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efi/libstub: Describe memory functions 

Provide descriptions of:

* efi_get_memory_map()
* efi_low_alloc_above()
* efi_free()

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20200218063038.3436-1-xypron.glpk@gmx.de
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
This commit is contained in:
Heinrich Schuchardt 2020-02-18 07:30:38 +01:00 committed by Ard Biesheuvel
parent e7ea37b00d
commit 1d9b176835
1 changed files with 34 additions and 2 deletions
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36
drivers/firmware/efi/libstub/mem.c
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@ -16,6 +16,15 @@ static inline bool mmap_has_headroom(unsigned long buff_size,
return slack / desc_size >= EFI_MMAP_NR_SLACK_SLOTS; return slack / desc_size >= EFI_MMAP_NR_SLACK_SLOTS;
} }
/**
* efi_get_memory_map() - get memory map
* @map: on return pointer to memory map
*
* Retrieve the UEFI memory map. The allocated memory leaves room for
* up to EFI_MMAP_NR_SLACK_SLOTS additional memory map entries.
*
* Return: status code
*/
efi_status_t efi_get_memory_map(struct efi_boot_memmap *map) efi_status_t efi_get_memory_map(struct efi_boot_memmap *map)
{ {
efi_memory_desc_t *m = NULL; efi_memory_desc_t *m = NULL;
@ -109,8 +118,20 @@ efi_status_t efi_allocate_pages(unsigned long size, unsigned long *addr,
} }
return EFI_SUCCESS; return EFI_SUCCESS;
} }
/* /**
* Allocate at the lowest possible address that is not below 'min'. * efi_low_alloc_above() - allocate pages at or above given address
* @size: size of the memory area to allocate
* @align: minimum alignment of the allocated memory area. It should
* a power of two.
* @addr: on exit the address of the allocated memory
* @min: minimum address to used for the memory allocation
*
* Allocate at the lowest possible address that is not below @min as
* EFI_LOADER_DATA. The allocated pages are aligned according to @align but at
* least EFI_ALLOC_ALIGN. The first allocated page will not below the address
* given by @min.
*
* Return: status code
*/ */
efi_status_t efi_low_alloc_above(unsigned long size, unsigned long align, efi_status_t efi_low_alloc_above(unsigned long size, unsigned long align,
unsigned long *addr, unsigned long min) unsigned long *addr, unsigned long min)
@ -187,6 +208,17 @@ efi_status_t efi_low_alloc_above(unsigned long size, unsigned long align,
return status; return status;
} }
/**
* efi_free() - free memory pages
* @size: size of the memory area to free in bytes
* @addr: start of the memory area to free (must be EFI_PAGE_SIZE
* aligned)
*
* @size is rounded up to a multiple of EFI_ALLOC_ALIGN which is an
* architecture specific multiple of EFI_PAGE_SIZE. So this function should
* only be used to return pages allocated with efi_allocate_pages() or
* efi_low_alloc_above().
*/
void efi_free(unsigned long size, unsigned long addr) void efi_free(unsigned long size, unsigned long addr)
{ {
unsigned long nr_pages; unsigned long nr_pages;