用户态调试接口
/sys/kernel/debug/irq/domains
root@vm0:~# ls /sys/kernel/debug/irq/domains/
DMAR-MSI INTEL-IR-MSI-0-3 PCI-MSI-3 '\_SB.PCI0.SFB'
INTEL-IR-0 IO-APIC-0 VECTOR default
root@vm0:~# cat /sys/kernel/debug/irq/domains/DMAR-MSI
name: DMAR-MSI
size: 0
mapped: 1
flags: 0x00000013
parent: VECTOR
name: VECTOR
size: 0
mapped: 41
flags: 0x00000003
Online bitmaps: 8
Global available: 1580
Global reserved: 13
Total allocated: 28
System: 38: 0-19,32,50,128,236,240-242,244,246-255
| CPU | avl | man | mac | act | vectors
0 197 0 0 4 33-35,48
1 197 0 0 4 33-36
2 197 0 0 4 33-36
3 197 0 0 4 33-36
4 198 0 0 3 33-35
5 198 0 0 3 33-35
6 198 0 0 3 33-35
7 198 0 0 3 33-35x86 初始化
对于x86来说__irq_domain_add在arch_early_irq_init中调用
初始化核心函数
[kernel/irq/irqdomain.c]
struct irq_domain *__irq_domain_add(struct device_node *of_node, int size,
irq_hw_number_t hwirq_max, int direct_max,
const struct irq_domain_ops *ops,
void *host_data)
{
struct irq_domain *domain;
domain = kzalloc_node(sizeof(*domain) + (sizeof(unsigned int) * size),
GFP_KERNEL, of_node_to_nid(of_node));
/* Fill structure */
INIT_RADIX_TREE(&domain->revmap_tree, GFP_KERNEL);
domain->ops = ops;
domain->host_data = host_data;
domain->of_node = of_node_get(of_node);
domain->hwirq_max = hwirq_max;
domain->revmap_size = size;
domain->revmap_direct_max_irq = direct_max;
irq_domain_check_hierarchy(domain);
mutex_lock(&irq_domain_mutex);
list_add(&domain->link, &irq_domain_list); // 加入全局链表
mutex_unlock(&irq_domain_mutex);
pr_debug("Added domain %s\n", domain->name);
return domain;
}
EXPORT_SYMBOL_GPL(__irq_domain_add);domain->ops 为：
static const struct irq_domain_ops x86_vector_domain_ops = {
.select = x86_vector_select,
.alloc = x86_vector_alloc_irqs,
.free = x86_vector_free_irqs,
.activate = x86_vector_activate,
.deactivate = x86_vector_deactivate,
#ifdef CONFIG_GENERIC_IRQ_DEBUGFS
.debug_show = x86_vector_debug_show,
#endif
};调用堆栈
[ 0.000000] dump_stack_lvl+0x45/0x63
[ 0.000000] dump_stack+0x10/0x12
[ 0.000000] __irq_domain_add+0x1a8/0x290
[ 0.000000] irq_domain_create_tree+0xb9/0xf0
[ 0.000000] arch_early_irq_init+0x3a/0x79
[ 0.000000] early_irq_init+0xe5/0xec
[ 0.000000] start_kernel+0x449/0x661
[ 0.000000] x86_64_start_reservations+0x24/0x26
[ 0.000000] x86_64_start_kernel+0x86/0x8a
[ 0.000000] secondary_startup_64_no_verify+0xc2/0xcb[ 0.002000] irq: ===========================__irq_domain_add===========================
[ 0.002000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.15.0+ #45
[ 0.002000] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[ 0.002000] Call Trace:
[ 0.002000] dump_stack_lvl+0x45/0x63
[ 0.002000] dump_stack+0x10/0x12
[ 0.002000] __irq_domain_add+0x1a8/0x290
[ 0.002000] irq_domain_create_hierarchy+0x1e/0x50
[ 0.002000] intel_setup_irq_remapping.part.0+0xc0/0x2b0
[ 0.002000] intel_prepare_irq_remapping+0x120/0x18a
[ 0.002000] irq_remapping_prepare+0x16/0x4e
[ 0.002000] enable_IR_x2apic+0x21/0x85
[ 0.002000] default_setup_apic_routing+0x11/0x60
[ 0.002000] apic_intr_mode_init+0x7c/0x10a
[ 0.002000] x86_late_time_init+0x1f/0x30
[ 0.002000] start_kernel+0x5a9/0x661
[ 0.002000] x86_64_start_reservations+0x24/0x26
[ 0.002000] x86_64_start_kernel+0x86/0x8a
[ 0.002000] secondary_startup_64_no_verify+0xc2/0xcb[ 0.002000] irq: ===========================__irq_domain_add===========================
[ 0.002000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.15.0+ #45
[ 0.002000] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[ 0.002000] Call Trace:
[ 0.002000] dump_stack_lvl+0x45/0x63
[ 0.002000] dump_stack+0x10/0x12
[ 0.002000] __irq_domain_add+0x1a8/0x290
[ 0.002000] irq_domain_create_hierarchy+0x3f/0x50
[ 0.002000] msi_create_irq_domain+0x8b/0x180
[ 0.002000] pci_msi_create_irq_domain+0x32/0x110
[ 0.002000] arch_create_remap_msi_irq_domain+0x3d/0x80
[ 0.002000] ? irq_domain_create_hierarchy+0x1e/0x50
[ 0.002000] intel_setup_irq_remapping.part.0+0xe3/0x2b0
[ 0.002000] intel_prepare_irq_remapping+0x120/0x18a
[ 0.002000] irq_remapping_prepare+0x16/0x4e
[ 0.002000] enable_IR_x2apic+0x21/0x85
[ 0.002000] default_setup_apic_routing+0x11/0x60
[ 0.002000] apic_intr_mode_init+0x7c/0x10a
[ 0.002000] x86_late_time_init+0x1f/0x30
[ 0.002000] start_kernel+0x5a9/0x661
[ 0.002000] x86_64_start_reservations+0x24/0x26
[ 0.002000] x86_64_start_kernel+0x86/0x8a
[ 0.002000] secondary_startup_64_no_verify+0xc2/0xcb
[ 0.003000] DMAR-IR: Enabled IRQ remapping in xapic mode[ 0.003000] irq: ===========================__irq_domain_add===========================
[ 0.003000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.15.0+ #45
[ 0.003000] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[ 0.003000] Call Trace:
[ 0.003000] dump_stack_lvl+0x45/0x63
[ 0.003000] dump_stack+0x10/0x12
[ 0.003000] __irq_domain_add+0x1a8/0x290
[ 0.003000] ? __irq_domain_alloc_fwnode+0x32/0xf0
[ 0.003000] irq_domain_create_hierarchy+0x3f/0x50
[ 0.003000] msi_create_irq_domain+0x8b/0x180
[ 0.003000] dmar_alloc_hwirq+0xe8/0x120
[ 0.003000] ? __ioapic_read_entry+0x35/0x50
[ 0.003000] ? clear_IO_APIC_pin+0x16c/0x240
[ 0.003000] dmar_set_interrupt.part.0+0x1b/0x60
[ 0.003000] enable_drhd_fault_handling+0x2a/0x6a
[ 0.003000] irq_remap_enable_fault_handling+0x25/0x28
[ 0.003000] apic_intr_mode_init+0xfd/0x10a
[ 0.003000] x86_late_time_init+0x1f/0x30
[ 0.003000] start_kernel+0x5a9/0x661
[ 0.003000] x86_64_start_reservations+0x24/0x26
[ 0.003000] x86_64_start_kernel+0x86/0x8a
[ 0.003000] secondary_startup_64_no_verify+0xc2/0xcb[ 0.003000] irq: ===========================__irq_domain_add===========================
[ 0.003000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.15.0+ #45
[ 0.003000] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[ 0.003000] Call Trace:
[ 0.003000] dump_stack_lvl+0x45/0x63
[ 0.003000] dump_stack+0x10/0x12
[ 0.003000] __irq_domain_add+0x1a8/0x290
[ 0.003000] mp_irqdomain_create+0xb1/0x170
[ 0.003000] ? __setup_irq+0x448/0x770
[ 0.003000] setup_IO_APIC+0x7a/0x87f
[ 0.003000] apic_intr_mode_init+0x102/0x10a
[ 0.003000] x86_late_time_init+0x1f/0x30
[ 0.003000] start_kernel+0x5a9/0x661
[ 0.003000] x86_64_start_reservations+0x24/0x26
[ 0.003000] x86_64_start_kernel+0x86/0x8a
[ 0.003000] secondary_startup_64_no_verify+0xc2/0xcb[ 0.016279] irq: ===========================__irq_domain_add===========================
[ 0.016279] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.15.0+ #45
[ 0.016279] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[ 0.016279] Call Trace:
[ 0.016279] dump_stack_lvl+0x45/0x63
[ 0.016279] dump_stack+0x10/0x12
[ 0.016279] __irq_domain_add+0x1a8/0x290
[ 0.016281] irq_domain_create_hierarchy+0x3f/0x50
[ 0.016282] msi_create_irq_domain+0x8b/0x180
[ 0.016285] pci_msi_create_irq_domain+0x32/0x110
[ 0.016287] native_create_pci_msi_domain+0x49/0x74
[ 0.016289] x86_create_pci_msi_domain+0xd/0x16
[ 0.016290] pci_arch_init+0x2e/0x76
[ 0.016296] ? pcibios_resource_survey+0x70/0x70
[ 0.016298] do_one_initcall+0x41/0x1c0
[ 0.016300] kernel_init_freeable+0x1d5/0x224
[ 0.016303] ? rest_init+0xc0/0xc0
[ 0.016310] kernel_init+0x15/0x110
[ 0.016312] ret_from_fork+0x1f/0x30[ 0.734619] irq: ===========================__irq_domain_add===========================
[ 0.734624] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 5.15.0+ #45
[ 0.734626] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[ 0.734630] Call Trace:
[ 0.734638] dump_stack_lvl+0x45/0x63
[ 0.734656] dump_stack+0x10/0x12
[ 0.734660] __irq_domain_add+0x1a8/0x290
[ 0.734674] i2c_register_adapter+0x299/0x480
[ 0.734685] i2c_add_adapter+0x57/0x80
[ 0.734686] i801_probe.cold+0x70/0x2a8
[ 0.734694] local_pci_probe+0x43/0x80
[ 0.734710] pci_device_probe+0xfd/0x1b0
[ 0.734712] really_probe+0xcd/0x3f0
[ 0.734720] ? pm_runtime_barrier+0x43/0x80
[ 0.734728] __driver_probe_device+0x104/0x180
[ 0.734730] driver_probe_device+0x1e/0x90
[ 0.734731] __driver_attach+0xa7/0x1a0
[ 0.734733] ? __device_attach_driver+0xe0/0xe0
[ 0.734735] bus_for_each_dev+0x77/0xc0
[ 0.734738] driver_attach+0x19/0x20
[ 0.734739] bus_add_driver+0x130/0x1f0
[ 0.734745] driver_register+0x90/0xf0
[ 0.734746] ? smbalert_driver_init+0x14/0x14
[ 0.734758] __pci_register_driver+0x63/0x70
[ 0.734760] i2c_i801_init+0xa8/0xc7
[ 0.734763] ? i2c_register_driver+0x7b/0xb0
[ 0.734764] ? smbalert_driver_init+0x14/0x14
[ 0.734767] do_one_initcall+0x41/0x1c0
[ 0.734770] kernel_init_freeable+0x1d5/0x224
[ 0.734775] ? rest_init+0xc0/0xc0
[ 0.734782] kernel_init+0x15/0x110
[ 0.734784] ret_from_fork+0x1f/0x30