From mboxrd@z Thu Jan 1 00:00:00 1970 From: asamson@codeaurora.org (Azriel Samson) Date: Fri, 4 Dec 2015 14:53:38 -0700 Subject: ARM64 kexec/kdump timeline In-Reply-To: References: <555E37FC.9020800@codeaurora.org> <1432239334.1922.7.camel@infradead.org> <55653538.8020206@codeaurora.org> <2420285.dn5MbvMKXS@wuerfel> <55664FD9.1090808@codeaurora.org> <556BFAD1.7010907@redhat.com> Message-ID: <56620B62.5060800@codeaurora.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi, On 7/13/2015 3:03 AM, AKASHI, Takahiro wrote: > Sorry for not replying soon. > > On 9 July 2015 at 08:03, Azriel Samson > wrote: > > > > Hi, > > > > When booting the crash kernel with ACPI, how do you ensure that the ACPI > > tables fall within the kernel's memmap region? > > I was able to boot with ACPI when the crash kernel's memory overlapped > > with the ACPI tables(based on the "crashkernel" and "mem" boot > arguments). > > I don't think this is a right way to use kdump in ACPI environment on arm64 > because "mem" parameter only limits the maximum size of usable memory > and so the crash dump data (/proc/vmcore) can get easily corrupted if > the reserved > memory region that the crash dump kernel can use also contains any > portion of > memory which belong to the crashed kernel. > > In the current implementation of arm64 kdump, kexec command manages to > exclude such memory regions by modifying the device tree passed on to > the crash dump kernel. > > > Is there a better way to make the ACPI tables available to the crash > kernel? > > So ACPI tables is not the only problem. > x86 seems to use "memmap" kernel parameter instead.(?) I was able to test kdump with the following patch from Mark Salter which is needed for supporting ACPI tables that lie outside of kernel RAM: https://git.fedorahosted.org/cgit/kernel-arm64.git/commit/?h=devel&id=a75bcec5679a2ff82f23c5cc335c77da158a6dc5 > > Thanks, > -Takahiro AKASHI > -- Thanks, Azriel Samson Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project