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Commit d8f8b844 authored by Mickaël Salaün's avatar Mickaël Salaün Committed by Richard Weinberger
Browse files

um: Add full asm/syscall.h support 

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: default avatarMickaël 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: default avatarRichard Weinberger <richard@nod.at>
Acked-by: default avatarKees Cook <keescook@chromium.org>
parent 4a0b8807

arch/um/include/asm/syscall-generic.h

0 → 100644
+138 −0
Original line number Diff line number Diff line 
/*

 * 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 */

arch/x86/um/asm/syscall.h

+1 −0
Original line number Diff line number Diff line 
#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,