On Wed, Oct 14, 2015 at 04:13:47PM -0500, Jeremy Linton wrote:
> On 10/14/2015 06:20 AM, Suzuki K. Poulose wrote:
>
> >+ * Checks if the selected granule size is supported by the CPU.
> >+ * If it doesn't park the CPU
>
> The problem is when you park the boot CPU.
>
> I think for EFI there is a slightly better error mechanism. This
> tweak will print an error and return to the EFI boot manager rather
> than hanging the machine without any notification. Now it prints:
>
> EFI stub: Booting Linux Kernel...
> EFI stub: ERROR: 16K granule not supported by this machine
> EFI stub: ERROR: Failed to relocate kernel
> FS4:\>
Neat. We should definitely have checks like this in the stub.
However, we still need checks in head.S, given !EFI systems, SMP, and
kexec, so this is a complementary mechanism.
Thanks,
Mark.
> Signed-off-by: Jeremy Linton <jeremy.lin...@arm.com>
> ---
> arch/arm64/kernel/efi-stub.c | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
>
> diff --git a/arch/arm64/kernel/efi-stub.c b/arch/arm64/kernel/efi-stub.c
> index 816120e..90fb868 100644
> --- a/arch/arm64/kernel/efi-stub.c
> +++ b/arch/arm64/kernel/efi-stub.c
> @@ -25,6 +25,20 @@ efi_status_t __init
> handle_kernel_image(efi_system_table_t *sys_table_arg,
> unsigned long kernel_size, kernel_memsize = 0;
> unsigned long nr_pages;
> void *old_image_addr = (void *)*image_addr;
> + u32 aa64mmfr0_el1;
> +
> +#ifdef CONFIG_ARM64_16K_PAGES
> + /*
> + * check to see if this kernel image is
> + * compatible with the current system
> + */
> + asm volatile("mrs %0, ID_AA64MMFR0_EL1" : "=r" (aa64mmfr0_el1));
> + aa64mmfr0_el1 >>= ID_AA64MMFR0_TGRAN16_SHIFT;
> + if ((aa64mmfr0_el1 & ID_AA64MMFR0_TGRAN4_ON) == 0) {
> + pr_efi_err(sys_table_arg, "16K granule not supported
> by this machine\n");
> + return EFI_UNSUPPORTED;
> + }
> +#endif
>
> /* Relocate the image, if required. */
> kernel_size = _edata - _text;
> --
> 2.4.3
>
>
>
>
>
>
>
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