Shutdown (embedded) linux from kernel-space

Question

I\'m working on a modified version of the 2.6.35 kernel for Olinuxino, an ARM9 based platform. I\'m trying to modify the power management driver (the architecture specific p

Answer 1

The most general way would be for your driver to invoke shutdown as a userspace helper:

static const char * const shutdown_argv[] = 
    { "/sbin/shutdown", "-h", "-P", "now", NULL };

call_usermodehelper(shutdown_argv[0], shutdown_argv, NULL, UMH_NO_WAIT);

(Presuming you have a /sbin/shutdown binary installed). This will shut userspace down cleanly, unmount filesystems and then request the kernel shutdown and power off.

However, you may be able to do better than this - for example if you can guarantee that there's no disk filesystems mounted read/write, you could tell a kernel thread to invoke the kernel_power_off() function (it shouldn't be done from interrupt context).