From e38457c361b30c5a2379cc767877c3e5c2505dc6 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Fri, 24 Jul 2015 12:38:27 +0100 Subject: [PATCH] arm64: efi: prefer AllocatePages() over efi_low_alloc() for vmlinux When allocating memory for the kernel image, try the AllocatePages() boot service to obtain memory at the preferred offset of 'dram_base + TEXT_OFFSET', and only revert to efi_low_alloc() if that fails. This is the only way to allocate at the base of DRAM if DRAM starts at 0x0, since efi_low_alloc() refuses to allocate at 0x0. Tested-by: Haojian Zhuang Reviewed-by: Mark Rutland Signed-off-by: Ard Biesheuvel Signed-off-by: Will Deacon --- arch/arm64/kernel/efi-stub.c | 41 ++++++++++++++++++++++++++++++++--------- 1 file changed, 32 insertions(+), 9 deletions(-) diff --git a/arch/arm64/kernel/efi-stub.c b/arch/arm64/kernel/efi-stub.c index f5374065ad53..816120ece6bc 100644 --- a/arch/arm64/kernel/efi-stub.c +++ b/arch/arm64/kernel/efi-stub.c @@ -13,7 +13,7 @@ #include #include -efi_status_t __init handle_kernel_image(efi_system_table_t *sys_table, +efi_status_t __init handle_kernel_image(efi_system_table_t *sys_table_arg, unsigned long *image_addr, unsigned long *image_size, unsigned long *reserve_addr, @@ -23,21 +23,44 @@ efi_status_t __init handle_kernel_image(efi_system_table_t *sys_table, { efi_status_t status; unsigned long kernel_size, kernel_memsize = 0; + unsigned long nr_pages; + void *old_image_addr = (void *)*image_addr; /* Relocate the image, if required. */ kernel_size = _edata - _text; if (*image_addr != (dram_base + TEXT_OFFSET)) { kernel_memsize = kernel_size + (_end - _edata); - status = efi_low_alloc(sys_table, kernel_memsize + TEXT_OFFSET, - SZ_2M, reserve_addr); + + /* + * First, try a straight allocation at the preferred offset. + * This will work around the issue where, if dram_base == 0x0, + * efi_low_alloc() refuses to allocate at 0x0 (to prevent the + * address of the allocation to be mistaken for a FAIL return + * value or a NULL pointer). It will also ensure that, on + * platforms where the [dram_base, dram_base + TEXT_OFFSET) + * interval is partially occupied by the firmware (like on APM + * Mustang), we can still place the kernel at the address + * 'dram_base + TEXT_OFFSET'. + */ + *image_addr = *reserve_addr = dram_base + TEXT_OFFSET; + nr_pages = round_up(kernel_memsize, EFI_ALLOC_ALIGN) / + EFI_PAGE_SIZE; + status = efi_call_early(allocate_pages, EFI_ALLOCATE_ADDRESS, + EFI_LOADER_DATA, nr_pages, + (efi_physical_addr_t *)reserve_addr); if (status != EFI_SUCCESS) { - pr_efi_err(sys_table, "Failed to relocate kernel\n"); - return status; + kernel_memsize += TEXT_OFFSET; + status = efi_low_alloc(sys_table_arg, kernel_memsize, + SZ_2M, reserve_addr); + + if (status != EFI_SUCCESS) { + pr_efi_err(sys_table_arg, "Failed to relocate kernel\n"); + return status; + } + *image_addr = *reserve_addr + TEXT_OFFSET; } - memcpy((void *)*reserve_addr + TEXT_OFFSET, (void *)*image_addr, - kernel_size); - *image_addr = *reserve_addr + TEXT_OFFSET; - *reserve_size = kernel_memsize + TEXT_OFFSET; + memcpy((void *)*image_addr, old_image_addr, kernel_size); + *reserve_size = kernel_memsize; } -- 2.11.0