arch/arm64/kernel/sys.c

   1 /*
   2  * AArch64-specific system calls implementation
   3  *
   4  * Copyright (C) 2012 ARM Ltd.
   5  * Author: Catalin Marinas <catalin.marinas@arm.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <linux/compiler.h>
  21 #include <linux/errno.h>
  22 #include <linux/fs.h>
  23 #include <linux/mm.h>
  24 #include <linux/export.h>
  25 #include <linux/sched.h>
  26 #include <linux/slab.h>
  27 #include <linux/syscalls.h>
  28
  29 /*
  30  * Clone a task - this clones the calling program thread.
  31  */
  32 asmlinkage long sys_clone(unsigned long clone_flags, unsigned long newsp,
  33                           int __user *parent_tidptr, unsigned long tls_val,
  34                           int __user *child_tidptr, struct pt_regs *regs)
  35 {
  36         if (!newsp)
  37                 newsp = regs->sp;
  38         /* 16-byte aligned stack mandatory on AArch64 */
  39         if (newsp & 15)
  40                 return -EINVAL;
  41         return do_fork(clone_flags, newsp, regs, 0, parent_tidptr, child_tidptr);
  42 }
  43
  44 /*
  45  * sys_execve() executes a new program.
  46  */
  47 asmlinkage long sys_execve(const char __user *filenamei,
  48                            const char __user *const __user *argv,
  49                            const char __user *const __user *envp,
  50                            struct pt_regs *regs)
  51 {
  52         long error;
  53         char * filename;
  54
  55         filename = getname(filenamei);
  56         error = PTR_ERR(filename);
  57         if (IS_ERR(filename))
  58                 goto out;
  59         error = do_execve(filename, argv, envp, regs);
  60         putname(filename);
  61 out:
  62         return error;
  63 }
  64
  65 int kernel_execve(const char *filename,
  66                   const char *const argv[],
  67                   const char *const envp[])
  68 {
  69         struct pt_regs regs;
  70         int ret;
  71
  72         memset(&regs, 0, sizeof(struct pt_regs));
  73         ret = do_execve(filename,
  74                         (const char __user *const __user *)argv,
  75                         (const char __user *const __user *)envp, &regs);
  76         if (ret < 0)
  77                 goto out;
  78
  79         /*
  80          * Save argc to the register structure for userspace.
  81          */
  82         regs.regs[0] = ret;
  83
  84         /*
  85          * We were successful.  We won't be returning to our caller, but
  86          * instead to user space by manipulating the kernel stack.
  87          */
  88         asm(    "add    x0, %0, %1\n\t"
  89                 "mov    x1, %2\n\t"
  90                 "mov    x2, %3\n\t"
  91                 "bl     memmove\n\t"    /* copy regs to top of stack */
  92                 "mov    x27, #0\n\t"    /* not a syscall */
  93                 "mov    x28, %0\n\t"    /* thread structure */
  94                 "mov    sp, x0\n\t"     /* reposition stack pointer */
  95                 "b      ret_to_user"
  96                 :
  97                 : "r" (current_thread_info()),
  98                   "Ir" (THREAD_START_SP - sizeof(regs)),
  99                   "r" (&regs),
 100                   "Ir" (sizeof(regs))
 101                 : "x0", "x1", "x2", "x27", "x28", "x30", "memory");
 102
 103  out:
 104         return ret;
 105 }
 106 EXPORT_SYMBOL(kernel_execve);
 107
 108 asmlinkage long sys_mmap(unsigned long addr, unsigned long len,
 109                          unsigned long prot, unsigned long flags,
 110                          unsigned long fd, off_t off)
 111 {
 112         if (offset_in_page(off) != 0)
 113                 return -EINVAL;
 114
 115         return sys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT);
 116 }
 117
 118 /*
 119  * Wrappers to pass the pt_regs argument.
 120  */
 121 #define sys_execve              sys_execve_wrapper
 122 #define sys_clone               sys_clone_wrapper
 123 #define sys_rt_sigreturn        sys_rt_sigreturn_wrapper
 124 #define sys_sigaltstack         sys_sigaltstack_wrapper
 125
 126 #include <asm/syscalls.h>
 127
 128 #undef __SYSCALL
 129 #define __SYSCALL(nr, sym)      [nr] = sym,
 130
 131 /*
 132  * The sys_call_table array must be 4K aligned to be accessible from
 133  * kernel/entry.S.
 134  */
 135 void *sys_call_table[__NR_syscalls] __aligned(4096) = {
 136         [0 ... __NR_syscalls - 1] = sys_ni_syscall,
 137 #include <asm/unistd.h>
 138 };