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

[Baicar, Tyler]

Hello Russell,

Thank you for the feedback! Responses below

On 10/11/2016 12:52 PM, Russell King - ARM Linux wrote:
On Fri, Oct 07, 2016 at 03:31:14PM -0600, Tyler Baicar wrote:
+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);
This is utterly silly.  Why are you using memcpy() to access individual
bytes of a u8 pointer?  What's wrong with:

                sec = timestamp[0];
                min = timestamp[1];
                hour = timestamp[2];
                day = timestamp[4];
                mon = timestamp[5];
                year = timestamp[6];
                century = timestamp[7];

or even do the conversion here:

                sec = bcd2bin(timestamp[0]);
... etc ...
Yes, that will be a lot cleaner especially with moving the conversion here.

+               printk("%stime: ", pfx);
+               printk("%7s", 0x01 & *(timestamp + 3) ? "precise" : "");
+               printk(" %02d:%02d:%02d %02d%02d-%02d-%02d\n",
+                       bcd2bin(hour), bcd2bin(min), bcd2bin(sec),
+                       bcd2bin(century), bcd2bin(year), bcd2bin(mon),
+                       bcd2bin(day));
+       }
It's also a good idea to (as much as possible) keep to single printk()
statements - which makes the emission of the string more atomic wrt
other CPUs and contexts.  So, this should probably become (with the
conversion being done at the assignment of sec etc):

                printk("%stime: %7s %02d:%02d:%02d %02d%02d-%02d-%02d\n",
                        pfx, 0x01 & timestamp[3] ? "precise" : "",
                        hour, min, sec, century, year, mon, day);

which, IMHO, looks a lot nicer and doesn't risk some other printk()
getting between each individual part of the line.
I will make this change in the next version. This printk does look a lot 
nicer and avoids other prints from getting in the middle (I actually 
just saw that happen in testing a couple days ago)
+}
+
  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)
+               cper_estatus_print_section_v300(pfx,
+                       (const struct acpi_hest_generic_data_v300 *)gdata);
+
        severity = gdata->error_severity;
        printk("%s""Error %d, type: %s\n", pfx, sec_no,
               cper_severity_str(severity));
Not sure why you have the "" here - %sError works just as well and the
"" is just obfuscation - the compiler will eliminate the double-double
quote and merge the strings anyway.

I will remove the "" in the next version.

Thanks,
Tyler

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