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Commit 964d9784 authored by Suravee Suthikulpanit's avatar Suravee Suthikulpanit Committed by Thomas Gleixner
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x86/CPU/AMD: Fix LLC ID bit-shift calculation 



The current logic incorrectly calculates the LLC ID from the APIC ID.

Unless specified otherwise, the LLC ID should be calculated by removing
the Core and Thread ID bits from the least significant end of the APIC
ID. For more info, see "ApicId Enumeration Requirements" in any Fam17h
PPR document.

[ bp: Improve commit message. ]

Fixes: 68091ee7 ("Calculate last level cache ID from number of sharing threads")
Signed-off-by: default avatarSuravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1528915390-30533-1-git-send-email-suravee.suthikulpanit@amd.com
parent 7731b8bc

arch/x86/kernel/cpu/cacheinfo.c

+1 −1
Original line number Diff line number Diff line
@@ -671,7 +671,7 @@ void cacheinfo_amd_init_llc_id(struct cpuinfo_x86 *c, int cpu, u8 node_id) 
			num_sharing_cache = ((eax >> 14) & 0xfff) + 1;



		if (num_sharing_cache) {

			int bits = get_count_order(num_sharing_cache) - 1;

			int bits = get_count_order(num_sharing_cache);



			per_cpu(cpu_llc_id, cpu) = c->apicid >> bits;

		}