[PATCH 2/3] platform/x86/amd/hsmp: Add explicit metric DRAM mapping and per-socket mutexes

[Muralidhara M K]

Add hsmp_destroy_metric_read_locks(), hsmp_init_metric_read_locks(), and
switch metric table DRAM from devm_ioremap() to ioremap() so ACPI can
coordinate teardown.  Embed struct mutex metric_read_lock in each
hsmp_socket for later serialization of metric table reads.

Call the new helpers from the platform driver probe and remove paths
so non-ACPI builds initialize and tear down metric_read_lock consistently
with the ACPI driver.

Signed-off-by: Muralidhara M K <muralidhara.mk@xxxxxxx>
---
 drivers/platform/x86/amd/hsmp/hsmp.c | 38 ++++++++++++++++++++++++++--
 drivers/platform/x86/amd/hsmp/hsmp.h |  5 ++++
 drivers/platform/x86/amd/hsmp/plat.c |  3 +++
 3 files changed, 44 insertions(+), 2 deletions(-)

diff --git a/drivers/platform/x86/amd/hsmp/hsmp.c b/drivers/platform/x86/amd/hsmp/hsmp.c
index 631ffc0978d1..81b6c24c3d3a 100644
--- a/drivers/platform/x86/amd/hsmp/hsmp.c
+++ b/drivers/platform/x86/amd/hsmp/hsmp.c
@@ -12,7 +12,11 @@
 #include <linux/acpi.h>
 #include <linux/delay.h>
 #include <linux/device.h>
+#include <linux/io.h>
+#include <linux/mutex.h>
+#include <linux/nospec.h>
 #include <linux/semaphore.h>
+#include <linux/slab.h>
 #include <linux/sysfs.h>
 
 #include "hsmp.h"
@@ -379,6 +383,37 @@ ssize_t hsmp_metric_tbl_read(struct hsmp_socket *sock, char *buf, size_t size)
 }
 EXPORT_SYMBOL_NS_GPL(hsmp_metric_tbl_read, "AMD_HSMP");
 
+void hsmp_init_metric_read_locks(struct hsmp_plat_device *pdev, u16 num_sockets)
+{
+	u16 i;
+
+	if (!pdev->sock || !num_sockets)
+		return;
+
+	for (i = 0; i < num_sockets; i++)
+		mutex_init(&pdev->sock[i].metric_read_lock);
+}
+EXPORT_SYMBOL_NS_GPL(hsmp_init_metric_read_locks, "AMD_HSMP");
+
+void hsmp_destroy_metric_read_locks(struct hsmp_plat_device *pdev, u16 num_sockets)
+{
+	u16 i;
+
+	if (!pdev->sock || !num_sockets)
+		return;
+
+	for (i = 0; i < num_sockets; i++) {
+		struct hsmp_socket *s = &pdev->sock[i];
+
+		if (s->metric_tbl_addr) {
+			iounmap(s->metric_tbl_addr);
+			s->metric_tbl_addr = NULL;
+		}
+		mutex_destroy(&s->metric_read_lock);
+	}
+}
+EXPORT_SYMBOL_NS_GPL(hsmp_destroy_metric_read_locks, "AMD_HSMP");
+
 int hsmp_get_tbl_dram_base(u16 sock_ind)
 {
 	struct hsmp_socket *sock = &hsmp_pdev.sock[sock_ind];
@@ -403,8 +438,7 @@ int hsmp_get_tbl_dram_base(u16 sock_ind)
 		dev_err(sock->dev, "Invalid DRAM address for metric table\n");
 		return -ENOMEM;
 	}
-	sock->metric_tbl_addr = devm_ioremap(sock->dev, dram_addr,
-					     sizeof(struct hsmp_metric_table));
+	sock->metric_tbl_addr = ioremap(dram_addr, sizeof(struct hsmp_metric_table));
 	if (!sock->metric_tbl_addr) {
 		dev_err(sock->dev, "Failed to ioremap metric table addr\n");
 		return -ENOMEM;
diff --git a/drivers/platform/x86/amd/hsmp/hsmp.h b/drivers/platform/x86/amd/hsmp/hsmp.h
index 0509a442eaae..91bc21232646 100644
--- a/drivers/platform/x86/amd/hsmp/hsmp.h
+++ b/drivers/platform/x86/amd/hsmp/hsmp.h
@@ -15,6 +15,7 @@
 #include <linux/hwmon.h>
 #include <linux/kconfig.h>
 #include <linux/miscdevice.h>
+#include <linux/mutex.h>
 #include <linux/pci.h>
 #include <linux/semaphore.h>
 #include <linux/sysfs.h>
@@ -41,6 +42,8 @@ struct hsmp_socket {
 	struct bin_attribute hsmp_attr;
 	struct hsmp_mbaddr_info mbinfo;
 	void __iomem *metric_tbl_addr;
+	/* Protects metric table snapshot reads for this socket */
+	struct mutex metric_read_lock;
 	void __iomem *virt_base_addr;
 	struct semaphore hsmp_sem;
 	char name[HSMP_ATTR_GRP_NAME_SIZE];
@@ -63,7 +66,9 @@ long hsmp_ioctl(struct file *fp, unsigned int cmd, unsigned long arg);
 void hsmp_misc_deregister(void);
 int hsmp_misc_register(struct device *dev);
 int hsmp_get_tbl_dram_base(u16 sock_ind);
+void hsmp_init_metric_read_locks(struct hsmp_plat_device *pdev, u16 num_sockets);
 ssize_t hsmp_metric_tbl_read(struct hsmp_socket *sock, char *buf, size_t size);
+void hsmp_destroy_metric_read_locks(struct hsmp_plat_device *pdev, u16 num_sockets);
 struct hsmp_plat_device *get_hsmp_pdev(void);
 #if IS_ENABLED(CONFIG_HWMON)
 int hsmp_create_sensor(struct device *dev, u16 sock_ind);
diff --git a/drivers/platform/x86/amd/hsmp/plat.c b/drivers/platform/x86/amd/hsmp/plat.c
index e07f68575055..f61d6cd13e3b 100644
--- a/drivers/platform/x86/amd/hsmp/plat.c
+++ b/drivers/platform/x86/amd/hsmp/plat.c
@@ -211,6 +211,8 @@ static int hsmp_pltdrv_probe(struct platform_device *pdev)
 	if (!hsmp_pdev->sock)
 		return -ENOMEM;
 
+	hsmp_init_metric_read_locks(hsmp_pdev, hsmp_pdev->num_sockets);
+
 	ret = init_platform_device(&pdev->dev);
 	if (ret) {
 		dev_err(&pdev->dev, "Failed to init HSMP mailbox\n");
@@ -230,6 +232,7 @@ static int hsmp_pltdrv_probe(struct platform_device *pdev)
 static void hsmp_pltdrv_remove(struct platform_device *pdev)
 {
 	hsmp_misc_deregister();
+	hsmp_destroy_metric_read_locks(hsmp_pdev, hsmp_pdev->num_sockets);
 }
 
 static struct platform_driver amd_hsmp_driver = {
-- 
2.34.1