From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.11]) (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 7BDFD3BB11D for ; Wed, 1 Jul 2026 21:36:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.11 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782941769; cv=none; b=kW/5R6WAyArgulCLGGIO+5S+xQHKc2SCiMlsNW7rAbXfwayvjbSYf3WzW7jscFv7YUFcvZbDJKYZlaLCMdXhm8guIRqI2L/JsaRG2zF0RZVRM/AfwcKcMEtnntAQfUXfe9DDC33bYgIxMLpjNZFyHGmnJrp0fsaT/avNPvX2MAI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782941769; c=relaxed/simple; bh=F37m85hW8RG+a99sL0JXQH5ji6WJWLPmL4njF/Y2IX8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=BA3UdtGXyZoKF/woNiKqe4BfMl2yCKNEJlLBA7gqfNI/Yc1WSiZT5dhYUlqKXsc+RAXE0Yh2ntNFQniontcxj8TvXU+EtN0J7sR2wJ09Aw83kGT8Vn6oeBck1y2CUm8PsoTsGrFXGyiqK2Z3LCOq96cJQQO/Q8rIsAt/PH5J6ps= 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=EKeGgUXO; arc=none smtp.client-ip=192.198.163.11 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="EKeGgUXO" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1782941767; x=1814477767; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=F37m85hW8RG+a99sL0JXQH5ji6WJWLPmL4njF/Y2IX8=; b=EKeGgUXOIRpja62wTdoMtQL5pxa038wcUCUkvMQnxfUNkJh9SCO9+NQ8 5IoafHMYz7MH6+8JPt0KAjak5YLAYq+DavJUbpNqx4WoEu1izzES3IHjJ bbPpoCwYonbH2gi/irVS7DY+sa2jGyOdfqM3n9A6zjIGr2fSUKJ8APh1I 8loGbjnvID2QvGDODK/XLylbgpjCFC0AxNNZ60ILGaUMh9Bu/fchoBScD GWg/3MXsst3TcY0q6BZaFhfasYRZq0eMf+632Pas5inx1i7K5b44ryfZw 4QxvNSDlLqF6fZRCYPKE1BdRb73/X9soKfvV2wZdaWMGN8PA4ew/JtEcZ Q==; X-CSE-ConnectionGUID: ta+4E+6vT/iEmjqRnHKedg== X-CSE-MsgGUID: TXrAa6N+TF6hvDIYVYu7AA== X-IronPort-AV: E=McAfee;i="6800,10657,11834"; a="94285826" X-IronPort-AV: E=Sophos;i="6.25,142,1779174000"; d="scan'208";a="94285826" Received: from orviesa008.jf.intel.com ([10.64.159.148]) by fmvoesa105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Jul 2026 14:36:05 -0700 X-CSE-ConnectionGUID: jcfBRf91R3m0JTtlsk2kmw== X-CSE-MsgGUID: bmVoNay8Seil5NAfZn9Wyg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.25,142,1779174000"; d="scan'208";a="252242545" Received: from mdroper-mobl2.amr.corp.intel.com (HELO agluck-desk3.intel.com) ([10.124.221.120]) by orviesa008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Jul 2026 14:36:04 -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 v9 09/12] arm,x86/resctrl: Resolve INTEL_PMT_TELEMETRY symbols at runtime Date: Wed, 1 Jul 2026 14:35:50 -0700 Message-ID: <20260701213553.15222-10-tony.luck@intel.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260701213553.15222-1-tony.luck@intel.com> References: <20260701213553.15222-1-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 resctrl is always built-in, but INTEL_PMT_TELEMETRY and INTEL_TPMI are logically independent and should be loadable modules. Switch AET to use the function-pointer registration API instead of direct link-time references to PMT symbols. Prepare for the file system to call resctrl_arch_pre_mount() on every mount by moving AET enumeration into resctrl_arch_pre_mount() and cleanup into resctrl_arch_unmount(). This allows the PMT module to be unloaded whenever the filesystem is not mounted. Remove intel_aet_exit because all cleanup now happens in the unmount path. Note that the Linux file system code does not serialize calls to fs_context_operations::get_tree(), so there may be arbitrarily many parallel calls if users invoke mount(2) multiple times. Use "pmt_in_use" to detect nested mount attempts. event_group::num_rmid may be reset (reduced) during enumeration. This is not worth resetting on unmount because the same reduction would occur on each subsequent mount. Signed-off-by: Tony Luck -- v9: Drop broken atomic ops introduced in v8 Check pmt_in_use in intel_aet_pre_mount() to detect nested mount flow. --- include/linux/resctrl.h | 6 +++ arch/x86/kernel/cpu/resctrl/internal.h | 23 ++++++++-- arch/x86/kernel/cpu/resctrl/core.c | 25 +++++++++-- arch/x86/kernel/cpu/resctrl/intel_aet.c | 58 +++++++++++++++++++++---- drivers/resctrl/mpam_resctrl.c | 4 ++ 5 files changed, 101 insertions(+), 15 deletions(-) diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h index e1501ee72d28..4dc41dc99dc2 100644 --- a/include/linux/resctrl.h +++ b/include/linux/resctrl.h @@ -564,6 +564,12 @@ void resctrl_offline_cpu(unsigned int cpu); */ void resctrl_arch_pre_mount(void); +/* + * Architecture hook called when mount fails, or on unmount. + * No locks are held. + */ +void resctrl_arch_unmount(void); + /** * resctrl_arch_rmid_read() - Read the eventid counter corresponding to rmid * for this resource and domain. diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h index e3cfa0c10e92..a891017f69ec 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); +void intel_aet_unmount(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 void intel_aet_unmount(void) { } static inline int intel_aet_read_event(int domid, u32 rmid, void *arch_priv, u64 *val) { return -EINVAL; @@ -253,4 +253,19 @@ static inline void intel_aet_mon_domain_setup(int cpu, int id, struct rdt_resour static inline bool intel_handle_aet_option(bool force_off, char *tok) { return false; } #endif +#ifdef CONFIG_INTEL_PMT_TELEMETRY_MODULE +static inline bool intel_aet_try_module_get(struct module *mod) +{ + return try_module_get(mod); +} + +static inline void intel_aet_module_put(struct module *mod) +{ + module_put(mod); +} +#else +static inline bool intel_aet_try_module_get(struct module *mod) { return true; } +static inline void intel_aet_module_put(struct module *mod) { } +#endif + #endif /* _ASM_X86_RESCTRL_INTERNAL_H */ diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c index 3169441a2d40..3ef620d8e0c8 100644 --- a/arch/x86/kernel/cpu/resctrl/core.c +++ b/arch/x86/kernel/cpu/resctrl/core.c @@ -16,10 +16,12 @@ #define pr_fmt(fmt) "resctrl: " fmt +#include #include #include #include #include +#include #include #include @@ -798,7 +800,7 @@ 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; /* @@ -814,6 +816,25 @@ void resctrl_arch_pre_mount(void) cpus_read_unlock(); } +void resctrl_arch_unmount(void) +{ + struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_PERF_PKG].r_resctrl; + int cpu; + + intel_aet_unmount(); + + if (!r->mon_capable) + return; + + cpus_read_lock(); + mutex_lock(&domain_list_lock); + for_each_online_cpu(cpu) + domain_remove_cpu_mon(cpu, r); + r->mon_capable = false; + mutex_unlock(&domain_list_lock); + cpus_read_unlock(); +} + enum { RDT_FLAG_CMT, RDT_FLAG_MBM_TOTAL, @@ -1187,8 +1208,6 @@ late_initcall(resctrl_arch_late_init); static void __exit resctrl_arch_exit(void) { - intel_aet_exit(); - cpuhp_remove_state(rdt_online); resctrl_exit(); diff --git a/arch/x86/kernel/cpu/resctrl/intel_aet.c b/arch/x86/kernel/cpu/resctrl/intel_aet.c index c26bd813e057..c2e27ce52248 100644 --- a/arch/x86/kernel/cpu/resctrl/intel_aet.c +++ b/arch/x86/kernel/cpu/resctrl/intel_aet.c @@ -25,8 +25,8 @@ #include #include #include -#include #include +#include #include #include #include @@ -310,7 +310,7 @@ 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; @@ -319,14 +319,14 @@ 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); } } @@ -359,16 +359,58 @@ void intel_aet_unregister_enumeration(void) } EXPORT_SYMBOL_NS_GPL(intel_aet_unregister_enumeration, "INTEL_PMT"); -void __exit intel_aet_exit(void) +/* + * Track whether pmt_telemetry enumeration succeeded during mount to + * detect nested mount attempts and for use during unmount. + */ +static bool pmt_in_use; + +bool intel_aet_pre_mount(void) +{ + bool ret; + + guard(mutex)(&aet_register_lock); + + /* Nested mount attempt. File system code will return -EBUSY */ + if (pmt_in_use) + return false; + + if (!get_feature || !put_feature) + return false; + + if (!intel_aet_try_module_get(pmt_module)) + return false; + + ret = aet_get_events(); + + if (!ret) + intel_aet_module_put(pmt_module); + else + pmt_in_use = true; + + return ret; +} + +void intel_aet_unmount(void) { struct event_group **peg; + guard(mutex)(&aet_register_lock); + if (!pmt_in_use) + return; + for_each_event_group(peg) { - if ((*peg)->pfg) { - intel_pmt_put_feature_group((*peg)->pfg); - (*peg)->pfg = NULL; + struct event_group *e = *peg; + + if (e->pfg) { + for (int j = 0; j < e->num_events; j++) + resctrl_disable_mon_event(e->evts[j].id); + put_feature(e->pfg); + e->pfg = NULL; } } + intel_aet_module_put(pmt_module); + pmt_in_use = false; } #define DATA_VALID BIT_ULL(63) diff --git a/drivers/resctrl/mpam_resctrl.c b/drivers/resctrl/mpam_resctrl.c index 7079870ca894..5859cc0f5e37 100644 --- a/drivers/resctrl/mpam_resctrl.c +++ b/drivers/resctrl/mpam_resctrl.c @@ -162,6 +162,10 @@ void resctrl_arch_pre_mount(void) { } +void resctrl_arch_unmount(void) +{ +} + bool resctrl_arch_get_cdp_enabled(enum resctrl_res_level rid) { return mpam_resctrl_controls[rid].cdp_enabled; -- 2.54.0