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linux/arch/x86/include/uapi/asm/mtrr.h
Juergen Gross 973df19420 x86/mtrr: Don't let mtrr_type_lookup() return MTRR_TYPE_INVALID
mtrr_type_lookup() should always return a valid memory type. In case
there is no information available, it should return the default UC.

This will remove the last case where mtrr_type_lookup() can return
MTRR_TYPE_INVALID, so adjust the comment in include/uapi/asm/mtrr.h.

Note that removing the MTRR_TYPE_INVALID #define from that header
could break user code, so it has to stay.

At the same time the mtrr_type_lookup() stub for the !CONFIG_MTRR
case should set uniform to 1, as if the memory range would be
covered by no MTRR at all.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20230502120931.20719-15-jgross@suse.com
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
2023-06-01 15:04:33 +02:00

117 lines
3.9 KiB
C

/* SPDX-License-Identifier: LGPL-2.0+ WITH Linux-syscall-note */
/* Generic MTRR (Memory Type Range Register) ioctls.
Copyright (C) 1997-1999 Richard Gooch
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with this library; if not, write to the Free
Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
Richard Gooch may be reached by email at rgooch@atnf.csiro.au
The postal address is:
Richard Gooch, c/o ATNF, P. O. Box 76, Epping, N.S.W., 2121, Australia.
*/
#ifndef _UAPI_ASM_X86_MTRR_H
#define _UAPI_ASM_X86_MTRR_H
#include <linux/types.h>
#include <linux/ioctl.h>
#include <linux/errno.h>
#define MTRR_IOCTL_BASE 'M'
/* Warning: this structure has a different order from i386
on x86-64. The 32bit emulation code takes care of that.
But you need to use this for 64bit, otherwise your X server
will break. */
#ifdef __i386__
struct mtrr_sentry {
unsigned long base; /* Base address */
unsigned int size; /* Size of region */
unsigned int type; /* Type of region */
};
struct mtrr_gentry {
unsigned int regnum; /* Register number */
unsigned long base; /* Base address */
unsigned int size; /* Size of region */
unsigned int type; /* Type of region */
};
#else /* __i386__ */
struct mtrr_sentry {
__u64 base; /* Base address */
__u32 size; /* Size of region */
__u32 type; /* Type of region */
};
struct mtrr_gentry {
__u64 base; /* Base address */
__u32 size; /* Size of region */
__u32 regnum; /* Register number */
__u32 type; /* Type of region */
__u32 _pad; /* Unused */
};
#endif /* !__i386__ */
struct mtrr_var_range {
__u32 base_lo;
__u32 base_hi;
__u32 mask_lo;
__u32 mask_hi;
};
/* In the Intel processor's MTRR interface, the MTRR type is always held in
an 8 bit field: */
typedef __u8 mtrr_type;
#define MTRR_NUM_FIXED_RANGES 88
#define MTRR_MAX_VAR_RANGES 256
#define MTRRphysBase_MSR(reg) (0x200 + 2 * (reg))
#define MTRRphysMask_MSR(reg) (0x200 + 2 * (reg) + 1)
/* These are the various ioctls */
#define MTRRIOC_ADD_ENTRY _IOW(MTRR_IOCTL_BASE, 0, struct mtrr_sentry)
#define MTRRIOC_SET_ENTRY _IOW(MTRR_IOCTL_BASE, 1, struct mtrr_sentry)
#define MTRRIOC_DEL_ENTRY _IOW(MTRR_IOCTL_BASE, 2, struct mtrr_sentry)
#define MTRRIOC_GET_ENTRY _IOWR(MTRR_IOCTL_BASE, 3, struct mtrr_gentry)
#define MTRRIOC_KILL_ENTRY _IOW(MTRR_IOCTL_BASE, 4, struct mtrr_sentry)
#define MTRRIOC_ADD_PAGE_ENTRY _IOW(MTRR_IOCTL_BASE, 5, struct mtrr_sentry)
#define MTRRIOC_SET_PAGE_ENTRY _IOW(MTRR_IOCTL_BASE, 6, struct mtrr_sentry)
#define MTRRIOC_DEL_PAGE_ENTRY _IOW(MTRR_IOCTL_BASE, 7, struct mtrr_sentry)
#define MTRRIOC_GET_PAGE_ENTRY _IOWR(MTRR_IOCTL_BASE, 8, struct mtrr_gentry)
#define MTRRIOC_KILL_PAGE_ENTRY _IOW(MTRR_IOCTL_BASE, 9, struct mtrr_sentry)
/* MTRR memory types, which are defined in SDM */
#define MTRR_TYPE_UNCACHABLE 0
#define MTRR_TYPE_WRCOMB 1
/*#define MTRR_TYPE_ 2*/
/*#define MTRR_TYPE_ 3*/
#define MTRR_TYPE_WRTHROUGH 4
#define MTRR_TYPE_WRPROT 5
#define MTRR_TYPE_WRBACK 6
#define MTRR_NUM_TYPES 7
/*
* Invalid MTRR memory type. No longer used outside of MTRR code.
* Note, this value is allocated from the reserved values (0x7-0xff) of
* the MTRR memory types.
*/
#define MTRR_TYPE_INVALID 0xff
#endif /* _UAPI_ASM_X86_MTRR_H */