Re: [PATCH v17 05/15] arm64: kexec: skip relocation code for inplace kexec
flat view
From: Will Deacon <will@kernel.org>
Date: 2021-09-29 12:13:46
Also in:
kexec, linux-mm, lkml
On Thu, Sep 16, 2021 at 07:13:15PM -0400, Pasha Tatashin wrote:
In case of kdump or when segments are already in place the relocation is not needed, therefore the setup of relocation function and call to it can be skipped. Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Suggested-by: James Morse <james.morse@arm.com> --- arch/arm64/kernel/machine_kexec.c | 34 ++++++++++++++++++----------- arch/arm64/kernel/relocate_kernel.S | 3 --- 2 files changed, 21 insertions(+), 16 deletions(-)
[...]
quoted hunk ↗ jump to hunk
@@ -188,19 +190,25 @@ void machine_kexec(struct kimage *kimage) local_daif_mask(); /* - * cpu_soft_restart will shutdown the MMU, disable data caches, then - * transfer control to the kern_reloc which contains a copy of - * the arm64_relocate_new_kernel routine. arm64_relocate_new_kernel - * 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. + * Both restart and cpu_soft_restart will shutdown the MMU, disable data + * caches. However, restart will start new kernel or purgatory directly, + * cpu_soft_restart will transfer control to arm64_relocate_new_kernel * 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->arch.kern_reloc, kimage->head, kimage->start, - kimage->arch.dtb_mem); + if (kimage->head & IND_DONE) { + typeof(__cpu_soft_restart) *restart; + + cpu_install_idmap(); + restart = (void *)__pa_symbol(function_nocfi(__cpu_soft_restart)); + restart(is_hyp_nvhe(), kimage->start, kimage->arch.dtb_mem, + 0, 0);
Why can't you call: cpu_soft_restart(kimage->start, kimage->arch.dtb_mem, 0, 0); here instead of open-coding it? Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel