Local Advanced Programmable Interrupt Controller. More...

Collaboration diagram for Local APIC:

Detailed Description

Local Advanced Programmable Interrupt Controller.

Local APICs

Each CPU has its own local APIC, which, when used with the IO APICs, allows for more advanced interrupt handling in comparison to the traditional PIC, such as routing interrupts to specific CPUs, interrupt prioritization, and more. Most of its features are not used in PatchworkOS yet.

Additionally, the local APICs provide Inter-Processor Interrupts (IPIs) which allow a CPU to interrupt another CPU by using its local APIC.

Note: Its a common mistake to assume that the local APIC IDs are contiguous, or that they are the same as the CPU IDs, but this is not the case. The local APIC IDs are assigned by the firmware and can be any value.

See also: ACPI Specification Version 6.6

Data Structures
struct	lapic_t
	Local APIC Structure. More...

Macros
#define	LAPIC_REG_ID_OFFSET 24
	The offset at which the lapic id is stored in the LAPIC_REG_ID register.

Typedefs
typedef uint8_t	lapic_id_t
	Local APIC ID type.

Enumerations
enum	lapic_msr_flags_t { LAPIC_MSR_ENABLE = 0x800 , LAPIC_MSR_BSP = 0x100 }
	Local APIC MSR Flags. More...

enum	lapic_register_t { LAPIC_REG_ID = 0x020 , LAPIC_REG_VERSION = 0x030 , LAPIC_REG_TASK_PRIORITY = 0x080 , LAPIC_REG_ARBITRATION_PRIORITY = 0x090 , LAPIC_REG_PROCESSOR_PRIORITY = 0x0A0 , LAPIC_REG_EOI = 0x0B0 , LAPIC_REG_REMOTE_READ = 0x0C0 , LAPIC_REG_LOGICAL_DEST = 0x0D0 , LAPIC_REG_DEST_FORMAT = 0x0E0 , LAPIC_REG_SPURIOUS = 0x0F0 , LAPIC_REG_ISR_BASE = 0x100 , LAPIC_REG_TMR_BASE = 0x180 , LAPIC_REG_IRR_BASE = 0x200 , LAPIC_REG_ERROR_STATUS = 0x280 , LAPIC_REG_LVT_CMCI = 0x2F0 , LAPIC_REG_ICR0 = 0x300 , LAPIC_REG_ICR1 = 0x310 , LAPIC_REG_LVT_TIMER = 0x320 , LAPIC_REG_LVT_THERMAL = 0x330 , LAPIC_REG_LVT_PERFCTR = 0x340 , LAPIC_REG_LVT_LINT0 = 0x350 , LAPIC_REG_LVT_LINT1 = 0x360 , LAPIC_REG_LVT_ERROR = 0x370 , LAPIC_REG_TIMER_INITIAL_COUNT = 0x380 , LAPIC_REG_TIMER_CURRENT_COUNT = 0x390 , LAPIC_REG_TIMER_DIVIDER = 0x3E0 }
	Local APIC Registers. More...

enum	lapic_flags_t { LAPIC_SPURIOUS_ENABLE = (1 << 8) , LAPIC_LVT_MASKED = (1 << 16) }
	Local APIC Flags. More...

enum	lapic_icr_delivery_mode_t { LAPIC_ICR_FIXED = (0 << 8) , LAPIC_ICR_LOWEST_PRIORITY = (1 << 8) , LAPIC_ICR_SMI = (2 << 8) , LAPIC_ICR_NMI = (4 << 8) , LAPIC_ICR_INIT = (5 << 8) , LAPIC_ICR_STARTUP = (6 << 8) }
	Local APIC ICR Delivery Modes. More...

enum	lapic_icr_flags_t { LAPIC_ICR_CLEAR_INIT_LEVEL = (1 << 14) }
	Local APIC ICR Flags. More...

Functions
uint64_t	lapic_global_init (void)
	Initialize the local APIC subsystem.

void	lapic_init (cpu_t *cpu)
	Initialize the local APIC for a CPU.

uint32_t	lapic_read (uint32_t reg)
	Read from a local apic register.

void	lapic_write (uint32_t reg, uint32_t value)
	Write to a local apic register.

lapic_t *	lapic_get (uint32_t cpuId)
	Get the lapic data for the specified CPU.

void	lapic_send_init (lapic_id_t id)
	Send an INIT IPI to the specified local APIC.

void	lapic_send_sipi (lapic_id_t id, void *entryPoint)
	Send a Startup IPI (SIPI) to the specified local APIC.

Macro Definition Documentation

◆ LAPIC_REG_ID_OFFSET

#define LAPIC_REG_ID_OFFSET 24

The offset at which the lapic id is stored in the LAPIC_REG_ID register.

Definition at line 81 of file lapic.h.

Typedef Documentation

◆ lapic_id_t

typedef uint8_t lapic_id_t

Local APIC ID type.

Definition at line 32 of file lapic.h.

Enumeration Type Documentation

◆ lapic_msr_flags_t

enum lapic_msr_flags_t

Local APIC MSR Flags.

Enumerator
LAPIC_MSR_ENABLE
LAPIC_MSR_BSP

Definition at line 38 of file lapic.h.

◆ lapic_register_t

enum lapic_register_t

Local APIC Registers.

Enumerator
LAPIC_REG_ID
LAPIC_REG_VERSION
LAPIC_REG_TASK_PRIORITY
LAPIC_REG_ARBITRATION_PRIORITY
LAPIC_REG_PROCESSOR_PRIORITY
LAPIC_REG_EOI
LAPIC_REG_REMOTE_READ
LAPIC_REG_LOGICAL_DEST
LAPIC_REG_DEST_FORMAT
LAPIC_REG_SPURIOUS
LAPIC_REG_ISR_BASE
LAPIC_REG_TMR_BASE
LAPIC_REG_IRR_BASE
LAPIC_REG_ERROR_STATUS
LAPIC_REG_LVT_CMCI
LAPIC_REG_ICR0
LAPIC_REG_ICR1
LAPIC_REG_LVT_TIMER
LAPIC_REG_LVT_THERMAL
LAPIC_REG_LVT_PERFCTR
LAPIC_REG_LVT_LINT0
LAPIC_REG_LVT_LINT1
LAPIC_REG_LVT_ERROR
LAPIC_REG_TIMER_INITIAL_COUNT
LAPIC_REG_TIMER_CURRENT_COUNT
LAPIC_REG_TIMER_DIVIDER

Definition at line 48 of file lapic.h.

◆ lapic_flags_t

enum lapic_flags_t

Local APIC Flags.

Enumerator
LAPIC_SPURIOUS_ENABLE
LAPIC_LVT_MASKED

Definition at line 87 of file lapic.h.

◆ lapic_icr_delivery_mode_t

enum lapic_icr_delivery_mode_t

Local APIC ICR Delivery Modes.

Enumerator
LAPIC_ICR_FIXED
LAPIC_ICR_LOWEST_PRIORITY
LAPIC_ICR_SMI
LAPIC_ICR_NMI
LAPIC_ICR_INIT
LAPIC_ICR_STARTUP

Definition at line 97 of file lapic.h.

◆ lapic_icr_flags_t

enum lapic_icr_flags_t

Local APIC ICR Flags.

Enumerator
LAPIC_ICR_CLEAR_INIT_LEVEL

Definition at line 111 of file lapic.h.

Function Documentation

◆ lapic_global_init()

uint64_t lapic_global_init ( void )

Initialize the local APIC subsystem.

Returns: On success, 0. On failure, ERR.

Definition at line 76 of file lapic.c.

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◆ lapic_init()

void lapic_init ( cpu_t * cpu )

Initialize the local APIC for a CPU.

Parameters

cpu	The current CPU.

Definition at line 28 of file lapic.c.

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◆ lapic_read()

uint32_t lapic_read ( uint32_t reg )

Read from a local apic register.

Parameters

reg	The register to read from.

Returns: The value read from the register.

Definition at line 18 of file lapic.c.

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◆ lapic_write()

void lapic_write	(	uint32_t	reg,
		uint32_t	value
	)

Write to a local apic register.

Parameters

reg	The register to write to.
value	The value to write.

Definition at line 23 of file lapic.c.

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◆ lapic_get()

lapic_t * lapic_get ( uint32_t cpuId )

Get the lapic data for the specified CPU.

Parameters

cpuId The CPU ID.

Returns: Pointer to the lapic structure for the CPU.

Definition at line 49 of file lapic.c.

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◆ lapic_send_init()

void lapic_send_init ( lapic_id_t id )

Send an INIT IPI to the specified local APIC.

Sending an INIT IPI will cause the target CPU to enter the INIT state, preparing it for startup.

Parameters

id	The ID of the local APIC to send the INIT IPI to.

Definition at line 118 of file lapic.c.

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◆ lapic_send_sipi()

void lapic_send_sipi	(	lapic_id_t	id,
		void *	entryPoint
	)

Send a Startup IPI (SIPI) to the specified local APIC.

Sending a SIPI will cause the target CPU to start executing code at the specified entry point address.

Parameters

id	The ID of the local APIC to send the SIPI to.
entryPoint	The entry point address for the SIPI, must be page-aligned.

Definition at line 124 of file lapic.c.

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Detailed Description

Local APICs

Data Structures

Macros

Typedefs

Enumerations

Functions

Macro Definition Documentation

◆ LAPIC_REG_ID_OFFSET

Typedef Documentation

◆ lapic_id_t

Enumeration Type Documentation

◆ lapic_msr_flags_t

◆ lapic_register_t

◆ lapic_flags_t

◆ lapic_icr_delivery_mode_t

◆ lapic_icr_flags_t

Function Documentation

◆ lapic_global_init()

◆ lapic_init()

◆ lapic_read()

◆ lapic_write()

◆ lapic_get()

◆ lapic_send_init()

◆ lapic_send_sipi()