linux-kernel - [PATCH v4 7/7] x86/resctrl: Add debug files when mounted with debug option

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Message-ID: <168177451010.1758847.568218491528297451.stgit@bmoger-ubuntu>
Date:   Mon, 17 Apr 2023 18:35:10 -0500
From:   Babu Moger <babu.moger@....com>
To:     <corbet@....net>, <reinette.chatre@...el.com>,
        <tglx@...utronix.de>, <mingo@...hat.com>, <bp@...en8.de>
CC:     <fenghua.yu@...el.com>, <dave.hansen@...ux.intel.com>,
        <x86@...nel.org>, <hpa@...or.com>, <paulmck@...nel.org>,
        <akpm@...ux-foundation.org>, <quic_neeraju@...cinc.com>,
        <rdunlap@...radead.org>, <damien.lemoal@...nsource.wdc.com>,
        <songmuchun@...edance.com>, <peterz@...radead.org>,
        <jpoimboe@...nel.org>, <pbonzini@...hat.com>, <babu.moger@....com>,
        <chang.seok.bae@...el.com>, <pawan.kumar.gupta@...ux.intel.com>,
        <jmattson@...gle.com>, <daniel.sneddon@...ux.intel.com>,
        <sandipan.das@....com>, <tony.luck@...el.com>,
        <james.morse@....com>, <linux-doc@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <bagasdotme@...il.com>,
        <eranian@...gle.com>, <christophe.leroy@...roup.eu>,
        <pawan.kumar.gupta@...ux.intel.com>, <jarkko@...nel.org>,
        <adrian.hunter@...el.com>, <quic_jiles@...cinc.com>,
        <peternewman@...gle.com>, <babu.moger@....com>
Subject: [PATCH v4 7/7] x86/resctrl: Add debug files when mounted with debug
 option

Add the debug files to the resctrl hierarchy.

Signed-off-by: Babu Moger <babu.moger@....com>
---
 arch/x86/kernel/cpu/resctrl/internal.h |    1 +
 arch/x86/kernel/cpu/resctrl/rdtgroup.c |   54 +++++++++++++++++++++++++++++++-
 2 files changed, 54 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index 1eac07ebc31b..855109abb480 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -288,6 +288,7 @@ struct rdtgroup {
 #define RFTYPE_TOP			BIT(4)
 #define RFTYPE_RES_CACHE		BIT(5)
 #define RFTYPE_RES_MB			BIT(6)
+#define RFTYPE_DEBUG			BIT(7)
 #define RFTYPE_CTRL_INFO		(RFTYPE_INFO | RFTYPE_CTRL)
 #define RFTYPE_MON_INFO			(RFTYPE_INFO | RFTYPE_MON)
 #define RFTYPE_TOP_INFO			(RFTYPE_INFO | RFTYPE_TOP)
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 15ded0dd5b09..1ec4359348c2 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -1880,6 +1880,7 @@ static struct rftype res_common_files[] = {
 		.mode		= 0444,
 		.kf_ops		= &rdtgroup_kf_single_ops,
 		.seq_show	= rdtgroup_rmid_show,
+		.fflags		= RFTYPE_BASE | RFTYPE_DEBUG,
 	},
 	{
 		.name		= "schemata",
@@ -1909,6 +1910,7 @@ static struct rftype res_common_files[] = {
 		.mode		= 0444,
 		.kf_ops		= &rdtgroup_kf_single_ops,
 		.seq_show	= rdtgroup_closid_show,
+		.fflags		= RFTYPE_CTRL_BASE | RFTYPE_DEBUG,
 	},
 
 };
@@ -2420,6 +2422,49 @@ static int mkdir_mondata_all(struct kernfs_node *parent_kn,
 			     struct rdtgroup *prgrp,
 			     struct kernfs_node **mon_data_kn);
 
+static void resctrl_add_debug_files(void)
+{
+	struct rftype *rfts, *rft;
+	int len;
+
+	rfts = res_common_files;
+	len = ARRAY_SIZE(res_common_files);
+
+	lockdep_assert_held(&rdtgroup_mutex);
+
+	for (rft = rfts; rft < rfts + len; rft++) {
+		if (rft->fflags & RFTYPE_DEBUG) {
+			rft->fflags &= ~RFTYPE_DEBUG;
+			rdtgroup_add_file(rdtgroup_default.kn, rft);
+		}
+	}
+
+	kernfs_activate(rdtgroup_default.kn);
+}
+
+static void resctrl_remove_debug_files(void)
+{
+	struct rftype *rfts, *rft;
+	int len;
+
+	rfts = res_common_files;
+	len = ARRAY_SIZE(res_common_files);
+
+	lockdep_assert_held(&rdtgroup_mutex);
+
+	for (rft = rfts; rft < rfts + len; rft++) {
+		if (!strcmp(rft->name, "mon_hw_id")) {
+			rft->fflags |= RFTYPE_DEBUG;
+			kernfs_remove_by_name(rdtgroup_default.kn, rft->name);
+		} else if (!strcmp(rft->name, "ctrl_hw_id")) {
+			rft->fflags |= RFTYPE_DEBUG;
+			kernfs_remove_by_name(rdtgroup_default.kn, rft->name);
+		}
+	}
+
+	kernfs_activate(rdtgroup_default.kn);
+}
+
 static int rdt_enable_ctx(struct rdt_fs_context *ctx)
 {
 	int ret = 0;
@@ -2433,8 +2478,10 @@ static int rdt_enable_ctx(struct rdt_fs_context *ctx)
 	if (!ret && ctx->enable_mba_mbps)
 		ret = set_mba_sc(true);
 
-	if (!ret && ctx->enable_debug)
+	if (!ret && ctx->enable_debug) {
 		resctrl_debug = true;
+		resctrl_add_debug_files();
+	}
 
 	return ret;
 }
@@ -2851,6 +2898,11 @@ static void rdt_kill_sb(struct super_block *sb)
 
 	set_mba_sc(false);
 
+	if (resctrl_debug) {
+		resctrl_remove_debug_files();
+		resctrl_debug = false;
+	}
+
 	/*Put everything back to default values. */
 	for_each_alloc_capable_rdt_resource(r)
 		reset_all_ctrls(r);