x86: UV: Address interrupt/IO port operation conflict

This patch for SGI UV systems addresses a problem whereby
interrupt transactions being looped back from a local IOH,
through the hub to a local CPU can (erroneously) conflict with
IO port operations and other transactions.

To workaound this we set a high bit in the APIC IDs used for
interrupts. This bit appears to be ignored by the sockets, but
it avoids the conflict in the hub.

Signed-off-by: Dimitri Sivanich <sivanich@sgi.com>
LKML-Reference: <20101116222352.GA8155@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
___

 arch/x86/include/asm/uv/uv_hub.h   |    4 ++++
 arch/x86/include/asm/uv/uv_mmrs.h  |   19 ++++++++++++++++++-
 arch/x86/kernel/apic/x2apic_uv_x.c |   25 +++++++++++++++++++++++--
 arch/x86/platform/uv/tlb_uv.c      |    2 +-
 arch/x86/platform/uv/uv_time.c     |    4 +++-
 5 files changed, 49 insertions(+), 5 deletions(-)

2 files changed, 4 insertions, 2 deletions

diff --git a/arch/x86/platform/uv/tlb_uv.c b/arch/x86/platform/uv/tlb_uv.c
index a318194002b5..ba9caa808a9c 100644
--- a/arch/x86/platform/uv/tlb_uv.c
+++ b/arch/x86/platform/uv/tlb_uv.c
@@ -1455,7 +1455,7 @@ static void __init uv_init_uvhub(int uvhub, int vector)
          * the below initialization can't be in firmware because the
          * messaging IRQ will be determined by the OS
          */
-        apicid = uvhub_to_first_apicid(uvhub);
+        apicid = uvhub_to_first_apicid(uvhub) | uv_apicid_hibits;
         uv_write_global_mmr64(pnode, UVH_BAU_DATA_CONFIG,
                                       ((apicid << 32) | vector));
 }
diff --git a/arch/x86/platform/uv/uv_time.c b/arch/x86/platform/uv/uv_time.c
index 56e421bc379b..9daf5d1af9f1 100644
--- a/arch/x86/platform/uv/uv_time.c
+++ b/arch/x86/platform/uv/uv_time.c
@@ -89,6 +89,7 @@ static void uv_rtc_send_IPI(int cpu)
 
         apicid = cpu_physical_id(cpu);
         pnode = uv_apicid_to_pnode(apicid);
+        apicid |= uv_apicid_hibits;
         val = (1UL << UVH_IPI_INT_SEND_SHFT) |
               (apicid << UVH_IPI_INT_APIC_ID_SHFT) |
               (X86_PLATFORM_IPI_VECTOR << UVH_IPI_INT_VECTOR_SHFT);
@@ -107,6 +108,7 @@ static int uv_intr_pending(int pnode)
 static int uv_setup_intr(int cpu, u64 expires)
 {
         u64 val;
+        unsigned long apicid = cpu_physical_id(cpu) | uv_apicid_hibits;
         int pnode = uv_cpu_to_pnode(cpu);
 
         uv_write_global_mmr64(pnode, UVH_RTC1_INT_CONFIG,
@@ -117,7 +119,7 @@ static int uv_setup_intr(int cpu, u64 expires)
                 UVH_EVENT_OCCURRED0_RTC1_MASK);
 
         val = (X86_PLATFORM_IPI_VECTOR << UVH_RTC1_INT_CONFIG_VECTOR_SHFT) |
-                ((u64)cpu_physical_id(cpu) << UVH_RTC1_INT_CONFIG_APIC_ID_SHFT);
+                ((u64)apicid << UVH_RTC1_INT_CONFIG_APIC_ID_SHFT);
 
         /* Set configuration */
         uv_write_global_mmr64(pnode, UVH_RTC1_INT_CONFIG, val);