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um: Add full asm/syscall.h support

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Add subarchitecture-independent implementation of asm-generic/syscall.h
allowing access to user system call parameters and results:
* syscall_get_nr()
* syscall_rollback()
* syscall_get_error()
* syscall_get_return_value()
* syscall_set_return_value()
* syscall_get_arguments()
* syscall_set_arguments()
* syscall_get_arch() provided by arch/x86/um/asm/syscall.h

This provides the necessary syscall helpers needed by
HAVE_ARCH_SECCOMP_FILTER plus syscall_get_error().

This is inspired from Meredydd Luff's patch
(https://gerrit.chromium.org/gerrit/21425).

Signed-off-by: Mickaël Salaün <mic@digikod.net>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Will Drewry <wad@chromium.org>
Cc: Meredydd Luff <meredydd@senatehouse.org>
Cc: David Drysdale <drysdale@google.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Acked-by: Kees Cook <keescook@chromium.org>
This commit is contained in:
Mickaël Salaün 2015-12-29 21:35:46 +01:00 committed by Richard Weinberger
parent 4a0b880704
commit d8f8b84456
2 changed files with 139 additions and 0 deletions
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138
arch/um/include/asm/syscall-generic.h Normal file
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@ -0,0 +1,138 @@
/*
* Access to user system call parameters and results
*
* See asm-generic/syscall.h for function descriptions.
*
* Copyright (C) 2015 Mickaël Salaün <mic@digikod.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#ifndef __UM_SYSCALL_GENERIC_H
#define __UM_SYSCALL_GENERIC_H
#include <asm/ptrace.h>
#include <linux/err.h>
#include <linux/sched.h>
#include <sysdep/ptrace.h>
static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
{
return PT_REGS_SYSCALL_NR(regs);
}
static inline void syscall_rollback(struct task_struct *task,
struct pt_regs *regs)
{
/* do nothing */
}
static inline long syscall_get_error(struct task_struct *task,
struct pt_regs *regs)
{
const long error = regs_return_value(regs);
return IS_ERR_VALUE(error) ? error : 0;
}
static inline long syscall_get_return_value(struct task_struct *task,
struct pt_regs *regs)
{
return regs_return_value(regs);
}
static inline void syscall_set_return_value(struct task_struct *task,
struct pt_regs *regs,
int error, long val)
{
PT_REGS_SET_SYSCALL_RETURN(regs, (long) error ?: val);
}
static inline void syscall_get_arguments(struct task_struct *task,
struct pt_regs *regs,
unsigned int i, unsigned int n,
unsigned long *args)
{
const struct uml_pt_regs *r = &regs->regs;
switch (i) {
case 0:
if (!n--)
break;
*args++ = UPT_SYSCALL_ARG1(r);
case 1:
if (!n--)
break;
*args++ = UPT_SYSCALL_ARG2(r);
case 2:
if (!n--)
break;
*args++ = UPT_SYSCALL_ARG3(r);
case 3:
if (!n--)
break;
*args++ = UPT_SYSCALL_ARG4(r);
case 4:
if (!n--)
break;
*args++ = UPT_SYSCALL_ARG5(r);
case 5:
if (!n--)
break;
*args++ = UPT_SYSCALL_ARG6(r);
case 6:
if (!n--)
break;
default:
BUG();
break;
}
}
static inline void syscall_set_arguments(struct task_struct *task,
struct pt_regs *regs,
unsigned int i, unsigned int n,
const unsigned long *args)
{
struct uml_pt_regs *r = &regs->regs;
switch (i) {
case 0:
if (!n--)
break;
UPT_SYSCALL_ARG1(r) = *args++;
case 1:
if (!n--)
break;
UPT_SYSCALL_ARG2(r) = *args++;
case 2:
if (!n--)
break;
UPT_SYSCALL_ARG3(r) = *args++;
case 3:
if (!n--)
break;
UPT_SYSCALL_ARG4(r) = *args++;
case 4:
if (!n--)
break;
UPT_SYSCALL_ARG5(r) = *args++;
case 5:
if (!n--)
break;
UPT_SYSCALL_ARG6(r) = *args++;
case 6:
if (!n--)
break;
default:
BUG();
break;
}
}
/* See arch/x86/um/asm/syscall.h for syscall_get_arch() definition. */
#endif /* __UM_SYSCALL_GENERIC_H */

1
arch/x86/um/asm/syscall.h
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@ -1,6 +1,7 @@
#ifndef __UM_ASM_SYSCALL_H
#define __UM_ASM_SYSCALL_H
#include <asm/syscall-generic.h>
#include <uapi/linux/audit.h>
typedef asmlinkage long (*sys_call_ptr_t)(unsigned long, unsigned long,