99fc8d424b
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>
99 lines
2.6 KiB
C
99 lines
2.6 KiB
C
/*
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* local mtrr defines.
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*/
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#include <linux/types.h>
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#include <linux/stddef.h>
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#define MTRRcap_MSR 0x0fe
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#define MTRRdefType_MSR 0x2ff
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#define MTRRphysBase_MSR(reg) (0x200 + 2 * (reg))
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#define MTRRphysMask_MSR(reg) (0x200 + 2 * (reg) + 1)
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#define NUM_FIXED_RANGES 88
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#define MAX_VAR_RANGES 256
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#define MTRRfix64K_00000_MSR 0x250
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#define MTRRfix16K_80000_MSR 0x258
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#define MTRRfix16K_A0000_MSR 0x259
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#define MTRRfix4K_C0000_MSR 0x268
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#define MTRRfix4K_C8000_MSR 0x269
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#define MTRRfix4K_D0000_MSR 0x26a
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#define MTRRfix4K_D8000_MSR 0x26b
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#define MTRRfix4K_E0000_MSR 0x26c
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#define MTRRfix4K_E8000_MSR 0x26d
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#define MTRRfix4K_F0000_MSR 0x26e
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#define MTRRfix4K_F8000_MSR 0x26f
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#define MTRR_CHANGE_MASK_FIXED 0x01
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#define MTRR_CHANGE_MASK_VARIABLE 0x02
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#define MTRR_CHANGE_MASK_DEFTYPE 0x04
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/* In the Intel processor's MTRR interface, the MTRR type is always held in
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an 8 bit field: */
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typedef u8 mtrr_type;
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extern unsigned int mtrr_usage_table[MAX_VAR_RANGES];
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struct mtrr_ops {
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u32 vendor;
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u32 use_intel_if;
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// void (*init)(void);
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void (*set)(unsigned int reg, unsigned long base,
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unsigned long size, mtrr_type type);
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void (*set_all)(void);
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void (*get)(unsigned int reg, unsigned long *base,
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unsigned long *size, mtrr_type * type);
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int (*get_free_region)(unsigned long base, unsigned long size,
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int replace_reg);
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int (*validate_add_page)(unsigned long base, unsigned long size,
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unsigned int type);
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int (*have_wrcomb)(void);
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};
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extern int generic_get_free_region(unsigned long base, unsigned long size,
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int replace_reg);
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extern int generic_validate_add_page(unsigned long base, unsigned long size,
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unsigned int type);
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extern struct mtrr_ops generic_mtrr_ops;
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extern int positive_have_wrcomb(void);
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/* library functions for processor-specific routines */
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struct set_mtrr_context {
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unsigned long flags;
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unsigned long cr4val;
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u32 deftype_lo;
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u32 deftype_hi;
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u32 ccr3;
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};
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struct mtrr_var_range {
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u32 base_lo;
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u32 base_hi;
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u32 mask_lo;
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u32 mask_hi;
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};
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void set_mtrr_done(struct set_mtrr_context *ctxt);
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void set_mtrr_cache_disable(struct set_mtrr_context *ctxt);
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void set_mtrr_prepare_save(struct set_mtrr_context *ctxt);
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void get_mtrr_state(void);
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extern void set_mtrr_ops(struct mtrr_ops * ops);
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extern u64 size_or_mask, size_and_mask;
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extern struct mtrr_ops * mtrr_if;
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#define is_cpu(vnd) (mtrr_if && mtrr_if->vendor == X86_VENDOR_##vnd)
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#define use_intel() (mtrr_if && mtrr_if->use_intel_if == 1)
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extern unsigned int num_var_ranges;
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void mtrr_state_warn(void);
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const char *mtrr_attrib_to_str(int x);
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void mtrr_wrmsr(unsigned, unsigned, unsigned);
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