Commit-ID: 411cf9ee2946492c0ac7eca48422fcf94a723ce5
Gitweb: http://git.kernel.org/tip/411cf9ee2946492c0ac7eca48422fcf94a723ce5
Author: Oren Twaig <oren@xxxxxxxxxxx>
AuthorDate: Sun, 29 Jun 2014 13:01:08 +0300
Committer: H. Peter Anvin <hpa@xxxxxxxxx>
CommitDate: Sun, 13 Jul 2014 17:48:03 -0700
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@xxxxxxxxxxx>
Signed-off-by: Oren Twaig <oren@xxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1404036068-11674-1-git-send-email-oren@xxxxxxxxxxx
Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxx>
---
arch/x86/include/asm/apic.h | 8 ------
arch/x86/kernel/apic/apic.c | 60 +--------------------------------------------
2 files changed, 1 insertion(+), 67 deletions(-)
diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
index 69ed79a..b40ea7e 100644
--- a/arch/x86/include/asm/apic.h
+++ b/arch/x86/include/asm/apic.h
@@ -85,14 +85,6 @@ static inline bool apic_from_smp_config(void)
#include <asm/paravirt.h>
#endif
-#ifdef CONFIG_X86_64
-extern int is_vsmp_box(void);
-#else
-static inline int is_vsmp_box(void)
-{
- return 0;
-}
-#endif
extern int setup_profiling_timer(unsigned int);
static inline void native_apic_mem_write(u32 reg, u32 v)
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
--
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