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/sched/signal.h> 25 #include <linux/slab.h> 26 #include <linux/syscalls.h> 27 #include <linux/uaccess.h> 28 29 #include <asm/cacheflush.h> 30 #include <asm/unistd.h> 31 32 static long 33 __do_compat_cache_op(unsigned long start, unsigned long end) 34 { 35 long ret; 36 37 do { 38 unsigned long chunk = min(PAGE_SIZE, end - start); 39 40 if (fatal_signal_pending(current)) 41 return 0; 42 43 ret = __flush_cache_user_range(start, start + chunk); 44 if (ret) 45 return ret; 46 47 cond_resched(); 48 start += chunk; 49 } while (start < end); 50 51 return 0; 52 } 53 54 static inline long 55 do_compat_cache_op(unsigned long start, unsigned long end, int flags) 56 { 57 if (end < start || flags) 58 return -EINVAL; 59 60 if (!access_ok(VERIFY_READ, start, end - start)) 61 return -EFAULT; 62 63 return __do_compat_cache_op(start, end); 64 } 65 /* 66 * Handle all unrecognised system calls. 67 */ 68 long compat_arm_syscall(struct pt_regs *regs) 69 { 70 unsigned int no = regs->regs[7]; 71 72 switch (no) { 73 /* 74 * Flush a region from virtual address 'r0' to virtual address 'r1' 75 * _exclusive_. There is no alignment requirement on either address; 76 * user space does not need to know the hardware cache layout. 77 * 78 * r2 contains flags. It should ALWAYS be passed as ZERO until it 79 * is defined to be something else. For now we ignore it, but may 80 * the fires of hell burn in your belly if you break this rule. ;) 81 * 82 * (at a later date, we may want to allow this call to not flush 83 * various aspects of the cache. Passing '0' will guarantee that 84 * everything necessary gets flushed to maintain consistency in 85 * the specified region). 86 */ 87 case __ARM_NR_compat_cacheflush: 88 return do_compat_cache_op(regs->regs[0], regs->regs[1], regs->regs[2]); 89 90 case __ARM_NR_compat_set_tls: 91 current->thread.tp_value = regs->regs[0]; 92 93 /* 94 * Protect against register corruption from context switch. 95 * See comment in tls_thread_flush. 96 */ 97 barrier(); 98 write_sysreg(regs->regs[0], tpidrro_el0); 99 return 0; 100 101 default: 102 return -ENOSYS; 103 } 104 } 105