1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * Access to user system call parameters and results 4 * 5 * See asm-generic/syscall.h for descriptions of what we must do here. 6 */ 7 8 #ifndef _ASM_ARM_SYSCALL_H 9 #define _ASM_ARM_SYSCALL_H 10 11 #include <uapi/linux/audit.h> /* for AUDIT_ARCH_* */ 12 #include <linux/elf.h> /* for ELF_EM */ 13 #include <linux/err.h> 14 #include <linux/sched.h> 15 16 #include <asm/unistd.h> 17 18 #define NR_syscalls (__NR_syscalls) 19 20 extern const unsigned long sys_call_table[]; 21 22 static inline int syscall_get_nr(struct task_struct *task, 23 struct pt_regs *regs) 24 { 25 return task_thread_info(task)->syscall; 26 } 27 28 static inline void syscall_rollback(struct task_struct *task, 29 struct pt_regs *regs) 30 { 31 regs->ARM_r0 = regs->ARM_ORIG_r0; 32 } 33 34 static inline long syscall_get_error(struct task_struct *task, 35 struct pt_regs *regs) 36 { 37 unsigned long error = regs->ARM_r0; 38 return IS_ERR_VALUE(error) ? error : 0; 39 } 40 41 static inline long syscall_get_return_value(struct task_struct *task, 42 struct pt_regs *regs) 43 { 44 return regs->ARM_r0; 45 } 46 47 static inline void syscall_set_return_value(struct task_struct *task, 48 struct pt_regs *regs, 49 int error, long val) 50 { 51 regs->ARM_r0 = (long) error ? error : val; 52 } 53 54 #define SYSCALL_MAX_ARGS 7 55 56 static inline void syscall_get_arguments(struct task_struct *task, 57 struct pt_regs *regs, 58 unsigned int i, unsigned int n, 59 unsigned long *args) 60 { 61 if (n == 0) 62 return; 63 64 if (i + n > SYSCALL_MAX_ARGS) { 65 unsigned long *args_bad = args + SYSCALL_MAX_ARGS - i; 66 unsigned int n_bad = n + i - SYSCALL_MAX_ARGS; 67 pr_warn("%s called with max args %d, handling only %d\n", 68 __func__, i + n, SYSCALL_MAX_ARGS); 69 memset(args_bad, 0, n_bad * sizeof(args[0])); 70 n = SYSCALL_MAX_ARGS - i; 71 } 72 73 if (i == 0) { 74 args[0] = regs->ARM_ORIG_r0; 75 args++; 76 i++; 77 n--; 78 } 79 80 memcpy(args, ®s->ARM_r0 + 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_warn("%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->ARM_ORIG_r0 = args[0]; 99 args++; 100 i++; 101 n--; 102 } 103 104 memcpy(®s->ARM_r0 + i, args, n * sizeof(args[0])); 105 } 106 107 static inline int syscall_get_arch(void) 108 { 109 /* ARM tasks don't change audit architectures on the fly. */ 110 return AUDIT_ARCH_ARM; 111 } 112 113 #endif /* _ASM_ARM_SYSCALL_H */ 114