![Bjorn Helgaas](/assets/img/avatar_default.png)
This prevents allocation of the last 2MB before 4GB. The experiment described here shows Windows 7 ignoring the last 1MB: https://bugzilla.kernel.org/show_bug.cgi?id=23542#c27 This patch ignores the top 2MB instead of just 1MB because H. Peter Anvin says "There will be ROM at the top of the 32-bit address space; it's a fact of the architecture, and on at least older systems it was common to have a shadow 1 MiB below." Acked-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
150 lines
4.5 KiB
C
150 lines
4.5 KiB
C
#ifndef _ASM_X86_E820_H
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#define _ASM_X86_E820_H
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#define E820MAP 0x2d0 /* our map */
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#define E820MAX 128 /* number of entries in E820MAP */
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/*
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* Legacy E820 BIOS limits us to 128 (E820MAX) nodes due to the
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* constrained space in the zeropage. If we have more nodes than
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* that, and if we've booted off EFI firmware, then the EFI tables
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* passed us from the EFI firmware can list more nodes. Size our
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* internal memory map tables to have room for these additional
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* nodes, based on up to three entries per node for which the
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* kernel was built: MAX_NUMNODES == (1 << CONFIG_NODES_SHIFT),
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* plus E820MAX, allowing space for the possible duplicate E820
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* entries that might need room in the same arrays, prior to the
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* call to sanitize_e820_map() to remove duplicates. The allowance
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* of three memory map entries per node is "enough" entries for
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* the initial hardware platform motivating this mechanism to make
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* use of additional EFI map entries. Future platforms may want
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* to allow more than three entries per node or otherwise refine
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* this size.
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*/
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/*
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* Odd: 'make headers_check' complains about numa.h if I try
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* to collapse the next two #ifdef lines to a single line:
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* #if defined(__KERNEL__) && defined(CONFIG_EFI)
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*/
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#ifdef __KERNEL__
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#ifdef CONFIG_EFI
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#include <linux/numa.h>
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#define E820_X_MAX (E820MAX + 3 * MAX_NUMNODES)
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#else /* ! CONFIG_EFI */
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#define E820_X_MAX E820MAX
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#endif
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#else /* ! __KERNEL__ */
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#define E820_X_MAX E820MAX
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#endif
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#define E820NR 0x1e8 /* # entries in E820MAP */
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#define E820_RAM 1
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#define E820_RESERVED 2
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#define E820_ACPI 3
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#define E820_NVS 4
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#define E820_UNUSABLE 5
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/*
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* reserved RAM used by kernel itself
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* if CONFIG_INTEL_TXT is enabled, memory of this type will be
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* included in the S3 integrity calculation and so should not include
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* any memory that BIOS might alter over the S3 transition
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*/
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#define E820_RESERVED_KERN 128
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#ifndef __ASSEMBLY__
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#include <linux/types.h>
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struct e820entry {
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__u64 addr; /* start of memory segment */
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__u64 size; /* size of memory segment */
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__u32 type; /* type of memory segment */
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} __attribute__((packed));
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struct e820map {
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__u32 nr_map;
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struct e820entry map[E820_X_MAX];
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};
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#define ISA_START_ADDRESS 0xa0000
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#define ISA_END_ADDRESS 0x100000
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#define BIOS_BEGIN 0x000a0000
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#define BIOS_END 0x00100000
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#define BIOS_ROM_BASE 0xffe00000
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#define BIOS_ROM_END 0xffffffff
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#ifdef __KERNEL__
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/* see comment in arch/x86/kernel/e820.c */
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extern struct e820map e820;
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extern struct e820map e820_saved;
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extern unsigned long pci_mem_start;
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extern int e820_any_mapped(u64 start, u64 end, unsigned type);
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extern int e820_all_mapped(u64 start, u64 end, unsigned type);
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extern void e820_add_region(u64 start, u64 size, int type);
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extern void e820_print_map(char *who);
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extern int
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sanitize_e820_map(struct e820entry *biosmap, int max_nr_map, u32 *pnr_map);
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extern u64 e820_update_range(u64 start, u64 size, unsigned old_type,
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unsigned new_type);
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extern u64 e820_remove_range(u64 start, u64 size, unsigned old_type,
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int checktype);
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extern void update_e820(void);
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extern void e820_setup_gap(void);
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extern int e820_search_gap(unsigned long *gapstart, unsigned long *gapsize,
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unsigned long start_addr, unsigned long long end_addr);
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struct setup_data;
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extern void parse_e820_ext(struct setup_data *data, unsigned long pa_data);
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#if defined(CONFIG_X86_64) || \
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(defined(CONFIG_X86_32) && defined(CONFIG_HIBERNATION))
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extern void e820_mark_nosave_regions(unsigned long limit_pfn);
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#else
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static inline void e820_mark_nosave_regions(unsigned long limit_pfn)
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{
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}
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#endif
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#ifdef CONFIG_MEMTEST
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extern void early_memtest(unsigned long start, unsigned long end);
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#else
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static inline void early_memtest(unsigned long start, unsigned long end)
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{
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}
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#endif
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extern unsigned long e820_end_of_ram_pfn(void);
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extern unsigned long e820_end_of_low_ram_pfn(void);
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extern u64 early_reserve_e820(u64 startt, u64 sizet, u64 align);
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void memblock_x86_fill(void);
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void memblock_find_dma_reserve(void);
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extern void finish_e820_parsing(void);
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extern void e820_reserve_resources(void);
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extern void e820_reserve_resources_late(void);
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extern void setup_memory_map(void);
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extern char *default_machine_specific_memory_setup(void);
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/*
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* Returns true iff the specified range [s,e) is completely contained inside
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* the ISA region.
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*/
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static inline bool is_ISA_range(u64 s, u64 e)
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{
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return s >= ISA_START_ADDRESS && e <= ISA_END_ADDRESS;
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}
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#endif /* __KERNEL__ */
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#endif /* __ASSEMBLY__ */
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#ifdef __KERNEL__
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#include <linux/ioport.h>
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#define HIGH_MEMORY (1024*1024)
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#endif /* __KERNEL__ */
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#endif /* _ASM_X86_E820_H */
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