
early_reserve_e820() is an early hack for kexec that does a limited fixup of the mptable and passes it to the kexec kernel as if it was the real thing. For this it needs to allocate memory - but no memory allocator is available yet beyond the memblock allocator, so early_reserve_e820() is really a wrapper around memblock_alloc() plus a hack to update the e820_table_firmware entries. The name 'reserve' is really a bit of a misnomer, as 'reserved' memory typically means memory completely inaccessible to the kernel - while here what we want to do is a special RAM allocation for our own purposes and insert that as RAM_RESERVED. Rename the function to e820__memblock_alloc_reserved() to better signal this dual purpose, plus document it better, which was omitted when it was merged. The barely comprehensible and cryptic comment: /* * pre allocated 4k and reserved it in memblock and e820_table_firmware */ u64 __init e820__memblock_alloc_reserved(u64 size, u64 align) ... does not count as documentation, replace it with: /* * Allocate the requested number of bytes with the requsted alignment * and return (the physical address) to the caller. Also register this * range in the 'firmware' E820 table. * * This allows kexec to fake a new mptable, as if it came from the real * system. */ u64 __init e820__memblock_alloc_reserved(u64 size, u64 align) No change in functionality. Cc: Alex Thorlton <athorlton@sgi.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Huang, Ying <ying.huang@intel.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul Jackson <pj@sgi.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rafael J. Wysocki <rjw@sisk.pl> Cc: Tejun Heo <tj@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Yinghai Lu <yinghai@kernel.org> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
44 lines
1.6 KiB
C
44 lines
1.6 KiB
C
#ifndef _ASM_E820_API_H
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#define _ASM_E820_API_H
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#include <asm/e820/types.h>
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extern struct e820_table *e820_table;
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extern struct e820_table *e820_table_firmware;
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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 sanitize_e820_table(struct e820_entry *biosmap, int max_nr_map, u32 *pnr_map);
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extern u64 e820_update_range(u64 start, u64 size, unsigned old_type, unsigned new_type);
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extern u64 e820_remove_range(u64 start, u64 size, unsigned old_type, 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 void e820__memory_setup_extended(u64 phys_addr, u32 data_len);
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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 e820__memblock_alloc_reserved(u64 sizet, u64 align);
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extern void e820__memblock_setup(void);
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extern void e820_reserve_setup_data(void);
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extern void e820__finish_early_params(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 e820__memory_setup(void);
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extern char *e820__memory_setup_default(void);
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extern void e820_reallocate_tables(void);
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extern void e820_mark_nosave_regions(unsigned long limit_pfn);
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/*
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* Returns true iff the specified range [start,end) 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 start, u64 end)
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{
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return start >= ISA_START_ADDRESS && end <= ISA_END_ADDRESS;
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}
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#endif /* _ASM_E820_API_H */
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