x86, UV, BAU: Extend for more than 16 cpus per socket

Fix a hard-coded limit of a maximum of 16 cpu's per socket.

The UV Broadcast Assist Unit code initializes by scanning the
cpu topology of the system and assigning a master cpu for each
socket and UV hub. That scan had an assumption of a limit of 16
cpus per socket. With Westmere we are going over that limit.
The UV hub hardware will allow up to 32.

If the scan finds the system has gone over that limit it returns
an error and we print a warning and fall back to doing TLB
shootdowns without the BAU.

Signed-off-by: Cliff Wickman <cpw@sgi.com>
Cc: <stable@kernel.org> # .37.x
LKML-Reference: <E1PZol7-0000mM-77@eag09.americas.sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 18 insertions, 4 deletions

diff --git a/arch/x86/platform/uv/tlb_uv.c b/arch/x86/platform/uv/tlb_uv.c
index ba9caa808a9c..df58e9cad96a 100644
--- a/arch/x86/platform/uv/tlb_uv.c
+++ b/arch/x86/platform/uv/tlb_uv.c
@@ -1341,7 +1341,7 @@ uv_activation_descriptor_init(int node, int pnode)
 
         /*
          * each bau_desc is 64 bytes; there are 8 (UV_ITEMS_PER_DESCRIPTOR)
-         * per cpu; and up to 32 (UV_ADP_SIZE) cpu's per uvhub
+         * per cpu; and one per cpu on the uvhub (UV_ADP_SIZE)
          */
         bau_desc = kmalloc_node(sizeof(struct bau_desc) * UV_ADP_SIZE
                                 * UV_ITEMS_PER_DESCRIPTOR, GFP_KERNEL, node);
@@ -1490,7 +1490,7 @@ calculate_destination_timeout(void)
 /*
  * initialize the bau_control structure for each cpu
  */
-static void __init uv_init_per_cpu(int nuvhubs)
+static int __init uv_init_per_cpu(int nuvhubs)
 {
         int i;
         int cpu;
@@ -1507,7 +1507,7 @@ static void __init uv_init_per_cpu(int nuvhubs)
         struct bau_control *smaster = NULL;
         struct socket_desc {
                 short num_cpus;
-                short cpu_number[16];
+                short cpu_number[MAX_CPUS_PER_SOCKET];
         };
         struct uvhub_desc {
                 unsigned short socket_mask;
@@ -1540,6 +1540,10 @@ static void __init uv_init_per_cpu(int nuvhubs)
                 sdp = &bdp->socket[socket];
                 sdp->cpu_number[sdp->num_cpus] = cpu;
                 sdp->num_cpus++;
+                if (sdp->num_cpus > MAX_CPUS_PER_SOCKET) {
+                        printk(KERN_EMERG "%d cpus per socket invalid\n", sdp->num_cpus);
+                        return 1;
+                }
         }
         for (uvhub = 0; uvhub < nuvhubs; uvhub++) {
                 if (!(*(uvhub_mask + (uvhub/8)) & (1 << (uvhub%8))))
@@ -1570,6 +1574,12 @@ static void __init uv_init_per_cpu(int nuvhubs)
                                 bcp->uvhub_master = hmaster;
                                 bcp->uvhub_cpu = uv_cpu_hub_info(cpu)->
                                                 blade_processor_id;
+                                if (bcp->uvhub_cpu >= MAX_CPUS_PER_UVHUB) {
+                                        printk(KERN_EMERG
+                                                "%d cpus per uvhub invalid\n",
+                                                bcp->uvhub_cpu);
+                                        return 1;
+                                }
                         }
 nextsocket:
                         socket++;
@@ -1595,6 +1605,7 @@ nextsocket:
                 bcp->congested_reps = congested_reps;
                 bcp->congested_period = congested_period;
         }
+        return 0;
 }
 
 /*
@@ -1625,7 +1636,10 @@ static int __init uv_bau_init(void)
         spin_lock_init(&disable_lock);
         congested_cycles = microsec_2_cycles(congested_response_us);
 
-        uv_init_per_cpu(nuvhubs);
+        if (uv_init_per_cpu(nuvhubs)) {
+                nobau = 1;
+                return 0;
+        }
 
         uv_partition_base_pnode = 0x7fffffff;
         for (uvhub = 0; uvhub < nuvhubs; uvhub++)