jos/user/faultio.c

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2018-10-24 17:44:45 -07:00
// test user-level fault handler -- alloc pages to fix faults
#include <inc/lib.h>
#include <inc/x86.h>
void
umain(int argc, char **argv)
{
int x, r;
int nsecs = 1;
int secno = 0;
int diskno = 1;
if (read_eflags() & FL_IOPL_3)
cprintf("eflags wrong\n");
// this outb to select disk 1 should result in a general protection
// fault, because user-level code shouldn't be able to use the io space.
outb(0x1F6, 0xE0 | (1<<4));
cprintf("%s: made it here --- bug\n");
}