System Calls. More...

Data Structures
struct	syscall_ctx_t
	Per thread syscall context. More...

struct	syscall_descriptor_t
	A syscall descriptor. More...

Macros
#define	SYS_PROCESS_EXIT 0

#define	SYS_THREAD_EXIT 1

#define	SYS_SPAWN 2

#define	SYS_NANOSLEEP 3

#define	SYS_ERRNO 4

#define	SYS_GETPID 5

#define	SYS_GETTID 6

#define	SYS_UPTIME 7

#define	SYS_UNIX_EPOCH 8

#define	SYS_OPEN 9

#define	SYS_OPEN2 10

#define	SYS_CLOSE 11

#define	SYS_READ 12

#define	SYS_WRITE 13

#define	SYS_SEEK 14

#define	SYS_IOCTL 15

#define	SYS_CHDIR 16

#define	SYS_POLL 17

#define	SYS_STAT 18

#define	SYS_MMAP 19

#define	SYS_MUNMAP 20

#define	SYS_MPROTECT 21

#define	SYS_GETDENTS 22

#define	SYS_THREAD_CREATE 23

#define	SYS_YIELD 24

#define	SYS_DUP 25

#define	SYS_DUP2 26

#define	SYS_FUTEX 27

#define	SYS_REMOVE 28

#define	SYS_LINK 29

#define	SYS_SHARE 30

#define	SYS_CLAIM 31

#define	SYS_BIND 32

#define	SYS_TOTAL_AMOUNT 33

#define	SYSCALL_DEFINE(num, returnType, ...)
	Macro to define a syscall.

Functions
void	syscall_entry (void)
	Assembly entry point for syscalls.

void	syscall_ctx_init (syscall_ctx_t ctx, stack_pointer_t kernelStack)
	Initialize a per-thread syscall context.

void	syscall_ctx_load (syscall_ctx_t *ctx)
	Load a syscall context into the CPU.

void	syscall_table_init (void)
	Initialize the syscall table.

void	syscalls_cpu_init (void)
	Initalize syscalls on the current CPU.

uint64_t	syscall_handler (uint64_t rdi, uint64_t rsi, uint64_t rdx, uint64_t rcx, uint64_t r8, uint64_t r9, uint64_t number)
	C syscall handler.

Variables
syscall_descriptor_t	_syscallTableStart []
	Linker defined start of the syscall table.

syscall_descriptor_t	_syscallTableEnd []
	Linker defined end of the syscall table.

Detailed Description

System Calls.

System calls provide a controlled interface for user-space applications to request services from the kernel, such as file operations, process management, and inter-process communication.

See also: SYSCALL instruction; SYSRET instruction

Macro Definition Documentation

◆ SYS_BIND

#define SYS_BIND 32

Definition at line 54 of file syscalls.h.

◆ SYS_CHDIR

#define SYS_CHDIR 16

Definition at line 38 of file syscalls.h.

◆ SYS_CLAIM

#define SYS_CLAIM 31

Definition at line 53 of file syscalls.h.

◆ SYS_CLOSE

#define SYS_CLOSE 11

Definition at line 33 of file syscalls.h.

◆ SYS_DUP

#define SYS_DUP 25

Definition at line 47 of file syscalls.h.

◆ SYS_DUP2

#define SYS_DUP2 26

Definition at line 48 of file syscalls.h.

◆ SYS_ERRNO

#define SYS_ERRNO 4

Definition at line 26 of file syscalls.h.

◆ SYS_FUTEX

#define SYS_FUTEX 27

Definition at line 49 of file syscalls.h.

◆ SYS_GETDENTS

#define SYS_GETDENTS 22

Definition at line 44 of file syscalls.h.

◆ SYS_GETPID

#define SYS_GETPID 5

Definition at line 27 of file syscalls.h.

◆ SYS_GETTID

#define SYS_GETTID 6

Definition at line 28 of file syscalls.h.

◆ SYS_IOCTL

#define SYS_IOCTL 15

Definition at line 37 of file syscalls.h.

◆ SYS_LINK

#define SYS_LINK 29

Definition at line 51 of file syscalls.h.

◆ SYS_MMAP

#define SYS_MMAP 19

Definition at line 41 of file syscalls.h.

◆ SYS_MPROTECT

#define SYS_MPROTECT 21

Definition at line 43 of file syscalls.h.

◆ SYS_MUNMAP

#define SYS_MUNMAP 20

Definition at line 42 of file syscalls.h.

◆ SYS_NANOSLEEP

#define SYS_NANOSLEEP 3

Definition at line 25 of file syscalls.h.

◆ SYS_OPEN

#define SYS_OPEN 9

Definition at line 31 of file syscalls.h.

◆ SYS_OPEN2

#define SYS_OPEN2 10

Definition at line 32 of file syscalls.h.

◆ SYS_POLL

#define SYS_POLL 17

Definition at line 39 of file syscalls.h.

◆ SYS_PROCESS_EXIT

#define SYS_PROCESS_EXIT 0

Definition at line 22 of file syscalls.h.

◆ SYS_READ

#define SYS_READ 12

Definition at line 34 of file syscalls.h.

◆ SYS_REMOVE

#define SYS_REMOVE 28

Definition at line 50 of file syscalls.h.

◆ SYS_SEEK

#define SYS_SEEK 14

Definition at line 36 of file syscalls.h.

◆ SYS_SHARE

#define SYS_SHARE 30

Definition at line 52 of file syscalls.h.

◆ SYS_SPAWN

#define SYS_SPAWN 2

Definition at line 24 of file syscalls.h.

◆ SYS_STAT

#define SYS_STAT 18

Definition at line 40 of file syscalls.h.

◆ SYS_THREAD_CREATE

#define SYS_THREAD_CREATE 23

Definition at line 45 of file syscalls.h.

◆ SYS_THREAD_EXIT

#define SYS_THREAD_EXIT 1

Definition at line 23 of file syscalls.h.

◆ SYS_TOTAL_AMOUNT

#define SYS_TOTAL_AMOUNT 33

Definition at line 56 of file syscalls.h.

◆ SYS_UNIX_EPOCH

#define SYS_UNIX_EPOCH 8

Definition at line 30 of file syscalls.h.

◆ SYS_UPTIME

#define SYS_UPTIME 7

Definition at line 29 of file syscalls.h.

◆ SYS_WRITE

#define SYS_WRITE 13

Definition at line 35 of file syscalls.h.

◆ SYS_YIELD

#define SYS_YIELD 24

Definition at line 46 of file syscalls.h.

◆ SYSCALL_DEFINE

#define SYSCALL_DEFINE	(	num,
		returnType,
		...
	)

Value:

    returnType syscall_handler_##num(__VA_ARGS__); \
    const syscall_descriptor_t __syscall_##num __attribute__((used, section(".syscall_table"))) = { \
        .number = (num), \
        .handler = (void*)syscall_handler_##num, \
    }; \
    returnType syscall_handler_##num(__VA_ARGS__)

Macro to define a syscall.

Uses the linker section to define a system call in the syscall table.

Parameters

num	The syscall number, must be unique, check `include/kernel/syscalls.h` for existing numbers.
returnType	The return type of the syscall handler.
...	The arguments of the syscall handler, can be no more then 6 arguments. To avoid using the stack to pass arguments to a syscall.

Definition at line 100 of file syscalls.h.

Function Documentation

◆ syscall_ctx_init()

void syscall_ctx_init	(	syscall_ctx_t *	ctx,
		stack_pointer_t *	kernelStack
	)

Initialize a per-thread syscall context.

Parameters

ctx	The syscall context to initialize.
kernelStack	The kernel stack of the thread.

Definition at line 50 of file syscalls.c.

References syscall_ctx_t::kernelRsp, stack_pointer_t::top, and syscall_ctx_t::userRsp.

Referenced by thread_init().

◆ syscall_ctx_load()

void syscall_ctx_load ( syscall_ctx_t * ctx )

Load a syscall context into the CPU.

Definition at line 56 of file syscalls.c.

References MSR_GS_BASE, MSR_KERNEL_GS_BASE, and msr_write().

Referenced by thread_load().

◆ syscall_entry()

void syscall_entry ( void )

extern

Assembly entry point for syscalls.

Responsible for switching stacks.

Referenced by syscalls_cpu_init().

◆ syscall_handler()

uint64_t syscall_handler	(	uint64_t	rdi,
		uint64_t	rsi,
		uint64_t	rdx,
		uint64_t	rcx,
		uint64_t	r8,
		uint64_t	r9,
		uint64_t	number
	)

C syscall handler.

This is called from the assembly syscall_entry() function.

Parameters

rdi	First argument.
rsi	Second argument.
rdx	Third argument.
rcx	Fourth argument.
r8	Fifth argument.
r9	Sixth argument.
number	The syscall number.

Returns: The return value of the syscall.

Definition at line 72 of file syscalls.c.

References ENOSYS, ERR, errno, syscall_descriptor_t::handler, INTERRUPT_NOTE, lapic_self_id(), lapic_send_ipi(), LOG_DEBUG, note_queue_length(), NULL, sched_thread_unsafe(), and syscall_get_descriptor().

◆ syscall_table_init()

void syscall_table_init ( void )

Initialize the syscall table.

This will sort the syscall table and verify that all syscalls are present.

Definition at line 23 of file syscalls.c.

References _syscallTableEnd, _syscallTableStart, assert, LOG_INFO, qsort(), SYS_TOTAL_AMOUNT, and syscall_descriptor_cmp().

Referenced by init_finalize().

◆ syscalls_cpu_init()

void syscalls_cpu_init ( void )

Initalize syscalls on the current CPU.

This will setup the MSR registers required for syscalls.

Definition at line 39 of file syscalls.c.

References EFER_SYSCALL_ENABLE, GDT_KERNEL_CODE, GDT_RING3, GDT_USER_CODE, MSR_EFER, MSR_LSTAR, msr_read(), MSR_STAR, MSR_SYSCALL_FLAG_MASK, msr_write(), RFLAGS_AUX_CARRY, RFLAGS_DIRECTION, RFLAGS_INTERRUPT_ENABLE, RFLAGS_IOPL, RFLAGS_NESTED_TASK, RFLAGS_TRAP, and syscall_entry().

Referenced by cpu_init().

Variable Documentation

◆ _syscallTableEnd

syscall_descriptor_t _syscallTableEnd[]

extern

Linker defined end of the syscall table.

Referenced by syscall_table_init().

◆ _syscallTableStart

syscall_descriptor_t _syscallTableStart[]

extern

Linker defined start of the syscall table.

Referenced by syscall_get_descriptor(), and syscall_table_init().

Data Structures

Macros

Functions

Variables

Detailed Description

Macro Definition Documentation

◆ SYS_BIND

◆ SYS_CHDIR

◆ SYS_CLAIM

◆ SYS_CLOSE

◆ SYS_DUP

◆ SYS_DUP2

◆ SYS_ERRNO

◆ SYS_FUTEX

◆ SYS_GETDENTS

◆ SYS_GETPID

◆ SYS_GETTID

◆ SYS_IOCTL

◆ SYS_LINK

◆ SYS_MMAP

◆ SYS_MPROTECT

◆ SYS_MUNMAP

◆ SYS_NANOSLEEP

◆ SYS_OPEN

◆ SYS_OPEN2

◆ SYS_POLL

◆ SYS_PROCESS_EXIT

◆ SYS_READ

◆ SYS_REMOVE

◆ SYS_SEEK

◆ SYS_SHARE

◆ SYS_SPAWN

◆ SYS_STAT

◆ SYS_THREAD_CREATE

◆ SYS_THREAD_EXIT

◆ SYS_TOTAL_AMOUNT

◆ SYS_UNIX_EPOCH

◆ SYS_UPTIME

◆ SYS_WRITE

◆ SYS_YIELD

◆ SYSCALL_DEFINE

Function Documentation

◆ syscall_ctx_init()

◆ syscall_ctx_load()

◆ syscall_entry()

◆ syscall_handler()

◆ syscall_table_init()

◆ syscalls_cpu_init()

Variable Documentation

◆ _syscallTableEnd

◆ _syscallTableStart