + cpu_name, cpuid & 15, elf_platform); #if defined(CONFIG_SMP) - for_each_online_cpu(i) { /* * glibc reads /proc/cpuinfo to determine the number of * online processors, looking for lines beginning with @@ -1070,42 +1072,40 @@ static int c_show(struct seq_file *m, void *v) seq_printf(m, "BogoMIPS\t: %lu.%02lu\n\n", per_cpu(cpu_data, i).loops_per_jiffy / (500000UL/HZ), (per_cpu(cpu_data, i).loops_per_jiffy / (5000UL/HZ)) % 100); - } -#else /* CONFIG_SMP */ - seq_printf(m, "BogoMIPS\t: %lu.%02lu\n", - loops_per_jiffy / (500000/HZ), - (loops_per_jiffy / (5000/HZ)) % 100); +#else + seq_printf(m, "BogoMIPS\t: %lu.%02lu\n", + loops_per_jiffy / (500000/HZ), + (loops_per_jiffy / (5000/HZ)) % 100); #endif + /* dump out the processor features */ + seq_puts(m, "Features\t: "); - /* dump out the processor features */ - seq_puts(m, "Features\t: "); + for (j = 0; hwcap_str[j]; j++) + if (elf_hwcap & (1 << j)) + seq_printf(m, "%s ", hwcap_str[j]); - for (i = 0; hwcap_str[i]; i++) - if (elf_hwcap & (1 << i)) - seq_printf(m, "%s ", hwcap_str[i]); + seq_printf(m, "\nCPU implementer\t: 0x%02x\n", cpuid >> 24); + seq_printf(m, "CPU architecture: %s\n", + proc_arch[cpu_architecture()]); - seq_printf(m, "\nCPU implementer\t: 0x%02x\n", read_cpuid_id() >> 24); - seq_printf(m, "CPU architecture: %s\n", proc_arch[cpu_architecture()]); - - if ((read_cpuid_id() & 0x0008f000) == 0x00000000) { - /* pre-ARM7 */ - seq_printf(m, "CPU part\t: %07x\n", read_cpuid_id() >> 4); - } else { - if ((read_cpuid_id() & 0x0008f000) == 0x00007000) { - /* ARM7 */ - seq_printf(m, "CPU variant\t: 0x%02x\n", - (read_cpuid_id() >> 16) & 127); + if ((cpuid & 0x0008f000) == 0x00000000) { + /* pre-ARM7 */ + seq_printf(m, "CPU part\t: %07x\n", cpuid >> 4); } else { - /* post-ARM7 */ - seq_printf(m, "CPU variant\t: 0x%x\n", - (read_cpuid_id() >> 20) & 15); + if ((cpuid & 0x0008f000) == 0x00007000) { + /* ARM7 */ + seq_printf(m, "CPU variant\t: 0x%02x\n", + (cpuid >> 16) & 127); + } else { + /* post-ARM7 */ + seq_printf(m, "CPU variant\t: 0x%x\n", + (cpuid >> 20) & 15); + } + seq_printf(m, "CPU part\t: 0x%03x\n", + (cpuid >> 4) & 0xfff); } - seq_printf(m, "CPU part\t: 0x%03x\n", - (read_cpuid_id() >> 4) & 0xfff); + seq_printf(m, "CPU revision\t: %d\n\n", cpuid & 15); } - seq_printf(m, "CPU revision\t: %d\n", read_cpuid_id() & 15); - - seq_puts(m, "\n"); seq_printf(m, "Hardware\t: %s\n", machine_name); seq_printf(m, "Revision\t: %04x\n", system_rev); diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c index f0bcb1e..73f407e 100644 --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -211,6 +211,7 @@ static void __cpuinit smp_store_cpu_info(unsigned int cpuid) struct cpuinfo_arm *cpu_info = &per_cpu(cpu_data, cpuid); cpu_info->loops_per_jiffy = loops_per_jiffy; + cpu_info->cpuid = read_cpuid_id(); store_cpu_topology(cpuid); }