1. 根目录:
2. arch
3. metag
4. kernel
5. sys_metag.c

/*
 * This file contains various random system calls that
 * have a non-standard calling sequence on the Linux/Meta
 * platform.
 */

#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/syscalls.h>
#include <linux/mman.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/uaccess.h>
#include <linux/unistd.h>
#include <asm/cacheflush.h>
#include <asm/core_reg.h>
#include <asm/global_lock.h>
#include <asm/switch.h>
#include <asm/syscall.h>
#include <asm/syscalls.h>
#include <asm/user_gateway.h>

#define merge_64(hi, lo) ((((unsigned long long)(hi)) << 32) + \
			  ((lo) & 0xffffffffUL))

int metag_mmap_check(unsigned long addr, unsigned long len,
		     unsigned long flags)
{
	/* We can't have people trying to write to the bottom of the
	 * memory map, there are mysterious unspecified things there that
	 * we don't want people trampling on.
	 */
	if ((flags & MAP_FIXED) && (addr < TASK_UNMAPPED_BASE))
		return -EINVAL;

	return 0;
}

asmlinkage long sys_mmap2(unsigned long addr, unsigned long len,
			  unsigned long prot, unsigned long flags,
			  unsigned long fd, unsigned long pgoff)
{
	/* The shift for mmap2 is constant, regardless of PAGE_SIZE setting. */
	if (pgoff & ((1 << (PAGE_SHIFT - 12)) - 1))
		return -EINVAL;

	pgoff >>= PAGE_SHIFT - 12;

	return sys_mmap_pgoff(addr, len, prot, flags, fd, pgoff);
}

asmlinkage int sys_metag_setglobalbit(char __user *addr, int mask)
{
	char tmp;
	int ret = 0;
	unsigned int flags;

	if (!((__force unsigned int)addr >= LINCORE_BASE))
		return -EFAULT;

	__global_lock2(flags);

	metag_data_cache_flush((__force void *)addr, sizeof(mask));

	ret = __get_user(tmp, addr);
	if (ret)
		goto out;
	tmp |= mask;
	ret = __put_user(tmp, addr);

	metag_data_cache_flush((__force void *)addr, sizeof(mask));

out:
	__global_unlock2(flags);

	return ret;
}

#define TXDEFR_FPU_MASK ((0x1f << 16) | 0x1f)

asmlinkage void sys_metag_set_fpu_flags(unsigned int flags)
{
	unsigned int temp;

	flags &= TXDEFR_FPU_MASK;

	temp = __core_reg_get(TXDEFR);
	temp &= ~TXDEFR_FPU_MASK;
	temp |= flags;
	__core_reg_set(TXDEFR, temp);
}

asmlinkage int sys_metag_set_tls(void __user *ptr)
{
	current->thread.tls_ptr = ptr;
	set_gateway_tls(ptr);

	return 0;
}

asmlinkage void *sys_metag_get_tls(void)
{
	return (__force void *)current->thread.tls_ptr;
}

asmlinkage long sys_truncate64_metag(const char __user *path, unsigned long lo,
				     unsigned long hi)
{
	return sys_truncate64(path, merge_64(hi, lo));
}

asmlinkage long sys_ftruncate64_metag(unsigned int fd, unsigned long lo,
				      unsigned long hi)
{
	return sys_ftruncate64(fd, merge_64(hi, lo));
}

asmlinkage long sys_fadvise64_64_metag(int fd, unsigned long offs_lo,
				       unsigned long offs_hi,
				       unsigned long len_lo,
				       unsigned long len_hi, int advice)
{
	return sys_fadvise64_64(fd, merge_64(offs_hi, offs_lo),
				merge_64(len_hi, len_lo), advice);
}

asmlinkage long sys_readahead_metag(int fd, unsigned long lo, unsigned long hi,
				    size_t count)
{
	return sys_readahead(fd, merge_64(hi, lo), count);
}

asmlinkage ssize_t sys_pread64_metag(unsigned long fd, char __user *buf,
				     size_t count, unsigned long lo,
				     unsigned long hi)
{
	return sys_pread64(fd, buf, count, merge_64(hi, lo));
}

asmlinkage ssize_t sys_pwrite64_metag(unsigned long fd, char __user *buf,
				      size_t count, unsigned long lo,
				      unsigned long hi)
{
	return sys_pwrite64(fd, buf, count, merge_64(hi, lo));
}

asmlinkage long sys_sync_file_range_metag(int fd, unsigned long offs_lo,
					  unsigned long offs_hi,
					  unsigned long len_lo,
					  unsigned long len_hi,
					  unsigned int flags)
{
	return sys_sync_file_range(fd, merge_64(offs_hi, offs_lo),
				   merge_64(len_hi, len_lo), flags);
}

/* Provide the actual syscall number to call mapping. */
#undef __SYSCALL
#define __SYSCALL(nr, call) [nr] = (call),

/*
 * We need wrappers for anything with unaligned 64bit arguments
 */
#define sys_truncate64		sys_truncate64_metag
#define sys_ftruncate64		sys_ftruncate64_metag
#define sys_fadvise64_64	sys_fadvise64_64_metag
#define sys_readahead		sys_readahead_metag
#define sys_pread64		sys_pread64_metag
#define sys_pwrite64		sys_pwrite64_metag
#define sys_sync_file_range	sys_sync_file_range_metag

/*
 * Note that we can't include <linux/unistd.h> here since the header
 * guard will defeat us; <asm/unistd.h> checks for __SYSCALL as well.
 */
const void *sys_call_table[__NR_syscalls] = {
	[0 ... __NR_syscalls-1] = sys_ni_syscall,
#include <asm/unistd.h>
};