arch/arm64/kernel/sys_compat.c

   1 /*
   2  * Based on arch/arm/kernel/sys_arm.c
   3  *
   4  * Copyright (C) People who wrote linux/arch/i386/kernel/sys_i386.c
   5  * Copyright (C) 1995, 1996 Russell King.
   6  * Copyright (C) 2012 ARM Ltd.
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 #include <linux/compat.h>
  22 #include <linux/personality.h>
  23 #include <linux/sched.h>
  24 #include <linux/slab.h>
  25 #include <linux/syscalls.h>
  26 #include <linux/uaccess.h>
  27
  28 #include <asm/cacheflush.h>
  29 #include <asm/unistd32.h>
  30
  31 asmlinkage int compat_sys_fork(void)
  32 {
  33         return do_fork(SIGCHLD, 0, current_pt_regs(), 0, NULL, NULL);
  34 }
  35
  36 asmlinkage int compat_sys_vfork(void)
  37 {
  38         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, 0,
  39                        current_pt_regs(), 0, NULL, NULL);
  40 }
  41
  42 asmlinkage int compat_sys_sched_rr_get_interval(compat_pid_t pid,
  43                                                 struct compat_timespec __user *interval)
  44 {
  45         struct timespec t;
  46         int ret;
  47         mm_segment_t old_fs = get_fs();
  48
  49         set_fs(KERNEL_DS);
  50         ret = sys_sched_rr_get_interval(pid, (struct timespec __user *)&t);
  51         set_fs(old_fs);
  52         if (put_compat_timespec(&t, interval))
  53                 return -EFAULT;
  54         return ret;
  55 }
  56
  57 static inline void
  58 do_compat_cache_op(unsigned long start, unsigned long end, int flags)
  59 {
  60         struct mm_struct *mm = current->active_mm;
  61         struct vm_area_struct *vma;
  62
  63         if (end < start || flags)
  64                 return;
  65
  66         down_read(&mm->mmap_sem);
  67         vma = find_vma(mm, start);
  68         if (vma && vma->vm_start < end) {
  69                 if (start < vma->vm_start)
  70                         start = vma->vm_start;
  71                 if (end > vma->vm_end)
  72                         end = vma->vm_end;
  73                 up_read(&mm->mmap_sem);
  74                 __flush_cache_user_range(start & PAGE_MASK, PAGE_ALIGN(end));
  75                 return;
  76         }
  77         up_read(&mm->mmap_sem);
  78 }
  79
  80 /*
  81  * Handle all unrecognised system calls.
  82  */
  83 long compat_arm_syscall(struct pt_regs *regs)
  84 {
  85         unsigned int no = regs->regs[7];
  86
  87         switch (no) {
  88         /*
  89          * Flush a region from virtual address 'r0' to virtual address 'r1'
  90          * _exclusive_.  There is no alignment requirement on either address;
  91          * user space does not need to know the hardware cache layout.
  92          *
  93          * r2 contains flags.  It should ALWAYS be passed as ZERO until it
  94          * is defined to be something else.  For now we ignore it, but may
  95          * the fires of hell burn in your belly if you break this rule. ;)
  96          *
  97          * (at a later date, we may want to allow this call to not flush
  98          * various aspects of the cache.  Passing '0' will guarantee that
  99          * everything necessary gets flushed to maintain consistency in
 100          * the specified region).
 101          */
 102         case __ARM_NR_compat_cacheflush:
 103                 do_compat_cache_op(regs->regs[0], regs->regs[1], regs->regs[2]);
 104                 return 0;
 105
 106         case __ARM_NR_compat_set_tls:
 107                 current->thread.tp_value = regs->regs[0];
 108                 asm ("msr tpidrro_el0, %0" : : "r" (regs->regs[0]));
 109                 return 0;
 110
 111         default:
 112                 return -ENOSYS;
 113         }
 114 }