[PATCH] x86/intel_cacheinfo: Fix LLC topology for AMD Fam17h systems

[PATCH] x86/intel_cacheinfo: Fix LLC topology for AMD Fam17h systems

[Aravind Gopalakrishnan]

On AMD Fam17h systems, the last level cache is not resident in
Northbridge. Therefore, we cannot assign cpu_llc_id to same
value as Node ID (as we have been doing currently)

We should rather look at the ApicID bits of the core to provide
us the last level cache ID info. Doing that here.

Signed-off-by: Aravind Gopalakrishnan <Aravind.Gopalakrishnan@amd.com>
---
 arch/x86/kernel/cpu/intel_cacheinfo.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/arch/x86/kernel/cpu/intel_cacheinfo.c b/arch/x86/kernel/cpu/intel_cacheinfo.c
index e38d338..897a483 100644
--- a/arch/x86/kernel/cpu/intel_cacheinfo.c
+++ b/arch/x86/kernel/cpu/intel_cacheinfo.c
@@ -636,6 +636,9 @@ static int find_num_cache_leaves(struct cpuinfo_x86 *c)
 
 void init_amd_cacheinfo(struct cpuinfo_x86 *c)
 {
+	unsigned int cpu = c->cpu_index;
+	unsigned int apicid = c->apicid;
+	unsigned int socket_id, core_complex_id;
 
 	if (cpu_has_topoext) {
 		num_cache_leaves = find_num_cache_leaves(c);
@@ -645,6 +648,17 @@ void init_amd_cacheinfo(struct cpuinfo_x86 *c)
 		else
 			num_cache_leaves = 3;
 	}
+
+	/*
+	 * Fix percpu cpu_llc_id here as LLC topology is different
+	 * for Fam17h systems.
+	 */
+	 if (c->x86 != 0x17 || !cpuid_edx(0x80000006))
+		return;
+
+	socket_id = (apicid >> c->x86_coreid_bits) - 1;
+	core_complex_id = (apicid & ((1 << c->x86_coreid_bits) - 1)) >> 3;
+	per_cpu(cpu_llc_id, cpu) = (socket_id << 3) | core_complex_id;
 }
 
 unsigned int init_intel_cacheinfo(struct cpuinfo_x86 *c)
-- 
2.6.1

Re: [PATCH] x86/intel_cacheinfo: Fix LLC topology for AMD Fam17h systems

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 828 bytes --]

Hi Aravind,

[auto build test ERROR on bp/for-next]
[also ERROR on: v4.3 next-20151103]

url:    https://github.com/0day-ci/linux/commits/Aravind-Gopalakrishnan/x86-intel_cacheinfo-Fix-LLC-topology-for-AMD-Fam17h-systems/20151104-031725
base:   https://github.com/0day-ci/linux Aravind-Gopalakrishnan/x86-intel_cacheinfo-Fix-LLC-topology-for-AMD-Fam17h-systems/20151104-031725
config: i386-tinyconfig (attached as .config)
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

All errors (new ones prefixed by >>):

   arch/x86/built-in.o: In function `init_amd_cacheinfo':
>> (.text+0x6aec): undefined reference to `cpu_llc_id'

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
[-- Type: application/octet-stream, Size: 6035 bytes --]

Re: [PATCH] x86/intel_cacheinfo: Fix LLC topology for AMD Fam17h systems

[Aravind Gopalakrishnan]

On 11/3/2015 1:27 PM, kbuild test robot wrote:
> Hi Aravind,
>
> [auto build test ERROR on bp/for-next]
> [also ERROR on: v4.3 next-20151103]
>
> url:    https://github.com/0day-ci/linux/commits/Aravind-Gopalakrishnan/x86-intel_cacheinfo-Fix-LLC-topology-for-AMD-Fam17h-systems/20151104-031725
> base:   https://github.com/0day-ci/linux Aravind-Gopalakrishnan/x86-intel_cacheinfo-Fix-LLC-topology-for-AMD-Fam17h-systems/20151104-031725
> config: i386-tinyconfig (attached as .config)
> reproduce:
>          # save the attached .config to linux build tree
>          make ARCH=i386
>
> All errors (new ones prefixed by >>):
>
>     arch/x86/built-in.o: In function `init_amd_cacheinfo':
>>> (.text+0x6aec): undefined reference to `cpu_llc_id'
>

Thanks for the catch!

cpu_llc_id references should be wrapped under #ifdef CONFIG_SMP.

Did that and kernel build worked with the attached config.

Will send a V2 with the fix.

Thanks,
-Aravind.

Re: [PATCH] x86/intel_cacheinfo: Fix LLC topology for AMD Fam17h systems

[Borislav Petkov]

On Tue, Nov 03, 2015 at 01:41:53PM -0600, Aravind Gopalakrishnan wrote:
> cpu_llc_id references should be wrapped under #ifdef CONFIG_SMP.
> 
> Did that and kernel build worked with the attached config.
> 
> Will send a V2 with the fix.

Why aren't you doing all that figuring out what the llc_id is in
amd_detect_cmp() which is already CONFIG_SMP ifdeffed?

Which is where that code belongs anyway...

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.

Re: [PATCH] x86/intel_cacheinfo: Fix LLC topology for AMD Fam17h systems

[Aravind Gopalakrishnan]

On 11/3/2015 1:52 PM, Borislav Petkov wrote:
> On Tue, Nov 03, 2015 at 01:41:53PM -0600, Aravind Gopalakrishnan wrote:
>> cpu_llc_id references should be wrapped under #ifdef CONFIG_SMP.
>>
>> Did that and kernel build worked with the attached config.
>>
>> Will send a V2 with the fix.
> Why aren't you doing all that figuring out what the llc_id is in
> amd_detect_cmp() which is already CONFIG_SMP ifdeffed?
>
> Which is where that code belongs anyway...
>

Since we needed to modify last level cache IDs, I thought 
init_amd_cacheinfo() might be a logical place to put it.

But you are right, makes sense to move it to amd_detect_cmp().
I'll do that in V2.

Thanks,
-Aravind.