From mboxrd@z Thu Jan 1 00:00:00 1970 From: takahiro.akashi@linaro.org (AKASHI Takahiro) Date: Fri, 27 Jul 2018 16:22:43 +0900 Subject: [PATCH v12 13/16] arm64: kexec_file: invoke the kernel without purgatory In-Reply-To: References: <20180724065759.19186-1-takahiro.akashi@linaro.org> <20180724065759.19186-14-takahiro.akashi@linaro.org> Message-ID: <20180727072242.GH11258@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thu, Jul 26, 2018 at 02:36:07PM +0100, James Morse wrote: > Hi Akashi, > > 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. I haven't noticed Mark's patch. I'm going to have to refresh my memory regarding why I introduced el2_switch when I implemented kdump. According to my current memory, however, I added kvm_arch_hardware_enable/disable(), and associated functions, to gracefully shutdown EL2 in case of kexec. Since we have no chance to call reset function (via notifier) at kdump, I believed that el2_switch was necessary for better chance of successful kdump. Thanks, -Takahiro AKASHI > Thanks, > > James > > > 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); > > +#else > > + 0); > > +#endif > > > > BUG(); /* Should never get here. */ > > }