Implement acpi_unregister_ioapic() to support ACPI based IOAPIC hot-removal.
An IOAPIC could only be removed when all its pins are unused.
Signed-off-by: Jiang Liu <jiang.liu@xxxxxxxxxxxxxxx>
---
arch/x86/include/asm/io_apic.h | 1 +
arch/x86/kernel/acpi/boot.c | 13 +++++++---
arch/x86/kernel/apic/io_apic.c | 55 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 65 insertions(+), 4 deletions(-)
diff --git a/arch/x86/include/asm/io_apic.h b/arch/x86/include/asm/io_apic.h
index 94d05bd6586f..ce63cf34c93c 100644
--- a/arch/x86/include/asm/io_apic.h
+++ b/arch/x86/include/asm/io_apic.h
@@ -190,6 +190,7 @@ extern int mp_map_gsi_to_irq(u32 gsi, unsigned int flags);
extern void mp_unmap_irq(int irq);
extern int mp_register_ioapic(int id, u32 address, u32 gsi_base,
struct ioapic_domain_cfg *cfg);
+extern int mp_unregister_ioapic(u32 gsi_base);
extern int mp_irqdomain_map(struct irq_domain *domain, unsigned int virq,
irq_hw_number_t hwirq);
extern void mp_irqdomain_unmap(struct irq_domain *domain, unsigned int virq);
diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index c5a0abd0be82..28d50c70cac9 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -798,15 +798,20 @@ int acpi_register_ioapic(acpi_handle handle, u64 phys_addr, u32 gsi_base)
return ret;
}
-
EXPORT_SYMBOL(acpi_register_ioapic);
int acpi_unregister_ioapic(acpi_handle handle, u32 gsi_base)
{
- /* TBD */
- return -EINVAL;
-}
+ int ret = -ENOSYS;
+
+#ifdef CONFIG_ACPI_HOTPLUG_IOAPIC
+ down_write(&acpi_ioapic_rwsem);
+ ret = mp_unregister_ioapic(gsi_base);
+ up_write(&acpi_ioapic_rwsem);
+#endif
+ return ret;
+}
EXPORT_SYMBOL(acpi_unregister_ioapic);
static int __init acpi_parse_sbf(struct acpi_table_header *table)
diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index 1b6a64ed2472..5711689e4307 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -112,6 +112,7 @@ static struct ioapic {
struct ioapic_domain_cfg irqdomain_cfg;
struct irq_domain *irqdomain;
struct mp_pin_info *pin_info;
+ struct resource *iomem_res;
} ioapics[MAX_IO_APICS];
#define mpc_ioapic_ver(ioapic_idx) ioapics[ioapic_idx].mp_config.apicver
@@ -250,6 +251,12 @@ static void alloc_ioapic_saved_registers(int idx)
pr_err("IOAPIC %d: suspend/resume impossible!\n", idx);
}
+static void free_ioapic_saved_registers(int idx)
+{
+ kfree(ioapics[idx].saved_registers);
+ ioapics[idx].saved_registers = NULL;
+}
+
int __init arch_early_irq_init(void)
{
struct irq_cfg *cfg;
@@ -2967,6 +2974,16 @@ static int mp_irqdomain_create(int ioapic)
return 0;
}
+static void ioapic_destroy_irqdomain(int idx)
+{
+ if (ioapics[idx].irqdomain) {
+ irq_domain_remove(ioapics[idx].irqdomain);
+ ioapics[idx].irqdomain = NULL;
+ }
+ kfree(ioapics[idx].pin_info);
+ ioapics[idx].pin_info = NULL;
+}
+
void __init setup_IO_APIC(void)
{
int ioapic;
@@ -3728,6 +3745,7 @@ static struct resource * __init ioapic_setup_resources(void)
snprintf(mem, IOAPIC_RESOURCE_NAME_SIZE, "IOAPIC %u", i);
mem += IOAPIC_RESOURCE_NAME_SIZE;
num++;
+ ioapics[i].iomem_res = res;
}
ioapic_resources = res;
@@ -3950,6 +3968,43 @@ int mp_register_ioapic(int id, u32 address, u32 gsi_base,
return 0;
}
+int mp_unregister_ioapic(u32 gsi_base)
+{
+ int ioapic, pin;
+ int found = 0;
+ struct mp_pin_info *pin_info;
+
+ for_each_ioapic(ioapic)
+ if (ioapics[ioapic].gsi_config.gsi_base == gsi_base) {
+ found = 1;
+ break;
+ }
+ if (!found) {
+ pr_warn("can't find IOAPIC for GSI %d\n", gsi_base);
+ return -ENODEV;
+ }
+
+ for_each_pin(ioapic, pin) {
+ pin_info = mp_pin_info(ioapic, pin);
+ if (pin_info->count) {
+ pr_warn("pin%d on IOAPIC%d is still in use.\n",
+ pin, ioapic);
+ return -EBUSY;
+ }
+ }
+
+ /* Mark entry not present */
+ ioapics[ioapic].nr_registers = 0;
+ ioapic_destroy_irqdomain(ioapic);
+ free_ioapic_saved_registers(ioapic);
+ if (ioapics[ioapic].iomem_res)
+ release_resource(ioapics[ioapic].iomem_res);
+ clear_fixmap(FIX_IO_APIC_BASE_0 + ioapic);
+ memset(&ioapics[ioapic], 0, sizeof(ioapics[ioapic]));
+
+ return 0;
+}
+
int mp_irqdomain_map(struct irq_domain *domain, unsigned int virq,
irq_hw_number_t hwirq)
{
--
1.7.10.4
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