[PATCH v8 1/4] platform/x86/amd/hsmp: Recognize Family 1Ah client platforms and hide server-only paths

[Muralidhara M K]

Add is_client_platform(), based on the ACPI-reported PM profile and
an AMD vendor check, to detect Family 1Ah client platforms, Models
80h-8Fh and E0h-E3h.

Use is_client_platform() to:

- Hide every ACPI sysfs device attribute except smu_fw_version and
  protocol_version on client platforms.
- Hide the metrics_bin sysfs binary attribute on client platforms.
- Skip hsmp_create_sensor() in init_acpi() on client platforms.
- Exclude client platforms from the HSMP_GET_METRIC_TABLE_DRAM_ADDR
  lookup in init_acpi().
- Register /dev/hsmp at 0600 on client platforms, 0644 on server.

Signed-off-by: Muralidhara M K <muralidhara.mk@xxxxxxx>
---
 drivers/platform/x86/amd/hsmp/acpi.c | 24 +++++++++++++++++++-----
 drivers/platform/x86/amd/hsmp/hsmp.c |  8 +++++++-
 drivers/platform/x86/amd/hsmp/hsmp.h | 23 +++++++++++++++++++++++
 3 files changed, 49 insertions(+), 6 deletions(-)

diff --git a/drivers/platform/x86/amd/hsmp/acpi.c b/drivers/platform/x86/amd/hsmp/acpi.c
index ddd7a04ee753..1e5028aea54b 100644
--- a/drivers/platform/x86/amd/hsmp/acpi.c
+++ b/drivers/platform/x86/amd/hsmp/acpi.c
@@ -300,16 +300,26 @@ static umode_t hsmp_is_sock_attr_visible(struct kobject *kobj,
 	 * so that userspace which expects the file to exist gets a clear
 	 * -EOPNOTSUPP from the read handler instead of -ENOENT, and is
 	 * pointed at HSMP_IOCTL_GET_TELEMETRY_DATA as the supported path.
+	 * Hide metrics_bin on client platforms.
 	 */
-	if (hsmp_pdev->proto_ver >= HSMP_PROTO_VER6)
+	if (!is_client_platform() && hsmp_pdev->proto_ver >= HSMP_PROTO_VER6)
 		return battr->attr.mode;
 
 	return 0;
 }
 
+/* Defined below by HSMP_DEV_ATTR() */
+static struct hsmp_sys_attr hattr_smu_fw_version;
+static struct hsmp_sys_attr hattr_protocol_version;
+
 static umode_t hsmp_is_sock_dev_attr_visible(struct kobject *kobj,
 					     struct attribute *attr, int id)
 {
+	/* Hide every attribute except smu_fw_version and protocol_version on client platforms */
+	if (is_client_platform() && attr != &hattr_smu_fw_version.dattr.attr &&
+	    attr != &hattr_protocol_version.dattr.attr)
+		return 0;
+
 	return attr->mode;
 }
 
@@ -557,15 +567,19 @@ static int init_acpi(struct device *dev)
 		return ret;
 	}
 
-	if (hsmp_pdev->proto_ver >= HSMP_PROTO_VER6) {
+	/* Exclude client platforms from the metric table DRAM base lookup */
+	if (!is_client_platform() && hsmp_pdev->proto_ver >= HSMP_PROTO_VER6) {
 		ret = hsmp_get_tbl_dram_base(sock_ind);
 		if (ret)
 			dev_info(dev, "Failed to init metric table\n");
 	}
 
-	ret = hsmp_create_sensor(dev, sock_ind);
-	if (ret)
-		dev_info(dev, "Failed to register HSMP sensors with hwmon\n");
+	/* Skip hwmon registration on client platforms */
+	if (!is_client_platform()) {
+		ret = hsmp_create_sensor(dev, sock_ind);
+		if (ret)
+			dev_info(dev, "Failed to register HSMP sensors with hwmon\n");
+	}
 
 	dev_set_drvdata(dev, &hsmp_pdev->sock[sock_ind]);
 
diff --git a/drivers/platform/x86/amd/hsmp/hsmp.c b/drivers/platform/x86/amd/hsmp/hsmp.c
index 5e123a4ecea9..d32d5a907aae 100644
--- a/drivers/platform/x86/amd/hsmp/hsmp.c
+++ b/drivers/platform/x86/amd/hsmp/hsmp.c
@@ -720,7 +720,13 @@ int hsmp_misc_register(struct device *dev)
 	 */
 	hsmp_pdev.mdev.parent	= dev;
 	hsmp_pdev.mdev.nodename	= HSMP_DEVNODE_NAME;
-	hsmp_pdev.mdev.mode	= 0644;
+	/*
+	 * hsmp_msg_desc_table[] only describes server messages. On client
+	 * platforms, msg_id mappings differ, making access checks unreliable.
+	 * Restrict /dev/hsmp to root until client-specific validation is
+	 * added.
+	 */
+	hsmp_pdev.mdev.mode	= is_client_platform() ? 0600 : 0644;
 
 	return misc_register(&hsmp_pdev.mdev);
 }
diff --git a/drivers/platform/x86/amd/hsmp/hsmp.h b/drivers/platform/x86/amd/hsmp/hsmp.h
index 8dbff16a87b1..62ba795dc8c5 100644
--- a/drivers/platform/x86/amd/hsmp/hsmp.h
+++ b/drivers/platform/x86/amd/hsmp/hsmp.h
@@ -10,6 +10,9 @@
 #ifndef HSMP_H
 #define HSMP_H
 
+#include <asm/amd/hsmp.h>
+
+#include <linux/acpi.h>
 #include <linux/compiler_types.h>
 #include <linux/device.h>
 #include <linux/hwmon.h>
@@ -17,6 +20,7 @@
 #include <linux/miscdevice.h>
 #include <linux/mutex.h>
 #include <linux/pci.h>
+#include <linux/processor.h>
 #include <linux/rwsem.h>
 #include <linux/semaphore.h>
 #include <linux/sysfs.h>
@@ -32,6 +36,25 @@
 
 #define DRIVER_VERSION		"2.6"
 
+/* True when the ACPI-reported PM profile indicates a client platform */
+static inline bool is_client_platform(void)
+{
+	if (!IS_ENABLED(CONFIG_ACPI))
+		return false;
+
+	if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD)
+		return false;
+
+	switch (acpi_gbl_FADT.preferred_profile) {
+	case PM_DESKTOP:
+	case PM_MOBILE:
+	case PM_TABLET:
+		return true;
+	default:
+		return false;
+	}
+}
+
 struct hsmp_mbaddr_info {
 	u32 base_addr;
 	u32 msg_id_off;
-- 
2.34.1