Viewing file:  syscall.h (2.99 KB) -rw-r--r--
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/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Access to user system call parameters and results
*
* Copyright (C) 2008 Red Hat, Inc. All rights reserved.
*
* See asm-generic/syscall.h for descriptions of what we must do here.
*/
#ifndef _ASM_SYSCALL_H
#define _ASM_SYSCALL_H 1
#include <uapi/linux/audit.h>
#include <linux/sched.h>
#include <linux/thread_info.h>
/* ftrace syscalls requires exporting the sys_call_table */
extern const unsigned long sys_call_table[];
extern const unsigned long compat_sys_call_table[];
static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
{
/*
* Note that we are returning an int here. That means 0xffffffff, ie.
* 32-bit negative 1, will be interpreted as -1 on a 64-bit kernel.
* This is important for seccomp so that compat tasks can set r0 = -1
* to reject the syscall.
*/
if (trap_is_syscall(regs))
return regs->gpr[0];
else
return -1;
}
static inline void syscall_rollback(struct task_struct *task,
struct pt_regs *regs)
{
regs->gpr[3] = regs->orig_gpr3;
}
static inline long syscall_get_error(struct task_struct *task,
struct pt_regs *regs)
{
if (trap_is_scv(regs)) {
unsigned long error = regs->gpr[3];
return IS_ERR_VALUE(error) ? error : 0;
} else {
/*
* If the system call failed,
* regs->gpr[3] contains a positive ERRORCODE.
*/
return (regs->ccr & 0x10000000UL) ? -regs->gpr[3] : 0;
}
}
static inline long syscall_get_return_value(struct task_struct *task,
struct pt_regs *regs)
{
return regs->gpr[3];
}
static inline void syscall_set_return_value(struct task_struct *task,
struct pt_regs *regs,
int error, long val)
{
if (trap_is_scv(regs)) {
regs->gpr[3] = (long) error ?: val;
} else {
/*
* In the general case it's not obvious that we must deal with
* CCR here, as the syscall exit path will also do that for us.
* However there are some places, eg. the signal code, which
* check ccr to decide if the value in r3 is actually an error.
*/
if (error) {
regs->ccr |= 0x10000000L;
regs->gpr[3] = error;
} else {
regs->ccr &= ~0x10000000L;
regs->gpr[3] = val;
}
}
}
static inline void syscall_get_arguments(struct task_struct *task,
struct pt_regs *regs,
unsigned long *args)
{
unsigned long val, mask = -1UL;
unsigned int n = 6;
if (is_tsk_32bit_task(task))
mask = 0xffffffff;
while (n--) {
if (n == 0)
val = regs->orig_gpr3;
else
val = regs->gpr[3 + n];
args[n] = val & mask;
}
}
static inline void syscall_set_arguments(struct task_struct *task,
struct pt_regs *regs,
const unsigned long *args)
{
memcpy(®s->gpr[3], args, 6 * sizeof(args[0]));
/* Also copy the first argument into orig_gpr3 */
regs->orig_gpr3 = args[0];
}
static inline int syscall_get_arch(struct task_struct *task)
{
if (is_tsk_32bit_task(task))
return AUDIT_ARCH_PPC;
else if (IS_ENABLED(CONFIG_CPU_LITTLE_ENDIAN))
return AUDIT_ARCH_PPC64LE;
else
return AUDIT_ARCH_PPC64;
}
#endif /* _ASM_SYSCALL_H */
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