[PATCH 2/8] x86/platform/UV: Fix 2 socket config problem

Mike Travis
2017-01-13T15:21:24Z

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A UV4 chassis with only 2 sockets configured can unexpectedly
target the wrong UV hub. Fix the problem by limiting the minimum
size of a partition to 4 sockets even if only 2 are configured.

Signed-off-by: Mike Travis <travis@sgi.com>
Acked-by: Dimitri Sivanich <sivanich@hpe.com>
Reviewed-by: Russ Anderson <rja@hpe.com>
---
arch/x86/kernel/apic/x2apic_uv_x.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

--- linux.orig/arch/x86/kernel/apic/x2apic_uv_x.c
+++ linux/arch/x86/kernel/apic/x2apic_uv_x.c
@@ -56,6 +56,7 @@ static struct {
unsigned int socketid_shift; /* aka pnode_shift for UV1/2/3 */
unsigned int pnode_mask;
unsigned int gpa_shift;
+ unsigned int gnode_shift;
} uv_cpuid;

int uv_min_hub_revision_id;
@@ -133,6 +134,7 @@ static int __init early_get_pnodeid(void
break;
case UV4_HUB_PART_NUMBER:
uv_min_hub_revision_id += UV4_HUB_REVISION_BASE - 1;
+ uv_cpuid.gnode_shift = 2; /* min partition is 4 sockets */
break;
}

@@ -1074,8 +1076,10 @@ void __init uv_init_hub_info(struct uv_h
(1UL << uv_cpuid.gpa_shift) - 1;

node_id.v = uv_read_local_mmr(UVH_NODE_ID);
+ uv_cpuid.gnode_shift = max_t(unsigned int,
+ uv_cpuid.gnode_shift, mn.n_val);
hub_info->gnode_extra =
- (node_id.s.node_id & ~((1 << mn.n_val) - 1)) >> 1;
+ (node_id.s.node_id & ~((1 << uv_cpuid.gnode_shift) - 1)) >> 1;

hub_info->gnode_upper =
((unsigned long)hub_info->gnode_extra << mn.m_val);

--