From 43a9f69692b232d1c64c913a27507eb14a1c47fd Mon Sep 17 00:00:00 2001 From: Matt Fleming Date: Fri, 13 Feb 2015 15:46:56 +0000 Subject: [PATCH] Revert "efi/libstub: Call get_memory_map() to obtain map and desc sizes" This reverts commit d1a8d66b9177105e898e73716f97eb61842c457a. Ard reported a boot failure when running UEFI under Qemu and Xen and experimenting with various Tianocore build options, "As it turns out, when allocating room for the UEFI memory map using UEFI's AllocatePool (), it may result in two new memory map entries being created, for instance, when using Tianocore's preallocated region feature. For example, the following region 0x00005ead5000-0x00005ebfffff [Conventional Memory| | | | | |WB|WT|WC|UC] may be split like this 0x00005ead5000-0x00005eae2fff [Conventional Memory| | | | | |WB|WT|WC|UC] 0x00005eae3000-0x00005eae4fff [Loader Data | | | | | |WB|WT|WC|UC] 0x00005eae5000-0x00005ebfffff [Conventional Memory| | | | | |WB|WT|WC|UC] if the preallocated Loader Data region was chosen to be right in the middle of the original free space. After patch d1a8d66b9177 ("efi/libstub: Call get_memory_map() to obtain map and desc sizes"), this is not being dealt with correctly anymore, as the existing logic to allocate room for a single additional entry has become insufficient." Mark requested to reinstate the old loop we had before commit d1a8d66b9177, which grows the memory map buffer until it's big enough to hold the EFI memory map. Acked-by: Ard Biesheuvel Acked-by: Mark Rutland Signed-off-by: Matt Fleming --- drivers/firmware/efi/libstub/efi-stub-helper.c | 16 ++++++---------- 1 file changed, 6 insertions(+), 10 deletions(-) diff --git a/drivers/firmware/efi/libstub/efi-stub-helper.c b/drivers/firmware/efi/libstub/efi-stub-helper.c index d073e3946383..9bd9fbb5bea8 100644 --- a/drivers/firmware/efi/libstub/efi-stub-helper.c +++ b/drivers/firmware/efi/libstub/efi-stub-helper.c @@ -66,29 +66,25 @@ efi_status_t efi_get_memory_map(efi_system_table_t *sys_table_arg, unsigned long key; u32 desc_version; - *map_size = 0; - *desc_size = 0; - key = 0; - status = efi_call_early(get_memory_map, map_size, NULL, - &key, desc_size, &desc_version); - if (status != EFI_BUFFER_TOO_SMALL) - return EFI_LOAD_ERROR; - + *map_size = sizeof(*m) * 32; +again: /* * Add an additional efi_memory_desc_t because we're doing an * allocation which may be in a new descriptor region. */ - *map_size += *desc_size; + *map_size += sizeof(*m); status = efi_call_early(allocate_pool, EFI_LOADER_DATA, *map_size, (void **)&m); if (status != EFI_SUCCESS) goto fail; + *desc_size = 0; + key = 0; status = efi_call_early(get_memory_map, map_size, m, &key, desc_size, &desc_version); if (status == EFI_BUFFER_TOO_SMALL) { efi_call_early(free_pool, m); - return EFI_LOAD_ERROR; + goto again; } if (status != EFI_SUCCESS) -- 2.20.1