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 <linux/err.h> 20 21 22 static inline int syscall_get_nr(struct task_struct *task, 23 struct pt_regs *regs) 24 { 25 return regs->syscallno; 26 } 27 28 static inline void syscall_rollback(struct task_struct *task, 29 struct pt_regs *regs) 30 { 31 regs->regs[0] = regs->orig_x0; 32 } 33 34 35 static inline long syscall_get_error(struct task_struct *task, 36 struct pt_regs *regs) 37 { 38 unsigned long error = regs->regs[0]; 39 return IS_ERR_VALUE(error) ? error : 0; 40 } 41 42 static inline long syscall_get_return_value(struct task_struct *task, 43 struct pt_regs *regs) 44 { 45 return regs->regs[0]; 46 } 47 48 static inline void syscall_set_return_value(struct task_struct *task, 49 struct pt_regs *regs, 50 int error, long val) 51 { 52 regs->regs[0] = (long) error ? error : val; 53 } 54 55 #define SYSCALL_MAX_ARGS 6 56 57 static inline void syscall_get_arguments(struct task_struct *task, 58 struct pt_regs *regs, 59 unsigned int i, unsigned int n, 60 unsigned long *args) 61 { 62 if (n == 0) 63 return; 64 65 if (i + n > SYSCALL_MAX_ARGS) { 66 unsigned long *args_bad = args + SYSCALL_MAX_ARGS - i; 67 unsigned int n_bad = n + i - SYSCALL_MAX_ARGS; 68 pr_warning("%s called with max args %d, handling only %d\n", 69 __func__, i + n, SYSCALL_MAX_ARGS); 70 memset(args_bad, 0, n_bad * sizeof(args[0])); 71 } 72 73 if (i == 0) { 74 args[0] = regs->orig_x0; 75 args++; 76 i++; 77 n--; 78 } 79 80 memcpy(args, ®s->regs[i], n * sizeof(args[0])); 81 } 82 83 static inline void syscall_set_arguments(struct task_struct *task, 84 struct pt_regs *regs, 85 unsigned int i, unsigned int n, 86 const unsigned long *args) 87 { 88 if (n == 0) 89 return; 90 91 if (i + n > SYSCALL_MAX_ARGS) { 92 pr_warning("%s called with max args %d, handling only %d\n", 93 __func__, i + n, SYSCALL_MAX_ARGS); 94 n = SYSCALL_MAX_ARGS - i; 95 } 96 97 if (i == 0) { 98 regs->orig_x0 = args[0]; 99 args++; 100 i++; 101 n--; 102 } 103 104 memcpy(®s->regs[i], args, n * sizeof(args[0])); 105 } 106 107 #endif /* __ASM_SYSCALL_H */ 108