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While setting up the FDT for kexec, CPU nodes that are added after the
system boots and reserved memory ranges are incorporated into the
initial_boot_params (base FDT).
However, they are not taken into account when determining the additional
size needed for the kexec FDT. As a result, kexec fails to load,
generating the following error:
[1116.774451] Error updating memory reserve map: FDT_ERR_NOSPACE
kexec_file_load failed: No such process
Therefore, consider the extra size for CPU nodes added post-system boot
and reserved memory ranges while preparing the kexec FDT.
While adding a new parameter to the setup_new_fdt_ppc64 function, it was
noticed that there were a couple of unused parameters, so they were
removed.
Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20240510102235.2269496-2-sourabhjain@linux.ibm.com
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Due to CPU/Memory hotplug or online/offline events, the elfcorehdr
(which describes the CPUs and memory of the crashed kernel) and FDT
(Flattened Device Tree) of kdump image becomes outdated. Consequently,
attempting dump collection with an outdated elfcorehdr or FDT can lead
to failed or inaccurate dump collection.
Going forward, CPU hotplug or online/offline events are referred as
CPU/Memory add/remove events.
The current solution to address the above issue involves monitoring the
CPU/Memory add/remove events in userspace using udev rules and whenever
there are changes in CPU and memory resources, the entire kdump image
is loaded again. The kdump image includes kernel, initrd, elfcorehdr,
FDT, purgatory. Given that only elfcorehdr and FDT get outdated due to
CPU/Memory add/remove events, reloading the entire kdump image is
inefficient. More importantly, kdump remains inactive for a substantial
amount of time until the kdump reload completes.
To address the aforementioned issue, commit 247262756121 ("crash: add
generic infrastructure for crash hotplug support") added a generic
infrastructure that allows architectures to selectively update the kdump
image component during CPU or memory add/remove events within the kernel
itself.
In the event of a CPU or memory add/remove events, the generic crash
hotplug event handler, `crash_handle_hotplug_event()`, is triggered. It
then acquires the necessary locks to update the kdump image and invokes
the architecture-specific crash hotplug handler,
`arch_crash_handle_hotplug_event()`, to update the required kdump image
components.
This patch adds crash hotplug handler for PowerPC and enable support to
update the kdump image on CPU add/remove events. Support for memory
add/remove events is added in a subsequent patch with the title
"powerpc: add crash memory hotplug support"
As mentioned earlier, only the elfcorehdr and FDT kdump image components
need to be updated in the event of CPU or memory add/remove events.
However, on PowerPC architecture crash hotplug handler only updates the
FDT to enable crash hotplug support for CPU add/remove events. Here's
why.
The elfcorehdr on PowerPC is built with possible CPUs, and thus, it does
not need an update on CPU add/remove events. On the other hand, the FDT
needs to be updated on CPU add events to include the newly added CPU. If
the FDT is not updated and the kernel crashes on a newly added CPU, the
kdump kernel will fail to boot due to the unavailability of the crashing
CPU in the FDT. During the early boot, it is expected that the boot CPU
must be a part of the FDT; otherwise, the kernel will raise a BUG and
fail to boot. For more information, refer to commit 36ae37e3436b0
("powerpc: Make boot_cpuid common between 32 and 64-bit"). Since it is
okay to have an offline CPU in the kdump FDT, no action is taken in case
of CPU removal.
There are two system calls, `kexec_file_load` and `kexec_load`, used to
load the kdump image. Few changes have been made to ensure kernel can
safely update the FDT of kdump image loaded using both system calls.
For kexec_file_load syscall the kdump image is prepared in kernel. So to
support an increasing number of CPUs, the FDT is constructed with extra
buffer space to ensure it can accommodate a possible number of CPU
nodes. Additionally, a call to fdt_pack (which trims the unused space
once the FDT is prepared) is avoided if this feature is enabled.
For the kexec_load syscall, the FDT is updated only if the
KEXEC_CRASH_HOTPLUG_SUPPORT kexec flag is passed to the kernel by
userspace (kexec tools). When userspace passes this flag to the kernel,
it indicates that the FDT is built to accommodate possible CPUs, and the
FDT segment is excluded from SHA calculation, making it safe to update.
The changes related to this feature are kept under the CRASH_HOTPLUG
config, and it is enabled by default.
Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com>
Acked-by: Hari Bathini <hbathini@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20240326055413.186534-6-sourabhjain@linux.ibm.com
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CONFIG_KEXEC_FILE does not have to select CONFIG_CRASH_DUMP. Move
some code under CONFIG_CRASH_DUMP to support CONFIG_KEXEC_FILE and
!CONFIG_CRASH_DUMP case.
Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20240226103010.589537-3-hbathini@linux.ibm.com
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Then when specifying '-d' for kexec_file_load interface, loaded locations
of kernel/initrd/cmdline etc can be printed out to help debug.
Here replace pr_debug() with the newly added kexec_dprintk() in kexec_file
loading related codes.
Link: https://lkml.kernel.org/r/20231213055747.61826-7-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Conor Dooley <conor@kernel.org>
Cc: Joe Perches <joe@perches.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Uninitialized local variable "elf_info" would be passed to
kexec_free_elf_info() if kexec_build_elf_info() returns an error
in elf64_load().
If kexec_build_elf_info() returns an error, return the error
immediately.
Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210421163610.23775-2-nramas@linux.microsoft.com
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There are a few "goto out;" statements before the local variable "fdt"
is initialized through the call to of_kexec_alloc_and_setup_fdt() in
elf64_load(). This will result in an uninitialized "fdt" being passed
to kvfree() in this function if there is an error before the call to
of_kexec_alloc_and_setup_fdt().
If there is any error after fdt is allocated, but before it is
saved in the arch specific kimage struct, free the fdt.
Fixes: 3c985d31ad66 ("powerpc: Use common of_kexec_alloc_and_setup_fdt()")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210421163610.23775-1-nramas@linux.microsoft.com
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kexec_fdt_totalsize_ppc64() includes the base FDT size in its size
calculation, but commit 3c985d31ad66 ("powerpc: Use common
of_kexec_alloc_and_setup_fdt()") changed the kexec code to use the
generic function of_kexec_alloc_and_setup_fdt() which already includes
the base FDT size. That change made the code overestimate the size a bit
by counting twice the space required for the kernel command line and
/chosen properties.
Therefore change kexec_fdt_totalsize_ppc64() to calculate just the extra
space needed by the kdump kernel, and change the function name so that it
better reflects what the function is now doing.
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Reviewed-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Reviewed-by: Hari Bathini <hbathini@linux.ibm.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
[robh: reword commit msg as no longer a fix from merging to branches]
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210220005204.1417200-1-bauerman@linux.ibm.com
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The code for setting up the /chosen node in the device tree
and updating the memory reservation for the next kernel has been
moved to of_kexec_alloc_and_setup_fdt() defined in "drivers/of/kexec.c".
Use the common of_kexec_alloc_and_setup_fdt() to setup the device tree
and update the memory reservation for kexec for powerpc.
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210221174930.27324-8-nramas@linux.microsoft.com
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On systems with large amount of memory, loading kdump kernel through
kexec_file_load syscall may fail with the below error:
"Failed to update fdt with linux,drconf-usable-memory property"
This happens because the size estimation for kdump kernel's FDT does
not account for the additional space needed to setup usable memory
properties. Fix it by accounting for the space needed to include
linux,usable-memory & linux,drconf-usable-memory properties while
estimating kdump kernel's FDT size.
Fixes: 6ecd0163d360 ("powerpc/kexec_file: Add appropriate regions for memory reserve map")
Cc: stable@vger.kernel.org # v5.9+
Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/161243826811.119001.14083048209224609814.stgit@hbathini
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Prepare elf headers for the crashing kernel's core file using
crash_prepare_elf64_headers() and pass on this info to kdump kernel by
updating its command line with elfcorehdr parameter. Also, add
elfcorehdr location to reserve map to avoid it from being stomped on
while booting.
Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Tested-by: Pingfan Liu <piliu@redhat.com>
Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
[mpe: Ensure cmdline is nul terminated]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/159602298855.575379.15819225623219909517.stgit@hbathini
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Though kdump kernel boots from loaded address, the first 64KB of it is
copied down to real 0. So, setup a backup region and let purgatory
copy the first 64KB of crashed kernel into this backup region before
booting into kdump kernel. Update reserve map with backup region and
crashed kernel's memory to avoid kdump kernel from accidentially using
that memory.
Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/159602294718.575379.16216507537038008623.stgit@hbathini
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crashkernel region could have an overlap with special memory regions
like OPAL, RTAS, TCE table & such. These regions are referred to as
excluded memory ranges. Setup these ranges during image probe in order
to avoid them while finding the buffer for different kdump segments.
Override arch_kexec_locate_mem_hole() to locate a memory hole taking
these ranges into account.
Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/159602281047.575379.6636807148335160795.stgit@hbathini
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Some of the kexec_file_load code isn't PPC64 specific. Move PPC64
specific code from kexec/file_load.c to kexec/file_load_64.c. Also,
rename purgatory/trampoline.S to purgatory/trampoline_64.S in the same
spirit. No functional changes.
Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Tested-by: Pingfan Liu <piliu@redhat.com>
Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com>
Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/159602276920.575379.10390965946438306388.stgit@hbathini
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arch/powerpc/kernel/ contains 8 files dedicated to kexec.
Move them into a dedicated subdirectory.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
[mpe: Move to a/p/kexec, drop the 'machine' naming and use 'core' instead]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/afbef97ec6a978574a5cf91a4441000e0a9da42a.1572351221.git.christophe.leroy@c-s.fr
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