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/system_misc.h> 31 #include <asm/unistd.h> 32 33 static long 34 __do_compat_cache_op(unsigned long start, unsigned long end) 35 { 36 long ret; 37 38 do { 39 unsigned long chunk = min(PAGE_SIZE, end - start); 40 41 if (fatal_signal_pending(current)) 42 return 0; 43 44 ret = __flush_cache_user_range(start, start + chunk); 45 if (ret) 46 return ret; 47 48 cond_resched(); 49 start += chunk; 50 } while (start < end); 51 52 return 0; 53 } 54 55 static inline long 56 do_compat_cache_op(unsigned long start, unsigned long end, int flags) 57 { 58 if (end < start || flags) 59 return -EINVAL; 60 61 if (!access_ok(VERIFY_READ, (const void __user *)start, end - start)) 62 return -EFAULT; 63 64 return __do_compat_cache_op(start, end); 65 } 66 /* 67 * Handle all unrecognised system calls. 68 */ 69 long compat_arm_syscall(struct pt_regs *regs) 70 { 71 siginfo_t info; 72 unsigned int no = regs->regs[7]; 73 74 switch (no) { 75 /* 76 * Flush a region from virtual address 'r0' to virtual address 'r1' 77 * _exclusive_. There is no alignment requirement on either address; 78 * user space does not need to know the hardware cache layout. 79 * 80 * r2 contains flags. It should ALWAYS be passed as ZERO until it 81 * is defined to be something else. For now we ignore it, but may 82 * the fires of hell burn in your belly if you break this rule. ;) 83 * 84 * (at a later date, we may want to allow this call to not flush 85 * various aspects of the cache. Passing '0' will guarantee that 86 * everything necessary gets flushed to maintain consistency in 87 * the specified region). 88 */ 89 case __ARM_NR_compat_cacheflush: 90 return do_compat_cache_op(regs->regs[0], regs->regs[1], regs->regs[2]); 91 92 case __ARM_NR_compat_set_tls: 93 current->thread.uw.tp_value = regs->regs[0]; 94 95 /* 96 * Protect against register corruption from context switch. 97 * See comment in tls_thread_flush. 98 */ 99 barrier(); 100 write_sysreg(regs->regs[0], tpidrro_el0); 101 return 0; 102 103 default: 104 /* 105 * Calls 9f00xx..9f07ff are defined to return -ENOSYS 106 * if not implemented, rather than raising SIGILL. This 107 * way the calling program can gracefully determine whether 108 * a feature is supported. 109 */ 110 if ((no & 0xffff) <= 0x7ff) 111 return -ENOSYS; 112 break; 113 } 114 115 clear_siginfo(&info); 116 info.si_signo = SIGILL; 117 info.si_errno = 0; 118 info.si_code = ILL_ILLTRP; 119 info.si_addr = (void __user *)instruction_pointer(regs) - 120 (compat_thumb_mode(regs) ? 2 : 4); 121 122 arm64_notify_die("Oops - bad compat syscall(2)", regs, &info, no); 123 return 0; 124 } 125