From: Andi Kleen <andi@firstfloor.org>
To: x86@kernel.org
Cc: linux-kernel@vger.kernel.org, Andi Kleen <ak@linux.intel.com>
Subject: [PATCH] x86: Report Intel platform_id in /proc/cpuinfo
Date: Tue, 31 May 2016 14:24:54 -0700 [thread overview]
Message-ID: <1464729894-108356-1-git-send-email-andi@firstfloor.org> (raw)
From: Andi Kleen <ak@linux.intel.com>
We have a need to distinguish systems based on their platform ID.
For example this is useful to distinguish systems with L4 cache
versus ones without.
There is a 5 bit identifier (also called processor flags) in
the IA32_PLATFORM_ID MSR that can give a more fine grained
identification of the CPU than just the model number/stepping.
IA32_PLATFORM_ID is architectural.
The processor flags are already used in the microcode driver.
The MSR can be also accessed through /dev/cpu/*/msr, but that
requires root and is awkward.
This patch just exports the value retrieved by the microcode
driver in /proc/cpuinfo. If the microcode driver is disabled
it won't be shown, but that seems reasonable.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
---
arch/x86/include/asm/processor.h | 1 +
arch/x86/kernel/cpu/microcode/intel.c | 1 +
arch/x86/kernel/cpu/proc.c | 2 ++
3 files changed, 4 insertions(+)
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 20c11d1..bc4b0ef 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -136,6 +136,7 @@ struct cpuinfo_x86 {
/* Index into per_cpu list: */
u16 cpu_index;
u32 microcode;
+ u32 platform_id;
};
#define X86_VENDOR_INTEL 0
diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c
index ee81c54..6244a88 100644
--- a/arch/x86/kernel/cpu/microcode/intel.c
+++ b/arch/x86/kernel/cpu/microcode/intel.c
@@ -812,6 +812,7 @@ static int collect_cpu_info(int cpu_num, struct cpu_signature *csig)
/* get processor flags from MSR 0x17 */
rdmsr(MSR_IA32_PLATFORM_ID, val[0], val[1]);
csig->pf = 1 << ((val[1] >> 18) & 7);
+ cpu_data(cpu_num).platform_id = (val[1] >> 18) & 7;
}
csig->rev = c->microcode;
diff --git a/arch/x86/kernel/cpu/proc.c b/arch/x86/kernel/cpu/proc.c
index 18ca99f..1c4e4f5 100644
--- a/arch/x86/kernel/cpu/proc.c
+++ b/arch/x86/kernel/cpu/proc.c
@@ -76,6 +76,8 @@ static int show_cpuinfo(struct seq_file *m, void *v)
seq_puts(m, "stepping\t: unknown\n");
if (c->microcode)
seq_printf(m, "microcode\t: 0x%x\n", c->microcode);
+ if (c->platform_id)
+ seq_printf(m, "platform_id\t: %d\n", c->platform_id);
if (cpu_has(c, X86_FEATURE_TSC)) {
unsigned int freq = cpufreq_quick_get(cpu);
--
2.8.2
next reply other threads:[~2016-06-01 4:39 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-31 21:24 Andi Kleen [this message]
2016-06-02 18:27 ` [PATCH] x86: Report Intel platform_id in /proc/cpuinfo Henrique de Moraes Holschuh
2016-06-02 22:54 ` Andi Kleen
-- strict thread matches above, loose matches on Subject: below --
2016-10-18 23:23 Andi Kleen
2016-09-23 18:02 Andi Kleen
2016-09-23 0:48 Andi Kleen
2016-09-23 8:12 ` Thomas Gleixner
2016-06-02 15:51 Andi Kleen
2016-06-21 16:05 ` Andi Kleen
2016-06-22 11:54 ` Henrique de Moraes Holschuh
2016-09-21 12:30 ` Thomas Gleixner
2016-05-05 10:12 Andi Kleen
2016-05-06 12:42 ` Henrique de Moraes Holschuh
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1464729894-108356-1-git-send-email-andi@firstfloor.org \
--to=andi@firstfloor.org \
--cc=ak@linux.intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).