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/unistd.h> 30 31 static inline void 32 do_compat_cache_op(unsigned long start, unsigned long end, int flags) 33 { 34 struct mm_struct *mm = current->active_mm; 35 struct vm_area_struct *vma; 36 37 if (end < start || flags) 38 return; 39 40 down_read(&mm->mmap_sem); 41 vma = find_vma(mm, start); 42 if (vma && vma->vm_start < end) { 43 if (start < vma->vm_start) 44 start = vma->vm_start; 45 if (end > vma->vm_end) 46 end = vma->vm_end; 47 up_read(&mm->mmap_sem); 48 __flush_cache_user_range(start & PAGE_MASK, PAGE_ALIGN(end)); 49 return; 50 } 51 up_read(&mm->mmap_sem); 52 } 53 54 /* 55 * Handle all unrecognised system calls. 56 */ 57 long compat_arm_syscall(struct pt_regs *regs) 58 { 59 unsigned int no = regs->regs[7]; 60 61 switch (no) { 62 /* 63 * Flush a region from virtual address 'r0' to virtual address 'r1' 64 * _exclusive_. There is no alignment requirement on either address; 65 * user space does not need to know the hardware cache layout. 66 * 67 * r2 contains flags. It should ALWAYS be passed as ZERO until it 68 * is defined to be something else. For now we ignore it, but may 69 * the fires of hell burn in your belly if you break this rule. ;) 70 * 71 * (at a later date, we may want to allow this call to not flush 72 * various aspects of the cache. Passing '0' will guarantee that 73 * everything necessary gets flushed to maintain consistency in 74 * the specified region). 75 */ 76 case __ARM_NR_compat_cacheflush: 77 do_compat_cache_op(regs->regs[0], regs->regs[1], regs->regs[2]); 78 return 0; 79 80 case __ARM_NR_compat_set_tls: 81 current->thread.tp_value = regs->regs[0]; 82 83 /* 84 * Protect against register corruption from context switch. 85 * See comment in tls_thread_flush. 86 */ 87 barrier(); 88 asm ("msr tpidrro_el0, %0" : : "r" (regs->regs[0])); 89 return 0; 90 91 default: 92 return -ENOSYS; 93 } 94 } 95