1 /* 2 * Copyright (C) 2012 ARM Ltd. 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope that it will be useful, 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 * GNU General Public License for more details. 12 * 13 * You should have received a copy of the GNU General Public License 14 * along with this program. If not, see <http://www.gnu.org/licenses/>. 15 */ 16 #ifndef __ASM_SYSCALL_H 17 #define __ASM_SYSCALL_H 18 19 #include <uapi/linux/audit.h> 20 #include <linux/compat.h> 21 #include <linux/err.h> 22 23 typedef long (*syscall_fn_t)(struct pt_regs *regs); 24 25 extern const syscall_fn_t sys_call_table[]; 26 27 #ifdef CONFIG_COMPAT 28 extern const syscall_fn_t compat_sys_call_table[]; 29 #endif 30 31 static inline int syscall_get_nr(struct task_struct *task, 32 struct pt_regs *regs) 33 { 34 return regs->syscallno; 35 } 36 37 static inline void syscall_rollback(struct task_struct *task, 38 struct pt_regs *regs) 39 { 40 regs->regs[0] = regs->orig_x0; 41 } 42 43 44 static inline long syscall_get_error(struct task_struct *task, 45 struct pt_regs *regs) 46 { 47 unsigned long error = regs->regs[0]; 48 return IS_ERR_VALUE(error) ? error : 0; 49 } 50 51 static inline long syscall_get_return_value(struct task_struct *task, 52 struct pt_regs *regs) 53 { 54 return regs->regs[0]; 55 } 56 57 static inline void syscall_set_return_value(struct task_struct *task, 58 struct pt_regs *regs, 59 int error, long val) 60 { 61 regs->regs[0] = (long) error ? error : val; 62 } 63 64 #define SYSCALL_MAX_ARGS 6 65 66 static inline void syscall_get_arguments(struct task_struct *task, 67 struct pt_regs *regs, 68 unsigned int i, unsigned int n, 69 unsigned long *args) 70 { 71 if (n == 0) 72 return; 73 74 if (i + n > SYSCALL_MAX_ARGS) { 75 unsigned long *args_bad = args + SYSCALL_MAX_ARGS - i; 76 unsigned int n_bad = n + i - SYSCALL_MAX_ARGS; 77 pr_warning("%s called with max args %d, handling only %d\n", 78 __func__, i + n, SYSCALL_MAX_ARGS); 79 memset(args_bad, 0, n_bad * sizeof(args[0])); 80 } 81 82 if (i == 0) { 83 args[0] = regs->orig_x0; 84 args++; 85 i++; 86 n--; 87 } 88 89 memcpy(args, ®s->regs[i], n * sizeof(args[0])); 90 } 91 92 static inline void syscall_set_arguments(struct task_struct *task, 93 struct pt_regs *regs, 94 unsigned int i, unsigned int n, 95 const unsigned long *args) 96 { 97 if (n == 0) 98 return; 99 100 if (i + n > SYSCALL_MAX_ARGS) { 101 pr_warning("%s called with max args %d, handling only %d\n", 102 __func__, i + n, SYSCALL_MAX_ARGS); 103 n = SYSCALL_MAX_ARGS - i; 104 } 105 106 if (i == 0) { 107 regs->orig_x0 = args[0]; 108 args++; 109 i++; 110 n--; 111 } 112 113 memcpy(®s->regs[i], args, n * sizeof(args[0])); 114 } 115 116 /* 117 * We don't care about endianness (__AUDIT_ARCH_LE bit) here because 118 * AArch64 has the same system calls both on little- and big- endian. 119 */ 120 static inline int syscall_get_arch(void) 121 { 122 if (is_compat_task()) 123 return AUDIT_ARCH_ARM; 124 125 return AUDIT_ARCH_AARCH64; 126 } 127 128 #endif /* __ASM_SYSCALL_H */ 129