unlocked_ioctl  与 compat_ioctl 的区别

.unlocked_ioctl = spidev_ioctl,	32  位 程序 ->32位 kernel 64  位 程序 ->64位 kernel
.compat_ioctl = spidev_compat_ioctl,	32  位 程序 ->64位 kernel

 测试流程:

static const struct file_operations spidev_fops = {......unlocked_ioctl = spidev_ioctl,.compat_ioctl = spidev_compat_ioctl,.....
};

编译测试程序:

        arm-linux-gnueabihf-gcc -static spi-ioctl.c -o spi-ioctl-32
        aarch64-linux-gnu-gcc          spi-ioctl.c -o spi-ioctl

测试
niyu@raspberrypi:~$ file spi-ioctl spi-ioctl-32
spi-ioctl:    ELF 64-bit LSB pie executable, ARM aarch64, version 1 (SYSV), dynamically ..
spi-ioctl-32: ELF 32-bit LSB executable, ARM, EABI5 version 1 (GNU/Linux), statically ....

niyu@raspberrypi:~$
niyu@raspberrypi:~$ sudo dmesg -c > /dev/null
niyu@raspberrypi:~$ ./spi-ioctl
Current SPI mode: 0x0
niyu@raspberrypi:~$ sudo dmesg
[ 1124.885644] ########## spidev_open
[ 1124.885669] ########## spidev_ioctl
niyu@raspberrypi:~$
niyu@raspberrypi:~$
niyu@raspberrypi:~$ sudo dmesg -c > /dev/null
niyu@raspberrypi:~$ ./spi-ioctl-32
Current SPI mode: 0x0
niyu@raspberrypi:~$ sudo dmesg
[ 1140.444986] ########## spidev_open
[ 1140.445012] ########## spidev_compat_ioctl
[ 1140.445022] ########## spidev_ioctl
niyu@raspberrypi:~$