On 14 July 2014 17:25, Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> wrote:
> If we fail to relocate the kernel Image to its preferred offset of TEXT_OFFSET
> bytes above the base of DRAM, accept the lowest alternative mapping available
> instead of aborting. 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@xxxxxxxxxx>
> ---
> This is a proposed bug fix for arm64 platforms that fail to boot through EFI
> due to the fact that some bits of EFI itself are occupying the low end of DRAM.
>
> Note that this code now triggers an 'unused function' warning for
> efi_relocate_kernel(), as that is no longer used. This warning will disappear
> automatically once the already queued up EFISTUB refactoring patches will
> get merged for 3.17.
>
> arch/arm64/kernel/efi-stub.c | 18 ++++++------------
> 1 file changed, 6 insertions(+), 12 deletions(-)
>
> diff --git a/arch/arm64/kernel/efi-stub.c b/arch/arm64/kernel/efi-stub.c
> index 60e98a639ac5..5165b3accefe 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);
> + 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;
This still needs a '+ TEXT_OFFSET' btw
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