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Date: Tue, 27 Oct 2009 08:21:20 -0700
From: Mike Travis <travis@....com>
To: Dmitry Adamushko <dmitry.adamushko@...il.com>
CC: Ingo Molnar <mingo@...e.hu>,
Tigran Aivazian <tigran@...azian.fsnet.co.uk>,
Thomas Gleixner <tglx@...utronix.de>,
Andrew Morton <akpm@...ux-foundation.org>,
Jack Steiner <steiner@....com>,
"H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
Andreas Mohr <andi@...as.de>, Hugh Dickins <hugh@...itas.com>,
Hannes Eder <hannes@...neseder.net>,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH 6/8] SGI x86_64 UV: Limit the number of microcode messages
[Another approach is shown below.]
Dmitry Adamushko wrote:
> 2009/10/26 Mike Travis <travis@....com>:
>>
>> Ingo Molnar wrote:
>>> * Dmitry Adamushko <dmitry.adamushko@...il.com> wrote:
>>>
>>>> 2009/10/24 Tigran Aivazian <tigran@...azian.fsnet.co.uk>:
>>>>> On Sat, 24 Oct 2009, Dmitry Adamushko wrote:
>>>>>>> - printk(KERN_INFO "microcode: CPU%d sig=0x%x, pf=0x%x,
>>>>>>> revision=0x%x\n",
>>>>>>> + if (cpu_num < 4 || !limit_console_output(false))
>>>>>>> + printk(KERN_INFO
>>>>>>> + "microcode: CPU%d sig=0x%x, pf=0x%x,
>>>>>>> revision=0x%x\n",
>>>>>>> cpu_num, csig->sig, csig->pf, csig->rev);
>>>>>>>
>>>>>> Hmm, I guess we wouldn't lose a lot by simply removing those messages
>>>>>> completely. Per-cpu pf/revision is available via /sys anyway.
>>>>> The reason for printing them is that the pf (possibly others?) can
>>>>> change by the update and so the log has this info handy.
>>>> We might store the old sig/pf/revision set as well, export them via
>>>> /sys or/and print them at update-to-new-microcode time.
>>>>
>>>> If it's really so useful to have this info in the log and, at the same
>>>> time, to avoid the flood of messages (which, I guess for the majority
>>>> of systems, are the same) at startup time, we might delay the printout
>>>> until the end of microcode_init(). Then do something like this:
>>>>
>>>> microcode cpu0: up to date version sig, pf, rev // let's say,
>>>> it was updated by BIOS
>>>> microcode cpus [1 ... 16] : update from sig, pf, rev to sig, pf2, rev2.
>>>>
>>>> Anyway, my humble opinion, is that (at the very least) the current
>>>> patch should be accompanied by a similar version for amd.
>>> yeah. Since we load new microcode on all cpus it's enough to print it for
>>> the boot CPU or so.
>>>
>>> Having the precise microcode version printed (or exposed somewhere in
>>> /sys) is useful - sometimes when there's a weird crash in some prototype CPU
>>> one of the first questions from hw vendors is 'which precise microcode
>>> version was that?'.
>>>
>>> Ingo
>> I would agree especially in the case where not all the cpus are exactly
>> the same. But so far, I've only seen variations of the speed of the cpus
>> not it's generic type, in an SSI. So the version of the microcode was
>> identical in all cases.
>
> I guess that (at least) a bootup cpu can be updated by BIOS so that it
> may appear to be different.
> Perhaps, cases where some 'broken' cpus have been replaced for others
> with a different "revision" (but still compatible otherwise) might be
> rare but possible (say, big machines with hot-pluggable cpus) ?
>
> btw., I was thinking of having something like this:
>
> microcode: cpus [K...L] platform-specific-format (e.g. for Intel :
> sig, pf, rev)
> microcode: updating...
> microcode: cpus [K...L] platform-specific-format (e.g. for Intel :
> sig, pf, rev)
>
> or even just,
>
> microcode: cpus [ K...L] updated from platform-specific-format-1 to
> platform-specific-format-2
>
>
>> Thanks,
>> Mike
>>
>
>
> -- Dmitry
Here's another approach...
I wasn't sure how to trigger the printing of the summary, so I winged it.
Looking closer it would appear that perhaps adding a new "summarize"
function to the microcode_ops struct could trigger it? Note this version
builds but I haven't yet tested it on a live system.
Thanks,
Mike
SGI x86_64 UV: Limit the number of microcode messages
Limit number of microcode messages of the form:
[ 50.887135] microcode: CPU0 sig=0x206e5, pf=0x4, revision=0xffff001
Cc: Tigran Aivazian <tigran@...azian.fsnet.co.uk>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: x86@...nel.org
Cc: Dmitry Adamushko <dmitry.adamushko@...il.com>
Cc: Andreas Mohr <andi@...as.de>
Cc: Hannes Eder <hannes@...neseder.net>
Cc: linux-kernel@...r.kernel.org
Signed-off-by: Mike Travis <travis@....com>
---
arch/x86/kernel/microcode_intel.c | 73 +++++++++++++++++++++++++++++++++++++-
1 file changed, 72 insertions(+), 1 deletion(-)
--- linux.orig/arch/x86/kernel/microcode_intel.c
+++ linux/arch/x86/kernel/microcode_intel.c
@@ -137,6 +137,52 @@
#define exttable_size(et) ((et)->count * EXT_SIGNATURE_SIZE + EXT_HEADER_SIZE)
+static struct cpu_signature *cpusigs;
+static cpumask_var_t cpusigslist;
+static int cpusigs_error;
+
+static void summarize_cpu_info(void)
+{
+ char buf[128];
+ int cpu;
+ cpumask_var_t cpulist;
+
+ if (cpusigs_error || !alloc_cpumask_var(&cpulist, GFP_KERNEL)) {
+ printk(KERN_INFO "Can't print microcode summary\n");
+ return;
+ }
+
+ while ((cpu = cpumask_first(cpusigslist)) < nr_cpu_ids) {
+ struct cpu_signature *csig = &cpusigs[cpu];
+ int ncpu = cpu;
+
+ cpumask_clear(cpulist);
+ cpumask_set_cpu(cpu, cpulist);
+
+ /* gather all cpu info with same data */
+ while ((ncpu = cpumask_next(ncpu, cpusigslist)) < nr_cpu_ids)
+ if (csig->sig == cpusigs[ncpu].sig &&
+ csig->pf == cpusigs[ncpu].pf &&
+ csig->rev == cpusigs[ncpu].rev)
+ cpumask_set_cpu(ncpu, cpulist);
+
+ cpulist_scnprintf(buf, sizeof(buf), cpulist);
+
+ printk(KERN_INFO
+ "microcode: CPU%s: sig=0x%x, pf=0x%x, revision=0x%x\n",
+ buf, csig->sig, csig->pf, csig->rev);
+
+ /* clear bits we just processed */
+ cpumask_xor(cpusigslist, cpusigslist, cpulist);
+ }
+
+ /* cleanup */
+ free_cpumask_var(cpulist);
+ free_cpumask_var(cpusigslist);
+ vfree(cpusigs);
+ cpusigs_error = 0;
+}
+
static int collect_cpu_info(int cpu_num, struct cpu_signature *csig)
{
struct cpuinfo_x86 *c = &cpu_data(cpu_num);
@@ -165,9 +211,34 @@
/* get the current revision from MSR 0x8B */
rdmsr(MSR_IA32_UCODE_REV, val[0], csig->rev);
- printk(KERN_INFO "microcode: CPU%d sig=0x%x, pf=0x%x, revision=0x%x\n",
+ if (!cpusigs && !cpusigs_error) {
+ if (!alloc_cpumask_var(&cpusigslist, GFP_KERNEL))
+ cpusigs_error = 1;
+ else {
+ cpusigs = vmalloc(sizeof(*cpusigs) * nr_cpu_ids);
+ if (!cpusigs) {
+ free_cpumask_var(cpusigslist);
+ cpusigs_error = 1;
+ }
+ }
+ }
+
+ if (cpusigs_error || cpu_num == 0)
+ printk(KERN_INFO
+ "microcode: CPU%d sig=0x%x, pf=0x%x, revision=0x%x\n",
cpu_num, csig->sig, csig->pf, csig->rev);
+ else if (!cpusigs_error) {
+ cpusigs[cpu_num].sig = csig->sig;
+ cpusigs[cpu_num].pf = csig->pf;
+ cpusigs[cpu_num].rev = csig->rev;
+ cpumask_set_cpu(cpu_num, cpusigslist);
+
+ /* (XXX Need better method for when to print summary) */
+ if (cpu_num == (num_present_cpus() - 1))
+ summarize_cpu_info();
+ }
+
return 0;
}
--
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