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author | Oren Twaig <oren@scalemp.com> | 2014-06-29 13:01:08 +0300 |
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committer | H. Peter Anvin <hpa@zytor.com> | 2014-07-13 17:48:03 -0700 |
commit | 411cf9ee2946492c0ac7eca48422fcf94a723ce5 (patch) | |
tree | a151a728aaf0f631405f5a47ea534b0bffd65cf4 /arch/x86/kernel/apic/apic.c | |
parent | b81975eade8c6495f3c4d6746d22bdc95f617777 (diff) | |
download | op-kernel-dev-411cf9ee2946492c0ac7eca48422fcf94a723ce5.zip op-kernel-dev-411cf9ee2946492c0ac7eca48422fcf94a723ce5.tar.gz |
x86, vsmp: Remove is_vsmp_box() from apic_is_clustered_box()
When a vSMP Foundation box is detected, the function apic_cluster_num() counts
the number of APIC clusters found. If more than one found, a multi board
configuration is assumed, and TSC marked as unstable. This behavior is
incorrect as vSMP Foundation may use processors from single node only, attached
to memory of other nodes - and such node may have more than one APIC cluster
(typically any recent intel box has more than single APIC_CLUSTERID(x)).
To fix this, we simply remove the code which detects a vSMP Foundation box and
affects apic_is_clusted_box() return value. This can be done because later the
kernel checks by itself if the TSC is stable using the
check_tsc_sync_[source|target]() functions and marks TSC as unstable if needed.
Acked-by: Shai Fultheim <shai@scalemp.com>
Signed-off-by: Oren Twaig <oren@scalemp.com>
Link: http://lkml.kernel.org/r/1404036068-11674-1-git-send-email-oren@scalemp.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'arch/x86/kernel/apic/apic.c')
-rw-r--r-- | arch/x86/kernel/apic/apic.c | 60 |
1 files changed, 1 insertions, 59 deletions
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index ca1bd75..6b35d30 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -2451,51 +2451,6 @@ static void apic_pm_activate(void) { } #ifdef CONFIG_X86_64 -static int apic_cluster_num(void) -{ - int i, clusters, zeros; - unsigned id; - u16 *bios_cpu_apicid; - DECLARE_BITMAP(clustermap, NUM_APIC_CLUSTERS); - - bios_cpu_apicid = early_per_cpu_ptr(x86_bios_cpu_apicid); - bitmap_zero(clustermap, NUM_APIC_CLUSTERS); - - for (i = 0; i < nr_cpu_ids; i++) { - /* are we being called early in kernel startup? */ - if (bios_cpu_apicid) { - id = bios_cpu_apicid[i]; - } else if (i < nr_cpu_ids) { - if (cpu_present(i)) - id = per_cpu(x86_bios_cpu_apicid, i); - else - continue; - } else - break; - - if (id != BAD_APICID) - __set_bit(APIC_CLUSTERID(id), clustermap); - } - - /* Problem: Partially populated chassis may not have CPUs in some of - * the APIC clusters they have been allocated. Only present CPUs have - * x86_bios_cpu_apicid entries, thus causing zeroes in the bitmap. - * Since clusters are allocated sequentially, count zeros only if - * they are bounded by ones. - */ - clusters = 0; - zeros = 0; - for (i = 0; i < NUM_APIC_CLUSTERS; i++) { - if (test_bit(i, clustermap)) { - clusters += 1 + zeros; - zeros = 0; - } else - ++zeros; - } - - return clusters; -} - static int multi_checked; static int multi; @@ -2540,20 +2495,7 @@ static void dmi_check_multi(void) int apic_is_clustered_box(void) { dmi_check_multi(); - if (multi) - return 1; - - if (!is_vsmp_box()) - return 0; - - /* - * ScaleMP vSMPowered boxes have one cluster per board and TSCs are - * not guaranteed to be synced between boards - */ - if (apic_cluster_num() > 1) - return 1; - - return 0; + return multi; } #endif |