arm64/efi: do not assume DRAM base is aligned to 2 MB

The current arm64 Image relocation code in the UEFI stub assumes that the dram_base argument it receives is always a multiple of 2 MB. In reality, it is simply the lowest start address of all RAM entries in the UEFI memory map, which means it could be any multiple of 4 KB. Since the arm64 kernel Image needs to reside TEXT_OFFSET bytes beyond a 2 MB aligned base, or it will fail to boot, make sure we round dram_base to 2 MB before using it to calculate the relocation address.

Ard Biesheuvel committed 11 years ago

Commit 73effcc1 parent 97029701 file · +12 −2Browse files

Unified · Split

arch/arm64/kernel/efi-stub.c+12−2

@@ -25,10 +25,20 @@ efi_status_t __init handle_kernel_image(efi_system_table_t *sys_table_arg, · 24 unmodified lines
25	25	unsigned long kernel_size, kernel_memsize = 0;
26	26	unsigned long nr_pages;
27	27	void old_image_addr = (void )*image_addr;
	28	+ unsigned long preferred_offset;
	29	+
	30	+ /*
	31	+ * The preferred offset of the kernel Image is TEXT_OFFSET bytes beyond
	32	+ * a 2 MB aligned base, which itself may be lower than dram_base, as
	33	+ * long as the resulting offset equals or exceeds it.
	34	+ */
	35	+ preferred_offset = round_down(dram_base, SZ_2M) + TEXT_OFFSET;
	36	+ if (preferred_offset < dram_base)
	37	+ preferred_offset += SZ_2M;
28	38
29	39	/* Relocate the image, if required. */
30	40	kernel_size = _edata - _text;
31		− if (*image_addr != (dram_base + TEXT_OFFSET)) {
	41	+ if (*image_addr != preferred_offset) {
32	42	kernel_memsize = kernel_size + (_end - _edata);
33	43
34	44	/*
@@ -42,7 +52,7 @@ efi_status_t __init handle_kernel_image(efi_system_table_t *sys_table_arg, · 7 unmodified lines
42	52	* Mustang), we can still place the kernel at the address
43	53	* 'dram_base + TEXT_OFFSET'.
44	54	*/
45		− image_addr = reserve_addr = dram_base + TEXT_OFFSET;
	55	+ image_addr = reserve_addr = preferred_offset;
46	56	nr_pages = round_up(kernel_memsize, EFI_ALLOC_ALIGN) /
47	57	EFI_PAGE_SIZE;
48	58	status = efi_call_early(allocate_pages, EFI_ALLOCATE_ADDRESS,