[tip:x86/platform] x86/platform/uv/BAU: Disable software timeout on UV4 hardware

[tip-bot for Andrew Banman]

Commit-ID:  e879c1124a6c5c3367f20a254909605e7ee938c1
Gitweb:     http://git.kernel.org/tip/e879c1124a6c5c3367f20a254909605e7ee938c1
Author:     Andrew Banman <abanman@xxxxxxx>
AuthorDate: Wed, 21 Sep 2016 11:09:19 -0500
Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Thu, 22 Sep 2016 11:16:14 +0200

x86/platform/uv/BAU: Disable software timeout on UV4 hardware

Software timeouts are not currently supported on BAU for UV4. Instead, the
BAU will rely on hardware-level fairness protocols to determine broadcast
timeouts.

Do not call enable_timeouts or calculate_destination_timeout on UV4. These
functions write to pre-UV4 MMRs so they generate error messages on UV4.

Signed-off-by: Andrew Banman <abanman@xxxxxxx>
Acked-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Acked-by: Mike Travis <travis@xxxxxxx>
Acked-by: Dimitri Sivanich <sivanich@xxxxxxx>
Acked-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: akpm@xxxxxxxxxxxxxxxxxxxx
Cc: rja@xxxxxxx
Link: http://lkml.kernel.org/r/1474474161-265604-9-git-send-email-abanman@xxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 arch/x86/platform/uv/tlb_uv.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/x86/platform/uv/tlb_uv.c b/arch/x86/platform/uv/tlb_uv.c
index ddbeb16..72a5de7 100644
--- a/arch/x86/platform/uv/tlb_uv.c
+++ b/arch/x86/platform/uv/tlb_uv.c
@@ -2109,7 +2109,8 @@ static int __init init_per_cpu(int nuvhubs, int base_part_pnode)
 	void *vp;
 	struct uvhub_desc *uvhub_descs;
 
-	timeout_us = calculate_destination_timeout();
+	if (is_uv3_hub() || is_uv2_hub() || is_uv1_hub())
+		timeout_us = calculate_destination_timeout();
 
 	vp = kmalloc(nuvhubs * sizeof(struct uvhub_desc), GFP_KERNEL);
 	uvhub_descs = (struct uvhub_desc *)vp;
@@ -2171,7 +2172,9 @@ static int __init uv_bau_init(void)
 			uv_base_pnode = uv_blade_to_pnode(uvhub);
 	}
 
-	enable_timeouts();
+	/* software timeouts are not supported on UV4 */
+	if (is_uv3_hub() || is_uv2_hub() || is_uv1_hub())
+		enable_timeouts();
 
 	if (init_per_cpu(nuvhubs, uv_base_pnode)) {
 		set_bau_off();