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 extern const void *sys_call_table[]; 24 25 static inline int syscall_get_nr(struct task_struct *task, 26 struct pt_regs *regs) 27 { 28 return regs->syscallno; 29 } 30 31 static inline void syscall_rollback(struct task_struct *task, 32 struct pt_regs *regs) 33 { 34 regs->regs[0] = regs->orig_x0; 35 } 36 37 38 static inline long syscall_get_error(struct task_struct *task, 39 struct pt_regs *regs) 40 { 41 unsigned long error = regs->regs[0]; 42 return IS_ERR_VALUE(error) ? error : 0; 43 } 44 45 static inline long syscall_get_return_value(struct task_struct *task, 46 struct pt_regs *regs) 47 { 48 return regs->regs[0]; 49 } 50 51 static inline void syscall_set_return_value(struct task_struct *task, 52 struct pt_regs *regs, 53 int error, long val) 54 { 55 regs->regs[0] = (long) error ? error : val; 56 } 57 58 #define SYSCALL_MAX_ARGS 6 59 60 static inline void syscall_get_arguments(struct task_struct *task, 61 struct pt_regs *regs, 62 unsigned int i, unsigned int n, 63 unsigned long *args) 64 { 65 if (n == 0) 66 return; 67 68 if (i + n > SYSCALL_MAX_ARGS) { 69 unsigned long *args_bad = args + SYSCALL_MAX_ARGS - i; 70 unsigned int n_bad = n + i - SYSCALL_MAX_ARGS; 71 pr_warning("%s called with max args %d, handling only %d\n", 72 __func__, i + n, SYSCALL_MAX_ARGS); 73 memset(args_bad, 0, n_bad * sizeof(args[0])); 74 } 75 76 if (i == 0) { 77 args[0] = regs->orig_x0; 78 args++; 79 i++; 80 n--; 81 } 82 83 memcpy(args, ®s->regs[i], n * sizeof(args[0])); 84 } 85 86 static inline void syscall_set_arguments(struct task_struct *task, 87 struct pt_regs *regs, 88 unsigned int i, unsigned int n, 89 const unsigned long *args) 90 { 91 if (n == 0) 92 return; 93 94 if (i + n > SYSCALL_MAX_ARGS) { 95 pr_warning("%s called with max args %d, handling only %d\n", 96 __func__, i + n, SYSCALL_MAX_ARGS); 97 n = SYSCALL_MAX_ARGS - i; 98 } 99 100 if (i == 0) { 101 regs->orig_x0 = args[0]; 102 args++; 103 i++; 104 n--; 105 } 106 107 memcpy(®s->regs[i], args, n * sizeof(args[0])); 108 } 109 110 /* 111 * We don't care about endianness (__AUDIT_ARCH_LE bit) here because 112 * AArch64 has the same system calls both on little- and big- endian. 113 */ 114 static inline int syscall_get_arch(void) 115 { 116 if (is_compat_task()) 117 return AUDIT_ARCH_ARM; 118 119 return AUDIT_ARCH_AARCH64; 120 } 121 122 #endif /* __ASM_SYSCALL_H */ 123