On 05/08/15 at 08:19pm, Dave Young wrote: > Hi, > > On 04/24/15 at 04:53pm, AKASHI Takahiro wrote: > > Please read the following commits for arm64-specific constraints: > > arm64: kdump: reserve memory for crash dump kernel > > arm64: kdump: do not go into EL2 before starting a crash dump kernel > > > > Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org> > > --- > > Documentation/kdump/kdump.txt | 31 ++++++++++++++++++++++++++++++- > > arch/arm64/Kconfig | 12 ++++++++++++ > > 2 files changed, 42 insertions(+), 1 deletion(-) > > > > diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt > > index bc4bd5a..f9cf6f5 100644 > > --- a/Documentation/kdump/kdump.txt > > +++ b/Documentation/kdump/kdump.txt > > @@ -18,7 +18,7 @@ memory image to a dump file on the local disk, or across the network to > > a remote system. > > > > Kdump and kexec are currently supported on the x86, x86_64, ppc64, ia64, > > -s390x and arm architectures. > > +s390x, arm and arm64 architectures. > > > > When the system kernel boots, it reserves a small section of memory for > > the dump-capture kernel. This ensures that ongoing Direct Memory Access > > @@ -249,6 +249,29 @@ Dump-capture kernel config options (Arch Dependent, arm) > > > > AUTO_ZRELADDR=y > > > > +Dump-capture kernel config options (Arch Dependent, arm64) > > +---------------------------------------------------------- > > + > > +1) Disable symmetric multi-processing support under "Processor type and > > + features": > > + > > + CONFIG_SMP=n > > + > > + (If CONFIG_SMP=y, then specify maxcpus=1 on the kernel command line > > + when loading the dump-capture kernel, see section "Load the Dump-capture > > + Kernel".) > > + > > +2) Under uefi, the maximum memory size on the dump-capture kernel must be > > + limited by specifying: > > + > > + mem=X[MG] > > + > > + where X should be less than or equal to the size in "crashkernel=" > > + boot parameter. Kexec-tools will automatically add this. > > I noticed you are passing mem=X in kexec-tools, Pratyush found a problem > that vmcore is corrupted because kdump kernel is using the crash notes memory. > > How does kdump kernel know the system ram range especially the mem_start? > Only with the size from mem=? parammeter? > > In X86 because it use E820 so kexec-tools can pass the memory range to kdump > kernel even for UEFI booting. But in arm64 may need find other way to > communicate with 2nd kernel like memmap=exactmap in X86.. Discussed with Pratyush in irc, he mentioned that start address is get from kernel->entry which was passed by kexec-tools. So sorry for the noise, it will works fine with the UEFI mem= limitation fix from Mark Salter > > > + > > +3) Currently, kvm will not be initialized on the dump-capture kernel even > > + if it is configured. > > + > > Extended crashkernel syntax > > =========================== > > > > @@ -312,6 +335,7 @@ Boot into System Kernel > > any space below the alignment point may be overwritten by the dump-capture kernel, > > which means it is possible that the vmcore is not that precise as expected. > > > > + On arm64, use "crashkernel=Y at X". > > > > Load the Dump-capture Kernel > > ============================ > > @@ -334,6 +358,8 @@ For s390x: > > - Use image or bzImage > > For arm: > > - Use zImage > > +For arm64: > > + - Use vmlinux > > > > If you are using a uncompressed vmlinux image then use following command > > to load dump-capture kernel. > > @@ -377,6 +403,9 @@ For s390x: > > For arm: > > "1 maxcpus=1 reset_devices" > > > > +For arm64: > > + "1 maxcpus=1 mem=X[MG] reset_devices" > > + > > Notes on loading the dump-capture kernel: > > > > * By default, the ELF headers are stored in ELF64 format to support > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > > index 5716edf..8e2f545 100644 > > --- a/arch/arm64/Kconfig > > +++ b/arch/arm64/Kconfig > > @@ -562,6 +562,18 @@ config KEXEC > > but it is independent of the system firmware. And like a reboot > > you can start any kernel with it, not just Linux. > > > > +config CRASH_DUMP > > + bool "Build kdump crash kernel" > > + help > > + Generate crash dump after being started by kexec. This should > > + be normally only set in special crash dump kernels which are > > + loaded in the main kernel with kexec-tools into a specially > > + reserved region and then later executed after a crash by > > + kdump/kexec. The crash dump kernel must be compiled to a > > + memory address not used by the main kernel. > > + > > + For more details see Documentation/kdump/kdump.txt > > + > > config XEN_DOM0 > > def_bool y > > depends on XEN > > -- > > 1.7.9.5 > > > > > > _______________________________________________ > > kexec mailing list > > kexec at lists.infradead.org > > http://lists.infradead.org/mailman/listinfo/kexec > > > > > > _______________________________________________ > kexec mailing list > kexec at lists.infradead.org > http://lists.infradead.org/mailman/listinfo/kexec > >
