Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 920 insertions, 0 deletions

diff --git a/drivers/acpi/pci_link.c b/drivers/acpi/pci_link.c
new file mode 100644
index 000000000..e6ed13aee
--- /dev/null
+++ b/drivers/acpi/pci_link.c
@@ -0,0 +1,920 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  pci_link.c - ACPI PCI Interrupt Link Device Driver ($Revision: 34 $)
+ *
+ *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
+ *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
+ *  Copyright (C) 2002       Dominik Brodowski <devel@brodo.de>
+ *
+ * TBD:
+ *	1. Support more than one IRQ resource entry per link device (index).
+ *	2. Implement start/stop mechanism and use ACPI Bus Driver facilities
+ *	   for IRQ management (e.g. start()->_SRS).
+ */
+
+#define pr_fmt(fmt) "ACPI: PCI: " fmt
+
+#include <linux/syscore_ops.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/spinlock.h>
+#include <linux/pm.h>
+#include <linux/pci.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/acpi.h>
+#include <linux/irq.h>
+
+#include "internal.h"
+
+#define ACPI_PCI_LINK_MAX_POSSIBLE	16
+
+static int acpi_pci_link_add(struct acpi_device *device,
+			     const struct acpi_device_id *not_used);
+static void acpi_pci_link_remove(struct acpi_device *device);
+
+static const struct acpi_device_id link_device_ids[] = {
+	{"PNP0C0F", 0},
+	{"", 0},
+};
+
+static struct acpi_scan_handler pci_link_handler = {
+	.ids = link_device_ids,
+	.attach = acpi_pci_link_add,
+	.detach = acpi_pci_link_remove,
+};
+
+/*
+ * If a link is initialized, we never change its active and initialized
+ * later even the link is disable. Instead, we just repick the active irq
+ */
+struct acpi_pci_link_irq {
+	u32 active;		/* Current IRQ */
+	u8 triggering;		/* All IRQs */
+	u8 polarity;		/* All IRQs */
+	u8 resource_type;
+	u8 possible_count;
+	u32 possible[ACPI_PCI_LINK_MAX_POSSIBLE];
+	u8 initialized:1;
+	u8 reserved:7;
+};
+
+struct acpi_pci_link {
+	struct list_head		list;
+	struct acpi_device		*device;
+	struct acpi_pci_link_irq	irq;
+	int				refcnt;
+};
+
+static LIST_HEAD(acpi_link_list);
+static DEFINE_MUTEX(acpi_link_lock);
+static int sci_irq = -1, sci_penalty;
+
+/* --------------------------------------------------------------------------
+                            PCI Link Device Management
+   -------------------------------------------------------------------------- */
+
+/*
+ * set context (link) possible list from resource list
+ */
+static acpi_status acpi_pci_link_check_possible(struct acpi_resource *resource,
+						void *context)
+{
+	struct acpi_pci_link *link = context;
+	acpi_handle handle = link->device->handle;
+	u32 i;
+
+	switch (resource->type) {
+	case ACPI_RESOURCE_TYPE_START_DEPENDENT:
+	case ACPI_RESOURCE_TYPE_END_TAG:
+		return AE_OK;
+	case ACPI_RESOURCE_TYPE_IRQ:
+		{
+			struct acpi_resource_irq *p = &resource->data.irq;
+			if (!p->interrupt_count) {
+				acpi_handle_debug(handle,
+						  "Blank _PRS IRQ resource\n");
+				return AE_OK;
+			}
+			for (i = 0;
+			     (i < p->interrupt_count
+			      && i < ACPI_PCI_LINK_MAX_POSSIBLE); i++) {
+				if (!p->interrupts[i]) {
+					acpi_handle_debug(handle,
+							  "Invalid _PRS IRQ %d\n",
+							  p->interrupts[i]);
+					continue;
+				}
+				link->irq.possible[i] = p->interrupts[i];
+				link->irq.possible_count++;
+			}
+			link->irq.triggering = p->triggering;
+			link->irq.polarity = p->polarity;
+			link->irq.resource_type = ACPI_RESOURCE_TYPE_IRQ;
+			break;
+		}
+	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
+		{
+			struct acpi_resource_extended_irq *p =
+			    &resource->data.extended_irq;
+			if (!p->interrupt_count) {
+				acpi_handle_debug(handle,
+						  "Blank _PRS EXT IRQ resource\n");
+				return AE_OK;
+			}
+			for (i = 0;
+			     (i < p->interrupt_count
+			      && i < ACPI_PCI_LINK_MAX_POSSIBLE); i++) {
+				if (!p->interrupts[i]) {
+					acpi_handle_debug(handle,
+							  "Invalid _PRS IRQ %d\n",
+							  p->interrupts[i]);
+					continue;
+				}
+				link->irq.possible[i] = p->interrupts[i];
+				link->irq.possible_count++;
+			}
+			link->irq.triggering = p->triggering;
+			link->irq.polarity = p->polarity;
+			link->irq.resource_type = ACPI_RESOURCE_TYPE_EXTENDED_IRQ;
+			break;
+		}
+	default:
+		acpi_handle_debug(handle, "_PRS resource type 0x%x is not IRQ\n",
+				  resource->type);
+		return AE_OK;
+	}
+
+	return AE_CTRL_TERMINATE;
+}
+
+static int acpi_pci_link_get_possible(struct acpi_pci_link *link)
+{
+	acpi_handle handle = link->device->handle;
+	acpi_status status;
+
+	status = acpi_walk_resources(handle, METHOD_NAME__PRS,
+				     acpi_pci_link_check_possible, link);
+	if (ACPI_FAILURE(status)) {
+		acpi_handle_debug(handle, "_PRS not present or invalid");
+		return 0;
+	}
+
+	acpi_handle_debug(handle, "Found %d possible IRQs\n",
+			  link->irq.possible_count);
+
+	return 0;
+}
+
+static acpi_status acpi_pci_link_check_current(struct acpi_resource *resource,
+					       void *context)
+{
+	int *irq = context;
+
+	switch (resource->type) {
+	case ACPI_RESOURCE_TYPE_START_DEPENDENT:
+	case ACPI_RESOURCE_TYPE_END_TAG:
+		return AE_OK;
+	case ACPI_RESOURCE_TYPE_IRQ:
+		{
+			struct acpi_resource_irq *p = &resource->data.irq;
+			if (!p->interrupt_count) {
+				/*
+				 * IRQ descriptors may have no IRQ# bits set,
+				 * particularly those w/ _STA disabled
+				 */
+				pr_debug("Blank _CRS IRQ resource\n");
+				return AE_OK;
+			}
+			*irq = p->interrupts[0];
+			break;
+		}
+	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
+		{
+			struct acpi_resource_extended_irq *p =
+			    &resource->data.extended_irq;
+			if (!p->interrupt_count) {
+				/*
+				 * extended IRQ descriptors must
+				 * return at least 1 IRQ
+				 */
+				pr_debug("Blank _CRS EXT IRQ resource\n");
+				return AE_OK;
+			}
+			*irq = p->interrupts[0];
+			break;
+		}
+		break;
+	default:
+		pr_debug("_CRS resource type 0x%x is not IRQ\n",
+			 resource->type);
+		return AE_OK;
+	}
+
+	return AE_CTRL_TERMINATE;
+}
+
+/*
+ * Run _CRS and set link->irq.active
+ *
+ * return value:
+ * 0 - success
+ * !0 - failure
+ */
+static int acpi_pci_link_get_current(struct acpi_pci_link *link)
+{
+	acpi_handle handle = link->device->handle;
+	acpi_status status;
+	int result = 0;
+	int irq = 0;
+
+	link->irq.active = 0;
+
+	/* in practice, status disabled is meaningless, ignore it */
+	if (acpi_strict) {
+		/* Query _STA, set link->device->status */
+		result = acpi_bus_get_status(link->device);
+		if (result) {
+			acpi_handle_err(handle, "Unable to read status\n");
+			goto end;
+		}
+
+		if (!link->device->status.enabled) {
+			acpi_handle_debug(handle, "Link disabled\n");
+			return 0;
+		}
+	}
+
+	/*
+	 * Query and parse _CRS to get the current IRQ assignment.
+	 */
+
+	status = acpi_walk_resources(handle, METHOD_NAME__CRS,
+				     acpi_pci_link_check_current, &irq);
+	if (ACPI_FAILURE(status)) {
+		acpi_evaluation_failure_warn(handle, "_CRS", status);
+		result = -ENODEV;
+		goto end;
+	}
+
+	if (acpi_strict && !irq) {
+		acpi_handle_err(handle, "_CRS returned 0\n");
+		result = -ENODEV;
+	}
+
+	link->irq.active = irq;
+
+	acpi_handle_debug(handle, "Link at IRQ %d\n", link->irq.active);
+
+      end:
+	return result;
+}
+
+static int acpi_pci_link_set(struct acpi_pci_link *link, int irq)
+{
+	struct {
+		struct acpi_resource res;
+		struct acpi_resource end;
+	} *resource;
+	struct acpi_buffer buffer = { 0, NULL };
+	acpi_handle handle = link->device->handle;
+	acpi_status status;
+	int result;
+
+	if (!irq)
+		return -EINVAL;
+
+	resource = kzalloc(sizeof(*resource) + 1, irqs_disabled() ? GFP_ATOMIC: GFP_KERNEL);
+	if (!resource)
+		return -ENOMEM;
+
+	buffer.length = sizeof(*resource) + 1;
+	buffer.pointer = resource;
+
+	switch (link->irq.resource_type) {
+	case ACPI_RESOURCE_TYPE_IRQ:
+		resource->res.type = ACPI_RESOURCE_TYPE_IRQ;
+		resource->res.length = sizeof(struct acpi_resource);
+		resource->res.data.irq.triggering = link->irq.triggering;
+		resource->res.data.irq.polarity =
+		    link->irq.polarity;
+		if (link->irq.triggering == ACPI_EDGE_SENSITIVE)
+			resource->res.data.irq.shareable =
+			    ACPI_EXCLUSIVE;
+		else
+			resource->res.data.irq.shareable = ACPI_SHARED;
+		resource->res.data.irq.interrupt_count = 1;
+		resource->res.data.irq.interrupts[0] = irq;
+		break;
+
+	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
+		resource->res.type = ACPI_RESOURCE_TYPE_EXTENDED_IRQ;
+		resource->res.length = sizeof(struct acpi_resource);
+		resource->res.data.extended_irq.producer_consumer =
+		    ACPI_CONSUMER;
+		resource->res.data.extended_irq.triggering =
+		    link->irq.triggering;
+		resource->res.data.extended_irq.polarity =
+		    link->irq.polarity;
+		if (link->irq.triggering == ACPI_EDGE_SENSITIVE)
+			resource->res.data.extended_irq.shareable =
+			    ACPI_EXCLUSIVE;
+		else
+			resource->res.data.extended_irq.shareable = ACPI_SHARED;
+		resource->res.data.extended_irq.interrupt_count = 1;
+		resource->res.data.extended_irq.interrupts[0] = irq;
+		/* ignore resource_source, it's optional */
+		break;
+	default:
+		acpi_handle_err(handle, "Invalid resource type %d\n",
+				link->irq.resource_type);
+		result = -EINVAL;
+		goto end;
+
+	}
+	resource->end.type = ACPI_RESOURCE_TYPE_END_TAG;
+	resource->end.length = sizeof(struct acpi_resource);
+
+	/* Attempt to set the resource */
+	status = acpi_set_current_resources(link->device->handle, &buffer);
+
+	/* check for total failure */
+	if (ACPI_FAILURE(status)) {
+		acpi_evaluation_failure_warn(handle, "_SRS", status);
+		result = -ENODEV;
+		goto end;
+	}
+
+	/* Query _STA, set device->status */
+	result = acpi_bus_get_status(link->device);
+	if (result) {
+		acpi_handle_err(handle, "Unable to read status\n");
+		goto end;
+	}
+	if (!link->device->status.enabled)
+		acpi_handle_warn(handle, "Disabled and referenced, BIOS bug\n");
+
+	/* Query _CRS, set link->irq.active */
+	result = acpi_pci_link_get_current(link);
+	if (result) {
+		goto end;
+	}
+
+	/*
+	 * Is current setting not what we set?
+	 * set link->irq.active
+	 */
+	if (link->irq.active != irq) {
+		/*
+		 * policy: when _CRS doesn't return what we just _SRS
+		 * assume _SRS worked and override _CRS value.
+		 */
+		acpi_handle_warn(handle, "BIOS reported IRQ %d, using IRQ %d\n",
+				 link->irq.active, irq);
+		link->irq.active = irq;
+	}
+
+	acpi_handle_debug(handle, "Set IRQ %d\n", link->irq.active);
+
+      end:
+	kfree(resource);
+	return result;
+}
+
+/* --------------------------------------------------------------------------
+                            PCI Link IRQ Management
+   -------------------------------------------------------------------------- */
+
+/*
+ * "acpi_irq_balance" (default in APIC mode) enables ACPI to use PIC Interrupt
+ * Link Devices to move the PIRQs around to minimize sharing.
+ *
+ * "acpi_irq_nobalance" (default in PIC mode) tells ACPI not to move any PIC IRQs
+ * that the BIOS has already set to active.  This is necessary because
+ * ACPI has no automatic means of knowing what ISA IRQs are used.  Note that
+ * if the BIOS doesn't set a Link Device active, ACPI needs to program it
+ * even if acpi_irq_nobalance is set.
+ *
+ * A tables of penalties avoids directing PCI interrupts to well known
+ * ISA IRQs. Boot params are available to over-ride the default table:
+ *
+ * List interrupts that are free for PCI use.
+ * acpi_irq_pci=n[,m]
+ *
+ * List interrupts that should not be used for PCI:
+ * acpi_irq_isa=n[,m]
+ *
+ * Note that PCI IRQ routers have a list of possible IRQs,
+ * which may not include the IRQs this table says are available.
+ *
+ * Since this heuristic can't tell the difference between a link
+ * that no device will attach to, vs. a link which may be shared
+ * by multiple active devices -- it is not optimal.
+ *
+ * If interrupt performance is that important, get an IO-APIC system
+ * with a pin dedicated to each device.  Or for that matter, an MSI
+ * enabled system.
+ */
+
+#define ACPI_MAX_ISA_IRQS	16
+
+#define PIRQ_PENALTY_PCI_POSSIBLE	(16*16)
+#define PIRQ_PENALTY_PCI_USING		(16*16*16)
+#define PIRQ_PENALTY_ISA_TYPICAL	(16*16*16*16)
+#define PIRQ_PENALTY_ISA_USED		(16*16*16*16*16)
+#define PIRQ_PENALTY_ISA_ALWAYS		(16*16*16*16*16*16)
+
+static int acpi_isa_irq_penalty[ACPI_MAX_ISA_IRQS] = {
+	PIRQ_PENALTY_ISA_ALWAYS,	/* IRQ0 timer */
+	PIRQ_PENALTY_ISA_ALWAYS,	/* IRQ1 keyboard */
+	PIRQ_PENALTY_ISA_ALWAYS,	/* IRQ2 cascade */
+	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ3 serial */
+	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ4 serial */
+	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ5 sometimes SoundBlaster */
+	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ6 */
+	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ7 parallel, spurious */
+	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ8 rtc, sometimes */
+	0,				/* IRQ9  PCI, often acpi */
+	0,				/* IRQ10 PCI */
+	0,				/* IRQ11 PCI */
+	PIRQ_PENALTY_ISA_USED,		/* IRQ12 mouse */
+	PIRQ_PENALTY_ISA_USED,		/* IRQ13 fpe, sometimes */
+	PIRQ_PENALTY_ISA_USED,		/* IRQ14 ide0 */
+	PIRQ_PENALTY_ISA_USED,		/* IRQ15 ide1 */
+	/* >IRQ15 */
+};
+
+static int acpi_irq_pci_sharing_penalty(u32 irq)
+{
+	struct acpi_pci_link *link;
+	int penalty = 0;
+	int i;
+
+	list_for_each_entry(link, &acpi_link_list, list) {
+		/*
+		 * If a link is active, penalize its IRQ heavily
+		 * so we try to choose a different IRQ.
+		 */
+		if (link->irq.active && link->irq.active == irq)
+			penalty += PIRQ_PENALTY_PCI_USING;
+
+		/*
+		 * penalize the IRQs PCI might use, but not as severely.
+		 */
+		for (i = 0; i < link->irq.possible_count; i++)
+			if (link->irq.possible[i] == irq)
+				penalty += PIRQ_PENALTY_PCI_POSSIBLE /
+					link->irq.possible_count;
+	}
+
+	return penalty;
+}
+
+static int acpi_irq_get_penalty(u32 irq)
+{
+	int penalty = 0;
+
+	if (irq == sci_irq)
+		penalty += sci_penalty;
+
+	if (irq < ACPI_MAX_ISA_IRQS)
+		return penalty + acpi_isa_irq_penalty[irq];
+
+	return penalty + acpi_irq_pci_sharing_penalty(irq);
+}
+
+int __init acpi_irq_penalty_init(void)
+{
+	struct acpi_pci_link *link;
+	int i;
+
+	/*
+	 * Update penalties to facilitate IRQ balancing.
+	 */
+	list_for_each_entry(link, &acpi_link_list, list) {
+
+		/*
+		 * reflect the possible and active irqs in the penalty table --
+		 * useful for breaking ties.
+		 */
+		if (link->irq.possible_count) {
+			int penalty =
+			    PIRQ_PENALTY_PCI_POSSIBLE /
+			    link->irq.possible_count;
+
+			for (i = 0; i < link->irq.possible_count; i++) {
+				if (link->irq.possible[i] < ACPI_MAX_ISA_IRQS)
+					acpi_isa_irq_penalty[link->irq.
+							 possible[i]] +=
+					    penalty;
+			}
+
+		} else if (link->irq.active &&
+				(link->irq.active < ACPI_MAX_ISA_IRQS)) {
+			acpi_isa_irq_penalty[link->irq.active] +=
+			    PIRQ_PENALTY_PCI_POSSIBLE;
+		}
+	}
+
+	return 0;
+}
+
+static int acpi_irq_balance = -1;	/* 0: static, 1: balance */
+
+static int acpi_pci_link_allocate(struct acpi_pci_link *link)
+{
+	acpi_handle handle = link->device->handle;
+	u32 irq;
+	int i;
+
+	if (link->irq.initialized) {
+		if (link->refcnt == 0)
+			/* This means the link is disabled but initialized */
+			acpi_pci_link_set(link, link->irq.active);
+		return 0;
+	}
+
+	/*
+	 * search for active IRQ in list of possible IRQs.
+	 */
+	for (i = 0; i < link->irq.possible_count; ++i) {
+		if (link->irq.active == link->irq.possible[i])
+			break;
+	}
+	/*
+	 * forget active IRQ that is not in possible list
+	 */
+	if (i == link->irq.possible_count) {
+		if (acpi_strict)
+			acpi_handle_warn(handle, "_CRS %d not found in _PRS\n",
+					 link->irq.active);
+		link->irq.active = 0;
+	}
+
+	/*
+	 * if active found, use it; else pick entry from end of possible list.
+	 */
+	if (link->irq.active)
+		irq = link->irq.active;
+	else
+		irq = link->irq.possible[link->irq.possible_count - 1];
+
+	if (acpi_irq_balance || !link->irq.active) {
+		/*
+		 * Select the best IRQ.  This is done in reverse to promote
+		 * the use of IRQs 9, 10, 11, and >15.
+		 */
+		for (i = (link->irq.possible_count - 1); i >= 0; i--) {
+			if (acpi_irq_get_penalty(irq) >
+			    acpi_irq_get_penalty(link->irq.possible[i]))
+				irq = link->irq.possible[i];
+		}
+	}
+	if (acpi_irq_get_penalty(irq) >= PIRQ_PENALTY_ISA_ALWAYS) {
+		acpi_handle_err(handle,
+				"No IRQ available. Try pci=noacpi or acpi=off\n");
+		return -ENODEV;
+	}
+
+	/* Attempt to enable the link device at this IRQ. */
+	if (acpi_pci_link_set(link, irq)) {
+		acpi_handle_err(handle,
+				"Unable to set IRQ. Try pci=noacpi or acpi=off\n");
+		return -ENODEV;
+	} else {
+		if (link->irq.active < ACPI_MAX_ISA_IRQS)
+			acpi_isa_irq_penalty[link->irq.active] +=
+				PIRQ_PENALTY_PCI_USING;
+
+		acpi_handle_info(handle, "Enabled at IRQ %d\n",
+				 link->irq.active);
+	}
+
+	link->irq.initialized = 1;
+	return 0;
+}
+
+/**
+ * acpi_pci_link_allocate_irq(): Retrieve a link device GSI
+ *
+ * @handle: Handle for the link device
+ * @index: GSI index
+ * @triggering: pointer to store the GSI trigger
+ * @polarity: pointer to store GSI polarity
+ * @name: pointer to store link device name
+ * @gsi: pointer to store GSI number
+ *
+ * Returns:
+ *	0 on success with @triggering, @polarity, @name, @gsi initialized.
+ *	-ENODEV on failure
+ */
+int acpi_pci_link_allocate_irq(acpi_handle handle, int index, int *triggering,
+			       int *polarity, char **name, u32 *gsi)
+{
+	struct acpi_device *device = acpi_fetch_acpi_dev(handle);
+	struct acpi_pci_link *link;
+
+	if (!device) {
+		acpi_handle_err(handle, "Invalid link device\n");
+		return -ENODEV;
+	}
+
+	link = acpi_driver_data(device);
+	if (!link) {
+		acpi_handle_err(handle, "Invalid link context\n");
+		return -ENODEV;
+	}
+
+	/* TBD: Support multiple index (IRQ) entries per Link Device */
+	if (index) {
+		acpi_handle_err(handle, "Invalid index %d\n", index);
+		return -ENODEV;
+	}
+
+	mutex_lock(&acpi_link_lock);
+	if (acpi_pci_link_allocate(link)) {
+		mutex_unlock(&acpi_link_lock);
+		return -ENODEV;
+	}
+
+	if (!link->irq.active) {
+		mutex_unlock(&acpi_link_lock);
+		acpi_handle_err(handle, "Link active IRQ is 0!\n");
+		return -ENODEV;
+	}
+	link->refcnt++;
+	mutex_unlock(&acpi_link_lock);
+
+	if (triggering)
+		*triggering = link->irq.triggering;
+	if (polarity)
+		*polarity = link->irq.polarity;
+	if (name)
+		*name = acpi_device_bid(link->device);
+	acpi_handle_debug(handle, "Link is referenced\n");
+	*gsi = link->irq.active;
+
+	return 0;
+}
+
+/*
+ * We don't change link's irq information here.  After it is reenabled, we
+ * continue use the info
+ */
+int acpi_pci_link_free_irq(acpi_handle handle)
+{
+	struct acpi_device *device = acpi_fetch_acpi_dev(handle);
+	struct acpi_pci_link *link;
+
+	if (!device) {
+		acpi_handle_err(handle, "Invalid link device\n");
+		return -1;
+	}
+
+	link = acpi_driver_data(device);
+	if (!link) {
+		acpi_handle_err(handle, "Invalid link context\n");
+		return -1;
+	}
+
+	mutex_lock(&acpi_link_lock);
+	if (!link->irq.initialized) {
+		mutex_unlock(&acpi_link_lock);
+		acpi_handle_err(handle, "Link isn't initialized\n");
+		return -1;
+	}
+#ifdef	FUTURE_USE
+	/*
+	 * The Link reference count allows us to _DISable an unused link
+	 * and suspend time, and set it again  on resume.
+	 * However, 2.6.12 still has irq_router.resume
+	 * which blindly restores the link state.
+	 * So we disable the reference count method
+	 * to prevent duplicate acpi_pci_link_set()
+	 * which would harm some systems
+	 */
+	link->refcnt--;
+#endif
+	acpi_handle_debug(handle, "Link is dereferenced\n");
+
+	if (link->refcnt == 0)
+		acpi_evaluate_object(link->device->handle, "_DIS", NULL, NULL);
+
+	mutex_unlock(&acpi_link_lock);
+	return link->irq.active;
+}
+
+/* --------------------------------------------------------------------------
+                                 Driver Interface
+   -------------------------------------------------------------------------- */
+
+static int acpi_pci_link_add(struct acpi_device *device,
+			     const struct acpi_device_id *not_used)
+{
+	acpi_handle handle = device->handle;
+	struct acpi_pci_link *link;
+	int result;
+	int i;
+
+	link = kzalloc_obj(struct acpi_pci_link);
+	if (!link)
+		return -ENOMEM;
+
+	link->device = device;
+	device->driver_data = link;
+
+	mutex_lock(&acpi_link_lock);
+	result = acpi_pci_link_get_possible(link);
+	if (result)
+		goto end;
+
+	/* query and set link->irq.active */
+	acpi_pci_link_get_current(link);
+
+	pr_info("Interrupt link %s configured for IRQ %d\n",
+		acpi_device_bid(device), link->irq.active);
+
+	for (i = 0; i < link->irq.possible_count; i++) {
+		if (link->irq.active != link->irq.possible[i])
+			acpi_handle_debug(handle, "Possible IRQ %d\n",
+					  link->irq.possible[i]);
+	}
+
+	if (!link->device->status.enabled)
+		pr_info("Interrupt link %s disabled\n", acpi_device_bid(device));
+
+	list_add_tail(&link->list, &acpi_link_list);
+
+      end:
+	/* disable all links -- to be activated on use */
+	acpi_evaluate_object(handle, "_DIS", NULL, NULL);
+	mutex_unlock(&acpi_link_lock);
+
+	if (result)
+		kfree(link);
+
+	acpi_dev_clear_dependencies(device);
+
+	return result < 0 ? result : 1;
+}
+
+static int acpi_pci_link_resume(struct acpi_pci_link *link)
+{
+	if (link->refcnt && link->irq.active && link->irq.initialized)
+		return (acpi_pci_link_set(link, link->irq.active));
+
+	return 0;
+}
+
+static void irqrouter_resume(void *data)
+{
+	struct acpi_pci_link *link;
+
+	list_for_each_entry(link, &acpi_link_list, list) {
+		acpi_pci_link_resume(link);
+	}
+}
+
+static void acpi_pci_link_remove(struct acpi_device *device)
+{
+	struct acpi_pci_link *link;
+
+	link = acpi_driver_data(device);
+
+	mutex_lock(&acpi_link_lock);
+	list_del(&link->list);
+	mutex_unlock(&acpi_link_lock);
+
+	kfree(link);
+}
+
+/*
+ * modify acpi_isa_irq_penalty[] from cmdline
+ */
+static int __init acpi_irq_penalty_update(char *str, int used)
+{
+	int i;
+
+	for (i = 0; i < 16; i++) {
+		int retval;
+		int irq;
+		int new_penalty;
+
+		retval = get_option(&str, &irq);
+
+		if (!retval)
+			break;	/* no number found */
+
+		/* see if this is a ISA IRQ */
+		if ((irq < 0) || (irq >= ACPI_MAX_ISA_IRQS))
+			continue;
+
+		if (used)
+			new_penalty = acpi_isa_irq_penalty[irq] +
+					PIRQ_PENALTY_ISA_USED;
+		else
+			new_penalty = 0;
+
+		acpi_isa_irq_penalty[irq] = new_penalty;
+		if (retval != 2)	/* no next number */
+			break;
+	}
+	return 1;
+}
+
+/*
+ * We'd like PNP to call this routine for the
+ * single ISA_USED value for each legacy device.
+ * But instead it calls us with each POSSIBLE setting.
+ * There is no ISA_POSSIBLE weight, so we simply use
+ * the (small) PCI_USING penalty.
+ */
+void acpi_penalize_isa_irq(int irq, int active)
+{
+	if ((irq >= 0) && (irq < ARRAY_SIZE(acpi_isa_irq_penalty)))
+		acpi_isa_irq_penalty[irq] +=
+		  (active ? PIRQ_PENALTY_ISA_USED : PIRQ_PENALTY_PCI_USING);
+}
+
+bool acpi_isa_irq_available(int irq)
+{
+	return irq >= 0 && (irq >= ARRAY_SIZE(acpi_isa_irq_penalty) ||
+		    acpi_irq_get_penalty(irq) < PIRQ_PENALTY_ISA_ALWAYS);
+}
+
+void acpi_penalize_sci_irq(int irq, int trigger, int polarity)
+{
+	sci_irq = irq;
+
+	if (trigger == ACPI_MADT_TRIGGER_LEVEL &&
+	    polarity == ACPI_MADT_POLARITY_ACTIVE_LOW)
+		sci_penalty = PIRQ_PENALTY_PCI_USING;
+	else
+		sci_penalty = PIRQ_PENALTY_ISA_ALWAYS;
+}
+
+/*
+ * Over-ride default table to reserve additional IRQs for use by ISA
+ * e.g. acpi_irq_isa=5
+ * Useful for telling ACPI how not to interfere with your ISA sound card.
+ */
+static int __init acpi_irq_isa(char *str)
+{
+	return acpi_irq_penalty_update(str, 1);
+}
+
+__setup("acpi_irq_isa=", acpi_irq_isa);
+
+/*
+ * Over-ride default table to free additional IRQs for use by PCI
+ * e.g. acpi_irq_pci=7,15
+ * Used for acpi_irq_balance to free up IRQs to reduce PCI IRQ sharing.
+ */
+static int __init acpi_irq_pci(char *str)
+{
+	return acpi_irq_penalty_update(str, 0);
+}
+
+__setup("acpi_irq_pci=", acpi_irq_pci);
+
+static int __init acpi_irq_nobalance_set(char *str)
+{
+	acpi_irq_balance = 0;
+	return 1;
+}
+
+__setup("acpi_irq_nobalance", acpi_irq_nobalance_set);
+
+static int __init acpi_irq_balance_set(char *str)
+{
+	acpi_irq_balance = 1;
+	return 1;
+}
+
+__setup("acpi_irq_balance", acpi_irq_balance_set);
+
+static const struct syscore_ops irqrouter_syscore_ops = {
+	.resume = irqrouter_resume,
+};
+
+static struct syscore irqrouter_syscore = {
+	.ops = &irqrouter_syscore_ops,
+};
+
+void __init acpi_pci_link_init(void)
+{
+	if (acpi_noirq)
+		return;
+
+	if (acpi_irq_balance == -1) {
+		/* no command line switch: enable balancing in IOAPIC mode */
+		if (acpi_irq_model == ACPI_IRQ_MODEL_IOAPIC)
+			acpi_irq_balance = 1;
+		else
+			acpi_irq_balance = 0;
+	}
+	register_syscore(&irqrouter_syscore);
+	acpi_scan_add_handler(&pci_link_handler);
+}