1 /* SPDX-License-Identifier: GPL-2.0-only */ 2 /* 3 * Copyright (C) 2012 ARM Ltd. 4 */ 5 #ifndef __ASM_SYSCALL_H 6 #define __ASM_SYSCALL_H 7 8 #include <uapi/linux/audit.h> 9 #include <linux/compat.h> 10 #include <linux/err.h> 11 12 typedef long (*syscall_fn_t)(const struct pt_regs *regs); 13 14 extern const syscall_fn_t sys_call_table[]; 15 16 #ifdef CONFIG_COMPAT 17 extern const syscall_fn_t compat_sys_call_table[]; 18 #endif 19 20 static inline int syscall_get_nr(struct task_struct *task, 21 struct pt_regs *regs) 22 { 23 return regs->syscallno; 24 } 25 26 static inline void syscall_rollback(struct task_struct *task, 27 struct pt_regs *regs) 28 { 29 regs->regs[0] = regs->orig_x0; 30 } 31 32 static inline long syscall_get_return_value(struct task_struct *task, 33 struct pt_regs *regs) 34 { 35 unsigned long val = regs->regs[0]; 36 37 if (is_compat_thread(task_thread_info(task))) 38 val = sign_extend64(val, 31); 39 40 return val; 41 } 42 43 static inline long syscall_get_error(struct task_struct *task, 44 struct pt_regs *regs) 45 { 46 unsigned long error = syscall_get_return_value(task, regs); 47 48 return IS_ERR_VALUE(error) ? error : 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 if (error) 56 val = error; 57 58 if (is_compat_thread(task_thread_info(task))) 59 val = lower_32_bits(val); 60 61 regs->regs[0] = 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 long *args) 69 { 70 args[0] = regs->orig_x0; 71 args++; 72 73 memcpy(args, ®s->regs[1], 5 * sizeof(args[0])); 74 } 75 76 /* 77 * We don't care about endianness (__AUDIT_ARCH_LE bit) here because 78 * AArch64 has the same system calls both on little- and big- endian. 79 */ 80 static inline int syscall_get_arch(struct task_struct *task) 81 { 82 if (is_compat_thread(task_thread_info(task))) 83 return AUDIT_ARCH_ARM; 84 85 return AUDIT_ARCH_AARCH64; 86 } 87 88 #endif /* __ASM_SYSCALL_H */ 89