[RFC Patch V1 3/4] x86, irq, ACPI: implement interface to support ACPI based IOAPIC hot-addition

From: Jiang Liu
Date: Tue May 27 2014 - 04:23:17 EST


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

Signed-off-by: Jiang Liu <jiang.liu@xxxxxxxxxxxxxxx>
---
arch/x86/kernel/acpi/boot.c | 18 ++++++++++++++++--
arch/x86/kernel/apic/io_apic.c | 24 +++++++++++++++++++++---
2 files changed, 37 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index a1b388e88bcb..d807e16f8fec 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -655,8 +655,22 @@ 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_X86_IO_APIC
+ unsigned long long uid;
+ acpi_status status;
+
+ status = acpi_evaluate_integer(handle, METHOD_NAME__UID, NULL, &uid);
+ if (ACPI_FAILURE(status))
+ uid = 0;
+
+ down_write(&acpi_ioapic_rwsem);
+ ret = mp_register_ioapic((int)uid, phys_addr, gsi_base,
+ acpi_create_irqdomain, NULL);
+ 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 f70fa239f34b..4bddff760ff4 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -3802,7 +3802,13 @@ 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;
}

int mp_register_ioapic(int id, u32 address, u32 gsi_base,
@@ -3818,8 +3824,15 @@ int mp_register_ioapic(int id, u32 address, u32 gsi_base,
}
for_each_ioapic(ioapic)
if (ioapics[ioapic].mp_config.apicaddr == address) {
- pr_warn("address 0x%x conflicts with IOAPIC%d\n",
- address, ioapic);
+ /*
+ * IOAPIC unit may also be visible in PCI scope.
+ * When ioapic PCI driver's probe() is called,
+ * the IOAPIC unit may have already been initialized
+ * at boot time.
+ */
+ if (!ioapic_initialized)
+ pr_warn("address 0x%x conflicts with IOAPIC%d\n",
+ address, ioapic);
return -EEXIST;
}

@@ -3875,6 +3888,11 @@ int mp_register_ioapic(int id, u32 address, u32 gsi_base,
if (nr_ioapics <= idx)
nr_ioapics = idx + 1;

+ if (ioapic_initialized && ioapic_create_irqdomain(idx)) {
+ clear_fixmap(FIX_IO_APIC_BASE_0 + idx);
+ return -ENOMEM;
+ }
+
/* Set nr_registers to mark entry present */
ioapics[idx].nr_registers = entries;

--
1.7.10.4

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