Arm Linux 2.6.24添加系统调用

# gedit  arch/arm/kernel/sys_arm.c
-----------------------------------------------------------
asmlinkage long sys_arm_fadvise64_64(int fd, int advice,
loff_t offset, loff_t len)
{
return sys_fadvise64_64(fd, offset, len, advice);
}

asmlinkage int sys_kmd(unsigned int p_addr)
{
printk("p_addr = 0x%x\n", p_addr);
return p_addr;
}

# gedit  include/asm-arm/unistd.h
-----------------------------------------------------------
#define __NR_fallocate            (__NR_SYSCALL_BASE+352)
#define __NR_kmd                 (__NR_SYSCALL_BASE+353)

# gedit arch/arm/kernel/calls.S
-----------------------------------------------------------
CALL(sys_fallocate)
CALL(sys_kmd)

测试提供调用
-----------------------------------------------------------
#define _GNU_SOURCE        /* or _BSD_SOURCE or _SVID_SOURCE */
#include <unistd.h>
#include <sys/syscall.h>   /* For SYS_xxx definitions */

#define __NR_kmd                 (__NR_SYSCALL_BASE+353)

int kmd (unsigned int p_addr)
{
syscall (__NR_kmd, p_addr);
return 0;
}

int main ()
{
kmd (0x100000);
}

# arm-linux-gcc kmd.c -static
# cp a.out /tftpboot/
# tftp -g -r a.out 192.168.1.160
# ./a.out
p_addr = 0x100000

#if 1
#define DISP_LINE_LEN              (16)
#define MAX_LINE_LENGTH_BYTES     (64)
#define DEFAULT_LINE_LENGTH_BYTES (16)

#define int8_t      char
#define int16_t     short
#define int32_t     long
#define int64_t     long long
#define uint8_t     u_char
#define uint16_t    u_short
#define uint32_t    u_long
#define uint64_t    unsigned long long
#define t_scalar_t  int
#define t_uscalar_t unsigned int
#define uintptr_t   unsigned long

/*
* Print data buffer in hex and ascii form to the terminal.
*
* data reads are buffered so that each memory address is only read once.
* Useful when displaying the contents of volatile registers.
*
* parameters:
*    addr: Starting address to display at start of line
*    data: pointer to data buffer
*    width: data value width.  May be 1, 2, or 4.
*    count: number of values to display
*    linelen: Number of values to print per line; specify 0 for default length
*/
int print_buffer (ulong addr, void *data, uint width, uint count, uint linelen)
{
uint8_t linebuf[MAX_LINE_LENGTH_BYTES];
uint32_t *uip = (void *) linebuf;
uint16_t *usp = (void *) linebuf;
uint8_t  *ucp = (void *) linebuf;
int i;
if (linelen * width > MAX_LINE_LENGTH_BYTES)
linelen = MAX_LINE_LENGTH_BYTES / width;
if (linelen < 1)
linelen = DEFAULT_LINE_LENGTH_BYTES / width;
while (count)
{
printk ("%08lx:", addr);

/* check for overflow condition */
if (count < linelen)
linelen = count;

/* Copy from memory into linebuf and print hex values */
for (i = 0; i < linelen; i++)
{
if (width == 4)
{
uip[i] = *(volatile uint32_t *) data;
printk (" %08x", (unsigned int)uip[i]);
}
else if (width == 2)
{
usp[i] = *(volatile uint16_t *) data;
printk (" %04x", usp[i]);
}
else
{
ucp[i] = *(volatile uint8_t *) data;
printk (" %02x", ucp[i]);
} data += width;
}

#if 0
/* Print data in ASCII characters */
printk ("    ");
for (i = 0; i < linelen * width; i++)
fputc (isprint (ucp[i]) && (ucp[i] < 0x80) ? ucp[i] : '.', stdout);

fputc ('\n', stdout);
#endif
printk("\n");
/* update references */
addr += linelen * width;
count -= linelen;
}
return 0;
}

asmlinkage int sys_kmd(unsigned int v_addr)
{
ulong length = 64, p_addr = 0, size = 4;
if (0 == v_addr)
{
printk("v_addr = %x\n", (unsigned int)v_addr);
return -1;
}
p_addr = virt_to_phys((void *)v_addr);
printk("v_addr   <--> p_addr\n");
printk("%08x <--> %08x\n", (unsigned int)v_addr,
(unsigned int)p_addr);
print_buffer (v_addr, (void *) v_addr, size, length,
DISP_LINE_LEN / size);

return 0;
}
#endif