1 /* 2 * Copyright (C) 2003 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) 3 * Copyright 2003 PathScale, Inc. 4 * 5 * Licensed under the GPL 6 */ 7 8 #include <linux/sched.h> 9 #include <linux/sched/mm.h> 10 #include <linux/syscalls.h> 11 #include <linux/uaccess.h> 12 #include <asm/prctl.h> /* XXX This should get the constants from libc */ 13 #include <registers.h> 14 #include <os.h> 15 #include <registers.h> 16 17 long arch_prctl(struct task_struct *task, int option, 18 unsigned long __user *arg2) 19 { 20 unsigned long *ptr = arg2, tmp; 21 long ret; 22 int pid = task->mm->context.id.u.pid; 23 24 /* 25 * With ARCH_SET_FS (and ARCH_SET_GS is treated similarly to 26 * be safe), we need to call arch_prctl on the host because 27 * setting %fs may result in something else happening (like a 28 * GDT or thread.fs being set instead). So, we let the host 29 * fiddle the registers and thread struct and restore the 30 * registers afterwards. 31 * 32 * So, the saved registers are stored to the process (this 33 * needed because a stub may have been the last thing to run), 34 * arch_prctl is run on the host, then the registers are read 35 * back. 36 */ 37 switch (option) { 38 case ARCH_SET_FS: 39 case ARCH_SET_GS: 40 ret = restore_pid_registers(pid, ¤t->thread.regs.regs); 41 if (ret) 42 return ret; 43 break; 44 case ARCH_GET_FS: 45 case ARCH_GET_GS: 46 /* 47 * With these two, we read to a local pointer and 48 * put_user it to the userspace pointer that we were 49 * given. If addr isn't valid (because it hasn't been 50 * faulted in or is just bogus), we want put_user to 51 * fault it in (or return -EFAULT) instead of having 52 * the host return -EFAULT. 53 */ 54 ptr = &tmp; 55 } 56 57 ret = os_arch_prctl(pid, option, ptr); 58 if (ret) 59 return ret; 60 61 switch (option) { 62 case ARCH_SET_FS: 63 current->thread.arch.fs = (unsigned long) ptr; 64 ret = save_registers(pid, ¤t->thread.regs.regs); 65 break; 66 case ARCH_SET_GS: 67 ret = save_registers(pid, ¤t->thread.regs.regs); 68 break; 69 case ARCH_GET_FS: 70 ret = put_user(tmp, arg2); 71 break; 72 case ARCH_GET_GS: 73 ret = put_user(tmp, arg2); 74 break; 75 } 76 77 return ret; 78 } 79 80 SYSCALL_DEFINE2(arch_prctl, int, option, unsigned long, arg2) 81 { 82 return arch_prctl(current, option, (unsigned long __user *) arg2); 83 } 84 85 void arch_switch_to(struct task_struct *to) 86 { 87 if ((to->thread.arch.fs == 0) || (to->mm == NULL)) 88 return; 89 90 arch_prctl(to, ARCH_SET_FS, (void __user *) to->thread.arch.fs); 91 } 92 93 SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len, 94 unsigned long, prot, unsigned long, flags, 95 unsigned long, fd, unsigned long, off) 96 { 97 if (off & ~PAGE_MASK) 98 return -EINVAL; 99 100 return ksys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT); 101 } 102