Re: [PATCH 08/17] Generalize relocate_kernel() for use by otherarchitectures.

From: Matt Fleming
Date: Wed Sep 18 2013 - 08:12:48 EST


On Mon, 16 Sep, at 09:11:24PM, Roy Franz wrote:
> Rename relocate_kernel() to efi_relocate_kernel(), and take
> parameters rather than x86 specific structure. Add max_addr
> argument as for ARM we have some address constraints that we
> need to enforce when relocating the kernel. Add alloc_size
> parameter for use by ARM64 which uses an uncompressed kernel,
> and needs to allocate space for BSS.
>
> Signed-off-by: Roy Franz <roy.franz@xxxxxxxxxx>
> ---
> arch/x86/boot/compressed/eboot.c | 12 ++++--
> drivers/firmware/efi/efi-stub-helper.c | 74 ++++++++++++++++++++++----------
> 2 files changed, 60 insertions(+), 26 deletions(-)

This commit breaks my ASUS machine.

> - /*
> - * The EFI firmware loader could have placed the kernel image
> - * anywhere in memory, but the kernel has various restrictions
> - * on the max physical address it can run at. Attempt to move
> - * the kernel to boot_params.pref_address, or as low as
> - * possible.
> - */

[...]

> +
> + /* The EFI firmware loader could have placed the kernel image
> + * anywhere in memory, but the kernel has restrictions on the
> + * anywhere in memory, but the kernel has restrictions on the
> + * max physical address it can run at. Some architectures
> + * also have a prefered address, so first try to relocate
> + * to the preferred address.
> + */

Please don't change the comment style of code in the future.

> + nr_pages = round_up(alloc_size, EFI_PAGE_SIZE) / EFI_PAGE_SIZE;
> + status = efi_call_phys4(sys_table_arg->boottime->allocate_pages,
> EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
> - nr_pages, &start);
> + nr_pages, &efi_addr);
> + new_addr = efi_addr;
> + /* If preferred address allocation failed allocate as low as
> + * possible. */
> if (status != EFI_SUCCESS) {
> - status = efi_low_alloc(sys_table, hdr->init_size,
> - hdr->kernel_alignment, &start);
> - if (status != EFI_SUCCESS)
> - efi_printk(sys_table, "Failed to alloc mem for kernel\n");
> + status = efi_low_alloc(sys_table_arg, alloc_size, 0,
> + &new_addr);

This is wrong. You've dropped the hdr->kernel_alignment argument, and
the relaxed alignment of this allocation stops my machine from booting.

--
Matt Fleming, Intel Open Source Technology Center
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