From 81a71176740624ef3b1bff50c51e7b4aa187353d Mon Sep 17 00:00:00 2001
From: Mike Travis <travis@sgi.com>
Date: Fri, 13 Jan 2017 09:21:12 -0600
Subject: [PATCH] x86/platform/UV: Fix 2 socket config problem
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>
Reviewed-by: Russ Anderson <rja@hpe.com>
Acked-by: Dimitri Sivanich <sivanich@hpe.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170113152111.313888353@asylum.americas.sgi.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/kernel/apic/x2apic_uv_x.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kernel/apic/x2apic_uv_x.c b/arch/x86/kernel/apic/x2apic_uv_x.c
index 43930787cab9..97ea712fc72f 100644
--- a/arch/x86/kernel/apic/x2apic_uv_x.c
+++ b/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_hub_info_s *hub_info)
(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);
--
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