[PATCH 3/3] arm64/efi: efistub: don't abort if base of DRAM is occupied

[Mark Salter]

On Tue, 2014-07-29 at 12:49 +0200, Ard Biesheuvel wrote:
> If we cannot relocate the kernel Image to its preferred offset of base of DRAM
> plus TEXT_OFFSET, instead relocate it to the lowest available 2 MB boundary plus
> TEXT_OFFSET. We may lose a bit of memory at the low end, but we can still
> proceed normally otherwise.
> 
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>
> ---
>  arch/arm64/kernel/efi-stub.c | 16 ++++++----------
>  1 file changed, 6 insertions(+), 10 deletions(-)

Tested on Mustang (with loss of 2MB free memory).

> 
> diff --git a/arch/arm64/kernel/efi-stub.c b/arch/arm64/kernel/efi-stub.c
> index 60e98a639ac5..460c00c41e57 100644
> --- a/arch/arm64/kernel/efi-stub.c
> +++ b/arch/arm64/kernel/efi-stub.c
> @@ -60,20 +60,16 @@ static efi_status_t handle_kernel_image(efi_system_table_t *sys_table,
>  	kernel_size = _edata - _text;
>  	if (*image_addr != (dram_base + TEXT_OFFSET)) {
>  		kernel_memsize = kernel_size + (_end - _edata);
> -		status = efi_relocate_kernel(sys_table, image_addr,
> -					     kernel_size, kernel_memsize,
> -					     dram_base + TEXT_OFFSET,
> -					     PAGE_SIZE);

Can we make efi_relocate_kernel static inline to get rid
of the "defined but unused" warning?

Otherwise:

Acked-by: Mark Salter <msalter at redhat.com>

> +		status = efi_low_alloc(sys_table, kernel_memsize + TEXT_OFFSET,
> +				       SZ_2M, reserve_addr);
>  		if (status != EFI_SUCCESS) {
>  			pr_efi_err(sys_table, "Failed to relocate kernel\n");
>  			return status;
>  		}
> -		if (*image_addr != (dram_base + TEXT_OFFSET)) {
> -			pr_efi_err(sys_table, "Failed to alloc kernel memory\n");
> -			efi_free(sys_table, kernel_memsize, *image_addr);
> -			return EFI_ERROR;
> -		}
> -		*image_size = kernel_memsize;
> +		memcpy((void *)*reserve_addr + TEXT_OFFSET, (void *)*image_addr,
> +		       kernel_size);
> +		*image_addr = *reserve_addr + TEXT_OFFSET;
> +		*reserve_size = kernel_memsize + TEXT_OFFSET;
>  	}
>  
>