Collaboration diagram for CPU:

Detailed Description

CPU.

CPU structures and functions.

Events

Each CPU can generate events which can be handled by registering event handlers using cpu_handler_register().

As an example, the CPU_ONLINE event allows other subsystems to perform per-CPU initialization on each CPU no matter when they are initialized or even if IPIs are available yet.

This is what makes it possible for SMP to be in a module, at the cost of the system being perhaps slightly unintuitive and edge case heavy.

For more details see cpu_handler_register(), cpu_handler_unregister(), and cpu_handlers_check().

Per-CPU Data

Todo:: Implement per-CPU data. Use separate linker section?

Modules
	GDT
	Global Descriptor Table.

	IDT
	Interrupt Descriptor Table.

	Interrupts
	Interrupt Handling.

	Port I/O
	I/O port operations and reservations.

	IPI
	Inter-Processor Interrupts (IPIs)

	IRQ
	Interrupt Requests (IRQs)

	SIMD
	SIMD context management.

	Stack Pointer
	Helpers for managing stacks.

	Syscall
	System Call Interface.

	TSS
	Task State Segment.

Data Structures
struct	cpu_event_t
	CPU event structure. More...

struct	cpu_handler_t

struct	cpu_t
	CPU structure. More...

Macros
#define	CPU_MAX (UINT8_MAX + 1)
	Maximum number of CPUs supported.

#define	CPU_ID_BOOTSTRAP 0
	ID of the bootstrap CPU.

#define	CPU_ID_INVALID UINT16_MAX
	Invalid CPU ID.

#define	CPU_STACK_CANARY 0x1234567890ABCDEFULL
	CPU stack canary value.

#define	CPU_MAX_EVENT_HANDLERS 32
	Maximum number of CPU event handlers that can be registered.

#define	CPU_FOR_EACH(cpu)
	Macro to iterate over all CPUs.

#define	CPU_MAX UINT8_MAX
	Maximum number of CPUs supported.

#define	CPU_ID_BOOTSTRAP 0
	ID of the bootstrap CPU.

#define	CPU_ID_INVALID UINT16_MAX
	Invalid CPU ID.

Typedefs
typedef uint16_t	cpuid_t
	Type used to identify a CPU.

typedef void(*	cpu_func_t) (cpu_t cpu, const cpu_event_t event)
	CPU event function type.

typedef uint16_t	cpuid_t
	Type used to identify a CPU.

Enumerations
enum	cpu_event_type_t { CPU_ONLINE , CPU_OFFLINE }
	CPU event types. More...

Functions
void	cpu_init_early (cpu_t *cpu)
	Only initialize the parts of the CPU structure needed for early boot.

void	cpu_init (cpu_t *cpu)
	Initializes the CPU represented by the `cpu_t` structure.

uint64_t	cpu_handler_register (cpu_func_t func)
	Registers a CPU event handler for all CPUs.

void	cpu_handler_unregister (cpu_func_t func)
	Unregisters a previously registered CPU event handler.

void	cpu_handlers_check (cpu_t *cpu)
	Checks if any handlers have been registered since the last check, and invokes them if so.

void	cpu_stacks_overflow_check (cpu_t *cpu)
	Checks for CPU stack overflows.

uint64_t	cpu_halt_others (void)
	Halts all other CPUs.

static uint16_t	cpu_amount (void)
	Gets the number of identified CPUs.

static cpu_t *	cpu_get_by_id (cpuid_t id)
	Gets a CPU structure by its ID.

static cpu_t *	cpu_get (void)
	Gets the current CPU structure.

static void	cpu_put (void)
	Releases the current CPU structure.

static cpu_t *	cpu_get_unsafe (void)
	Gets the current CPU structure without disabling interrupts.

static cpuid_t	cpu_get_id_unsafe (void)
	Gets the current CPU ID.

static cpu_t *	cpu_get_next (cpu_t *current)
	Gets the next CPU in the CPU array.

Variables
cpu_t *	_cpus [CPU_MAX]
	Array of pointers to cpu_t structures for each CPU, indexed by CPU ID.

uint16_t	_cpuAmount
	The number of CPUs currently identified.

Macro Definition Documentation

◆ CPU_MAX [1/2]

#define CPU_MAX (UINT8_MAX + 1)

Maximum number of CPUs supported.

Definition at line 51 of file cpu.h.

◆ CPU_ID_BOOTSTRAP [1/2]

#define CPU_ID_BOOTSTRAP 0

ID of the bootstrap CPU.

Definition at line 56 of file cpu.h.

◆ CPU_ID_INVALID [1/2]

#define CPU_ID_INVALID UINT16_MAX

Invalid CPU ID.

Definition at line 61 of file cpu.h.

◆ CPU_STACK_CANARY

#define CPU_STACK_CANARY 0x1234567890ABCDEFULL

CPU stack canary value.

Placed at the bottom of CPU stacks, we then check in the interrupt handler if any of the stacks have overflowed by checking if its canary has been modified.

Definition at line 74 of file cpu.h.

◆ CPU_MAX_EVENT_HANDLERS

#define CPU_MAX_EVENT_HANDLERS 32

Maximum number of CPU event handlers that can be registered.

We need to statically allocate the event handler array such that handlers can be registered before memory allocation has been initialized.

Definition at line 100 of file cpu.h.

◆ CPU_FOR_EACH

#define CPU_FOR_EACH ( cpu )

Value:

for (cpuid_t _cpuId = 0; _cpuId < _cpuAmount; _cpuId++) \

for (cpu_t* cpu = _cpus[_cpuId]; cpu != NULL; cpu = NULL)

_cpus

cpu_t * _cpus[CPU_MAX]

Array of pointers to cpu_t structures for each CPU, indexed by CPU ID.

Definition cpu.c:23

_cpuAmount

uint16_t _cpuAmount

The number of CPUs currently identified.

Definition cpu.c:24

cpuid_t

uint16_t cpuid_t

Type used to identify a CPU.

Definition cpu.h:66

NULL

#define NULL

Pointer error value.

Definition NULL.h:23

cpu_t

CPU structure.

Definition cpu.h:122

Macro to iterate over all CPUs.

The main reason for using this macro is to avoid changes the the internal implementation of how CPUs are stored affecting other parts of the code.

Parameters

cpu	Loop variable, a pointer to the current `cpu_t`.

Definition at line 339 of file cpu.h.

◆ CPU_MAX [2/2]

#define CPU_MAX UINT8_MAX

Maximum number of CPUs supported.

Definition at line 14 of file cpu_id.h.

◆ CPU_ID_BOOTSTRAP [2/2]

#define CPU_ID_BOOTSTRAP 0

ID of the bootstrap CPU.

Definition at line 19 of file cpu_id.h.

◆ CPU_ID_INVALID [2/2]

#define CPU_ID_INVALID UINT16_MAX

Invalid CPU ID.

Definition at line 24 of file cpu_id.h.

Typedef Documentation

◆ cpuid_t [1/2]

typedef uint16_t cpuid_t

Type used to identify a CPU.

Definition at line 66 of file cpu.h.

◆ cpu_func_t

typedef void(* cpu_func_t) (cpu_t *cpu, const cpu_event_t *event)

CPU event function type.

Definition at line 105 of file cpu.h.

◆ cpuid_t [2/2]

typedef uint16_t cpuid_t

Type used to identify a CPU.

Definition at line 29 of file cpu_id.h.

Enumeration Type Documentation

◆ cpu_event_type_t

enum cpu_event_type_t

CPU event types.

Enumerator
CPU_ONLINE
CPU_OFFLINE

Definition at line 80 of file cpu.h.

Function Documentation

◆ cpu_init_early()

void cpu_init_early ( cpu_t * cpu )

Only initialize the parts of the CPU structure needed for early boot.

The only reason we need this is to split the initialization of the bootstrap CPU to avoid circular dependencies during early boot and since we cant use memory allocation yet.

Parameters

cpu	The CPU structure to initialize.

Definition at line 30 of file cpu.c.

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◆ cpu_init()

void cpu_init ( cpu_t * cpu )

Initializes the CPU represented by the cpu_t structure.

Must be called on the CPU that will be represented by the cpu structure, after setting the CPU ID MSR using cpu_init_early().

Parameters

cpu	The CPU structure to initialize.

Definition at line 78 of file cpu.c.

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◆ cpu_handler_register()

uint64_t cpu_handler_register ( cpu_func_t func )

Registers a CPU event handler for all CPUs.

The registered handler will be immediately invoked with a CPU_ONLINE event on the current CPU, then invoked on all others when they call cpu_handlers_check() and on any new cpus when they are initialized.

Parameters

func	The event function to register a handler for.

Returns

On success, 0. On failure, ERR and errno is set to:

EINVAL: Invalid parameters.
EBUSY: Too many event handlers registered.
EEXIST: A handler with the same function is already registered.

Definition at line 100 of file cpu.c.

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◆ cpu_handler_unregister()

void cpu_handler_unregister ( cpu_func_t func )

Unregisters a previously registered CPU event handler.

Will be a no-op if the handler was not registered.

Parameters

func	The event function of the handler to unregister, or `NULL` for no-op.

Definition at line 150 of file cpu.c.

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◆ cpu_handlers_check()

void cpu_handlers_check ( cpu_t * cpu )

Checks if any handlers have been registered since the last check, and invokes them if so.

Parameters

cpu	The CPU to check, must be the current CPU.

Definition at line 172 of file cpu.c.

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◆ cpu_stacks_overflow_check()

void cpu_stacks_overflow_check ( cpu_t * cpu )

Checks for CPU stack overflows.

Checks the canary values at the bottom of each CPU stack and if its been modified panics.

Parameters

cpu	The CPU to check.

Definition at line 193 of file cpu.c.

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◆ cpu_halt_others()

uint64_t cpu_halt_others ( void )

Halts all other CPUs.

Returns: On success, 0. On failure, ERR and errno is set.

Definition at line 225 of file cpu.c.

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◆ cpu_amount()

static uint16_t cpu_amount ( void )

inlinestatic

Gets the number of identified CPUs.

Use this over _cpuAmount.

Returns: The number of identified CPUs.

Definition at line 234 of file cpu.h.

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◆ cpu_get_by_id()

static cpu_t * cpu_get_by_id ( cpuid_t id )

inlinestatic

Gets a CPU structure by its ID.

Parameters

id	The ID of the CPU to get.

Returns: A pointer to the CPU structure, or NULL if no CPU with the given ID exists.

Definition at line 245 of file cpu.h.

◆ cpu_get()

static cpu_t * cpu_get ( void )

inlinestatic

Gets the current CPU structure.

Disables interrupts to prevent migration to another CPU.

Should be followed be a call to cpu_put() to re-enable interrupts.

Returns: A pointer to the current CPU structure.

Definition at line 263 of file cpu.h.

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◆ cpu_put()

static void cpu_put ( void )

inlinestatic

Releases the current CPU structure.

Re-enables interrupts.

Definition at line 277 of file cpu.h.

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◆ cpu_get_unsafe()

static cpu_t * cpu_get_unsafe ( void )

inlinestatic

Gets the current CPU structure without disabling interrupts.

Warning: This function does not disable interrupts, it should thus only be used when interrupts are already disabled.

Returns: A pointer to the current CPU structure.

Definition at line 289 of file cpu.h.

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◆ cpu_get_id_unsafe()

static cpuid_t cpu_get_id_unsafe ( void )

inlinestatic

Gets the current CPU ID.

Warning: This function does not disable interrupts, it should thus only be used when interrupts are already disabled.

Returns: The current CPU ID.

Definition at line 306 of file cpu.h.

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◆ cpu_get_next()

static cpu_t * cpu_get_next ( cpu_t * current )

inlinestatic

Gets the next CPU in the CPU array.

Wraps around to the first CPU if the current CPU is the last one.

Parameters

current The current CPU.

Returns: A pointer to the next CPU.

Definition at line 321 of file cpu.h.

Variable Documentation

◆ _cpus

cpu_t* _cpus[CPU_MAX]

extern

Array of pointers to cpu_t structures for each CPU, indexed by CPU ID.

We make this global since its accessed very frequently, so its a slight optimization.

Definition at line 23 of file cpu.c.

◆ _cpuAmount

uint16_t _cpuAmount

extern

The number of CPUs currently identified.

Use cpu_amount() over this variable.

Definition at line 24 of file cpu.c.

Detailed Description

Events

Per-CPU Data

Modules

Data Structures

Macros

Typedefs

Enumerations

Functions

Variables

Macro Definition Documentation

◆ CPU_MAX [1/2]

◆ CPU_ID_BOOTSTRAP [1/2]

◆ CPU_ID_INVALID [1/2]

◆ CPU_STACK_CANARY

◆ CPU_MAX_EVENT_HANDLERS

◆ CPU_FOR_EACH

◆ CPU_MAX [2/2]

◆ CPU_ID_BOOTSTRAP [2/2]

◆ CPU_ID_INVALID [2/2]

Typedef Documentation

◆ cpuid_t [1/2]

◆ cpu_func_t

◆ cpuid_t [2/2]

Enumeration Type Documentation

◆ cpu_event_type_t

Function Documentation

◆ cpu_init_early()

◆ cpu_init()

◆ cpu_handler_register()

◆ cpu_handler_unregister()

◆ cpu_handlers_check()

◆ cpu_stacks_overflow_check()

◆ cpu_halt_others()

◆ cpu_amount()

◆ cpu_get_by_id()

◆ cpu_get()

◆ cpu_put()

◆ cpu_get_unsafe()

◆ cpu_get_id_unsafe()

◆ cpu_get_next()

Variable Documentation

◆ _cpus

◆ _cpuAmount