1 /* 2 * Access to user system call parameters and results 3 * 4 * Copyright IBM Corp. 2008 5 * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com) 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License (version 2 only) 9 * as published by the Free Software Foundation. 10 */ 11 12 #ifndef _ASM_SYSCALL_H 13 #define _ASM_SYSCALL_H 1 14 15 #include <linux/sched.h> 16 #include <linux/err.h> 17 #include <asm/ptrace.h> 18 19 /* 20 * The syscall table always contains 32 bit pointers since we know that the 21 * address of the function to be called is (way) below 4GB. So the "int" 22 * type here is what we want [need] for both 32 bit and 64 bit systems. 23 */ 24 extern const unsigned int sys_call_table[]; 25 26 static inline long syscall_get_nr(struct task_struct *task, 27 struct pt_regs *regs) 28 { 29 return test_tsk_thread_flag(task, TIF_SYSCALL) ? 30 (regs->int_code & 0xffff) : -1; 31 } 32 33 static inline void syscall_rollback(struct task_struct *task, 34 struct pt_regs *regs) 35 { 36 regs->gprs[2] = regs->orig_gpr2; 37 } 38 39 static inline long syscall_get_error(struct task_struct *task, 40 struct pt_regs *regs) 41 { 42 return IS_ERR_VALUE(regs->gprs[2]) ? regs->gprs[2] : 0; 43 } 44 45 static inline long syscall_get_return_value(struct task_struct *task, 46 struct pt_regs *regs) 47 { 48 return regs->gprs[2]; 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->gprs[2] = error ? -error : val; 56 } 57 58 static inline void syscall_get_arguments(struct task_struct *task, 59 struct pt_regs *regs, 60 unsigned int i, unsigned int n, 61 unsigned long *args) 62 { 63 unsigned long mask = -1UL; 64 65 BUG_ON(i + n > 6); 66 #ifdef CONFIG_COMPAT 67 if (test_tsk_thread_flag(task, TIF_31BIT)) 68 mask = 0xffffffff; 69 #endif 70 while (n-- > 0) 71 if (i + n > 0) 72 args[n] = regs->gprs[2 + i + n] & mask; 73 if (i == 0) 74 args[0] = regs->orig_gpr2 & mask; 75 } 76 77 static inline void syscall_set_arguments(struct task_struct *task, 78 struct pt_regs *regs, 79 unsigned int i, unsigned int n, 80 const unsigned long *args) 81 { 82 BUG_ON(i + n > 6); 83 while (n-- > 0) 84 if (i + n > 0) 85 regs->gprs[2 + i + n] = args[n]; 86 if (i == 0) 87 regs->orig_gpr2 = args[0]; 88 } 89 90 #endif /* _ASM_SYSCALL_H */ 91