s390/cio: export extended channel-path-measurement data

Add a per-CHPID binary sysfs attribute named "ext_measurement" that
provides access to extended channel-path-measurement data for the
associated channel path.

Note that while not all channel-paths provide extended measurement data
this attribute is created unconditionally for all channel paths because
channel-path measurement capabilities might change during run-time.
Reading from the attribute will only return data for channel-paths that
support extended measurement data.

Example:

$ echo 1 > /sys/devices/css0/cm_enable
$ xxd /sys/devices/css0/chp0.32/ext_measurement
00000000: 53e0 8002 0000 0095 0000 0000 59cc e034  S...........Y..4
00000010: 38b8 cc45 0000 0000 0000 0000 3e24 fe94  8..E........>$..
00000020: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000030: 0000 0000 0000 0000 0000 0000 0000 0000  ................

Reviewed-by: Vineeth Vijayan <vneethv@linux.ibm.com>
Tested-by: Vineeth Vijayan <vneethv@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>

Author: oberpar

drivers/s390/cio/chp.c

@@ -144,55 +144,65 @@ static ssize_t measurement_chars_read(struct file *filp, struct kobject *kobj,
 }
 static BIN_ATTR_ADMIN_RO(measurement_chars, sizeof(struct cmg_chars));
 
-static void chp_measurement_copy_block(struct cmg_entry *buf,
-				       struct channel_subsystem *css,
-				       struct chp_id chpid)
-{
-	void *area;
-	struct cmg_entry *entry, reference_buf;
-	int idx;
-
-	if (chpid.id < CSS_CUES_PER_PAGE) {
-		area = css->cub[0];
-		idx = chpid.id;
-	} else {
-		area = css->cub[1];
-		idx = chpid.id - CSS_CUES_PER_PAGE;
-	}
-	entry = area + (idx * sizeof(struct cmg_entry));
-	do {
-		memcpy(buf, entry, sizeof(*entry));
-		memcpy(&reference_buf, entry, sizeof(*entry));
-	} while (reference_buf.values[0] != buf->values[0]);
-}
-
-static ssize_t measurement_read(struct file *filp, struct kobject *kobj,
-				struct bin_attribute *bin_attr,
-				char *buf, loff_t off, size_t count)
+static ssize_t chp_measurement_copy_block(void *buf, loff_t off, size_t count,
+					  struct kobject *kobj, bool extended)
 {
 	struct channel_path *chp;
 	struct channel_subsystem *css;
 	struct device *device;
 	unsigned int size;
+	void *area, *entry;
+	int id, idx;
 
 	device = kobj_to_dev(kobj);
 	chp = to_channelpath(device);
 	css = to_css(chp->dev.parent);
+	id = chp->chpid.id;
 
-	size = sizeof(struct cmg_entry);
+	if (extended) {
+		/* Check if extended measurement data is available. */
+		if (!chp->extended)
+			return 0;
+
+		size = sizeof(struct cmg_ext_entry);
+		area = css->ecub[id / CSS_ECUES_PER_PAGE];
+		idx = id % CSS_ECUES_PER_PAGE;
+	} else {
+		size = sizeof(struct cmg_entry);
+		area = css->cub[id / CSS_CUES_PER_PAGE];
+		idx = id % CSS_CUES_PER_PAGE;
+	}
+	entry = area + (idx * size);
 
 	/* Only allow single reads. */
 	if (off || count < size)
 		return 0;
-	chp_measurement_copy_block((struct cmg_entry *)buf, css, chp->chpid);
-	count = size;
-	return count;
+
+	memcpy(buf, entry, size);
+
+	return size;
+}
+
+static ssize_t measurement_read(struct file *filp, struct kobject *kobj,
+				struct bin_attribute *bin_attr,
+				char *buf, loff_t off, size_t count)
+{
+	return chp_measurement_copy_block(buf, off, count, kobj, false);
 }
 static BIN_ATTR_ADMIN_RO(measurement, sizeof(struct cmg_entry));
 
+static ssize_t ext_measurement_read(struct file *filp, struct kobject *kobj,
+				    struct bin_attribute *bin_attr,
+				    char *buf, loff_t off, size_t count)
+{
+	return chp_measurement_copy_block(buf, off, count, kobj, true);
+}
+static BIN_ATTR_ADMIN_RO(ext_measurement, sizeof(struct cmg_ext_entry));
+
 static struct bin_attribute *measurement_attrs[] = {
 	&bin_attr_measurement_chars,
 	&bin_attr_measurement,
+	&bin_attr_ext_measurement,
 	NULL,
 };
 BIN_ATTRIBUTE_GROUPS(measurement);

drivers/s390/cio/chp.h

@@ -51,6 +51,7 @@ struct channel_path {
 	/* Channel-measurement related stuff: */
 	int cmg;
 	int shared;
+	int extended;
 	struct cmg_chars cmg_chars;
 };
 

drivers/s390/cio/chsc.c

@@ -871,11 +871,14 @@ int __chsc_do_secm(struct channel_subsystem *css, int enable)
 	struct {
 		struct chsc_header request;
 		u32 operation_code : 2;
-		u32 : 30;
+		u32 : 1;
+		u32 e : 1;
+		u32 : 28;
 		u32 key : 4;
 		u32 : 28;
 		dma64_t cub[CSS_NUM_CUB_PAGES];
-		u32 reserved[13];
+		dma64_t ecub[CSS_NUM_ECUB_PAGES];
+		u32 reserved[5];
 		struct chsc_header response;
 		u32 status : 8;
 		u32 : 4;
@@ -892,9 +895,12 @@ int __chsc_do_secm(struct channel_subsystem *css, int enable)
 	secm_area->request.code = 0x0016;
 
 	secm_area->key = PAGE_DEFAULT_KEY >> 4;
+	secm_area->e = 1;
 
 	for (i = 0; i < CSS_NUM_CUB_PAGES; i++)
 		secm_area->cub[i] = (__force dma64_t)virt_to_dma32(css->cub[i]);
+	for (i = 0; i < CSS_NUM_ECUB_PAGES; i++)
+		secm_area->ecub[i] = virt_to_dma64(css->ecub[i]);
 
 	secm_area->operation_code = enable ? 0 : 1;
 
@@ -929,6 +935,11 @@ static int cub_alloc(struct channel_subsystem *css)
 		if (!css->cub[i])
 			return -ENOMEM;
 	}
+	for (i = 0; i < CSS_NUM_ECUB_PAGES; i++) {
+		css->ecub[i] = (void *)get_zeroed_page(GFP_KERNEL);
+		if (!css->ecub[i])
+			return -ENOMEM;
+	}
 
 	return 0;
 }
@@ -941,6 +952,10 @@ static void cub_free(struct channel_subsystem *css)
 		free_page((unsigned long)css->cub[i]);
 		css->cub[i] = NULL;
 	}
+	for (i = 0; i < CSS_NUM_ECUB_PAGES; i++) {
+		free_page((unsigned long)css->ecub[i]);
+		css->ecub[i] = NULL;
+	}
 }
 
 int
@@ -1067,7 +1082,8 @@ int chsc_get_channel_measurement_chars(struct channel_path *chp)
 		u32 zeroes2;
 		u32 not_valid : 1;
 		u32 shared : 1;
-		u32 : 22;
+		u32 extended : 1;
+		u32 : 21;
 		u32 chpid : 8;
 		u32 cmcv : 5;
 		u32 : 11;
@@ -1079,6 +1095,7 @@ int chsc_get_channel_measurement_chars(struct channel_path *chp)
 
 	chp->shared = -1;
 	chp->cmg = -1;
+	chp->extended = 0;
 
 	if (!css_chsc_characteristics.scmc || !css_chsc_characteristics.secm)
 		return -EINVAL;
@@ -1108,6 +1125,7 @@ int chsc_get_channel_measurement_chars(struct channel_path *chp)
 
 	chp->cmg = scmc_area->cmg;
 	chp->shared = scmc_area->shared;
+	chp->extended = scmc_area->extended;
 	if (chp->cmg != 2 && chp->cmg != 3) {
 		/* No cmg-dependent data. */
 		goto out;

drivers/s390/cio/chsc.h

@@ -22,6 +22,11 @@ struct cmg_entry {
 	u32 values[NR_MEASUREMENT_ENTRIES];
 };
 
+#define NR_EXT_MEASUREMENT_ENTRIES 16
+struct cmg_ext_entry {
+	u32 values[NR_EXT_MEASUREMENT_ENTRIES];
+};
+
 struct channel_path_desc_fmt1 {
 	u8 flags;
 	u8 lsn;

drivers/s390/cio/css.h

@@ -40,6 +40,8 @@
 
 #define CSS_NUM_CUB_PAGES		2
 #define CSS_CUES_PER_PAGE		128
+#define CSS_NUM_ECUB_PAGES		4
+#define CSS_ECUES_PER_PAGE		64
 
 /*
  * Conditions used to specify which subchannels need evaluation
@@ -130,6 +132,7 @@ struct channel_subsystem {
 	/* channel measurement related */
 	int cm_enabled;
 	void *cub[CSS_NUM_CUB_PAGES];
+	void *ecub[CSS_NUM_ECUB_PAGES];
 	/* for orphaned ccw devices */
 	struct subchannel *pseudo_subchannel;
 };