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
 20extern const unsigned long sys_call_table[];
 21
 22static inline int syscall_get_nr(struct task_struct *task,
 23				 struct pt_regs *regs)
 24{
 25	return task_thread_info(task)->syscall;
 26}
 27
 28static inline void syscall_rollback(struct task_struct *task,
 29				    struct pt_regs *regs)
 30{
 31	regs->ARM_r0 = regs->ARM_ORIG_r0;
 32}
 33
 34static 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
 41static inline long syscall_get_return_value(struct task_struct *task,
 42					    struct pt_regs *regs)
 43{
 44	return regs->ARM_r0;
 45}
 46
 47static 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
 56static 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, &regs->ARM_r0 + i, n * sizeof(args[0]));
 81}
 82
 83static 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(&regs->ARM_r0 + i, args, n * sizeof(args[0]));
105}
106
107static 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 */