Files
android_kernel_xiaomi_sm8450/arch/x86/include/asm/e820/api.h
Ingo Molnar 5da217ca96 x86/boot/e820: Rename early_reserve_e820() to e820__memblock_alloc() and document it
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>
2017-01-28 14:42:30 +01:00

44 lines
1.6 KiB
C

#ifndef _ASM_E820_API_H
#define _ASM_E820_API_H
#include <asm/e820/types.h>
extern struct e820_table *e820_table;
extern struct e820_table *e820_table_firmware;
extern unsigned long pci_mem_start;
extern int e820_any_mapped(u64 start, u64 end, unsigned type);
extern int e820_all_mapped(u64 start, u64 end, unsigned type);
extern void e820_add_region(u64 start, u64 size, int type);
extern void e820_print_map(char *who);
extern int sanitize_e820_table(struct e820_entry *biosmap, int max_nr_map, u32 *pnr_map);
extern u64 e820_update_range(u64 start, u64 size, unsigned old_type, unsigned new_type);
extern u64 e820_remove_range(u64 start, u64 size, unsigned old_type, int checktype);
extern void update_e820(void);
extern void e820_setup_gap(void);
extern void e820__memory_setup_extended(u64 phys_addr, u32 data_len);
extern unsigned long e820_end_of_ram_pfn(void);
extern unsigned long e820_end_of_low_ram_pfn(void);
extern u64 e820__memblock_alloc_reserved(u64 sizet, u64 align);
extern void e820__memblock_setup(void);
extern void e820_reserve_setup_data(void);
extern void e820__finish_early_params(void);
extern void e820_reserve_resources(void);
extern void e820_reserve_resources_late(void);
extern void e820__memory_setup(void);
extern char *e820__memory_setup_default(void);
extern void e820_reallocate_tables(void);
extern void e820_mark_nosave_regions(unsigned long limit_pfn);
/*
* Returns true iff the specified range [start,end) is completely contained inside
* the ISA region.
*/
static inline bool is_ISA_range(u64 start, u64 end)
{
return start >= ISA_START_ADDRESS && end <= ISA_END_ADDRESS;
}
#endif /* _ASM_E820_API_H */