From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 00AE547A884 for ; Mon, 28 Sep 2026 22:15:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.17 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790633753; cv=none; b=Qu1xGO8tVQRcngFVyYbI4dpWZvWMmFCD+b5MHxtSVKaUhSqAInTqi60ItcfLx6/iE8mrjwojhl6Nbs5IBDdbM7Lg69WgQf790VMto69hMsl6xVep451vN7Ceg9jSUBUxG9GUfvbIgTC5c3jAq5v8ZVpKaKx/23fEQwBhdL2cZnQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790633753; c=relaxed/simple; bh=CrZns2872YAXZAGLZf8Ixtm78iyRWhipHBsf/gJfUR0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=nXEaU/n3mX2HpdoeNvzP+3RkCPn55qLYiIFu1dt3Ckua8YUTF52yIqVaRVlCtTG5rqorsbh2VzECZlXjZ+tl242kA58uicnJ5Vwvc0TdPPzWOMb1VihY/cAY1HckKer6LGxWs8EbFumRkiSsTkJCHynVZMYOD21snyAmVzlmgTM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=VHTSgA1r; arc=none smtp.client-ip=198.175.65.17 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="VHTSgA1r" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1790633748; x=1822169748; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=CrZns2872YAXZAGLZf8Ixtm78iyRWhipHBsf/gJfUR0=; b=VHTSgA1rqJ0E1A62VDunnFBd/5DLtUGI3jO0dF9EStOfyGSlhaYhqXy1 l4NEYpqqhzQHSsEdAVVCUMVr2teojoo7mQA9OXGPNjT8/4RKvkOSvGvJG U8ls/yfGA2aaX4v9Rp+QFug+HYsuIFbjkdsgpFszX9LHDHrbFWKYAnszy nhY+nIEmWK7YaaZwyQPCmSHcfq78EWJehJ38UdYHiAb3zJJwI2KoMS5vg tB/KqE/uY0bJhrSbchp9pmFPjKyomBQkYrneiaNwYLU7BXRsTrSvSGLNA VySIqWqwFjG6gVuxgcHUuwK3vu+En5RrLYk4jL4A9huDjUWv0KcfYdjUN Q==; X-CSE-ConnectionGUID: AcWt3JAqTEWYmZSxxdDQ0w== X-CSE-MsgGUID: 0NkRPJ+mRTq50F9FR1yRFw== X-IronPort-AV: E=McAfee;i="6800,10657,11919"; a="90387310" X-IronPort-AV: E=Sophos;i="6.27,129,1787036400"; d="scan'208";a="90387310" Received: from fmviesa007.fm.intel.com ([10.60.135.147]) by orvoesa109.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Sep 2026 15:15:20 -0700 X-CSE-ConnectionGUID: jgSydQ6JTqCEHRIbxiYoLQ== X-CSE-MsgGUID: 7ughns9VSpea1YYsElzxXQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.27,129,1787036400"; d="scan'208";a="274685525" Received: from lstrano-mobl6.amr.corp.intel.com (HELO agluck-desk3.intel.com) ([10.124.222.143]) by fmviesa007-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Sep 2026 15:15:19 -0700 From: Tony Luck To: Fenghua Yu , Reinette Chatre , Maciej Wieczor-Retman , Peter Newman , James Morse , Babu Moger , Drew Fustini , Dave Martin , Chen Yu , David E Box , x86@kernel.org Cc: Christoph Hellwig , linux-kernel@vger.kernel.org, patches@lists.linux.dev, Tony Luck Subject: [PATCH v13 18/25] x86/resctrl: Use registered function pointers for AET enumeration Date: Mon, 28 Sep 2026 15:15:02 -0700 Message-ID: <20260928221509.68002-19-tony.luck@intel.com> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260928221509.68002-1-tony.luck@intel.com> References: <20260928221509.68002-1-tony.luck@intel.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The pmt_telemetry driver registers enumeration functions with resctrl Application Energy Telemetry (AET) code. Use the function pointers instead of direct function calls in preparation for the telemetry driver to be a loadable module. The pmt_telemetry is forced to be built-in to the kernel, so it does not matter at this point that there is no matching module_put() for the try_module_get() in intel_aet_pre_mount(). This must be resolved with additions in the file system unmount path before pmt_telemetry can be configured as a module. Signed-off-by: Tony Luck --- v13: Replace intel_pmt_put_feature_group() call in intel_aet_exit() with call via registered function pointer. Explain in commit comment that pmt_telemetry is built-in so the try_module_get() is a no-op. --- arch/x86/kernel/cpu/resctrl/internal.h | 4 +-- arch/x86/kernel/cpu/resctrl/core.c | 2 +- arch/x86/kernel/cpu/resctrl/intel_aet.c | 37 ++++++++++++++++++++++--- 3 files changed, 36 insertions(+), 7 deletions(-) diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h index c038b7d80ce3..8406addc05f5 100644 --- a/arch/x86/kernel/cpu/resctrl/internal.h +++ b/arch/x86/kernel/cpu/resctrl/internal.h @@ -234,15 +234,15 @@ void rdt_domain_reconfigure_cdp(struct rdt_resource *r); void resctrl_arch_mbm_cntr_assign_set_one(struct rdt_resource *r); #ifdef CONFIG_X86_CPU_RESCTRL_INTEL_AET -bool intel_aet_get_events(void); void __exit intel_aet_exit(void); +bool intel_aet_pre_mount(void); int intel_aet_read_event(int domid, u32 rmid, void *arch_priv, u64 *val); void intel_aet_mon_domain_setup(int cpu, int id, struct rdt_resource *r, struct list_head *add_pos); bool intel_handle_aet_option(bool force_off, char *tok); #else -static inline bool intel_aet_get_events(void) { return false; } static inline void __exit intel_aet_exit(void) { } +static inline bool intel_aet_pre_mount(void) { return false; } static inline int intel_aet_read_event(int domid, u32 rmid, void *arch_priv, u64 *val) { return -EINVAL; diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c index 0262174df7ad..ac67b4523b2d 100644 --- a/arch/x86/kernel/cpu/resctrl/core.c +++ b/arch/x86/kernel/cpu/resctrl/core.c @@ -795,7 +795,7 @@ void resctrl_arch_pre_mount(void) struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_PERF_PKG].r_resctrl; int cpu; - if (!intel_aet_get_events()) + if (!intel_aet_pre_mount()) return; /* diff --git a/arch/x86/kernel/cpu/resctrl/intel_aet.c b/arch/x86/kernel/cpu/resctrl/intel_aet.c index 6c4f0bf3b876..fbe0a8761bb9 100644 --- a/arch/x86/kernel/cpu/resctrl/intel_aet.c +++ b/arch/x86/kernel/cpu/resctrl/intel_aet.c @@ -12,6 +12,7 @@ #define pr_fmt(fmt) "resctrl: " fmt #include +#include #include #include #include @@ -25,6 +26,7 @@ #include #include #include +#include #include #include #include @@ -293,6 +295,13 @@ static enum pmt_feature_id lookup_pfid(const char *pfname) return FEATURE_INVALID; } +/* + * Protects pmt_module, get_feature, put_feature against races between module + * load/unload of the pmt_telemetry module and mount/unmount of the resctrl + * file system. + */ +static DEFINE_MUTEX(aet_register_lock); + static struct module *pmt_module; static struct pmt_feature_group *(*get_feature)(enum pmt_feature_id id); static void (*put_feature)(struct pmt_feature_group *p); @@ -308,7 +317,7 @@ static void (*put_feature)(struct pmt_feature_group *p); * struct pmt_feature_group to indicate that its events are successfully * enabled. */ -bool intel_aet_get_events(void) +static bool aet_get_events(void) { struct pmt_feature_group *p; enum pmt_feature_id pfid; @@ -317,14 +326,14 @@ bool intel_aet_get_events(void) for_each_event_group(peg) { pfid = lookup_pfid((*peg)->pfname); - p = intel_pmt_get_regions_by_feature(pfid); + p = get_feature(pfid); if (IS_ERR_OR_NULL(p)) continue; if (enable_events(*peg, p)) { (*peg)->pfg = p; ret = true; } else { - intel_pmt_put_feature_group(p); + put_feature(p); } } @@ -335,6 +344,7 @@ void intel_aet_register_enumeration(struct module *module, struct pmt_feature_group *(*get)(enum pmt_feature_id id), void (*put)(struct pmt_feature_group *p)) { + guard(mutex)(&aet_register_lock); get_feature = get; put_feature = put; pmt_module = module; @@ -343,19 +353,38 @@ EXPORT_SYMBOL_NS_GPL(intel_aet_register_enumeration, "INTEL_PMT"); void intel_aet_unregister_enumeration(void) { + guard(mutex)(&aet_register_lock); pmt_module = NULL; get_feature = NULL; put_feature = NULL; } EXPORT_SYMBOL_NS_GPL(intel_aet_unregister_enumeration, "INTEL_PMT"); +bool intel_aet_pre_mount(void) +{ + guard(mutex)(&aet_register_lock); + + if (!get_feature || !put_feature) + return false; + + if (!try_module_get(pmt_module)) + return false; + + if (!aet_get_events()) { + module_put(pmt_module); + return false; + } + + return true; +} + void __exit intel_aet_exit(void) { struct event_group **peg; for_each_event_group(peg) { if ((*peg)->pfg) { - intel_pmt_put_feature_group((*peg)->pfg); + put_feature((*peg)->pfg); (*peg)->pfg = NULL; } } -- 2.55.0