cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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syscalls_64.c (2622B)

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