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For fadump case, passing additional parameters to dump capture kernel
helps in minimizing the memory footprint for it and also provides the
flexibility to disable components/modules, like hugepages, that are
hindering the boot process of the special dump capture environment.
Set up a dedicated parameter area to be passed to the capture kernel.
This area type is defined as RTAS_FADUMP_PARAM_AREA. Sysfs attribute
'/sys/kernel/fadump/bootargs_append' is exported to the userspace to
specify the additional parameters to be passed to the capture kernel
Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20240509115755.519982-3-hbathini@linux.ibm.com
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Currently, fadump on pseries assumes a single boot memory region even
though f/w supports more than one boot memory region. Add support for
more boot memory regions to make the implementation flexible for any
enhancements that introduce other region types. For this, rtas memory
structure for fadump is updated to have multiple boot memory regions
instead of just one. Additionally, methods responsible for creating
the fadump memory structure during both the first and second kernel
boot have been modified to take these multiple boot memory regions
into account. Also, a new callback has been added to the fadump_ops
structure to get the maximum boot memory regions supported by the
platform.
Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com>
Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20240509115755.519982-2-hbathini@linux.ibm.com
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Due to changes in memory resources caused by either memory hotplug or
online/offline events, the elfcorehdr, which describes the CPUs and
memory of the crashed kernel to the kernel that collects the dump (known
as second/fadump kernel), becomes outdated. Consequently, attempting
dump collection with an outdated elfcorehdr can lead to failed or
inaccurate dump collection.
Memory hotplug or online/offline events is referred as memory add/remove
events in reset of the commit message.
The current solution to address the aforementioned issue is as follows:
Monitor memory add/remove events in userspace using udev rules, and
re-register fadump whenever there are changes in memory resources. This
leads to the creation of a new elfcorehdr with updated system memory
information.
There are several notable issues associated with re-registering fadump
for every memory add/remove events.
1. Bulk memory add/remove events with udev-based fadump re-registration
can lead to race conditions and, more importantly, it creates a wide
window during which fadump is inactive until all memory add/remove
events are settled.
2. Re-registering fadump for every memory add/remove event is
inefficient.
3. The memory for elfcorehdr is allocated based on the memblock regions
available during early boot and remains fixed thereafter. However, if
elfcorehdr is later recreated with additional memblock regions, its
size will increase, potentially leading to memory corruption.
Address the aforementioned challenges by shifting the creation of
elfcorehdr from the first kernel (also referred as the crashed kernel),
where it was created and frequently recreated for every memory
add/remove event, to the fadump kernel. As a result, the elfcorehdr only
needs to be created once, thus eliminating the necessity to re-register
fadump during memory add/remove events.
At present, the first kernel prepares fadump header and stores it in the
fadump reserved area. The fadump header includes the start address of
the elfcorehdr, crashing CPU details, and other relevant information. In
the event of a crash in the first kernel, the second/fadump boots and
accesses the fadump header prepared by the first kernel. It then
performs the following steps in a platform-specific function
[rtas|opal]_fadump_process:
1. Sanity check for fadump header
2. Update CPU notes in elfcorehdr
Along with the above, update the setup_fadump()/fadump.c to create
elfcorehdr and set its address to the global variable elfcorehdr_addr
for the vmcore module to process it in the second/fadump kernel.
Section below outlines the information required to create the elfcorehdr
and the changes made to make it available to the fadump kernel if it's
not already.
To create elfcorehdr, the following crashed kernel information is
required: CPU notes, vmcoreinfo, and memory ranges.
At present, the CPU notes are already prepared in the fadump kernel, so
no changes are needed in that regard. The fadump kernel has access to
all crashed kernel memory regions, including boot memory regions that
are relocated by firmware to fadump reserved areas, so no changes for
that either. However, it is necessary to add new members to the fadump
header, i.e., the 'fadump_crash_info_header' structure, in order to pass
the crashed kernel's vmcoreinfo address and its size to fadump kernel.
In addition to the vmcoreinfo address and size, there are a few other
attributes also added to the fadump_crash_info_header structure.
1. version:
It stores the fadump header version, which is currently set to 1.
This provides flexibility to update the fadump crash info header in
the future without changing the magic number. For each change in the
fadump header, the version will be increased. This will help the
updated kernel determine how to handle kernel dumps from older
kernels. The magic number remains relevant for checking fadump header
corruption.
2. pt_regs_sz/cpu_mask_sz:
Store size of pt_regs and cpu_mask structure of first kernel. These
attributes are used to prevent dump processing if the sizes of
pt_regs or cpu_mask structure differ between the first and fadump
kernels.
Note: if either first/crashed kernel or second/fadump kernel do not have
the changes introduced here then kernel fail to collect the dump and
prints relevant error message on the console.
Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20240422195932.1583833-2-sourabhjain@linux.ibm.com
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Don't inherit headers "by chances" from asm/prom.h, asm/mpc52xx.h,
asm/pci.h etc...
Include the needed headers, and remove asm/prom.h when it was
needed exclusively for pulling necessary headers.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/be8bdc934d152a7d8ee8d1a840d5596e2f7d85e0.1646767214.git.christophe.leroy@csgroup.eu
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Print preserved area start address in fadump_region_show() function.
Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220406093839.206608-4-hbathini@linux.ibm.com
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On crash, boot memory area is copied to a destination address by f/w.
This region is setup as separate PT_LOAD segment with appropriate
offset to handle the different physical address and offset in vmcore.
If this destination address is not page aligned, reading the vmcore
with mmap is likely to fail forcing tools like makedumpfile to fall
back to regular read. Avoid mmap read failure by ensuring that the
destination address is always page aligned.
Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220406093839.206608-3-hbathini@linux.ibm.com
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An LPAR can be terminated by the POWER Hypervisor (PHYP) for various
reasons. If FADump was configured when PHYP terminates the LPAR,
platform-assisted dump is initiated to save the kernel dump. But CPU
register data would not be processed/saved in the vmcore in such case
because CPU mask is set in crash_fadump() at the time of kernel crash
and it remains unset in this case with LPAR being terminated by PHYP
abruptly.
To get around the problem, initialize cpu_mask to cpu_possible_mask
so as to ensure all possible CPUs' register data is processed for the
vmcore generated on PHYP terminated LPAR. Also, rename the crash info
member variable from online_mask to cpu_mask as it doesn't necessarily
have to be online CPU mask always.
Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Reviewed-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220404182137.59231-1-hbathini@linux.ibm.com
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Some functions defined in 'arch/powerpc/platforms/pseries' are
deserving of an `__init` macro attribute. These functions are only
called by other initialization functions and therefore should inherit
the attribute.
Also, change function declarations in header files to include `__init`.
Signed-off-by: Nick Child <nick.child@ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211216220035.605465-13-nick.child@ibm.com
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Fix sparse warnings:
arch/powerpc/platforms/pseries/rtas-fadump.c:250:6: warning:
symbol 'rtas_fadump_set_regval' was not declared. Should it be static?
Signed-off-by: Pu Lehui <pulehui@huawei.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210408062012.85973-1-pulehui@huawei.com
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_ALIGN_DOWN() is specific to powerpc
ALIGN_DOWN() is generic and does the same
Replace _ALIGN_DOWN() by ALIGN_DOWN()
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Link: https://lore.kernel.org/r/3911a86d6b5bfa7ad88cd7c82416fbe6bb47e793.1587407777.git.christophe.leroy@c-s.fr
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With support to copy multiple kernel boot memory regions owing to copy
size limitation, also handle holes in the memory area to be preserved.
Support as many as 128 kernel boot memory regions. This allows having
an adequate FADump capture kernel size for different scenarios.
Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/156821385448.5656.6124791213910877759.stgit@hbathini.in.ibm.com
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RMA_START is defined as '0' and there is even a BUILD_BUG_ON() to
make sure it is never anything else. Remove this macro and use '0'
instead as code change is needed anyway when it has to be something
else. Also, remove unused RMA_END macro.
Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/156821384096.5656.15026984053970204652.stgit@hbathini.in.ibm.com
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OPAL loads kernel & initrd at 512MB offset (256MB size), also exported
as ibm,opal/dump/fw-load-area. So, if boot memory size of FADump is
less than 768MB, kernel memory to be exported as '/proc/vmcore' would
be overwritten by f/w while loading kernel & initrd. To avoid such a
scenario, enforce a minimum boot memory size of 768MB on OPAL platform
and skip using FADump if a newer F/W version loads kernel & initrd
above 768MB.
Also, irrespective of RMA size, set the minimum boot memory size
expected on pseries platform at 320MB. This is to avoid inflating the
minimum memory requirements on systems with 512M/1024M RMA size.
Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/156821381414.5656.1592867278535469652.stgit@hbathini.in.ibm.com
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Move code that supports processing the crash'ed kernel's memory
preserved by firmware to platform specific callback functions.
Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/156821337690.5656.13050665924800177744.stgit@hbathini.in.ibm.com
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Improve how fadump_region contents are displayed by adding source
information of memory regions that are to be dumped by f/w.
Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/156821334740.5656.5897097884010195405.stgit@hbathini.in.ibm.com
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Move platform specific register/un-register code, the RTAS calls, to
register/un-register callback functions. This would also mean moving
code that initializes and prints the platform specific FADump data.
Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Reviewed-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/156821332856.5656.16380417702046411631.stgit@hbathini.in.ibm.com
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Introduce callback functions for platform specific operations like
register, unregister, invalidate & such. Also, define place-holders
for the same on pSeries platform.
Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/156821330286.5656.15538934400074110770.stgit@hbathini.in.ibm.com
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