Commit-ID: 25aa2957973d361081ac6c8b6e5a0d9d7a83fef6
Gitweb: http://git.kernel.org/tip/25aa2957973d361081ac6c8b6e5a0d9d7a83fef6
Author: Liu Ping Fan <kernelfans@xxxxxxxxx>
AuthorDate: Fri, 23 Aug 2013 16:58:47 +0800
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Mon, 26 Aug 2013 12:58:00 +0200
x86/ioapic: Check attr against the previous setting when programmed more than once
When programming ioapic pinX more than once, current code
does not check whether the later attr (trigger & polarity) is the
same as the former or not.
This causes broken semantics which can be observed in a qemu q35
machine, where ioapic's ioredtbl[x] can never be set as low-active,
even if the hpet driver registered it.
And hpet driver may share a high-level active IRQ line with other
devices. So in qemu, when hpet-dev asserts low-level as kernel
expects, the kernel has no response.
With this patch, we can observe an ioredtbl[x] set as low-active
for hpet.
Fix it by reporting -EBUSY to the caller, when attr is different.
Signed-off-by: Liu Ping Fan <pingfank@xxxxxxxxxxxxxxxxxx>
Cc: Kevin Hao <haokexin@xxxxxxxxx>
Cc: Len Brown <len.brown@xxxxxxxxx>
Cc: Yinghai Lu <yinghai@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/1377248327-19633-1-git-send-email-pingfank@xxxxxxxxxxxxxxxxxx
[ Made small readability edits to both the changelog and the code. ]
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/kernel/acpi/boot.c | 5 ++++-
arch/x86/kernel/apic/io_apic.c | 9 ++++++---
2 files changed, 10 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index 872a2d2..81aa73b 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -1120,6 +1120,7 @@ int mp_register_gsi(struct device *dev, u32 gsi, int trigger, int polarity)
int ioapic;
int ioapic_pin;
struct io_apic_irq_attr irq_attr;
+ int ret;
if (acpi_irq_model != ACPI_IRQ_MODEL_IOAPIC)
return gsi;
@@ -1149,7 +1150,9 @@ int mp_register_gsi(struct device *dev, u32 gsi, int trigger, int polarity)
set_io_apic_irq_attr(&irq_attr, ioapic, ioapic_pin,
trigger == ACPI_EDGE_SENSITIVE ? 0 : 1,
polarity == ACPI_ACTIVE_HIGH ? 0 : 1);
- io_apic_set_pci_routing(dev, gsi_to_irq(gsi), &irq_attr);
+ ret = io_apic_set_pci_routing(dev, gsi_to_irq(gsi), &irq_attr);
+ if (ret < 0)
+ gsi = INT_MIN;
return gsi;
}
diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index 260abc2..e63a5bd 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -3380,12 +3380,15 @@ int io_apic_setup_irq_pin_once(unsigned int irq, int node,
{
unsigned int ioapic_idx = attr->ioapic, pin = attr->ioapic_pin;
int ret;
+ struct IO_APIC_route_entry orig_entry;
/* Avoid redundant programming */
if (test_bit(pin, ioapics[ioapic_idx].pin_programmed)) {
- pr_debug("Pin %d-%d already programmed\n",
- mpc_ioapic_id(ioapic_idx), pin);
- return 0;
+ pr_debug("Pin %d-%d already programmed\n", mpc_ioapic_id(ioapic_idx), pin);
+ orig_entry = ioapic_read_entry(attr->ioapic, pin);
+ if (attr->trigger == orig_entry.trigger && attr->polarity == orig_entry.polarity)
+ return 0;
+ return -EBUSY;
}
ret = io_apic_setup_irq_pin(irq, node, attr);
if (!ret)
--
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