4f5aecdff2
As mentioned in kernel commit1d50e5d0c5("crash_core, vmcoreinfo: Append 'MAX_PHYSMEM_BITS' to vmcoreinfo"), SECTION_SIZE_BITS in the formula: #define SECTIONS_SHIFT (MAX_PHYSMEM_BITS - SECTION_SIZE_BITS) Besides SECTIONS_SHIFT, SECTION_SIZE_BITS is also used to calculate PAGES_PER_SECTION in makedumpfile just like kernel. Unfortunately, this arch-dependent macro SECTION_SIZE_BITS changes, e.g. recently in kernel commitf0b13ee232("arm64/sparsemem: reduce SECTION_SIZE_BITS"). But user space wants a stable interface to get this info. Such info is impossible to be deduced from a crashdump vmcore. Hence append SECTION_SIZE_BITS to vmcoreinfo. Link: https://lkml.kernel.org/r/20210608103359.84907-1-kernelfans@gmail.com Link: http://lists.infradead.org/pipermail/kexec/2021-June/022676.html Signed-off-by: Pingfan Liu <kernelfans@gmail.com> Acked-by: Baoquan He <bhe@redhat.com> Cc: Bhupesh Sharma <bhupesh.sharma@linaro.org> Cc: Kazuhito Hagio <k-hagio@ab.jp.nec.com> Cc: Dave Young <dyoung@redhat.com> Cc: Boris Petkov <bp@alien8.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: James Morse <james.morse@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Dave Anderson <anderson@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.