[Patch v8 01/18] x86: ACPI: Do not translate GSI number if IOAPIC is disabled

[Patch v8 01/18] x86: ACPI: Do not translate GSI number if IOAPIC is disabled

[Jiang Liu]

When IOAPIC is disabled, acpi_gsi_to_irq() should return gsi directly
instead of calling mp_map_gsi_to_irq() to translate gsi to IRQ by IOAPIC.
It fixes https://bugzilla.kernel.org/show_bug.cgi?id=84381.

This regression was introduced with commit 6b9fb7082409 "x86, ACPI,
irq: Consolidate algorithm of mapping (ioapic, pin) to IRQ number"

Reported-and-Tested-by: Thomas Richter <thor@math.tu-berlin.de>
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Thomas Richter <thor@math.tu-berlin.de>
Cc: rui.zhang@intel.com
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: <stable@vger.kernel.org> # 3.17
Link: http://lkml.kernel.org/r/1413816327-12850-1-git-send-email-jiang.liu@linux.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 arch/x86/kernel/acpi/boot.c |   13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index b436fc735aa4..eceba9d9e116 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -604,14 +604,19 @@ void __init acpi_pic_sci_set_trigger(unsigned int irq, u16 trigger)
 
 int acpi_gsi_to_irq(u32 gsi, unsigned int *irqp)
 {
-	int irq = mp_map_gsi_to_irq(gsi, IOAPIC_MAP_ALLOC | IOAPIC_MAP_CHECK);
+	int irq;
 
-	if (irq >= 0) {
+	if (acpi_irq_model == ACPI_IRQ_MODEL_PIC) {
+		*irqp = gsi;
+	} else {
+		irq = mp_map_gsi_to_irq(gsi,
+					IOAPIC_MAP_ALLOC | IOAPIC_MAP_CHECK);
+		if (irq < 0)
+			return -1;
 		*irqp = irq;
-		return 0;
 	}
 
-	return -1;
+	return 0;
 }
 EXPORT_SYMBOL_GPL(acpi_gsi_to_irq);
 
-- 
1.7.10.4

[Patch v8 03/18] x86, irq, ACPI: Return IRQ instead of GSI in mp_register_gsi()

[Jiang Liu]

Function mp_register_gsi() returns blindly the GSI number for the ACPI
SCI interrupt. That causes a regression when the GSI for ACPI SCI is
shared with other devices.

The regression was caused by commit 84245af7297ced9e8fe "x86, irq, ACPI:
Change __acpi_register_gsi to return IRQ number instead of GSI" and
exposed on a SuperMicro system, which shares one GSI between ACPI SCI
and PCI device, with following failure:

http://sourceforge.net/p/linux1394/mailman/linux1394-user/?viewmonth=201410
[    0.000000] ACPI: INT_SRC_OVR (bus 0 bus_irq 9 global_irq 20 low
level)
[    2.699224] firewire_ohci 0000:06:00.0: failed to allocate interrupt
20

Return mp_map_gsi_to_irq(gsi, 0) instead of the GSI number.

Reported-and-Tested-by: Daniel Robbins <drobbins@funtoo.org>
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Len Brown <len.brown@intel.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: <stable@vger.kernel.org> # 3.17
Link: http://lkml.kernel.org/r/1414387308-27148-4-git-send-email-jiang.liu@linux.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 arch/x86/kernel/acpi/boot.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index eceba9d9e116..e077c080a519 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -397,7 +397,7 @@ static int mp_register_gsi(struct device *dev, u32 gsi, int trigger,
 
 	/* Don't set up the ACPI SCI because it's already set up */
 	if (acpi_gbl_FADT.sci_interrupt == gsi)
-		return gsi;
+		return mp_map_gsi_to_irq(gsi, IOAPIC_MAP_ALLOC);
 
 	trigger = trigger == ACPI_EDGE_SENSITIVE ? 0 : 1;
 	polarity = polarity == ACPI_ACTIVE_HIGH ? 0 : 1;
-- 
1.7.10.4

[Patch v8 14/18] x86, irq, ACPI: Introduce a rwsem to protect IOAPIC operations from hotplug

[Jiang Liu]

We are going to support ACPI based IOAPIC hotplug, so introduce a rwsem
to protect IOAPIC data structures from IOAPIC hotplug. We choose to
serialize in ACPI instead of in the IOAPIC core because:
1) currently we are only plan to support ACPI based IOAPIC hotplug
2) it's much more cleaner and easier
3) It does't affect IOAPIC discovered by devicetree, SFI and mpparse.

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
---
 arch/x86/kernel/acpi/boot.c |   21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index e077c080a519..96d775580821 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -76,6 +76,19 @@ int acpi_fix_pin2_polarity __initdata;
 static u64 acpi_lapic_addr __initdata = APIC_DEFAULT_PHYS_BASE;
 #endif
 
+/*
+ * Locks related to IOAPIC hotplug
+ * Hotplug side:
+ * 	->lock_device_hotplug()	//device_hotplug_lock
+ *		->acpi_ioapic_lock
+ *			->ioapic_lock
+ * Interrupt mapping side:
+ *	->acpi_ioapic_lock
+ *		->ioapic_mutex
+ *			->ioapic_lock
+ */
+static DEFINE_MUTEX(acpi_ioapic_lock);
+
 /* --------------------------------------------------------------------------
                               Boot-time Configuration
    -------------------------------------------------------------------------- */
@@ -609,8 +622,10 @@ int acpi_gsi_to_irq(u32 gsi, unsigned int *irqp)
 	if (acpi_irq_model == ACPI_IRQ_MODEL_PIC) {
 		*irqp = gsi;
 	} else {
+		mutex_lock(&acpi_ioapic_lock);
 		irq = mp_map_gsi_to_irq(gsi,
 					IOAPIC_MAP_ALLOC | IOAPIC_MAP_CHECK);
+		mutex_unlock(&acpi_ioapic_lock);
 		if (irq < 0)
 			return -1;
 		*irqp = irq;
@@ -651,7 +666,9 @@ static int acpi_register_gsi_ioapic(struct device *dev, u32 gsi,
 	int irq = gsi;
 
 #ifdef CONFIG_X86_IO_APIC
+	mutex_lock(&acpi_ioapic_lock);
 	irq = mp_register_gsi(dev, gsi, trigger, polarity);
+	mutex_unlock(&acpi_ioapic_lock);
 #endif
 
 	return irq;
@@ -660,7 +677,9 @@ static int acpi_register_gsi_ioapic(struct device *dev, u32 gsi,
 static void acpi_unregister_gsi_ioapic(u32 gsi)
 {
 #ifdef CONFIG_X86_IO_APIC
+	mutex_lock(&acpi_ioapic_lock);
 	mp_unregister_gsi(gsi);
+	mutex_unlock(&acpi_ioapic_lock);
 #endif
 }
 
@@ -1186,7 +1205,9 @@ static void __init acpi_process_madt(void)
 			/*
 			 * Parse MADT IO-APIC entries
 			 */
+			mutex_lock(&acpi_ioapic_lock);
 			error = acpi_parse_madt_ioapic_entries();
+			mutex_unlock(&acpi_ioapic_lock);
 			if (!error) {
 				acpi_set_irq_model_ioapic();
 
-- 
1.7.10.4

[Patch v8 15/18] x86, irq, ACPI: Implement interface to support ACPI based IOAPIC hot-addition

[Jiang Liu]

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 96d775580821..61be446d93c6 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

Re: [Patch v8 15/18] x86, irq, ACPI: Implement interface to support ACPI based IOAPIC hot-addition

[Thomas Gleixner]

On Sun, 2 Nov 2014, Jiang Liu wrote:
> +	down_write(&acpi_ioapic_rwsem);

That wants to be acpi_ioapic_lock. Same issue in the following
patches. You fixed it up in the last patch.

Please don't resend. I folded the hunks back to the proper places
already.

Thanks,

	tglx

Re: [Patch v8 15/18] x86, irq, ACPI: Implement interface to support ACPI based IOAPIC hot-addition

[Jiang Liu]

On 2014/11/3 17:41, Thomas Gleixner wrote:
> On Sun, 2 Nov 2014, Jiang Liu wrote:
>> +	down_write(&acpi_ioapic_rwsem);
> 
> That wants to be acpi_ioapic_lock. Same issue in the following
> patches. You fixed it up in the last patch.
> 
> Please don't resend. I folded the hunks back to the proper places
> already.
Thanks, Thomas.

There's no changes for the second patch set "[Patch Part1 v3 00/20]
Prepare for enabling  hierarchy irqdomain on x86" at
https://lkml.org/lkml/2014/10/27/122.

It should apply cleanly onto this patch set, so I won't resend it.

I have also solved all issues related to interrupt remapping and
is testing new implementation for third and fourth patch sets.
Will send them out once passing all tests.

Regards!
Gerry

> 
> Thanks,
> 
> 	tglx
> 
> 
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> 

[Patch v8 16/18] x86, irq, ACPI: Implement interfaces to support ACPI based IOAPIC hot-removal

[Jiang Liu]

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@linux.intel.com>
---
 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 8741c1ea33c3..7c04b8ec22a4 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 61be446d93c6..37a990146e90 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -809,15 +809,20 @@ 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 4d9d87cc3259..9e5432ee2070 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;
@@ -2973,6 +2980,16 @@ 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;
@@ -3735,6 +3752,7 @@ 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;
@@ -3963,6 +3981,43 @@ 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

[Patch v8 17/18] x86, irq: Introduce helper to check whether an IOAPIC has been registered

[Jiang Liu]

Introduce acpi_ioapic_registered() to check whether an IOAPIC has already
been registered, it will be used when enabling IOAPIC hotplug.

Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
---
 arch/x86/include/asm/io_apic.h |    1 +
 arch/x86/kernel/acpi/boot.c    |   22 ++++++++++++++++++++++
 arch/x86/kernel/apic/io_apic.c |   11 +++++++++++
 include/linux/acpi.h           |    1 +
 4 files changed, 35 insertions(+)

diff --git a/arch/x86/include/asm/io_apic.h b/arch/x86/include/asm/io_apic.h
index 7c04b8ec22a4..ca742d5249db 100644
--- a/arch/x86/include/asm/io_apic.h
+++ b/arch/x86/include/asm/io_apic.h
@@ -191,6 +191,7 @@ 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_ioapic_registered(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 37a990146e90..0e18705cee1e 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -825,6 +825,28 @@ int acpi_unregister_ioapic(acpi_handle handle, u32 gsi_base)
 }
 EXPORT_SYMBOL(acpi_unregister_ioapic);
 
+/**
+ * acpi_ioapic_registered - Check whether IOAPIC assoicatied with @gsi_base
+ *			    has been registered
+ * @handle:	ACPI handle of the IOAPIC deivce
+ * @gsi_base:	GSI base associated with the IOAPIC
+ *
+ * Assume caller holds some type of lock to serialize acpi_ioapic_registered()
+ * with acpi_register_ioapic()/acpi_unregister_ioapic().
+ */
+int acpi_ioapic_registered(acpi_handle handle, u32 gsi_base)
+{
+	int ret = 0;
+
+#ifdef CONFIG_ACPI_HOTPLUG_IOAPIC
+	down_read(&acpi_ioapic_rwsem);
+	ret  = mp_ioapic_registered(gsi_base);
+	up_read(&acpi_ioapic_rwsem);
+#endif
+
+	return ret;
+}
+
 static int __init acpi_parse_sbf(struct acpi_table_header *table)
 {
 	struct acpi_table_boot *sb;
diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index 9e5432ee2070..df3858de3031 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -4018,6 +4018,17 @@ int mp_unregister_ioapic(u32 gsi_base)
 	return 0;
 }
 
+int mp_ioapic_registered(u32 gsi_base)
+{
+	int ioapic;
+
+	for_each_ioapic(ioapic)
+		if (ioapics[ioapic].gsi_config.gsi_base == gsi_base)
+			return 1;
+
+	return 0;
+}
+
 int mp_irqdomain_map(struct irq_domain *domain, unsigned int virq,
 		     irq_hw_number_t hwirq)
 {
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 77cecd0350e7..be6be0f91337 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -152,6 +152,7 @@ int acpi_get_ioapic_id(acpi_handle handle, u32 gsi_base, u64 *phys_addr);
 
 int acpi_register_ioapic(acpi_handle handle, u64 phys_addr, u32 gsi_base);
 int acpi_unregister_ioapic(acpi_handle handle, u32 gsi_base);
+int acpi_ioapic_registered(acpi_handle handle, u32 gsi_base);
 void acpi_irq_stats_init(void);
 extern u32 acpi_irq_handled;
 extern u32 acpi_irq_not_handled;
-- 
1.7.10.4

[Patch v8 18/18] x86, irq, ACPI: Implement ACPI driver to support IOAPIC hotplug

[Jiang Liu]

Enable support of IOAPIC hotplug by:
1) reintroducing ACPI based IOAPIC driver
2) enhance pci_root driver to hook hotplug events

The ACPI IOAPIC driver is always enabled if all of ACPI, PCI and IOAPIC
are enabled.

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
---
 arch/x86/kernel/acpi/boot.c |   12 +--
 drivers/acpi/Kconfig        |    6 ++
 drivers/acpi/Makefile       |    1 +
 drivers/acpi/internal.h     |    7 ++
 drivers/acpi/ioapic.c       |  235 +++++++++++++++++++++++++++++++++++++++++++
 drivers/acpi/pci_root.c     |    3 +
 6 files changed, 258 insertions(+), 6 deletions(-)
 create mode 100644 drivers/acpi/ioapic.c

diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index 0e18705cee1e..32e47f22593c 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -802,9 +802,9 @@ int acpi_register_ioapic(acpi_handle handle, u64 phys_addr, u32 gsi_base)
 		ioapic_id = (int)uid;
 	}
 
-	down_write(&acpi_ioapic_rwsem);
+	mutex_lock(&acpi_ioapic_lock);
 	ret  = mp_register_ioapic(ioapic_id, phys_addr, gsi_base, &cfg);
-	up_write(&acpi_ioapic_rwsem);
+	mutex_unlock(&acpi_ioapic_lock);
 #endif
 
 	return ret;
@@ -816,9 +816,9 @@ int acpi_unregister_ioapic(acpi_handle handle, u32 gsi_base)
 	int ret = -ENOSYS;
 
 #ifdef CONFIG_ACPI_HOTPLUG_IOAPIC
-	down_write(&acpi_ioapic_rwsem);
+	mutex_lock(&acpi_ioapic_lock);
 	ret  = mp_unregister_ioapic(gsi_base);
-	up_write(&acpi_ioapic_rwsem);
+	mutex_unlock(&acpi_ioapic_lock);
 #endif
 
 	return ret;
@@ -839,9 +839,9 @@ int acpi_ioapic_registered(acpi_handle handle, u32 gsi_base)
 	int ret = 0;
 
 #ifdef CONFIG_ACPI_HOTPLUG_IOAPIC
-	down_read(&acpi_ioapic_rwsem);
+	mutex_lock(&acpi_ioapic_lock);
 	ret  = mp_ioapic_registered(gsi_base);
-	up_read(&acpi_ioapic_rwsem);
+	mutex_unlock(&acpi_ioapic_lock);
 #endif
 
 	return ret;
diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index b23fe37f67c0..127bc2fc43be 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -315,6 +315,12 @@ config ACPI_HOTPLUG_MEMORY
 	  To compile this driver as a module, choose M here:
 	  the module will be called acpi_memhotplug.
 
+config ACPI_HOTPLUG_IOAPIC
+	bool
+	depends on PCI
+	depends on X86_IO_APIC
+	default y
+
 config ACPI_SBS
 	tristate "Smart Battery System"
 	depends on X86
diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index c3b2fcb729f3..3b283a232f7a 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -69,6 +69,7 @@ obj-$(CONFIG_ACPI_PROCESSOR)	+= processor.o
 obj-y				+= container.o
 obj-$(CONFIG_ACPI_THERMAL)	+= thermal.o
 obj-y				+= acpi_memhotplug.o
+obj-$(CONFIG_ACPI_HOTPLUG_IOAPIC) += ioapic.o
 obj-$(CONFIG_ACPI_BATTERY)	+= battery.o
 obj-$(CONFIG_ACPI_SBS)		+= sbshc.o
 obj-$(CONFIG_ACPI_SBS)		+= sbs.o
diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
index 447f6d679b29..73efdcb8d8ad 100644
--- a/drivers/acpi/internal.h
+++ b/drivers/acpi/internal.h
@@ -35,6 +35,13 @@ void acpi_int340x_thermal_init(void);
 int acpi_sysfs_init(void);
 void acpi_container_init(void);
 void acpi_memory_hotplug_init(void);
+#ifdef	CONFIG_ACPI_HOTPLUG_IOAPIC
+int acpi_ioapic_add(struct acpi_pci_root *root);
+int acpi_ioapic_remove(struct acpi_pci_root *root);
+#else
+static inline int acpi_ioapic_add(struct acpi_pci_root *root) { return 0; }
+static inline int acpi_ioapic_remove(struct acpi_pci_root *root) { return 0; }
+#endif
 #ifdef CONFIG_ACPI_DOCK
 void register_dock_dependent_device(struct acpi_device *adev,
 				    acpi_handle dshandle);
diff --git a/drivers/acpi/ioapic.c b/drivers/acpi/ioapic.c
new file mode 100644
index 000000000000..9a631a61e270
--- /dev/null
+++ b/drivers/acpi/ioapic.c
@@ -0,0 +1,235 @@
+/*
+ * IOAPIC/IOxAPIC/IOSAPIC driver
+ *
+ * Copyright (C) 2009 Fujitsu Limited.
+ * (c) Copyright 2009 Hewlett-Packard Development Company, L.P.
+ *
+ * Copyright (C) 2014 Intel Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Based on original drivers/pci/ioapic.c
+ *	Yinghai Lu <yinghai@kernel.org>
+ *	Jiang Liu <jiang.liu@intel.com>
+ */
+
+/*
+ * This driver manages I/O APICs added by hotplug after boot.
+ * We try to claim all I/O APIC devices, but those present at boot were
+ * registered when we parsed the ACPI MADT.
+ */
+
+#define pr_fmt(fmt) "ACPI : IOAPIC: " fmt
+
+#include <linux/slab.h>
+#include <linux/acpi.h>
+#include <linux/pci.h>
+#include <acpi/acpi.h>
+
+struct acpi_pci_ioapic {
+	acpi_handle	root_handle;
+	acpi_handle	handle;
+	u32		gsi_base;
+	struct resource	res;
+	struct pci_dev	*pdev;
+	struct list_head list;
+};
+
+static LIST_HEAD(ioapic_list);
+static DEFINE_MUTEX(ioapic_list_lock);
+
+static acpi_status setup_res(struct acpi_resource *acpi_res, void *data)
+{
+	struct resource *res = data;
+
+	memset(res, 0, sizeof(*res));
+	if (acpi_dev_resource_memory(acpi_res, res)) {
+		res->flags &= IORESOURCE_MEM;
+		if (res->flags)
+			return AE_OK;
+	} else if (acpi_dev_resource_address_space(acpi_res, res)) {
+		struct acpi_resource_address64 addr;
+
+		res->flags &= IORESOURCE_MEM;
+		if (res->flags &&
+		    ACPI_SUCCESS(acpi_resource_to_address64(acpi_res, &addr)) &&
+		    addr.info.mem.caching != ACPI_PREFETCHABLE_MEMORY) {
+			res->start += addr.translation_offset;
+			res->end += addr.translation_offset;
+			return AE_OK;
+		}
+	}
+	res->flags = 0;
+
+	return AE_OK;
+}
+
+static bool acpi_is_ioapic(acpi_handle handle, char **type)
+{
+	acpi_status status;
+	struct acpi_device_info *info;
+	char *hid = NULL;
+	bool match = false;
+
+	if (!acpi_has_method(handle, "_GSB"))
+		return false;
+
+	status = acpi_get_object_info(handle, &info);
+	if (ACPI_SUCCESS(status)) {
+		if (info->valid & ACPI_VALID_HID)
+			hid = info->hardware_id.string;
+		if (hid) {
+			if (strcmp(hid, "ACPI0009") == 0) {
+				*type = "IOxAPIC";
+				match = true;
+			} else if (strcmp(hid, "ACPI000A") == 0) {
+				*type = "IOAPIC";
+				match = true;
+			}
+		}
+		kfree(info);
+	}
+
+	return match;
+}
+
+static acpi_status handle_ioapic_add(acpi_handle handle, u32 lvl,
+				     void *context, void **rv)
+{
+	acpi_status status;
+	unsigned long long gsi_base;
+	struct acpi_pci_ioapic *ioapic;
+	struct pci_dev *dev = NULL;
+	struct resource *res = NULL;
+	char *type = NULL;
+
+	if (!acpi_is_ioapic(handle, &type))
+		return AE_OK;
+
+	mutex_lock(&ioapic_list_lock);
+	list_for_each_entry(ioapic, &ioapic_list, list)
+		if (ioapic->handle == handle) {
+			mutex_unlock(&ioapic_list_lock);
+			return AE_OK;
+		}
+
+	status = acpi_evaluate_integer(handle, "_GSB", NULL, &gsi_base);
+	if (ACPI_FAILURE(status)) {
+		acpi_handle_warn(handle, "failed to evaluate _GSB method\n");
+		goto exit;
+	}
+
+	ioapic = kzalloc(sizeof(*ioapic), GFP_KERNEL);
+	if (!ioapic) {
+		pr_err("cannot allocate memory for new IOAPIC\n");
+		goto exit;
+	} else {
+		ioapic->root_handle = (acpi_handle)context;
+		ioapic->handle = handle;
+		ioapic->gsi_base = (u32)gsi_base;
+		ioapic->res.flags = IORESOURCE_UNSET;
+	}
+
+	if (acpi_ioapic_registered(handle, (u32)gsi_base))
+		goto done;
+
+	dev = acpi_get_pci_dev(handle);
+	if (dev && pci_resource_len(dev, 0)) {
+		if (pci_enable_device(dev) < 0)
+			goto exit_put;
+		pci_set_master(dev);
+		if (pci_request_region(dev, 0, type))
+			goto exit_disable;
+		res = &dev->resource[0];
+		ioapic->pdev = dev;
+	} else {
+		pci_dev_put(dev);
+		dev = NULL;
+
+		res = &ioapic->res;
+		acpi_walk_resources(handle, METHOD_NAME__CRS, setup_res, res);
+		if (res->flags == IORESOURCE_UNSET) {
+			acpi_handle_warn(handle, "failed to get resource\n");
+			goto exit_free;
+		} else if (request_resource(&iomem_resource, res)) {
+			acpi_handle_warn(handle, "failed to insert resource\n");
+			goto exit_free;
+		}
+	}
+
+	if (acpi_register_ioapic(handle, res->start, (u32)gsi_base)) {
+		acpi_handle_warn(handle, "failed to register IOAPIC\n");
+		goto exit_release;
+	}
+done:
+	list_add(&ioapic->list, &ioapic_list);
+	mutex_unlock(&ioapic_list_lock);
+
+	if (dev)
+		dev_info(&dev->dev, "%s at %pR, GSI %u\n",
+			 type, res, (u32)gsi_base);
+	else
+		acpi_handle_info(handle, "%s at %pR, GSI %u\n",
+				 type, res, (u32)gsi_base);
+
+	return AE_OK;
+
+exit_release:
+	if (dev)
+		pci_release_region(dev, 0);
+	else
+		release_resource(res);
+exit_disable:
+	if (dev)
+		pci_disable_device(dev);
+exit_put:
+	if (dev)
+		pci_dev_put(dev);
+exit_free:
+	kfree(ioapic);
+exit:
+	mutex_unlock(&ioapic_list_lock);
+	*(acpi_status *)rv = AE_ERROR;
+	return AE_OK;
+}
+
+int acpi_ioapic_add(struct acpi_pci_root *root)
+{
+	acpi_status status, retval = AE_OK;
+
+	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, root->device->handle,
+				     UINT_MAX, handle_ioapic_add, NULL,
+				     root->device->handle, (void **)&retval);
+
+	return ACPI_SUCCESS(status) && ACPI_SUCCESS(retval) ? 0 : -ENODEV;
+}
+
+int acpi_ioapic_remove(struct acpi_pci_root *root)
+{
+	int retval = 0;
+	struct acpi_pci_ioapic *ioapic, *tmp;
+
+	mutex_lock(&ioapic_list_lock);
+	list_for_each_entry_safe(ioapic, tmp, &ioapic_list, list) {
+		if (root->device->handle != ioapic->root_handle)
+			continue;
+
+		if (acpi_unregister_ioapic(ioapic->handle, ioapic->gsi_base))
+			retval = -EBUSY;
+
+		if (ioapic->pdev) {
+			pci_release_region(ioapic->pdev, 0);
+			pci_disable_device(ioapic->pdev);
+			pci_dev_put(ioapic->pdev);
+		} else if (ioapic->res.flags != IORESOURCE_UNSET) {
+			release_resource(&ioapic->res);
+		}
+		list_del(&ioapic->list);
+		kfree(ioapic);
+	}
+	mutex_unlock(&ioapic_list_lock);
+
+	return retval;
+}
diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index cd4de7e038ea..f3f77689bafc 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -614,6 +614,7 @@ static int acpi_pci_root_add(struct acpi_device *device,
 	if (system_state != SYSTEM_BOOTING) {
 		pcibios_resource_survey_bus(root->bus);
 		pci_assign_unassigned_root_bus_resources(root->bus);
+		acpi_ioapic_add(root);
 	}
 
 	pci_lock_rescan_remove();
@@ -634,6 +635,8 @@ static void acpi_pci_root_remove(struct acpi_device *device)
 
 	pci_stop_root_bus(root->bus);
 
+	WARN_ON(acpi_ioapic_remove(root));
+
 	device_set_run_wake(root->bus->bridge, false);
 	pci_acpi_remove_bus_pm_notifier(device);
 
-- 
1.7.10.4