Commit d68b4b6f authored by Linus Torvalds's avatar Linus Torvalds
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Merge tag 'mm-nonmm-stable-2023-08-28-22-48' of... 

Merge tag 'mm-nonmm-stable-2023-08-28-22-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull non-MM updates from Andrew Morton:

 - An extensive rework of kexec and crash Kconfig from Eric DeVolder
   ("refactor Kconfig to consolidate KEXEC and CRASH options")

 - kernel.h slimming work from Andy Shevchenko ("kernel.h: Split out a
   couple of macros to args.h")

 - gdb feature work from Kuan-Ying Lee ("Add GDB memory helper
   commands")

 - vsprintf inclusion rationalization from Andy Shevchenko
   ("lib/vsprintf: Rework header inclusions")

 - Switch the handling of kdump from a udev scheme to in-kernel
   handling, by Eric DeVolder ("crash: Kernel handling of CPU and memory
   hot un/plug")

 - Many singleton patches to various parts of the tree

* tag 'mm-nonmm-stable-2023-08-28-22-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (81 commits)
  document while_each_thread(), change first_tid() to use for_each_thread()
  drivers/char/mem.c: shrink character device's devlist[] array
  x86/crash: optimize CPU changes
  crash: change crash_prepare_elf64_headers() to for_each_possible_cpu()
  crash: hotplug support for kexec_load()
  x86/crash: add x86 crash hotplug support
  crash: memory and CPU hotplug sysfs attributes
  kexec: exclude elfcorehdr from the segment digest
  crash: add generic infrastructure for crash hotplug support
  crash: move a few code bits to setup support of crash hotplug
  kstrtox: consistently use _tolower()
  kill do_each_thread()
  nilfs2: fix WARNING in mark_buffer_dirty due to discarded buffer reuse
  scripts/bloat-o-meter: count weak symbol sizes
  treewide: drop CONFIG_EMBEDDED
  lockdep: fix static memory detection even more
  lib/vsprintf: declare no_hash_pointers in sprintf.h
  lib/vsprintf: split out sprintf() and friends
  kernel/fork: stop playing lockless games for exe_file replacement
  adfs: delete unused "union adfs_dirtail" definition
  ...
parents b96a3e91 dce8f8ed

Documentation/ABI/testing/sysfs-devices-memory

+8 −0
Original line number Diff line number Diff line
@@ -110,3 +110,11 @@ Description: 
		link is created for memory section 9 on node0.



		/sys/devices/system/node/node0/memory9 -> ../../memory/memory9



What:		/sys/devices/system/memory/crash_hotplug

Date:		Aug 2023

Contact:	Linux kernel mailing list <linux-kernel@vger.kernel.org>

Description:

		(RO) indicates whether or not the kernel directly supports

		modifying the crash elfcorehdr for memory hot un/plug and/or

		on/offline changes.

Documentation/ABI/testing/sysfs-devices-system-cpu

+8 −0
Original line number Diff line number Diff line
@@ -688,3 +688,11 @@ Description: 
		(RO) the list of CPUs that are isolated and don't

		participate in load balancing. These CPUs are set by

		boot parameter "isolcpus=".



What:		/sys/devices/system/cpu/crash_hotplug

Date:		Aug 2023

Contact:	Linux kernel mailing list <linux-kernel@vger.kernel.org>

Description:

		(RO) indicates whether or not the kernel directly supports

		modifying the crash elfcorehdr for CPU hot un/plug and/or

		on/offline changes.

Documentation/admin-guide/mm/memory-hotplug.rst

+8 −0
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@@ -291,6 +291,14 @@ The following files are currently defined: 
		       Availability depends on the CONFIG_ARCH_MEMORY_PROBE

		       kernel configuration option.

``uevent``	       read-write: generic udev file for device subsystems.

``crash_hotplug``      read-only: when changes to the system memory map

		       occur due to hot un/plug of memory, this file contains

		       '1' if the kernel updates the kdump capture kernel memory

		       map itself (via elfcorehdr), or '0' if userspace must update

		       the kdump capture kernel memory map.



		       Availability depends on the CONFIG_MEMORY_HOTPLUG kernel

		       configuration option.

====================== =========================================================



.. note::

Documentation/core-api/cpu_hotplug.rst

+18 −0
Original line number Diff line number Diff line
@@ -741,6 +741,24 @@ will receive all events. A script like:: 


can process the event further.



When changes to the CPUs in the system occur, the sysfs file

/sys/devices/system/cpu/crash_hotplug contains '1' if the kernel

updates the kdump capture kernel list of CPUs itself (via elfcorehdr),

or '0' if userspace must update the kdump capture kernel list of CPUs.



The availability depends on the CONFIG_HOTPLUG_CPU kernel configuration

option.



To skip userspace processing of CPU hot un/plug events for kdump

(i.e. the unload-then-reload to obtain a current list of CPUs), this sysfs

file can be used in a udev rule as follows:



 SUBSYSTEM=="cpu", ATTRS{crash_hotplug}=="1", GOTO="kdump_reload_end"



For a CPU hot un/plug event, if the architecture supports kernel updates

of the elfcorehdr (which contains the list of CPUs), then the rule skips

the unload-then-reload of the kdump capture kernel.



Kernel Inline Documentations Reference

======================================

arch/Kconfig

+3 −14
Original line number Diff line number Diff line
@@ -11,19 +11,6 @@ source "arch/$(SRCARCH)/Kconfig" 


menu "General architecture-dependent options"



config CRASH_CORE

	bool



config KEXEC_CORE

	select CRASH_CORE

	bool



config KEXEC_ELF

	bool



config HAVE_IMA_KEXEC

	bool



config ARCH_HAS_SUBPAGE_FAULTS

	bool

	help
@@ -748,7 +735,9 @@ config HAS_LTO_CLANG 
	depends on $(success,$(AR) --help | head -n 1 | grep -qi llvm)

	depends on ARCH_SUPPORTS_LTO_CLANG

	depends on !FTRACE_MCOUNT_USE_RECORDMCOUNT

	depends on !KASAN || KASAN_HW_TAGS

	# https://github.com/ClangBuiltLinux/linux/issues/1721

	depends on (!KASAN || KASAN_HW_TAGS || CLANG_VERSION >= 170000) || !DEBUG_INFO

	depends on (!KCOV || CLANG_VERSION >= 170000) || !DEBUG_INFO

	depends on !GCOV_KERNEL

	help

	  The compiler and Kconfig options support building with Clang's