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s390/cio: export extended channel-path-measurement data
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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 <[email protected]>
Tested-by: Vineeth Vijayan <[email protected]>
Acked-by: Heiko Carstens <[email protected]>
Signed-off-by: Peter Oberparleiter <[email protected]>
Signed-off-by: Alexander Gordeev <[email protected]>
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@oberpar
oberpar authored and Alexander Gordeev committed Apr 12, 2024
1 parent b4691ba commit 2dc8903
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Showing 5 changed files with 69 additions and 32 deletions.
68 changes: 39 additions & 29 deletions drivers/s390/cio/chp.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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);
Expand Down
1 change: 1 addition & 0 deletions drivers/s390/cio/chp.h
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Original file line number Diff line number Diff line change
Expand Up @@ -51,6 +51,7 @@ struct channel_path {
/* Channel-measurement related stuff: */
int cmg;
int shared;
int extended;
struct cmg_chars cmg_chars;
};

Expand Down
24 changes: 21 additions & 3 deletions drivers/s390/cio/chsc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand All @@ -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;

Expand Down Expand Up @@ -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;
}
Expand All @@ -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
Expand Down Expand Up @@ -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;
Expand All @@ -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;
Expand Down Expand Up @@ -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;
Expand Down
5 changes: 5 additions & 0 deletions drivers/s390/cio/chsc.h
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Original file line number Diff line number Diff line change
Expand Up @@ -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;
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3 changes: 3 additions & 0 deletions drivers/s390/cio/css.h
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Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand Down Expand Up @@ -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;
};
Expand Down

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