1/*
  2 * Access to user system call parameters and results
  3 *
  4 * See asm-generic/syscall.h for descriptions of what we must do here.
  5 */
  6
  7#ifndef _ASM_ARM_SYSCALL_H
  8#define _ASM_ARM_SYSCALL_H
  9
 10#include <uapi/linux/audit.h> /* for AUDIT_ARCH_* */
 11#include <linux/elf.h> /* for ELF_EM */
 12#include <linux/err.h>
 13#include <linux/sched.h>
 14
 15#include <asm/unistd.h>
 16
 17#define NR_syscalls (__NR_syscalls)
 18
 19extern const unsigned long sys_call_table[];
 20
 21static inline int syscall_get_nr(struct task_struct *task,
 22				 struct pt_regs *regs)
 23{
 24	return task_thread_info(task)->syscall;
 25}
 26
 27static inline void syscall_rollback(struct task_struct *task,
 28				    struct pt_regs *regs)
 29{
 30	regs->ARM_r0 = regs->ARM_ORIG_r0;
 31}
 32
 33static inline long syscall_get_error(struct task_struct *task,
 34				     struct pt_regs *regs)
 35{
 36	unsigned long error = regs->ARM_r0;
 37	return IS_ERR_VALUE(error) ? error : 0;
 38}
 39
 40static inline long syscall_get_return_value(struct task_struct *task,
 41					    struct pt_regs *regs)
 42{
 43	return regs->ARM_r0;
 44}
 45
 46static inline void syscall_set_return_value(struct task_struct *task,
 47					    struct pt_regs *regs,
 48					    int error, long val)
 49{
 50	regs->ARM_r0 = (long) error ? error : val;
 51}
 52
 53#define SYSCALL_MAX_ARGS 7
 54
 55static inline void syscall_get_arguments(struct task_struct *task,
 56					 struct pt_regs *regs,
 57					 unsigned int i, unsigned int n,
 58					 unsigned long *args)
 59{
 60	if (n == 0)
 61		return;
 62
 63	if (i + n > SYSCALL_MAX_ARGS) {
 64		unsigned long *args_bad = args + SYSCALL_MAX_ARGS - i;
 65		unsigned int n_bad = n + i - SYSCALL_MAX_ARGS;
 66		pr_warn("%s called with max args %d, handling only %d\n",
 67			__func__, i + n, SYSCALL_MAX_ARGS);
 68		memset(args_bad, 0, n_bad * sizeof(args[0]));
 69		n = SYSCALL_MAX_ARGS - i;
 70	}
 71
 72	if (i == 0) {
 73		args[0] = regs->ARM_ORIG_r0;
 74		args++;
 75		i++;
 76		n--;
 77	}
 78
 79	memcpy(args, &regs->ARM_r0 + i, n * sizeof(args[0]));
 80}
 81
 82static inline void syscall_set_arguments(struct task_struct *task,
 83					 struct pt_regs *regs,
 84					 unsigned int i, unsigned int n,
 85					 const unsigned long *args)
 86{
 87	if (n == 0)
 88		return;
 89
 90	if (i + n > SYSCALL_MAX_ARGS) {
 91		pr_warn("%s called with max args %d, handling only %d\n",
 92			__func__, i + n, SYSCALL_MAX_ARGS);
 93		n = SYSCALL_MAX_ARGS - i;
 94	}
 95
 96	if (i == 0) {
 97		regs->ARM_ORIG_r0 = args[0];
 98		args++;
 99		i++;
100		n--;
101	}
102
103	memcpy(&regs->ARM_r0 + i, args, n * sizeof(args[0]));
104}
105
106static inline int syscall_get_arch(void)
107{
108	/* ARM tasks don't change audit architectures on the fly. */
109	return AUDIT_ARCH_ARM;
110}
111
112#endif /* _ASM_ARM_SYSCALL_H */