From 38ce65e1fed1cd5962add9b746ea70e49586b54a Mon Sep 17 00:00:00 2001 From: Alexander Graf Date: Wed, 30 Mar 2016 16:38:29 +0200 Subject: [PATCH] efi_loader: Always allocate the highest available address Some EFI applications (grub2) expect that an allocation always returns the highest available memory address for the given size. Without this, we may run into situations where the initrd gets allocated at a lower address than the kernel. This patch fixes booting in such situations for me. Signed-off-by: Alexander Graf --- lib/efi_loader/efi_memory.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) diff --git a/lib/efi_loader/efi_memory.c b/lib/efi_loader/efi_memory.c index c82b53f..8a1e249 100644 --- a/lib/efi_loader/efi_memory.c +++ b/lib/efi_loader/efi_memory.c @@ -13,6 +13,7 @@ #include #include #include +#include #include #include @@ -27,6 +28,31 @@ struct efi_mem_list { LIST_HEAD(efi_mem); /* + * Sorts the memory list from highest address to lowest address + * + * When allocating memory we should always start from the highest + * address chunk, so sort the memory list such that the first list + * iterator gets the highest address and goes lower from there. + */ +static int efi_mem_cmp(void *priv, struct list_head *a, struct list_head *b) +{ + struct efi_mem_list *mema = list_entry(a, struct efi_mem_list, link); + struct efi_mem_list *memb = list_entry(b, struct efi_mem_list, link); + + if (mema->desc.physical_start == memb->desc.physical_start) + return 0; + else if (mema->desc.physical_start < memb->desc.physical_start) + return 1; + else + return -1; +} + +static void efi_mem_sort(void) +{ + list_sort(NULL, &efi_mem, efi_mem_cmp); +} + +/* * Unmaps all memory occupied by the carve_desc region from the * list entry pointed to by map. * @@ -142,6 +168,9 @@ uint64_t efi_add_memory_map(uint64_t start, uint64_t pages, int memory_type, /* Add our new map */ list_add_tail(&newlist->link, &efi_mem); + /* And make sure memory is listed in descending order */ + efi_mem_sort(); + return start; }