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xen/pci: Move check for acpi_sci_override_gsi to xen_setup_acpi_sci.
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Previously we would check for acpi_sci_override_gsi == gsi every time
a PCI device was enabled. That works during early bootup, but later
on it could lead to triggering unnecessarily the acpi_gsi_to_irq(..) lookup.
The reason is that acpi_sci_override_gsi was declared in __initdata and
after early bootup could contain bogus values.

This patch moves the check for acpi_sci_override_gsi to the
site where the ACPI SCI is preset.

CC: stable@kernel.org
Reported-by: Raghavendra D Prabhu <rprabhu@wnohang.net>
Tested-by: Raghavendra D Prabhu <rprabhu@wnohang.net>
[http://lists.xensource.com/archives/html/xen-devel/2011-07/msg00154.html]
Suggested-by:  Ian Campbell <ijc@hellion.org.uk>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
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Konrad Rzeszutek Wilk committed Jul 7, 2011
1 parent 155a16f commit ee339fe
Showing 1 changed file with 28 additions and 28 deletions.
56 changes: 28 additions & 28 deletions arch/x86/pci/xen.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -327,13 +327,12 @@ int __init pci_xen_hvm_init(void)
}

#ifdef CONFIG_XEN_DOM0
static int xen_register_pirq(u32 gsi, int triggering)
static int xen_register_pirq(u32 gsi, int gsi_override, int triggering)
{
int rc, pirq, irq = -1;
struct physdev_map_pirq map_irq;
int shareable = 0;
char *name;
bool gsi_override = false;

if (!xen_pv_domain())
return -1;
Expand All @@ -345,31 +344,12 @@ static int xen_register_pirq(u32 gsi, int triggering)
shareable = 1;
name = "ioapic-level";
}

pirq = xen_allocate_pirq_gsi(gsi);
if (pirq < 0)
goto out;

/* Before we bind the GSI to a Linux IRQ, check whether
* we need to override it with bus_irq (IRQ) value. Usually for
* IRQs below IRQ_LEGACY_IRQ this holds IRQ == GSI, as so:
* ACPI: INT_SRC_OVR (bus 0 bus_irq 9 global_irq 9 low level)
* but there are oddballs where the IRQ != GSI:
* ACPI: INT_SRC_OVR (bus 0 bus_irq 9 global_irq 20 low level)
* which ends up being: gsi_to_irq[9] == 20
* (which is what acpi_gsi_to_irq ends up calling when starting the
* the ACPI interpreter and keels over since IRQ 9 has not been
* setup as we had setup IRQ 20 for it).
*/
if (gsi == acpi_sci_override_gsi) {
/* Check whether the GSI != IRQ */
acpi_gsi_to_irq(gsi, &irq);
if (irq != gsi)
/* Bugger, we MUST have that IRQ. */
gsi_override = true;
}
if (gsi_override)
irq = xen_bind_pirq_gsi_to_irq(irq, pirq, shareable, name);
if (gsi_override >= 0)
irq = xen_bind_pirq_gsi_to_irq(gsi_override, pirq, shareable, name);
else
irq = xen_bind_pirq_gsi_to_irq(gsi, pirq, shareable, name);
if (irq < 0)
Expand All @@ -392,7 +372,7 @@ static int xen_register_pirq(u32 gsi, int triggering)
return irq;
}

static int xen_register_gsi(u32 gsi, int triggering, int polarity)
static int xen_register_gsi(u32 gsi, int gsi_override, int triggering, int polarity)
{
int rc, irq;
struct physdev_setup_gsi setup_gsi;
Expand All @@ -403,7 +383,7 @@ static int xen_register_gsi(u32 gsi, int triggering, int polarity)
printk(KERN_DEBUG "xen: registering gsi %u triggering %d polarity %d\n",
gsi, triggering, polarity);

irq = xen_register_pirq(gsi, triggering);
irq = xen_register_pirq(gsi, gsi_override, triggering);

setup_gsi.gsi = gsi;
setup_gsi.triggering = (triggering == ACPI_EDGE_SENSITIVE ? 0 : 1);
Expand All @@ -425,6 +405,8 @@ static __init void xen_setup_acpi_sci(void)
int rc;
int trigger, polarity;
int gsi = acpi_sci_override_gsi;
int irq = -1;
int gsi_override = -1;

if (!gsi)
return;
Expand All @@ -441,7 +423,25 @@ static __init void xen_setup_acpi_sci(void)
printk(KERN_INFO "xen: sci override: global_irq=%d trigger=%d "
"polarity=%d\n", gsi, trigger, polarity);

gsi = xen_register_gsi(gsi, trigger, polarity);
/* Before we bind the GSI to a Linux IRQ, check whether
* we need to override it with bus_irq (IRQ) value. Usually for
* IRQs below IRQ_LEGACY_IRQ this holds IRQ == GSI, as so:
* ACPI: INT_SRC_OVR (bus 0 bus_irq 9 global_irq 9 low level)
* but there are oddballs where the IRQ != GSI:
* ACPI: INT_SRC_OVR (bus 0 bus_irq 9 global_irq 20 low level)
* which ends up being: gsi_to_irq[9] == 20
* (which is what acpi_gsi_to_irq ends up calling when starting the
* the ACPI interpreter and keels over since IRQ 9 has not been
* setup as we had setup IRQ 20 for it).
*/
/* Check whether the GSI != IRQ */
if (acpi_gsi_to_irq(gsi, &irq) == 0) {
if (irq >= 0 && irq != gsi)
/* Bugger, we MUST have that IRQ. */
gsi_override = irq;
}

gsi = xen_register_gsi(gsi, gsi_override, trigger, polarity);
printk(KERN_INFO "xen: acpi sci %d\n", gsi);

return;
Expand All @@ -450,7 +450,7 @@ static __init void xen_setup_acpi_sci(void)
static int acpi_register_gsi_xen(struct device *dev, u32 gsi,
int trigger, int polarity)
{
return xen_register_gsi(gsi, trigger, polarity);
return xen_register_gsi(gsi, -1 /* no GSI override */, trigger, polarity);
}

static int __init pci_xen_initial_domain(void)
Expand Down Expand Up @@ -489,7 +489,7 @@ void __init xen_setup_pirqs(void)
if (acpi_get_override_irq(irq, &trigger, &polarity) == -1)
continue;

xen_register_pirq(irq,
xen_register_pirq(irq, -1 /* no GSI override */,
trigger ? ACPI_LEVEL_SENSITIVE : ACPI_EDGE_SENSITIVE);
}
}
Expand Down

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