cachestat

query the page cache statistics of a file

sys_cachestat(unsigned int fd, struct cachestat_range *cstat_range, struct cachestat *cstat, unsigned int flags)

register	value
`r20`	451, the syscall number
`r26`	unsigned int fd
`r25`	struct cachestat_range *cstat_range
`r24`	struct cachestat *cstat
`r23`	unsigned int flags
`r28`	the return value

Then run ble 0x100(%sr2, %r0) to enter the kernel.

Same syscall on other architectures