recvmmsg

receive multiple messages on a socket

sys_recvmmsg(int fd, struct mmsghdr *mmsg, unsigned int vlen, unsigned int flags, struct __kernel_timespec *timeout)

register	value
`x8`	243, the syscall number
`x0`	int fd
`x1`	struct mmsghdr *mmsg
`x2`	unsigned int vlen
`x3`	unsigned int flags
`x4`	struct __kernel_timespec *timeout
`x0`	the return value

Then run svc #0 to enter the kernel.

Same syscall on other architectures