[Patch v7 15/18] x86, irq, ACPI: Implement interface to support ACPI based IOAPIC hot-addition

Jiang Liu
2014-10-27T05:21:34Z

Implement acpi_register_ioapic() and enhance mp_register_ioapic()
to support ACPI based IOAPIC hot-addition.

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
---
arch/x86/kernel/acpi/boot.c | 31 +++++++++++++++++++++++++++++--
arch/x86/kernel/apic/io_apic.c | 22 +++++++++++++++++++++-
2 files changed, 50 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index 3f6b665f5aa6..8205f6381d77 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -779,8 +779,35 @@ EXPORT_SYMBOL(acpi_unmap_lsapic);

int acpi_register_ioapic(acpi_handle handle, u64 phys_addr, u32 gsi_base)
{
- /* TBD */
- return -EINVAL;
+ int ret = -ENOSYS;
+#ifdef CONFIG_ACPI_HOTPLUG_IOAPIC
+ int ioapic_id;
+ u64 addr;
+ struct ioapic_domain_cfg cfg = {
+ .type = IOAPIC_DOMAIN_DYNAMIC,
+ .ops = &acpi_irqdomain_ops,
+ };
+
+ ioapic_id = acpi_get_ioapic_id(handle, gsi_base, &addr);
+ if (ioapic_id < 0) {
+ unsigned long long uid;
+ acpi_status status;
+
+ status = acpi_evaluate_integer(handle, METHOD_NAME__UID,
+ NULL, &uid);
+ if (ACPI_FAILURE(status)) {
+ acpi_handle_warn(handle, "failed to get IOAPIC ID.\n");
+ return -EINVAL;
+ }
+ ioapic_id = (int)uid;
+ }
+
+ down_write(&acpi_ioapic_rwsem);
+ ret = mp_register_ioapic(ioapic_id, phys_addr, gsi_base, &cfg);
+ up_write(&acpi_ioapic_rwsem);
+#endif
+
+ return ret;
}

EXPORT_SYMBOL(acpi_register_ioapic);
diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index 59267659e5b1..4d9d87cc3259 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -3853,7 +3853,13 @@ static int bad_ioapic_register(int idx)

static int find_free_ioapic_entry(void)
{
- return nr_ioapics;
+ int idx;
+
+ for (idx = 0; idx < MAX_IO_APICS; idx++)
+ if (ioapics[idx].nr_registers == 0)
+ return idx;
+
+ return MAX_IO_APICS;
}

/**
@@ -3869,6 +3875,7 @@ int mp_register_ioapic(int id, u32 address, u32 gsi_base,
u32 gsi_end;
int idx, ioapic, entries;
struct mp_ioapic_gsi *gsi_cfg;
+ bool hotplug = !!ioapic_initialized;

if (!address) {
pr_warn("Bogus (zero) I/O APIC address found, skipping!\n");
@@ -3927,6 +3934,19 @@ int mp_register_ioapic(int id, u32 address, u32 gsi_base,
ioapics[idx].irqdomain = NULL;
ioapics[idx].irqdomain_cfg = *cfg;

+ /*
+ * If mp_register_ioapic() is called during early boot stage when
+ * walking ACPI/SFI/DT tables, it's too early to create irqdomain,
+ * we are still using bootmem allocator. So delay it to setup_IO_APIC().
+ */
+ if (hotplug) {
+ if (mp_irqdomain_create(idx)) {
+ clear_fixmap(FIX_IO_APIC_BASE_0 + idx);
+ return -ENOMEM;
+ }
+ alloc_ioapic_saved_registers(idx);
+ }
+
if (gsi_cfg->gsi_end >= gsi_top)
gsi_top = gsi_cfg->gsi_end + 1;
if (nr_ioapics <= idx)
--
1.7.10.4