From: Ard Biesheuvel <ardb@xxxxxxxxxx> [ Commit bc5ddceff4c14494d83449ad45c985e6cd353fce upstream ] x86 will need to limit the kernel memory allocation to the lowest 512 MiB of memory, to match the behavior of the existing bare metal KASLR physical randomization logic. So in preparation for that, add a limit parameter to efi_random_alloc() and wire it up. Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx> Signed-off-by: Borislav Petkov (AMD) <bp@xxxxxxxxx> Link: https://lore.kernel.org/r/20230807162720.545787-22-ardb@xxxxxxxxxx Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx> --- drivers/firmware/efi/libstub/arm64-stub.c | 2 +- drivers/firmware/efi/libstub/efistub.h | 2 +- drivers/firmware/efi/libstub/randomalloc.c | 10 ++++++---- 3 files changed, 8 insertions(+), 6 deletions(-) diff --git a/drivers/firmware/efi/libstub/arm64-stub.c b/drivers/firmware/efi/libstub/arm64-stub.c index 40275c3131c8..16377b452119 100644 --- a/drivers/firmware/efi/libstub/arm64-stub.c +++ b/drivers/firmware/efi/libstub/arm64-stub.c @@ -181,7 +181,7 @@ efi_status_t handle_kernel_image(unsigned long *image_addr, */ status = efi_random_alloc(*reserve_size, min_kimg_align, reserve_addr, phys_seed, - EFI_LOADER_CODE); + EFI_LOADER_CODE, EFI_ALLOC_LIMIT); if (status != EFI_SUCCESS) efi_warn("efi_random_alloc() failed: 0x%lx\n", status); } else { diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h index 6f5a1a16db15..8a343ea1231a 100644 --- a/drivers/firmware/efi/libstub/efistub.h +++ b/drivers/firmware/efi/libstub/efistub.h @@ -905,7 +905,7 @@ efi_status_t efi_get_random_bytes(unsigned long size, u8 *out); efi_status_t efi_random_alloc(unsigned long size, unsigned long align, unsigned long *addr, unsigned long random_seed, - int memory_type); + int memory_type, unsigned long alloc_limit); efi_status_t efi_random_get_seed(void); diff --git a/drivers/firmware/efi/libstub/randomalloc.c b/drivers/firmware/efi/libstub/randomalloc.c index 1692d19ae80f..ed6f6087a9ea 100644 --- a/drivers/firmware/efi/libstub/randomalloc.c +++ b/drivers/firmware/efi/libstub/randomalloc.c @@ -16,7 +16,8 @@ */ static unsigned long get_entry_num_slots(efi_memory_desc_t *md, unsigned long size, - unsigned long align_shift) + unsigned long align_shift, + u64 alloc_limit) { unsigned long align = 1UL << align_shift; u64 first_slot, last_slot, region_end; @@ -29,7 +30,7 @@ static unsigned long get_entry_num_slots(efi_memory_desc_t *md, return 0; region_end = min(md->phys_addr + md->num_pages * EFI_PAGE_SIZE - 1, - (u64)EFI_ALLOC_LIMIT); + alloc_limit); if (region_end < size) return 0; @@ -54,7 +55,8 @@ efi_status_t efi_random_alloc(unsigned long size, unsigned long align, unsigned long *addr, unsigned long random_seed, - int memory_type) + int memory_type, + unsigned long alloc_limit) { unsigned long total_slots = 0, target_slot; unsigned long total_mirrored_slots = 0; @@ -76,7 +78,7 @@ efi_status_t efi_random_alloc(unsigned long size, efi_memory_desc_t *md = (void *)map->map + map_offset; unsigned long slots; - slots = get_entry_num_slots(md, size, ilog2(align)); + slots = get_entry_num_slots(md, size, ilog2(align), alloc_limit); MD_NUM_SLOTS(md) = slots; total_slots += slots; if (md->attribute & EFI_MEMORY_MORE_RELIABLE) -- 2.44.0.278.ge034bb2e1d-goog
