Re: [PATCH V3 02/10] ras: acpi/apei: cper: generic error data entry v3 per ACPI 6.1

From: Baicar, Tyler
Date: Wed Oct 12 2016 - 18:22:18 EST

Hello Suzuki,

Thank you for the feedback! Responses below.


On 10/11/2016 11:28 AM, Suzuki K Poulose wrote:
On 07/10/16 22:31, Tyler Baicar wrote:
Currently when a RAS error is reported it is not timestamped.
The ACPI 6.1 spec adds the timestamp field to the generic error
data entry v3 structure. The timestamp of when the firmware
generated the error is now being reported.

Signed-off-by: Jonathan (Zhixiong) Zhang <zjzhang@xxxxxxxxxxxxxx>
Signed-off-by: Richard Ruigrok <rruigrok@xxxxxxxxxxxxxx>
Signed-off-by: Tyler Baicar <tbaicar@xxxxxxxxxxxxxx>
Signed-off-by: Naveen Kaje <nkaje@xxxxxxxxxxxxxx>

Please could you keep the people who reviewed/commented on your series in the past,
whenever you post a new version ?
Do you mean to just send the new version to their e-mail directly in addition to the lists? If so, I will do that next time.

I know you provided good feedback on the previous patchset, but I did not have anyone specifically respond to add "reviewed-by:...". I don't think I should add reviewed-by for someone unless they specifically add it in a response :)

---
drivers/acpi/apei/ghes.c | 25 ++++++++++--
drivers/firmware/efi/cper.c | 97 +++++++++++++++++++++++++++++++++++++++------
2 files changed, 105 insertions(+), 17 deletions(-)

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index 3021f0e..c8488f1 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -80,6 +80,10 @@
((struct acpi_hest_generic_status *) \
((struct ghes_estatus_node *)(estatus_node) + 1))

+#define acpi_hest_generic_data_version(gdata) \
+ (gdata->revision >> 8)

...

+inline void *acpi_hest_generic_data_payload(struct acpi_hest_generic_data *gdata)
+{
+ return acpi_hest_generic_data_version(gdata) >= 3 ?
+ (void *)(((struct acpi_hest_generic_data_v300 *)(gdata)) + 1) :
+ gdata + 1;
+}
+



diff --git a/drivers/firmware/efi/cper.c b/drivers/firmware/efi/cper.c
index d425374..9fa1317 100644
--- a/drivers/firmware/efi/cper.c
+++ b/drivers/firmware/efi/cper.c

+#define acpi_hest_generic_data_version(gdata) \
+ (gdata->revision >> 8)
+

...

+static inline void *acpi_hest_generic_data_payload(struct acpi_hest_generic_data *gdata)
+{
+ return acpi_hest_generic_data_version(gdata) >= 3 ?
+ (void *)(((struct acpi_hest_generic_data_v300 *)(gdata)) + 1) :
+ gdata + 1;
+}

Could these go to a header file, so that we don't need duplicate definitions of these helpers in
different files ?

I think that should work to avoid duplication. I will move them to a header file in the next patchset.
+
+static void cper_estatus_print_section_v300(const char *pfx,
+ const struct acpi_hest_generic_data_v300 *gdata)
+{
+ __u8 hour, min, sec, day, mon, year, century, *timestamp;
+
+ if (gdata->validation_bits & ACPI_HEST_GEN_VALID_TIMESTAMP) {
+ timestamp = (__u8 *)&(gdata->time_stamp);
+ memcpy(&sec, timestamp, 1);
+ memcpy(&min, timestamp + 1, 1);
+ memcpy(&hour, timestamp + 2, 1);
+ memcpy(&day, timestamp + 4, 1);
+ memcpy(&mon, timestamp + 5, 1);
+ memcpy(&year, timestamp + 6, 1);
+ memcpy(&century, timestamp + 7, 1);
+ printk("%stime: ", pfx);
+ printk("%7s", 0x01 & *(timestamp + 3) ? "precise" : "");

What format is the (timestamp + 3) stored in ? Does it need conversion ?
The third byte of the timestamp is currently only used to determine if the time is precise or not. Bit 0 is used to specify that and the other bits in this byte are marked as reserved. This is shown in table 247 of the UEFI spec 2.6:

Byte 3:
Bit 0 – Timestamp is precise if this bit is set and correlates to the time of the error event.
Bit 7:1 – Reserved

+ printk(" %02d:%02d:%02d %02d%02d-%02d-%02d\n",
+ bcd2bin(hour), bcd2bin(min), bcd2bin(sec),
+ bcd2bin(century), bcd2bin(year), bcd2bin(mon),
+ bcd2bin(day));
+ }

minor nit: Would it be easier to order/parse the error messages if the date
is printed first followed by time ?

i.e,
17:20:14 2016-09-15 Mon
vs
2016-09-15 Mon 17:20:14

e.g, people looking at a huge log, looking for logs from a specific date might
find the latter more useful to skip the messages.

The latter does seem like it would be better for parsing large logs. I can rearrange the order in the next patchset.
+}
+
static void cper_estatus_print_section(
- const char *pfx, const struct acpi_hest_generic_data *gdata, int sec_no)
+ const char *pfx, struct acpi_hest_generic_data *gdata, int sec_no)
{
uuid_le *sec_type = (uuid_le *)gdata->section_type;
__u16 severity;
char newpfx[64];

+ if ((gdata->revision >> 8) >= 0x03)

Could we use the helper defined above ?
Yes, I'll change this to use acpi_hest_generic_data_version(gdata) instead.

@@ -451,12 +497,22 @@ void cper_estatus_print(const char *pfx,
printk("%s""event severity: %s\n", pfx, cper_severity_str(severity));
data_len = estatus->data_length;
gdata = (struct acpi_hest_generic_data *)(estatus + 1);
+ if ((gdata->revision >> 8) >= 0x03)

Same as above, use the macro ?
Yes, I'll change this to use acpi_hest_generic_data_version(gdata) instead.

+ gdata_v3 = (struct acpi_hest_generic_data_v300 *)gdata;
+
snprintf(newpfx, sizeof(newpfx), "%s%s", pfx, INDENT_SP);
+
while (data_len >= sizeof(*gdata)) {
gedata_len = gdata->error_data_length;
cper_estatus_print_section(newpfx, gdata, sec_no);
- data_len -= gedata_len + sizeof(*gdata);
- gdata = (void *)(gdata + 1) + gedata_len;
+ if(gdata_v3) {
+ data_len -= gedata_len + sizeof(*gdata_v3);
+ gdata_v3 = (void *)(gdata_v3 + 1) + gedata_len;
+ gdata = (struct acpi_hest_generic_data *)gdata_v3;
+ } else {
+ data_len -= gedata_len + sizeof(*gdata);
+ gdata = (void *)(gdata + 1) + gedata_len;
+ }
sec_no++;
}

...


@@ -486,15 +543,29 @@ int cper_estatus_check(const struct acpi_hest_generic_status *estatus)
return rc;
data_len = estatus->data_length;
gdata = (struct acpi_hest_generic_data *)(estatus + 1);
- while (data_len >= sizeof(*gdata)) {
- gedata_len = gdata->error_data_length;
- if (gedata_len > data_len - sizeof(*gdata))
+
+ if ((gdata->revision >> 8) >= 0x03) {
+ gdata_v3 = (struct acpi_hest_generic_data_v300 *)gdata;
+ while (data_len >= sizeof(*gdata_v3)) {
+ gedata_len = gdata_v3->error_data_length;
+ if (gedata_len > data_len - sizeof(*gdata_v3))
+ return -EINVAL;
+ data_len -= gedata_len + sizeof(*gdata_v3);
+ gdata_v3 = (void *)(gdata_v3 + 1) + gedata_len;
+ }
+ if (data_len)
+ return -EINVAL;
+ } else {
+ while (data_len >= sizeof(*gdata)) {
+ gedata_len = gdata->error_data_length;
+ if (gedata_len > data_len - sizeof(*gdata))
+ return -EINVAL;
+ data_len -= gedata_len + sizeof(*gdata);
+ gdata = (void *)(gdata + 1) + gedata_len;
+ }
+ if (data_len)

As mentioned in the previous version, would it make sense to add some more
helpers to deal with record versions ? We seem to be doing the version switch and
code duplication at different places.

Does the following help ? Thoughts ?

#define acpi_hest_generic_data_error_length(gdata) (((struct acpi_hest_generic_data *)(gdata))->error_data_length)
#define acpi_hest_generic_data_size(gdata) \
((acpi_hest_generic_data_version(gdata) >= 3) ? \
sizeof(struct acpi_hest_generic_data_v300) : \
sizeof(struct acpi_hest_generic_data))
#define acpi_hest_generic_data_record_size(gdata)
(acpi_hest_generic_data_size(gdata) + \
acpi_hest_generic_data_error_length(gdata))
#define acpi_hest_generic_data_next(gdata) \
((void *)(gdata) + acpi_hest_generic_data_record_size(gdata))


Suzuki
These helpers will definitely help consolidate this code. I will use these in the next version to remove the code duplication here.

Thanks,
Tyler

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