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On some machines, buggy BIOSes don't properly setup WB MTRRs to cover all available RAM, meaning the last few megs (or even gigs) of memory will be marked uncached. Since Linux tends to allocate from high memory addresses first, this causes the machine to be unusably slow as soon as the kernel starts really using memory (i.e. right around init time). This patch works around the problem by scanning the MTRRs at boot and figuring out whether the current end_pfn value (setup by early e820 code) goes beyond the highest WB MTRR range, and if so, trimming it to match. A fairly obnoxious KERN_WARNING is printed too, letting the user know that not all of their memory is available due to a likely BIOS bug. Something similar could be done on i386 if needed, but the boot ordering would be slightly different, since the MTRR code on i386 depends on the boot_cpu_data structure being setup. This patch fixes a bug in the last patch that caused the code to run on non-Intel machines (AMD machines apparently don't need it and it's untested on other non-Intel machines, so best keep it off). Further enhancements and fixes from: Yinghai Lu <Yinghai.Lu@Sun.COM> Andi Kleen <ak@suse.de> Signed-off-by: Jesse Barnes <jesse.barnes@intel.com> Tested-by: Justin Piszcz <jpiszcz@lucidpixels.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Yinghai Lu <yhlu.kernel@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
169 lines
6.0 KiB
C
169 lines
6.0 KiB
C
/* Generic MTRR (Memory Type Range Register) ioctls.
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Copyright (C) 1997-1999 Richard Gooch
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public
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License as published by the Free Software Foundation; either
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version 2 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with this library; if not, write to the Free
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Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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Richard Gooch may be reached by email at rgooch@atnf.csiro.au
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The postal address is:
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Richard Gooch, c/o ATNF, P. O. Box 76, Epping, N.S.W., 2121, Australia.
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*/
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#ifndef _ASM_X86_MTRR_H
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#define _ASM_X86_MTRR_H
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#include <linux/ioctl.h>
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#include <linux/errno.h>
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#define MTRR_IOCTL_BASE 'M'
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struct mtrr_sentry
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{
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unsigned long base; /* Base address */
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unsigned int size; /* Size of region */
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unsigned int type; /* Type of region */
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};
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/* Warning: this structure has a different order from i386
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on x86-64. The 32bit emulation code takes care of that.
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But you need to use this for 64bit, otherwise your X server
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will break. */
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#ifdef __i386__
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struct mtrr_gentry
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{
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unsigned int regnum; /* Register number */
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unsigned long base; /* Base address */
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unsigned int size; /* Size of region */
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unsigned int type; /* Type of region */
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};
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#else /* __i386__ */
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struct mtrr_gentry
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{
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unsigned long base; /* Base address */
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unsigned int size; /* Size of region */
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unsigned int regnum; /* Register number */
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unsigned int type; /* Type of region */
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};
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#endif /* !__i386__ */
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/* These are the various ioctls */
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#define MTRRIOC_ADD_ENTRY _IOW(MTRR_IOCTL_BASE, 0, struct mtrr_sentry)
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#define MTRRIOC_SET_ENTRY _IOW(MTRR_IOCTL_BASE, 1, struct mtrr_sentry)
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#define MTRRIOC_DEL_ENTRY _IOW(MTRR_IOCTL_BASE, 2, struct mtrr_sentry)
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#define MTRRIOC_GET_ENTRY _IOWR(MTRR_IOCTL_BASE, 3, struct mtrr_gentry)
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#define MTRRIOC_KILL_ENTRY _IOW(MTRR_IOCTL_BASE, 4, struct mtrr_sentry)
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#define MTRRIOC_ADD_PAGE_ENTRY _IOW(MTRR_IOCTL_BASE, 5, struct mtrr_sentry)
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#define MTRRIOC_SET_PAGE_ENTRY _IOW(MTRR_IOCTL_BASE, 6, struct mtrr_sentry)
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#define MTRRIOC_DEL_PAGE_ENTRY _IOW(MTRR_IOCTL_BASE, 7, struct mtrr_sentry)
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#define MTRRIOC_GET_PAGE_ENTRY _IOWR(MTRR_IOCTL_BASE, 8, struct mtrr_gentry)
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#define MTRRIOC_KILL_PAGE_ENTRY _IOW(MTRR_IOCTL_BASE, 9, struct mtrr_sentry)
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/* These are the region types */
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#define MTRR_TYPE_UNCACHABLE 0
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#define MTRR_TYPE_WRCOMB 1
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/*#define MTRR_TYPE_ 2*/
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/*#define MTRR_TYPE_ 3*/
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#define MTRR_TYPE_WRTHROUGH 4
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#define MTRR_TYPE_WRPROT 5
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#define MTRR_TYPE_WRBACK 6
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#define MTRR_NUM_TYPES 7
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#ifdef __KERNEL__
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/* The following functions are for use by other drivers */
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# ifdef CONFIG_MTRR
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extern void mtrr_save_fixed_ranges(void *);
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extern void mtrr_save_state(void);
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extern int mtrr_add (unsigned long base, unsigned long size,
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unsigned int type, bool increment);
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extern int mtrr_add_page (unsigned long base, unsigned long size,
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unsigned int type, bool increment);
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extern int mtrr_del (int reg, unsigned long base, unsigned long size);
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extern int mtrr_del_page (int reg, unsigned long base, unsigned long size);
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extern void mtrr_centaur_report_mcr(int mcr, u32 lo, u32 hi);
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extern void mtrr_ap_init(void);
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extern void mtrr_bp_init(void);
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extern int mtrr_trim_uncached_memory(unsigned long end_pfn);
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# else
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#define mtrr_save_fixed_ranges(arg) do {} while (0)
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#define mtrr_save_state() do {} while (0)
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static __inline__ int mtrr_add (unsigned long base, unsigned long size,
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unsigned int type, bool increment)
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{
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return -ENODEV;
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}
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static __inline__ int mtrr_add_page (unsigned long base, unsigned long size,
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unsigned int type, bool increment)
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{
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return -ENODEV;
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}
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static __inline__ int mtrr_del (int reg, unsigned long base,
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unsigned long size)
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{
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return -ENODEV;
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}
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static __inline__ int mtrr_del_page (int reg, unsigned long base,
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unsigned long size)
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{
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return -ENODEV;
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}
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static inline int mtrr_trim_uncached_memory(unsigned long end_pfn)
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{
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return 0;
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}
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static __inline__ void mtrr_centaur_report_mcr(int mcr, u32 lo, u32 hi) {;}
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#define mtrr_ap_init() do {} while (0)
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#define mtrr_bp_init() do {} while (0)
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# endif
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#ifdef CONFIG_COMPAT
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#include <linux/compat.h>
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struct mtrr_sentry32
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{
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compat_ulong_t base; /* Base address */
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compat_uint_t size; /* Size of region */
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compat_uint_t type; /* Type of region */
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};
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struct mtrr_gentry32
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{
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compat_ulong_t regnum; /* Register number */
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compat_uint_t base; /* Base address */
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compat_uint_t size; /* Size of region */
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compat_uint_t type; /* Type of region */
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};
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#define MTRR_IOCTL_BASE 'M'
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#define MTRRIOC32_ADD_ENTRY _IOW(MTRR_IOCTL_BASE, 0, struct mtrr_sentry32)
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#define MTRRIOC32_SET_ENTRY _IOW(MTRR_IOCTL_BASE, 1, struct mtrr_sentry32)
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#define MTRRIOC32_DEL_ENTRY _IOW(MTRR_IOCTL_BASE, 2, struct mtrr_sentry32)
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#define MTRRIOC32_GET_ENTRY _IOWR(MTRR_IOCTL_BASE, 3, struct mtrr_gentry32)
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#define MTRRIOC32_KILL_ENTRY _IOW(MTRR_IOCTL_BASE, 4, struct mtrr_sentry32)
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#define MTRRIOC32_ADD_PAGE_ENTRY _IOW(MTRR_IOCTL_BASE, 5, struct mtrr_sentry32)
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#define MTRRIOC32_SET_PAGE_ENTRY _IOW(MTRR_IOCTL_BASE, 6, struct mtrr_sentry32)
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#define MTRRIOC32_DEL_PAGE_ENTRY _IOW(MTRR_IOCTL_BASE, 7, struct mtrr_sentry32)
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#define MTRRIOC32_GET_PAGE_ENTRY _IOWR(MTRR_IOCTL_BASE, 8, struct mtrr_gentry32)
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#define MTRRIOC32_KILL_PAGE_ENTRY _IOW(MTRR_IOCTL_BASE, 9, struct mtrr_sentry32)
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#endif /* CONFIG_COMPAT */
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#endif /* __KERNEL__ */
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#endif /* _ASM_X86_MTRR_H */
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