x86, UV: Initialize BAU hub map

Fix uninitialized uvhub_mask:

- An unitialized bit map variable was causing initialization of
  non-existant hubs (this one causes boot panics).

- And the bit map was too small for large machines.  This patch
  makes it dynamic in size.

- Fix the case where socket 0 has no enabled cpu's. Don't assume
  every hub has a socket 0.

- uv_init_per_cpu() should be __init.

Signed-off-by: Cliff Wickman <cpw@sgi.com>
Cc: <stable@kernel.org> # for .35.x
LKML-Reference: <E1Oeuyt-0004XS-0y@eag09.americas.sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 14 insertions, 12 deletions

diff --git a/arch/x86/kernel/tlb_uv.c b/arch/x86/kernel/tlb_uv.c
index 59efb5390b37..312ef0292815 100644
--- a/arch/x86/kernel/tlb_uv.c
+++ b/arch/x86/kernel/tlb_uv.c
@@ -1484,15 +1484,16 @@ calculate_destination_timeout(void)
 /*
  * initialize the bau_control structure for each cpu
  */
-static void uv_init_per_cpu(int nuvhubs)
+static void __init uv_init_per_cpu(int nuvhubs)
 {
         int i;
         int cpu;
         int pnode;
         int uvhub;
+        int have_hmaster;
         short socket = 0;
         unsigned short socket_mask;
-        unsigned int uvhub_mask;
+        unsigned char *uvhub_mask;
         struct bau_control *bcp;
         struct uvhub_desc *bdp;
         struct socket_desc *sdp;
@@ -1516,28 +1517,29 @@ static void uv_init_per_cpu(int nuvhubs)
         uvhub_descs = (struct uvhub_desc *)
                 kmalloc(nuvhubs * sizeof(struct uvhub_desc), GFP_KERNEL);
         memset(uvhub_descs, 0, nuvhubs * sizeof(struct uvhub_desc));
+        uvhub_mask = kzalloc((nuvhubs+7)/8, GFP_KERNEL);
         for_each_present_cpu(cpu) {
                 bcp = &per_cpu(bau_control, cpu);
                 memset(bcp, 0, sizeof(struct bau_control));
                 pnode = uv_cpu_hub_info(cpu)->pnode;
                 uvhub = uv_cpu_hub_info(cpu)->numa_blade_id;
-                uvhub_mask |= (1 << uvhub);
+                *(uvhub_mask + (uvhub/8)) |= (1 << (uvhub%8));
                 bdp = &uvhub_descs[uvhub];
                 bdp->num_cpus++;
                 bdp->uvhub = uvhub;
                 bdp->pnode = pnode;
                 /* kludge: 'assuming' one node per socket, and assuming that
                    disabling a socket just leaves a gap in node numbers */
-                socket = (cpu_to_node(cpu) & 1);;
+                socket = (cpu_to_node(cpu) & 1);
                 bdp->socket_mask |= (1 << socket);
                 sdp = &bdp->socket[socket];
                 sdp->cpu_number[sdp->num_cpus] = cpu;
                 sdp->num_cpus++;
         }
-        uvhub = 0;
-        while (uvhub_mask) {
-                if (!(uvhub_mask & 1))
-                        goto nexthub;
+        for (uvhub = 0; uvhub < nuvhubs; uvhub++) {
+                if (!(*(uvhub_mask + (uvhub/8)) & (1 << (uvhub%8))))
+                        continue;
+                have_hmaster = 0;
                 bdp = &uvhub_descs[uvhub];
                 socket_mask = bdp->socket_mask;
                 socket = 0;
@@ -1551,8 +1553,10 @@ static void uv_init_per_cpu(int nuvhubs)
                                 bcp->cpu = cpu;
                                 if (i == 0) {
                                         smaster = bcp;
-                                        if (socket == 0)
+                                        if (!have_hmaster) {
+                                                have_hmaster++;
                                                 hmaster = bcp;
+                                        }
                                 }
                                 bcp->cpus_in_uvhub = bdp->num_cpus;
                                 bcp->cpus_in_socket = sdp->num_cpus;
@@ -1566,11 +1570,9 @@ nextsocket:
                         socket++;
                         socket_mask = (socket_mask >> 1);
                 }
-nexthub:
-                uvhub++;
-                uvhub_mask = (uvhub_mask >> 1);
         }
         kfree(uvhub_descs);
+        kfree(uvhub_mask);
         for_each_present_cpu(cpu) {
                 bcp = &per_cpu(bau_control, cpu);
                 bcp->baudisabled = 0;