From 1d9b17683547348341b67705c578a1ca1882fd23 Mon Sep 17 00:00:00 2001 From: Heinrich Schuchardt Date: Tue, 18 Feb 2020 07:30:38 +0100 Subject: [PATCH] efi/libstub: Describe memory functions Provide descriptions of: * efi_get_memory_map() * efi_low_alloc_above() * efi_free() Signed-off-by: Heinrich Schuchardt Acked-by: Randy Dunlap Link: https://lore.kernel.org/r/20200218063038.3436-1-xypron.glpk@gmx.de Signed-off-by: Ard Biesheuvel --- drivers/firmware/efi/libstub/mem.c | 36 ++++++++++++++++++++++++++++-- 1 file changed, 34 insertions(+), 2 deletions(-) diff --git a/drivers/firmware/efi/libstub/mem.c b/drivers/firmware/efi/libstub/mem.c index 2499e04850818..94b029965f411 100644 --- a/drivers/firmware/efi/libstub/mem.c +++ b/drivers/firmware/efi/libstub/mem.c @@ -16,6 +16,15 @@ static inline bool mmap_has_headroom(unsigned long buff_size, 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_memory_desc_t *m = NULL; @@ -109,8 +118,20 @@ efi_status_t efi_allocate_pages(unsigned long size, unsigned long *addr, } 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, unsigned long *addr, unsigned long min) @@ -187,6 +208,17 @@ fail: 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) { unsigned long nr_pages; -- 2.30.2