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x86: UV: Address interrupt/IO port operation conflict

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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(-)
This commit is contained in:
Dimitri Sivanich
2010-11-16 16:23:52 -06:00
committed by Ingo Molnar
parent 9223081f54
commit 8191c9f692
5 changed files with 49 additions and 5 deletions
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4
arch/x86/platform/uv/uv_time.c
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@@ -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);