[Bugfix 2/3] xen/irq: Override ACPI IRQ management callback __acpi_unregister_gsi

Jiang Liu
2015-01-19T04:53:10Z

Xen overrides __acpi_register_gsi and leaves __acpi_unregister_gsi as is.
That means, an IRQ allocated by acpi_register_gsi_xen_hvm() or
acpi_register_gsi_xen() will be freed by acpi_unregister_gsi_ioapic(),
which may cause undesired effects. So override __acpi_unregister_gsi to
NULL for safety.

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
---
arch/x86/include/asm/acpi.h | 1 +
arch/x86/pci/xen.c | 2 ++
2 files changed, 3 insertions(+)

diff --git a/arch/x86/include/asm/acpi.h b/arch/x86/include/asm/acpi.h
index 0ab4f9fd2687..3a45668f6dc3 100644
--- a/arch/x86/include/asm/acpi.h
+++ b/arch/x86/include/asm/acpi.h
@@ -50,6 +50,7 @@ void acpi_pic_sci_set_trigger(unsigned int, u16);

extern int (*__acpi_register_gsi)(struct device *dev, u32 gsi,
int trigger, int polarity);
+extern void (*__acpi_unregister_gsi)(u32 gsi);

static inline void disable_acpi(void)
{
diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
index 6e5e89c3c644..9098d880c476 100644
--- a/arch/x86/pci/xen.c
+++ b/arch/x86/pci/xen.c
@@ -458,6 +458,7 @@ int __init pci_xen_hvm_init(void)
* just how GSIs get registered.
*/
__acpi_register_gsi = acpi_register_gsi_xen_hvm;
+ __acpi_unregister_gsi = NULL;
#endif

#ifdef CONFIG_PCI_MSI
@@ -482,6 +483,7 @@ int __init pci_xen_initial_domain(void)
pci_msi_ignore_mask = 1;
#endif
__acpi_register_gsi = acpi_register_gsi_xen;
+ __acpi_unregister_gsi = NULL;
/* Pre-allocate legacy irqs */
for (irq = 0; irq < nr_legacy_irqs(); irq++) {
int trigger, polarity;
--
1.7.10.4