linux-kernel - [PATCH v2 12/15] ACPI: platform_profile: Make sure all profile handlers agree on profile

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Message-ID: <20241028020131.8031-13-mario.limonciello@amd.com>
Date: Sun, 27 Oct 2024 21:01:28 -0500
From: Mario Limonciello <mario.limonciello@....com>
To: Hans de Goede <hdegoede@...hat.com>, Ilpo Järvinen
	<ilpo.jarvinen@...ux.intel.com>
CC: "Rafael J . Wysocki" <rafael@...nel.org>, Len Brown <lenb@...nel.org>,
	Maximilian Luz <luzmaximilian@...il.com>, Lee Chun-Yi <jlee@...e.com>, "Shyam
 Sundar S K" <Shyam-sundar.S-k@....com>, Corentin Chary
	<corentin.chary@...il.com>, "Luke D . Jones" <luke@...nes.dev>, Ike Panhc
	<ike.pan@...onical.com>, Henrique de Moraes Holschuh <hmh@....eng.br>,
	"Alexis Belmonte" <alexbelm48@...il.com>, Uwe Kleine-König
	<u.kleine-koenig@...gutronix.de>, Ai Chao <aichao@...inos.cn>, Gergo Koteles
	<soyer@....hu>, open list <linux-kernel@...r.kernel.org>, "open list:ACPI"
	<linux-acpi@...r.kernel.org>, "open list:MICROSOFT SURFACE PLATFORM PROFILE
 DRIVER" <platform-driver-x86@...r.kernel.org>, "open list:THINKPAD ACPI
 EXTRAS DRIVER" <ibm-acpi-devel@...ts.sourceforge.net>, Mark Pearson
	<mpearson-lenovo@...ebb.ca>, Matthew Schwartz <matthew.schwartz@...ux.dev>,
	Mario Limonciello <mario.limonciello@....com>
Subject: [PATCH v2 12/15] ACPI: platform_profile: Make sure all profile handlers agree on profile

If for any reason multiple profile handlers don't agree on the profile
set for the system then the value shown in sysfs can be wrong.

Explicitly check that they match.

Tested-by: Matthew Schwartz <matthew.schwartz@...ux.dev>
Signed-off-by: Mario Limonciello <mario.limonciello@....com>
---
 drivers/acpi/platform_profile.c | 61 ++++++++++++++++++++++++---------
 1 file changed, 45 insertions(+), 16 deletions(-)

diff --git a/drivers/acpi/platform_profile.c b/drivers/acpi/platform_profile.c
index db2ebd0393cf7..d22c4eb5f0c36 100644
--- a/drivers/acpi/platform_profile.c
+++ b/drivers/acpi/platform_profile.c
@@ -51,6 +51,45 @@ static unsigned long platform_profile_get_choices(void)
 	return seen;
 }
 
+/* expected to be called under mutex */
+static int platform_profile_get_active(enum platform_profile_option *profile)
+{
+	struct platform_profile_handler *handler;
+	enum platform_profile_option active = PLATFORM_PROFILE_LAST;
+	enum platform_profile_option active2 = PLATFORM_PROFILE_LAST;
+	int err;
+
+	list_for_each_entry(handler, &platform_profile_handler_list, list) {
+		if (active == PLATFORM_PROFILE_LAST)
+			err = handler->profile_get(handler, &active);
+		else
+			err = handler->profile_get(handler, &active2);
+		if (err) {
+			pr_err("Failed to get profile for handler %s\n", handler->name);
+			return err;
+		}
+
+		if (WARN_ON(active == PLATFORM_PROFILE_LAST))
+			return -EINVAL;
+		if (active2 == PLATFORM_PROFILE_LAST)
+			continue;
+
+		if (active != active2) {
+			pr_warn("Profile handlers don't agree on current profile\n");
+			return -EINVAL;
+		}
+		active = active2;
+	}
+
+	/* Check that profile is valid index */
+	if (WARN_ON((active < 0) || (active >= ARRAY_SIZE(profile_names))))
+		return -EIO;
+
+	*profile = active;
+
+	return 0;
+}
+
 static ssize_t platform_profile_choices_show(struct device *dev,
 					struct device_attribute *attr,
 					char *buf)
@@ -80,24 +119,14 @@ static ssize_t platform_profile_show(struct device *dev,
 	enum platform_profile_option profile = PLATFORM_PROFILE_BALANCED;
 	int err;
 
-	err = mutex_lock_interruptible(&profile_lock);
-	if (err)
-		return err;
-
-	if (!cur_profile) {
-		mutex_unlock(&profile_lock);
-		return -ENODEV;
+	scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &profile_lock) {
+		if (!platform_profile_is_registered())
+			return -ENODEV;
+		err = platform_profile_get_active(&profile);
+		if (err)
+			return err;
 	}
 
-	err = cur_profile->profile_get(cur_profile, &profile);
-	mutex_unlock(&profile_lock);
-	if (err)
-		return err;
-
-	/* Check that profile is valid index */
-	if (WARN_ON((profile < 0) || (profile >= ARRAY_SIZE(profile_names))))
-		return -EIO;
-
 	return sysfs_emit(buf, "%s\n", profile_names[profile]);
 }
 
-- 
2.43.0