From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Message-ID: <57DC18FC.9000807@arm.com> Date: Fri, 16 Sep 2016 17:08:28 +0100 From: James Morse MIME-Version: 1.0 Subject: Re: [PATCH v26 6/7] arm64: kdump: update a kernel doc References: <20160907042908.6232-1-takahiro.akashi@linaro.org> <20160907042908.6232-7-takahiro.akashi@linaro.org> In-Reply-To: <20160907042908.6232-7-takahiro.akashi@linaro.org> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: AKASHI Takahiro Cc: mark.rutland@arm.com, geoff@infradead.org, catalin.marinas@arm.com, will.deacon@arm.com, bauerman@linux.vnet.ibm.com, dyoung@redhat.com, kexec@lists.infradead.org, linux-arm-kernel@lists.infradead.org Hi Akashi, On 07/09/16 05:29, AKASHI Takahiro wrote: > This patch adds arch specific descriptions about kdump usage on arm64 > to kdump.txt. > diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt > @@ -249,6 +249,13 @@ Dump-capture kernel config options (Arch Dependent, arm) > > AUTO_ZRELADDR=y > > +Dump-capture kernel config options (Arch Dependent, arm64) > +---------------------------------------------------------- > + > +- Please note that kvm of the dump-capture kernel will not be enabled > + on non-VHE systems even if it is configured. This is because the CPU > + cannot be reset to EL2 on panic. Nit: cannot be -> will not be We could try to do this, but its more code that could prevent us reaching the kdump kernel, so we choose not to. > @@ -370,6 +381,9 @@ For s390x: > For arm: > "1 maxcpus=1 reset_devices" > > +For arm64: > + "1 maxcpus=1 reset_devices" > + 'maxcpus=1' is a bit fragile. Since 44dbcc93ab67145 ("arm64: Fix behavior of maxcpus=N") udev on ubuntu vivid (running on Juno) has taken it upon itself to bring the secondary cores online, even when booted with 'maxcpus=1'. Can we change the recomendation to "1 nosmp reset_devices"? Thanks, James _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec From mboxrd@z Thu Jan 1 00:00:00 1970 From: james.morse@arm.com (James Morse) Date: Fri, 16 Sep 2016 17:08:28 +0100 Subject: [PATCH v26 6/7] arm64: kdump: update a kernel doc In-Reply-To: <20160907042908.6232-7-takahiro.akashi@linaro.org> References: <20160907042908.6232-1-takahiro.akashi@linaro.org> <20160907042908.6232-7-takahiro.akashi@linaro.org> Message-ID: <57DC18FC.9000807@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Akashi, On 07/09/16 05:29, AKASHI Takahiro wrote: > This patch adds arch specific descriptions about kdump usage on arm64 > to kdump.txt. > diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt > @@ -249,6 +249,13 @@ Dump-capture kernel config options (Arch Dependent, arm) > > AUTO_ZRELADDR=y > > +Dump-capture kernel config options (Arch Dependent, arm64) > +---------------------------------------------------------- > + > +- Please note that kvm of the dump-capture kernel will not be enabled > + on non-VHE systems even if it is configured. This is because the CPU > + cannot be reset to EL2 on panic. Nit: cannot be -> will not be We could try to do this, but its more code that could prevent us reaching the kdump kernel, so we choose not to. > @@ -370,6 +381,9 @@ For s390x: > For arm: > "1 maxcpus=1 reset_devices" > > +For arm64: > + "1 maxcpus=1 reset_devices" > + 'maxcpus=1' is a bit fragile. Since 44dbcc93ab67145 ("arm64: Fix behavior of maxcpus=N") udev on ubuntu vivid (running on Juno) has taken it upon itself to bring the secondary cores online, even when booted with 'maxcpus=1'. Can we change the recomendation to "1 nosmp reset_devices"? Thanks, James