From: David E. Box david.e.box@linux.intel.com
[ Upstream commit bcdfa1f77ea7f67368d20384932a9d1e3047ddd2 ]
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@linux.intel.com Link: https://lore.kernel.org/r/20221105034228.1376677-1-david.e.box@linux.intel.c... Reviewed-by: Hans de Goede hdegoede@redhat.com Signed-off-by: Hans de Goede hdegoede@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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 659b1073033c..586a5877422b 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> @@ -18,6 +19,7 @@ #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
/* * Early implementations of PMT on client platforms have some @@ -41,6 +43,29 @@ 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 */ @@ -62,7 +87,11 @@ 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; }