In allocate_e820(), call the EFI get_memory_map() service directly instead of indirectly via efi_get_memory_map(). This avoids allocation of a buffer and return of the full EFI memory map, which is not needed here and would otherwise need to be freed.
Routine allocate_e820() only needs to know how many EFI memory descriptors there are in the map to allocate an adequately sized e820ext buffer, if it's needed. Note that since efi_get_memory_map() returns a memory map buffer sized with extra headroom, allocate_e820() now needs to explicitly factor that into the e820ext size calculation. Signed-off-by: Lenny Szubowicz <[email protected]> Suggested-by: Ard Biesheuvel <[email protected]> -- v2: - Instead of freeing the EFI memory map buffer allocated by efi_get_memory_map(), avoid the allocation in the first place. - Changed the title of the patch because the v1 title no longer applies. v1 ref: https://lore.kernel.org/lkml/[email protected]/ -- --- drivers/firmware/efi/libstub/efistub.h | 2 ++ drivers/firmware/efi/libstub/mem.c | 5 +++++ drivers/firmware/efi/libstub/x86-stub.c | 22 ++++++++-------------- 3 files changed, 15 insertions(+), 14 deletions(-) diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h index 67d26949fd26..191468b771b6 100644 --- a/drivers/firmware/efi/libstub/efistub.h +++ b/drivers/firmware/efi/libstub/efistub.h @@ -616,6 +616,8 @@ void efi_printk(char *str); void efi_free(unsigned long size, unsigned long addr); +unsigned int efi_get_mmap_nr_slack_slots(void); + char *efi_convert_cmdline(efi_loaded_image_t *image, int *cmd_line_len, unsigned long max_addr); diff --git a/drivers/firmware/efi/libstub/mem.c b/drivers/firmware/efi/libstub/mem.c index 869a79c8946f..fc8b4fb08505 100644 --- a/drivers/firmware/efi/libstub/mem.c +++ b/drivers/firmware/efi/libstub/mem.c @@ -7,6 +7,11 @@ #define EFI_MMAP_NR_SLACK_SLOTS 8 +unsigned int efi_get_mmap_nr_slack_slots(void) +{ + return EFI_MMAP_NR_SLACK_SLOTS; +} + static inline bool mmap_has_headroom(unsigned long buff_size, unsigned long map_size, unsigned long desc_size) diff --git a/drivers/firmware/efi/libstub/x86-stub.c b/drivers/firmware/efi/libstub/x86-stub.c index 05ccb229fb45..9a5ee0678434 100644 --- a/drivers/firmware/efi/libstub/x86-stub.c +++ b/drivers/firmware/efi/libstub/x86-stub.c @@ -606,24 +606,18 @@ static efi_status_t allocate_e820(struct boot_params *params, struct setup_data **e820ext, u32 *e820ext_size) { - unsigned long map_size, desc_size, buff_size; - struct efi_boot_memmap boot_map; - efi_memory_desc_t *map; + unsigned long map_size, desc_size; efi_status_t status; __u32 nr_desc; - boot_map.map = ↦ - boot_map.map_size = &map_size; - boot_map.desc_size = &desc_size; - boot_map.desc_ver = NULL; - boot_map.key_ptr = NULL; - boot_map.buff_size = &buff_size; + /* Only need the size of the mem map and size of each mem descriptor */ + map_size = 0; + status = efi_bs_call(get_memory_map, &map_size, NULL, NULL, + &desc_size, NULL); + if (status != EFI_BUFFER_TOO_SMALL) + return (status != EFI_SUCCESS) ? status : EFI_UNSUPPORTED; - status = efi_get_memory_map(&boot_map); - if (status != EFI_SUCCESS) - return status; - - nr_desc = buff_size / desc_size; + nr_desc = map_size / desc_size + efi_get_mmap_nr_slack_slots(); if (nr_desc > ARRAY_SIZE(params->e820_table)) { u32 nr_e820ext = nr_desc - ARRAY_SIZE(params->e820_table); -- 2.18.4
