On Sapphire Rapids, due to a hardware issue affecting the PUNIT telemetry
region, reads that are not done in QWORD quantities and alignment may
return incorrect data. Use a custom 64-bit copy for this region.
Signed-off-by: David E. Box <david.e.box@xxxxxxxxxxxxxxx>
---
drivers/platform/x86/intel/pmt/class.c | 31 +++++++++++++++++++++++++-
1 file changed, 30 insertions(+), 1 deletion(-)
diff --git a/drivers/platform/x86/intel/pmt/class.c b/drivers/platform/x86/intel/pmt/class.c
index 53d7fd2943b4..46598dcb634a 100644
--- a/drivers/platform/x86/intel/pmt/class.c
+++ b/drivers/platform/x86/intel/pmt/class.c
@@ -9,6 +9,7 @@
*/
#include <linux/kernel.h>
+#include <linux/io-64-nonatomic-lo-hi.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/pci.h>
@@ -19,6 +20,7 @@
#define PMT_XA_START 0
#define PMT_XA_MAX INT_MAX
#define PMT_XA_LIMIT XA_LIMIT(PMT_XA_START, PMT_XA_MAX)
+#define GUID_SPR_PUNIT 0x9956f43f
bool intel_pmt_is_early_client_hw(struct device *dev)
{
@@ -33,6 +35,29 @@ bool intel_pmt_is_early_client_hw(struct device *dev)
}
EXPORT_SYMBOL_GPL(intel_pmt_is_early_client_hw);
+static inline int
+pmt_memcpy64_fromio(void *to, const u64 __iomem *from, size_t count)
+{
+ int i, remain;
+ u64 *buf = to;
+
+ if (!IS_ALIGNED((unsigned long)from, 8))
+ return -EFAULT;
+
+ for (i = 0; i < count/8; i++)
+ buf[i] = readq(&from[i]);
+
+ /* Copy any remaining bytes */
+ remain = count % 8;
+ if (remain) {
+ u64 tmp = readq(&from[i]);
+
+ memcpy(&buf[i], &tmp, remain);
+ }
+
+ return count;
+}
+
/*
* sysfs
*/
@@ -54,7 +79,11 @@ intel_pmt_read(struct file *filp, struct kobject *kobj,
if (count > entry->size - off)
count = entry->size - off;
- memcpy_fromio(buf, entry->base + off, count);
+ if (entry->guid == GUID_SPR_PUNIT)
+ /* PUNIT on SPR only supports aligned 64-bit read */
+ count = pmt_memcpy64_fromio(buf, entry->base + off, count);
+ else
+ memcpy_fromio(buf, entry->base + off, count);
return count;
}
base-commit: 225469d4acbcb873358d7618bad6e0203b67b964
--
2.25.1
