Re: [PATCH v12 13/16] arm64: kexec_file: invoke the kernel without purgatory
From: James Morse
Date: Thu Jul 26 2018 - 09:36:14 EST
On 24/07/18 07:57, AKASHI Takahiro wrote:
> On arm64, purgatory would do almost nothing. So just invoke secondary
> kernel directly by jumping into its entry code.
> While, in this case, cpu_soft_restart() must be called with dtb address
> in the fifth argument, the behavior still stays compatible with kexec_load
> case as long as the argument is null.
This patch conflicts with commit 76f4e2da45b4 ("arm64: kexec: always reset to
EL2 if present") in the arm64 tree.
> diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
> index f76ea92dff91..830a5063e09d 100644
> --- a/arch/arm64/kernel/machine_kexec.c
> +++ b/arch/arm64/kernel/machine_kexec.c
> @@ -205,10 +205,18 @@ void machine_kexec(struct kimage *kimage)
> * uses physical addressing to relocate the new image to its final
> * position and transfers control to the image entry point when the
> * relocation is complete.
> + * In kexec case, kimage->start points to purgatory assuming that
> + * kernel entry and dtb address are embedded in purgatory by
> + * userspace (kexec-tools).
> + * In kexec_file case, the kernel starts directly without purgatory.
> cpu_soft_restart(kimage != kexec_crash_image,
> - reboot_code_buffer_phys, kimage->head, kimage->start, 0);
> + reboot_code_buffer_phys, kimage->head, kimage->start,
> +#ifdef CONFIG_KEXEC_FILE
> + kimage->arch.dtb_mem);
> + 0);
> BUG(); /* Should never get here. */