Implements an abstraction for CPU internals. More...

Namespaces
namespace	Interrupt
	Exception and Interrupt control.

Classes
class	CR
	Access to the Control Register. More...

class	MSR
	Access to the Model-Specific Register (MSR) More...

Enumerations
enum	CR0 : uintptr_t { CR0_PE = 1U << 0 , CR0_MP = 1U << 1 , CR0_EM = 1U << 2 , CR0_TS = 1U << 3 , CR0_ET = 1U << 4 , CR0_NE = 1U << 5 , CR0_WP = 1U << 16 , CR0_AM = 1U << 18 , CR0_NW = 1U << 29 , CR0_CD = 1U << 30 , CR0_PG = 1U << 31 }
	Control Register 0. More...

enum	CR4 : uintptr_t { CR4_VME = 1U << 0 , CR4_PVI = 1U << 1 , CR4_TSD = 1U << 2 , CR4_DE = 1U << 3 , CR4_PSE = 1U << 4 , CR4_PAE = 1U << 5 , CR4_MCE = 1U << 6 , CR4_PGE = 1U << 7 , CR4_PCE = 1U << 8 , CR4_OSFXSR = 1U << 9 , CR4_OSXMMEXCPT = 1U << 10 , CR4_UMIP = 1U << 11 , CR4_VMXE = 1U << 13 , CR4_SMXE = 1U << 14 , CR4_FSGSBASE = 1U << 16 , CR4_PCIDE = 1U << 17 , CR4_OSXSAVE = 1U << 18 , CR4_SMEP = 1U << 20 , CR4_SMAP = 1U << 21 , CR4_PKE = 1U << 22 }
	Control Register 4. More...

enum	MSRs : uint32_t { MSR_PLATFORM_INFO = 0xceU , MSR_TSC_DEADLINE = 0x6e0U , MSR_EFER = 0xC0000080U , MSR_STAR = 0xC0000081U , MSR_LSTAR = 0xC0000082U , MSR_SFMASK = 0xC0000084U , MSR_FS_BASE = 0xC0000100U , MSR_GS_BASE = 0xC0000101U , MSR_SHADOW_GS_BASE = 0xC0000102U }
	Model-Specific Register Identifiers. More...

enum	MSR_EFER : uintptr_t { MSR_EFER_SCE = 1U << 0 , MSR_EFER_LME = 1U << 8 , MSR_EFER_LMA = 1U << 10 , MSR_EFER_NXE = 1U << 11 , MSR_EFER_SVME = 1U << 12 , MSR_EFER_LMSLE = 1U << 13 , MSR_EFER_FFXSR = 1U << 14 , MSR_EFER_TCE = 1U << 15 }

Functions
void	init ()
	Initialize this CPU core.

void	exit ()
	Deinitialize this CPU core.

unsigned	getID ()
	Get the ID of the current CPU core using LAPIC::getID() with an internal lookup table.

unsigned	count ()
	Get number of available CPU cores.

unsigned	countOnline ()
	Get number of successfully started (and currently active) CPU cores.

bool	isOnline (uint8_t core_id)
	Check if CPU core is currently active.

void	pause ()
	Gives the core a hint that it is executing a spinloop and should sleep "shortly".

void	idle ()
	Halt the CPU core until the next interrupt.

void	die ()
	Permanently halts the core.

Constants
static unsigned	cores = 0
	Number of available CPU cores.

static unsigned	core_id [255]
	Lookup table for CPU core IDs with LAPIC ID as index.

static unsigned	online_cores = 0
	Number of currently online CPU cores.

static bool	online_core [Core::MAX]
	Lookup table for online CPU cores with CPU core ID as index.

const unsigned	MAX = 8
	Maximum number of supported CPUs.

Detailed Description

Implements an abstraction for CPU internals.

These internals include functions to allow or deny interrupts, access control registers.

Enumeration Type Documentation

◆ CR0

enum Core::CR0 : uintptr_t

Control Register 0.

See also: ISDMv3, 2.5 Control Registers

Enumerator
CR0_PE	Protected Mode enabled.
CR0_MP	Monitor co-processor.
CR0_EM	Emulation (no x87 floating-point unit present)
CR0_TS	Task switched.
CR0_ET	Extension type.
CR0_NE	Numeric error.
CR0_WP	Write protect.
CR0_AM	Alignment mask.
CR0_NW	Not-write through caching.
CR0_CD	Cache disable.
CR0_PG	Paging.

◆ CR4

enum Core::CR4 : uintptr_t

Control Register 4.

See also: ISDMv3, 2.5 Control Registers

Enumerator
CR4_VME	Virtual 8086 Mode Extensions.
CR4_PVI	Protected-mode Virtual Interrupts.
CR4_TSD	Time Stamp Disable.
CR4_DE	Debugging Extensions.
CR4_PSE	Page Size Extension.
CR4_PAE	Physical Address Extension.
CR4_MCE	Machine Check Exception.
CR4_PGE	Page Global Enabled.
CR4_PCE	Performance-Monitoring Counter enable.
CR4_OSFXSR	Operating system support for FXSAVE and FXRSTOR instructions.
CR4_OSXMMEXCPT	Operating System Support for Unmasked SIMD Floating-Point Exceptions.
CR4_UMIP	User-Mode Instruction Prevention.
CR4_VMXE	Virtual Machine Extensions Enable.
CR4_SMXE	Safer Mode Extensions Enable.
CR4_FSGSBASE	Enables the instructions RDFSBASE, RDGSBASE, WRFSBASE, and WRGSBASE.
CR4_PCIDE	PCID Enable.
CR4_OSXSAVE	XSAVE and Processor Extended States Enable.
CR4_SMEP	Supervisor Mode Execution Protection Enable.
CR4_SMAP	Supervisor Mode Access Prevention Enable.
CR4_PKE	Protection Key Enable.

◆ MSRs

enum Core::MSRs : uint32_t

Model-Specific Register Identifiers.

Selection of useful identifiers.

See also: ISDMv4

Enumerator
MSR_PLATFORM_INFO	Platform information including bus frequency (Intel)
MSR_TSC_DEADLINE	Register for LAPIC::Timer Deadline mode.
MSR_EFER	Extended Feature Enable Register,. See also Core::MSR_EFER
MSR_STAR	eip (protected mode), ring 0 and 3 segment bases
MSR_LSTAR	rip (long mode)
MSR_SFMASK	lower 32 bit: flag mask, if bit is set corresponding rflag is cleared through syscall
MSR_FS_BASE
MSR_GS_BASE	Current GS base pointer.
MSR_SHADOW_GS_BASE	Usually called `MSR_KERNEL_GS_BASE` but this is misleading.

◆ MSR_EFER

enum Core::MSR_EFER : uintptr_t

Enumerator
MSR_EFER_SCE	System Call Extensions.
MSR_EFER_LME	Long mode enable.
MSR_EFER_LMA	Long mode active.
MSR_EFER_NXE	No-Execute Enable.
MSR_EFER_SVME	Secure Virtual Machine Enable.
MSR_EFER_LMSLE	Long Mode Segment Limit Enable.
MSR_EFER_FFXSR	Fast `FXSAVE`/`FXRSTOR` instruction.
MSR_EFER_TCE	Translation Cache Extension.

Function Documentation

◆ init()

void Core::init ( )

Initialize this CPU core.

Mark this core as online and setup the cores LAPIC by assigning it a unique logical APIC ID

Note: Should only be called from kernel_init() during startup.

◆ exit()

void Core::exit ( )

Deinitialize this CPU core.

Mark this Core as offline

Note: Should only be called from kernel_init() after returning from main() or main_ap().

◆ getID()

unsigned Core::getID ( )

Get the ID of the current CPU core using LAPIC::getID() with an internal lookup table.

Returns: ID of current Core (a number between 0 and Core::MAX)

◆ count()

unsigned Core::count ( )

Get number of available CPU cores.

Returns: total number of cores

◆ countOnline()

unsigned Core::countOnline ( )

Get number of successfully started (and currently active) CPU cores.

Returns: total number of online cores

◆ isOnline()

bool Core::isOnline ( uint8_t core_id )

Check if CPU core is currently active.

Parameters

core_id ID of the CPU core

Returns: true if successfully started and is currently active

◆ pause()

void Core::pause ( )

inline

Gives the core a hint that it is executing a spinloop and should sleep "shortly".

Improves the over-all performance when executing a spinloop by waiting a short moment reduce the load on the memory.

See also: ISDMv2, Chapter 4. PAUSE - Spin Loop Hint

◆ idle()

void Core::idle ( )

inline

Halt the CPU core until the next interrupt.

Halts the current CPU core such that it will wake up on the next interrupt. Internally, this function first enables the interrupts via sti and then halts the core using hlt. Halted cores can only be woken by interrupts. The effect of sti is delayed by one instruction, making the sequence sti hlt atomic (if interrupts were disabled previously).

See also: ISDMv2, Chapter 4. STI - Set Interrupt Flag; ISDMv2, Chapter 3. HLT - Halt

◆ die()

void Core::die ( )

inline

Permanently halts the core.

Permanently halts the current CPU core. Internally, this function first disables the interrupts via cli and then halts the CPU core using hlt. As halted CPU cores can only be woken by interrupts, it is guaranteed that this core will be halted until the next reboot. The execution of die never returns. On multicore systems, only the executing CPU core will be halted permanently, other cores will continue execution.

See also: ISDMv2, Chapter 3. CLI - Clear Interrupt Flag; ISDMv2, Chapter 3. HLT - Halt

Constant Documentation

◆ cores

unsigned Core::cores = 0

static

Number of available CPU cores.

◆ core_id

unsigned Core::core_id[255]

static

Lookup table for CPU core IDs with LAPIC ID as index.

◆ online_cores

unsigned Core::online_cores = 0

static

Number of currently online CPU cores.

◆ online_core

bool Core::online_core[Core::MAX]

static

Lookup table for online CPU cores with CPU core ID as index.

◆ MAX

const unsigned Core::MAX = 8

Maximum number of supported CPUs.

Namespaces

Classes

Enumerations

Functions

Constants

Detailed Description

Enumeration Type Documentation

◆ CR0

◆ CR4

◆ MSRs

◆ MSR_EFER

Function Documentation

◆ init()

◆ exit()

◆ getID()

◆ count()

◆ countOnline()

◆ isOnline()

◆ pause()

◆ idle()

◆ die()

Constant Documentation

◆ cores

◆ core_id

◆ online_cores

◆ online_core

◆ MAX