Mike, On Mon, Apr 1, 2013 at 8:13 AM, Mike Frysinger <vapier@xxxxxxxxxx> wrote: > On Monday 01 April 2013 01:33:49 Changhee Han wrote: >> +Each architecture ABI has its own requirements on how system call >> arguments are passed to the kernel. +For system calls that have a glibc >> wrapper (i.g., most system calls) glibc handles the details of copy >> arguments to the right registers in a manner suitable for the >> architecture. > > these lines need to be wrapped > > "i.g." is incorrect ... you mean "i.e." > >> +However, when using >> +.BR syscall () >> +to make a system call, >> +the caller may need to handle architecture-dependent details. >> +For example, on ARM architecture, a >> +.I "long long" >> +argument is considered to be 8-byte aligned and to be split into two >> 4-byte arguments. + >> +.BR readahead () >> +system call could be called like below in ARM architecture. > > this has nothing to do with alignment. syscalls pass args via registers, and > in the 32bit ARM port, registers are 32bits wide. so in order to pass a 64bit > value, you have to manually split it up. So, I'm not familiar with all the details here. What is the purpose of the '0' argument that precedes 'offset' then? Cheers, Michael -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
