From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755006Ab3KGRSY (ORCPT ); Thu, 7 Nov 2013 12:18:24 -0500 Received: from mail-wi0-f174.google.com ([209.85.212.174]:64698 "EHLO mail-wi0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754564Ab3KGRRs (ORCPT ); Thu, 7 Nov 2013 12:17:48 -0500 From: Ard Biesheuvel To: x86@kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: gregkh@linuxfoundation.org, catalin.marinas@arm.com, will.deacon@arm.com, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, steve.capper@linaro.org, Ard Biesheuvel Subject: [RFC PATCH 2/4] cpu: advertise CPU features over udev in a generic way Date: Thu, 7 Nov 2013 18:17:35 +0100 Message-Id: <1383844657-17487-3-git-send-email-ard.biesheuvel@linaro.org> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <1383844657-17487-1-git-send-email-ard.biesheuvel@linaro.org> References: <1383844657-17487-1-git-send-email-ard.biesheuvel@linaro.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patch implements a generic modalias 'cpu:feature:...' which enables CPU feature flag based module loading in a generic way. All the arch needs to do is enable CONFIG_ARCH_HAS_CPU_AUTOPROBE and export a u32 called 'cpu_features'. (What each bit actually means is irrelevant on this level.) Signed-off-by: Ard Biesheuvel --- drivers/base/cpu.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c index 49c6f4b..a661d31 100644 --- a/drivers/base/cpu.c +++ b/drivers/base/cpu.c @@ -276,6 +276,30 @@ static void cpu_device_release(struct device *dev) } #ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE +ssize_t print_cpu_modalias(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + extern u32 __weak cpu_features; + ssize_t n; + int i; + u32 f; + + /* + * With 32 features maximum (taking 3 bytes each to print), we don't + * need to worry about overrunning the PAGE_SIZE sized buffer. + */ + n = sprintf(buf, "cpu:feature:"); + for (f = cpu_features, i = 0; f; f >>= 1, i++) + if (f & 1) + n += sprintf(&buf[n], ",%02X", i); + buf[n++] = '\n'; + return n; +} + +ssize_t __attribute__((weak, alias("print_cpu_modalias"))) +arch_print_cpu_modalias(struct device *, struct device_attribute *, char *); + static int cpu_uevent(struct device *dev, struct kobj_uevent_env *env) { char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL); -- 1.8.3.2