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