kernel-fxtec-pro1x/arch/x86/include/asm/syscall.h
H. Peter Anvin fca460f95e x32: Handle the x32 system call flag
x32 shares most system calls with x86-64, but unfortunately some
subsystem (the input subsystem is the chief offender) which require
is_compat() when operating with a 32-bit userspace.  The input system
actually has text files in sysfs whose meaning is dependent on
sizeof(long) in userspace!

We could solve this by having two completely disjoint system call
tables; requiring that each system call be duplicated.  This patch
takes a different approach: we add a flag to the system call number;
this flag doesn't affect the system call dispatch but requests compat
treatment from affected subsystems for the duration of the system call.

The change of cmpq to cmpl is safe since it immediately follows the
and.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2012-02-20 12:52:05 -08:00

217 lines
4.5 KiB
C

/*
* Access to user system call parameters and results
*
* Copyright (C) 2008-2009 Red Hat, Inc. All rights reserved.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU General Public License v.2.
*
* See asm-generic/syscall.h for descriptions of what we must do here.
*/
#ifndef _ASM_X86_SYSCALL_H
#define _ASM_X86_SYSCALL_H
#include <linux/sched.h>
#include <linux/err.h>
#include <asm/asm-offsets.h> /* For NR_syscalls */
#include <asm/unistd.h>
extern const unsigned long sys_call_table[];
/*
* Only the low 32 bits of orig_ax are meaningful, so we return int.
* This importantly ignores the high bits on 64-bit, so comparisons
* sign-extend the low 32 bits.
*/
static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
{
return regs->orig_ax & __SYSCALL_MASK;
}
static inline void syscall_rollback(struct task_struct *task,
struct pt_regs *regs)
{
regs->ax = regs->orig_ax & __SYSCALL_MASK;
}
static inline long syscall_get_error(struct task_struct *task,
struct pt_regs *regs)
{
unsigned long error = regs->ax;
#ifdef CONFIG_IA32_EMULATION
/*
* TS_COMPAT is set for 32-bit syscall entries and then
* remains set until we return to user mode.
*/
if (task_thread_info(task)->status & TS_COMPAT)
/*
* Sign-extend the value so (int)-EFOO becomes (long)-EFOO
* and will match correctly in comparisons.
*/
error = (long) (int) error;
#endif
return IS_ERR_VALUE(error) ? error : 0;
}
static inline long syscall_get_return_value(struct task_struct *task,
struct pt_regs *regs)
{
return regs->ax;
}
static inline void syscall_set_return_value(struct task_struct *task,
struct pt_regs *regs,
int error, long val)
{
regs->ax = (long) error ?: val;
}
#ifdef CONFIG_X86_32
static inline void syscall_get_arguments(struct task_struct *task,
struct pt_regs *regs,
unsigned int i, unsigned int n,
unsigned long *args)
{
BUG_ON(i + n > 6);
memcpy(args, &regs->bx + i, n * sizeof(args[0]));
}
static inline void syscall_set_arguments(struct task_struct *task,
struct pt_regs *regs,
unsigned int i, unsigned int n,
const unsigned long *args)
{
BUG_ON(i + n > 6);
memcpy(&regs->bx + i, args, n * sizeof(args[0]));
}
#else /* CONFIG_X86_64 */
static inline void syscall_get_arguments(struct task_struct *task,
struct pt_regs *regs,
unsigned int i, unsigned int n,
unsigned long *args)
{
# ifdef CONFIG_IA32_EMULATION
if (task_thread_info(task)->status & TS_COMPAT)
switch (i) {
case 0:
if (!n--) break;
*args++ = regs->bx;
case 1:
if (!n--) break;
*args++ = regs->cx;
case 2:
if (!n--) break;
*args++ = regs->dx;
case 3:
if (!n--) break;
*args++ = regs->si;
case 4:
if (!n--) break;
*args++ = regs->di;
case 5:
if (!n--) break;
*args++ = regs->bp;
case 6:
if (!n--) break;
default:
BUG();
break;
}
else
# endif
switch (i) {
case 0:
if (!n--) break;
*args++ = regs->di;
case 1:
if (!n--) break;
*args++ = regs->si;
case 2:
if (!n--) break;
*args++ = regs->dx;
case 3:
if (!n--) break;
*args++ = regs->r10;
case 4:
if (!n--) break;
*args++ = regs->r8;
case 5:
if (!n--) break;
*args++ = regs->r9;
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)
{
# ifdef CONFIG_IA32_EMULATION
if (task_thread_info(task)->status & TS_COMPAT)
switch (i) {
case 0:
if (!n--) break;
regs->bx = *args++;
case 1:
if (!n--) break;
regs->cx = *args++;
case 2:
if (!n--) break;
regs->dx = *args++;
case 3:
if (!n--) break;
regs->si = *args++;
case 4:
if (!n--) break;
regs->di = *args++;
case 5:
if (!n--) break;
regs->bp = *args++;
case 6:
if (!n--) break;
default:
BUG();
break;
}
else
# endif
switch (i) {
case 0:
if (!n--) break;
regs->di = *args++;
case 1:
if (!n--) break;
regs->si = *args++;
case 2:
if (!n--) break;
regs->dx = *args++;
case 3:
if (!n--) break;
regs->r10 = *args++;
case 4:
if (!n--) break;
regs->r8 = *args++;
case 5:
if (!n--) break;
regs->r9 = *args++;
case 6:
if (!n--) break;
default:
BUG();
break;
}
}
#endif /* CONFIG_X86_32 */
#endif /* _ASM_X86_SYSCALL_H */