From: Heinrich Schuchardt <xypron.glpk@gmx.de>
Date: Tue, 18 Feb 2020 07:30:38 +0100
Subject: efi/libstub: Describe memory functions
Patch-mainline: v5.7-rc1
Git-commit: 1d9b17683547348341b67705c578a1ca1882fd23
References: jsc#SLE-16407
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>
Acked-by: Lee, Chun-Yi <jlee@suse.com>
---
drivers/firmware/efi/libstub/mem.c | 36 ++++++++++++++++++++++++++++++++++--
1 file changed, 34 insertions(+), 2 deletions(-)
--- a/drivers/firmware/efi/libstub/mem.c
+++ b/drivers/firmware/efi/libstub/mem.c
@@ -16,6 +16,15 @@ static inline bool mmap_has_headroom(uns
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
}
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;