x86: make amd quad core 8 socket system not be clustered_box, #2 (322850af) · Commits · 戴 / test

quad core 8 socket system will have apic id lifting.the apic id range could be [4, 0x23]. and apic_is_clustered_box will think that need to three clusters and that is large than 2. So it is treated as clustered_box. and will get Marking TSC unstable due to TSCs unsynchronized even the CPUs have X86_FEATURE_CONSTANT_TSC set. this patch will check if the cpu is from AMD. Signed-off-by:

Yinghai Lu <yinghai.lu@sun.com> Signed-off-by:

Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/apic_64.c

+11 −1

Original line number	Diff line number	Diff line
		@@ -1180,9 +1180,19 @@ __cpuinit int apic_is_clustered_box(void)
		{
		int i, clusters, zeros;
		unsigned id;
		u16 *bios_cpu_apicid = x86_bios_cpu_apicid_early_ptr;
		u16 *bios_cpu_apicid;
		DECLARE_BITMAP(clustermap, NUM_APIC_CLUSTERS);

		/*
		* there is not this kind of box with AMD CPU yet.
		* Some AMD box with quadcore cpu and 8 sockets apicid
		* will be [4, 0x23] or [8, 0x27] could be thought to
		* have three apic_clusters. So go out early.
		*/
		if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD)
		return 0;

		bios_cpu_apicid = x86_bios_cpu_apicid_early_ptr;
		bitmap_zero(clustermap, NUM_APIC_CLUSTERS);

		for (i = 0; i < NR_CPUS; i++) {

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