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(-)
diff --git a/arch/x86/platform/uv/tlb_uv.c b/arch/x86/platform/uv/tlb_uv.c
index a318194..ba9caa8 100644
--- a/arch/x86/platform/uv/tlb_uv.c
+++ b/arch/x86/platform/uv/tlb_uv.c
@@ -1455,7 +1455,7 @@
* 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));
}