arch/loongarch/kernel/syscall.c

Source file repositories/reference/linux-study-clean/arch/loongarch/kernel/syscall.c

File Facts

System
Linux kernel
Corpus path
arch/loongarch/kernel/syscall.c
Extension
.c
Size
2272 bytes
Lines
85
Domain
Architecture Layer
Bucket
arch/loongarch
Inferred role
Architecture Layer: syscall or user/kernel boundary
Status
core implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len, unsigned long,
		prot, unsigned long, flags, unsigned long, fd, unsigned long, offset)
{
	if (offset & ~PAGE_MASK)
		return -EINVAL;

	return ksys_mmap_pgoff(addr, len, prot, flags, fd, offset >> PAGE_SHIFT);
}

SYSCALL_DEFINE6(mmap2, unsigned long, addr, unsigned long, len, unsigned long,
		 prot, unsigned long, flags, unsigned long, fd, unsigned long, offset)
{
	if (offset & (~PAGE_MASK >> 12))
		return -EINVAL;

	return ksys_mmap_pgoff(addr, len, prot, flags, fd, offset >> (PAGE_SHIFT - 12));
}

void *sys_call_table[__NR_syscalls] = {
	[0 ... __NR_syscalls - 1] = sys_ni_syscall,
#ifdef CONFIG_32BIT
#include <asm/syscall_table_32.h>
#else
#include <asm/syscall_table_64.h>
#endif
};

typedef long (*sys_call_fn)(unsigned long, unsigned long,
	unsigned long, unsigned long, unsigned long, unsigned long);

void noinstr __no_stack_protector do_syscall(struct pt_regs *regs)
{
	unsigned long nr;
	sys_call_fn syscall_fn;

	nr = regs->regs[11];
	/* Set for syscall restarting */
	if (nr < NR_syscalls)
		regs->regs[0] = nr + 1;

	regs->csr_era += 4;
	regs->orig_a0 = regs->regs[4];
	regs->regs[4] = -ENOSYS;

	nr = syscall_enter_from_user_mode(regs, nr);

	add_random_kstack_offset();

	if (nr < NR_syscalls) {
		syscall_fn = sys_call_table[array_index_nospec(nr, NR_syscalls)];
		regs->regs[4] = syscall_fn(regs->orig_a0, regs->regs[5], regs->regs[6],
					   regs->regs[7], regs->regs[8], regs->regs[9]);
	}

	syscall_exit_to_user_mode(regs);
}

Annotation

Implementation Notes