124 lines
2.7 KiB
C
124 lines
2.7 KiB
C
/* syscall parameter access functions
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*
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* Copyright (C) 2009 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public Licence
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* as published by the Free Software Foundation; either version
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* 2 of the Licence, or (at your option) any later version.
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*/
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#ifndef _ASM_SYSCALL_H
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#define _ASM_SYSCALL_H
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#include <linux/err.h>
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#include <asm/ptrace.h>
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/*
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* Get the system call number or -1
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*/
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static inline long syscall_get_nr(struct task_struct *task,
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struct pt_regs *regs)
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{
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return regs->syscallno;
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}
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/*
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* Restore the clobbered GR8 register
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* (1st syscall arg was overwritten with syscall return or error)
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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->gr8 = regs->orig_gr8;
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}
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/*
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* See if the syscall return value is an error, returning it if it is and 0 if
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* not
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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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return IS_ERR_VALUE(regs->gr8) ? regs->gr8 : 0;
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}
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/*
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* Get the syscall return value
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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->gr8;
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}
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/*
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* Set the syscall return value
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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 (error)
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regs->gr8 = -error;
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else
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regs->gr8 = val;
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}
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/*
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* Retrieve the system call arguments
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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 int i, unsigned int n,
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unsigned long *args)
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{
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/*
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* Do this simply for now. If we need to start supporting
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* fetching arguments from arbitrary indices, this will need some
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* extra logic. Presently there are no in-tree users that depend
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* on this behaviour.
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*/
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BUG_ON(i);
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/* Argument pattern is: GR8, GR9, GR10, GR11, GR12, GR13 */
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switch (n) {
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case 6: args[5] = regs->gr13;
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case 5: args[4] = regs->gr12;
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case 4: args[3] = regs->gr11;
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case 3: args[2] = regs->gr10;
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case 2: args[1] = regs->gr9;
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case 1: args[0] = regs->gr8;
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break;
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default:
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BUG();
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}
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}
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/*
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* Alter the system call arguments
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*/
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static inline void syscall_set_arguments(struct task_struct *task,
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struct pt_regs *regs,
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unsigned int i, unsigned int n,
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const unsigned long *args)
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{
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/* Same note as above applies */
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BUG_ON(i);
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switch (n) {
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case 6: regs->gr13 = args[5];
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case 5: regs->gr12 = args[4];
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case 4: regs->gr11 = args[3];
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case 3: regs->gr10 = args[2];
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case 2: regs->gr9 = args[1];
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case 1: regs->gr8 = args[0];
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break;
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default:
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BUG();
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}
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}
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#endif /* _ASM_SYSCALL_H */
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