From: Cliff Wickman Date: Fri, 16 Jul 2010 15:11:21 +0000 (-0500) Subject: x86, UV: Initialize BAU MMRs only on hubs with cpus X-Git-Tag: firefly_0821_release~9833^2~760^2~3 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=93a7ca0c3ebe5d931126f1fb732cb9c4518383d4;p=firefly-linux-kernel-4.4.55.git x86, UV: Initialize BAU MMRs only on hubs with cpus Remove the initialization of MMRs UVH_LB_BAU_SB_ACTIVATION_CONTROL and UVH_BAU_DATA_BROADCAST on UV hubs that have no active cpus. Such initialization on hubs with no active cpus would result in a kernel page fault. This is not of real high priority, because we don't have any such systems (with UV hubs that have no active cpus). But they will be coming. Signed-off-by: Cliff Wickman LKML-Reference: Signed-off-by: Ingo Molnar --- diff --git a/arch/x86/kernel/tlb_uv.c b/arch/x86/kernel/tlb_uv.c index abf3c31f14cf..59efb5390b37 100644 --- a/arch/x86/kernel/tlb_uv.c +++ b/arch/x86/kernel/tlb_uv.c @@ -1635,12 +1635,16 @@ static int __init uv_bau_init(void) alloc_intr_gate(vector, uv_bau_message_intr1); for_each_possible_blade(uvhub) { - pnode = uv_blade_to_pnode(uvhub); - /* INIT the bau */ - uv_write_global_mmr64(pnode, UVH_LB_BAU_SB_ACTIVATION_CONTROL, - ((unsigned long)1 << 63)); - mmr = 1; /* should be 1 to broadcast to both sockets */ - uv_write_global_mmr64(pnode, UVH_BAU_DATA_BROADCAST, mmr); + if (uv_blade_nr_possible_cpus(uvhub)) { + pnode = uv_blade_to_pnode(uvhub); + /* INIT the bau */ + uv_write_global_mmr64(pnode, + UVH_LB_BAU_SB_ACTIVATION_CONTROL, + ((unsigned long)1 << 63)); + mmr = 1; /* should be 1 to broadcast to both sockets */ + uv_write_global_mmr64(pnode, UVH_BAU_DATA_BROADCAST, + mmr); + } } return 0;