linux.git/arch/arm/kernel/setup.c, branch v6.18.21

Add a new optional ",cma" suffix to the crashkernel= command line option

2025-07-20T02:08:22+00:00

Patch series "kdump: crashkernel reservation from CMA", v5.

This series implements a way to reserve additional crash kernel memory
using CMA.

Currently, all the memory for the crash kernel is not usable by the 1st
(production) kernel.  It is also unmapped so that it can't be corrupted by
the fault that will eventually trigger the crash.  This makes sense for
the memory actually used by the kexec-loaded crash kernel image and initrd
and the data prepared during the load (vmcoreinfo, ...).  However, the
reserved space needs to be much larger than that to provide enough
run-time memory for the crash kernel and the kdump userspace.  Estimating
the amount of memory to reserve is difficult.  Being too careful makes
kdump likely to end in OOM, being too generous takes even more memory from
the production system.  Also, the reservation only allows reserving a
single contiguous block (or two with the "low" suffix).  I've seen systems
where this fails because the physical memory is fragmented.

By reserving additional crashkernel memory from CMA, the main crashkernel
reservation can be just large enough to fit the kernel and initrd image,
minimizing the memory taken away from the production system.  Most of the
run-time memory for the crash kernel will be memory previously available
to userspace in the production system.  As this memory is no longer
wasted, the reservation can be done with a generous margin, making kdump
more reliable.  Kernel memory that we need to preserve for dumping is
normally not allocated from CMA, unless it is explicitly allocated as
movable.  Currently this is only the case for memory ballooning and zswap.
Such movable memory will be missing from the vmcore.  User data is
typically not dumped by makedumpfile.  When dumping of user data is
intended this new CMA reservation cannot be used.

There are five patches in this series:

The first adds a new ",cma" suffix to the recenly introduced generic
crashkernel parsing code.  parse_crashkernel() takes one more argument to
store the cma reservation size.

The second patch implements reserve_crashkernel_cma() which performs the
reservation.  If the requested size is not available in a single range,
multiple smaller ranges will be reserved.

The third patch updates Documentation/, explicitly mentioning the
potential DMA corruption of the CMA-reserved memory.

The fourth patch adds a short delay before booting the kdump kernel,
allowing pending DMA transfers to finish.

The fifth patch enables the functionality for x86 as a proof of
concept. There are just three things every arch needs to do:
- call reserve_crashkernel_cma()
- include the CMA-reserved ranges in the physical memory map
- exclude the CMA-reserved ranges from the memory available
  through /proc/vmcore by excluding them from the vmcoreinfo
  PT_LOAD ranges.

Adding other architectures is easy and I can do that as soon as this
series is merged.

With this series applied, specifying
	crashkernel=100M craskhernel=1G,cma
on the command line will make a standard crashkernel reservation
of 100M, where kexec will load the kernel and initrd.

An additional 1G will be reserved from CMA, still usable by the production
system.  The crash kernel will have 1.1G memory available.  The 100M can
be reliably predicted based on the size of the kernel and initrd.

The new cma suffix is completely optional. When no
crashkernel=size,cma is specified, everything works as before.


This patch (of 5):

Add a new cma_size parameter to parse_crashkernel().  When not NULL, call
__parse_crashkernel to parse the CMA reservation size from
"crashkernel=size,cma" and store it in cma_size.

Set cma_size to NULL in all calls to parse_crashkernel().

Link: https://lkml.kernel.org/r/aEqnxxfLZMllMC8I@dwarf.suse.cz
Link: https://lkml.kernel.org/r/aEqoQckgoTQNULnh@dwarf.suse.cz
Signed-off-by: Jiri Bohac 
Cc: Baoquan He 
Cc: Dave Young 
Cc: Donald Dutile 
Cc: Michal Hocko 
Cc: Philipp Rudo 
Cc: Pingfan Liu 
Cc: Tao Liu 
Cc: Vivek Goyal 
Cc: David Hildenbrand 
Signed-off-by: Andrew Morton

mm/memblock: add memblock_alloc_or_panic interface

2025-01-26T04:22:38+00:00

Before SLUB initialization, various subsystems used memblock_alloc to
allocate memory.  In most cases, when memory allocation fails, an
immediate panic is required.  To simplify this behavior and reduce
repetitive checks, introduce `memblock_alloc_or_panic`.  This function
ensures that memory allocation failures result in a panic automatically,
improving code readability and consistency across subsystems that require
this behavior.

[guoweikang.kernel@gmail.com: arch/s390: save_area_alloc default failure behavior changed to panic]
  Link: https://lkml.kernel.org/r/20250109033136.2845676-1-guoweikang.kernel@gmail.com
  Link: https://lore.kernel.org/lkml/Z2fknmnNtiZbCc7x@kernel.org/
Link: https://lkml.kernel.org/r/20250102072528.650926-1-guoweikang.kernel@gmail.com
Signed-off-by: Guo Weikang 
Acked-by: Geert Uytterhoeven 	[m68k]
Reviewed-by: Alexander Gordeev 	[s390]
Acked-by: Mike Rapoport (Microsoft) 
Cc: Alexander Gordeev 
Signed-off-by: Andrew Morton

ARM: 9412/1: Convert to arch_cpu_is_hotpluggable()

2024-08-20T10:18:50+00:00

Convert arm32 to use the arch_cpu_is_hotpluggable() helper rather than
arch_register_cpu().

Signed-off-by: Jinjie Ruan 
Signed-off-by: Russell King (Oracle)

ARM: 9411/1: Switch over to GENERIC_CPU_DEVICES using arch_register_cpu()

2024-08-20T10:18:49+00:00

Currently, almost all architectures have switched to GENERIC_CPU_DEVICES,
except for arm32. Also switch over to GENERIC_CPU_DEVICES, and provide an
arch_register_cpu() that populates the hotpluggable flag for arm32.

The struct cpu in struct cpuinfo_arm is never used directly, remove
it to use the one GENERIC_CPU_DEVICES provides.

This also has the effect of moving the registration of CPUs from subsys to
driver core initialisation, prior to any initcalls running.

Signed-off-by: Jinjie Ruan 
Signed-off-by: Russell King (Oracle)

arm, crash: wrap crash dumping code into crash related ifdefs

2024-02-24T01:48:24+00:00

Now crash codes under kernel/ folder has been split out from kexec
code, crash dumping can be separated from kexec reboot in config
items on arm with some adjustments.

Here use CONFIG_CRASH_RESERVE ifdef to replace CONFIG_KEXEC ifdef.

Link: https://lkml.kernel.org/r/20240124051254.67105-14-bhe@redhat.com
Signed-off-by: Baoquan He 
Cc: Al Viro 
Cc: Eric W. Biederman 
Cc: Hari Bathini 
Cc: Pingfan Liu 
Cc: Klara Modin 
Cc: Michael Kelley 
Cc: Nathan Chancellor 
Cc: Stephen Rothwell 
Cc: Yang Li 
Signed-off-by: Andrew Morton

Merge tag 'tty-6.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

2023-11-04T01:44:25+00:00

Pull tty and serial updates from Greg KH:
 "Here is the big set of tty/serial driver changes for 6.7-rc1. Included
  in here are:

   - console/vgacon cleanups and removals from Arnd

   - tty core and n_tty cleanups from Jiri

   - lots of 8250 driver updates and cleanups

   - sc16is7xx serial driver updates

   - dt binding updates

   - first set of port lock wrapers from Thomas for the printk fixes
     coming in future releases

   - other small serial and tty core cleanups and updates

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'tty-6.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (193 commits)
  serdev: Replace custom code with device_match_acpi_handle()
  serdev: Simplify devm_serdev_device_open() function
  serdev: Make use of device_set_node()
  tty: n_gsm: add copyright Siemens Mobility GmbH
  tty: n_gsm: fix race condition in status line change on dead connections
  serial: core: Fix runtime PM handling for pending tx
  vgacon: fix mips/sibyte build regression
  dt-bindings: serial: drop unsupported samsung bindings
  tty: serial: samsung: drop earlycon support for unsupported platforms
  tty: 8250: Add note for PX-835
  tty: 8250: Fix IS-200 PCI ID comment
  tty: 8250: Add Brainboxes Oxford Semiconductor-based quirks
  tty: 8250: Add support for Intashield IX cards
  tty: 8250: Add support for additional Brainboxes PX cards
  tty: 8250: Fix up PX-803/PX-857
  tty: 8250: Fix port count of PX-257
  tty: 8250: Add support for Intashield IS-100
  tty: 8250: Add support for Brainboxes UP cards
  tty: 8250: Add support for additional Brainboxes UC cards
  tty: 8250: Remove UC-257 and UC-431
  ...

Merge tag 'mm-nonmm-stable-2023-11-02-14-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2023-11-03T06:53:31+00:00

Pull non-MM updates from Andrew Morton:
 "As usual, lots of singleton and doubleton patches all over the tree
  and there's little I can say which isn't in the individual changelogs.

  The lengthier patch series are

   - 'kdump: use generic functions to simplify crashkernel reservation
     in arch', from Baoquan He. This is mainly cleanups and
     consolidation of the 'crashkernel=' kernel parameter handling

   - After much discussion, David Laight's 'minmax: Relax type checks in
     min() and max()' is here. Hopefully reduces some typecasting and
     the use of min_t() and max_t()

   - A group of patches from Oleg Nesterov which clean up and slightly
     fix our handling of reads from /proc/PID/task/... and which remove
     task_struct.thread_group"

* tag 'mm-nonmm-stable-2023-11-02-14-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (64 commits)
  scripts/gdb/vmalloc: disable on no-MMU
  scripts/gdb: fix usage of MOD_TEXT not defined when CONFIG_MODULES=n
  .mailmap: add address mapping for Tomeu Vizoso
  mailmap: update email address for Claudiu Beznea
  tools/testing/selftests/mm/run_vmtests.sh: lower the ptrace permissions
  .mailmap: map Benjamin Poirier's address
  scripts/gdb: add lx_current support for riscv
  ocfs2: fix a spelling typo in comment
  proc: test ProtectionKey in proc-empty-vm test
  proc: fix proc-empty-vm test with vsyscall
  fs/proc/base.c: remove unneeded semicolon
  do_io_accounting: use sig->stats_lock
  do_io_accounting: use __for_each_thread()
  ocfs2: replace BUG_ON() at ocfs2_num_free_extents() with ocfs2_error()
  ocfs2: fix a typo in a comment
  scripts/show_delta: add __main__ judgement before main code
  treewide: mark stuff as __ro_after_init
  fs: ocfs2: check status values
  proc: test /proc/${pid}/statm
  compiler.h: move __is_constexpr() to compiler.h
  ...

console: fix up ARM screen_info reference

2023-10-17T14:34:02+00:00

Separating the VGA console screen_info from the EFI one unfortunately
caused a build failure for footbridge that I had never caught
with randconfig builds:

arch/arm/kernel/setup.c:932:27: error: static declaration of 'vgacon_screen_info' follows non-static declaration
  932 | static struct screen_info vgacon_screen_info = {
      |                           ^~~~~~~~~~~~~~~~~~
In file included from arch/arm/kernel/setup.c:44:
arch/arm/include/asm/setup.h:40:27: note: previous declaration of 'vgacon_screen_info' with type 'struct screen_info'
   40 | extern struct screen_info vgacon_screen_info;
      |                           ^~~~~~~~~~~~~~~~~~
arm-linux-gnueabi-ld: drivers/video/console/dummycon.o: in function `dummycon_init':
dummycon.c:(.text+0xe4): undefined reference to `screen_info'

Make sure the variable is global to avoid the conflict with the extern
declaration, and make it work in dummycon.c

Signed-off-by: Arnd Bergmann 
Link: https://lore.kernel.org/r/20231017093947.3627976-2-arnd@kernel.org
Signed-off-by: Greg Kroah-Hartman

vgacon: clean up global screen_info instances

2023-10-17T08:17:02+00:00

To prepare for completely separating the VGA console screen_info from
the one used in EFI/sysfb, rename the vgacon instances and make them
local as much as possible.

ia64 and arm both have confurations with vgacon and efi, but the contents
never overlaps because ia64 has no EFI framebuffer, and arm only has
vga console on legacy platforms without EFI. Renaming these is required
before the EFI screen_info can be moved into drivers/firmware.

The ia64 vga console is actually registered in two places from
setup_arch(), but one of them is wrong, so drop the one in pcdp.c and
fix the one in setup.c to use the correct conditional.

x86 has to keep them together, as the boot protocol is used to switch
between VGA text console and framebuffer through the screen_info data.

Acked-by: Javier Martinez Canillas 
Acked-by: Khalid Aziz 
Acked-by: Helge Deller 
Signed-off-by: Arnd Bergmann 
Link: https://lore.kernel.org/r/20231009211845.3136536-7-arnd@kernel.org
Signed-off-by: Greg Kroah-Hartman

vgacon: remove screen_info dependency

2023-10-17T08:17:02+00:00

The vga console driver is fairly self-contained, and only used by
architectures that explicitly initialize the screen_info settings.

Chance every instance that picks the vga console by setting conswitchp
to call a function instead, and pass a reference to the screen_info
there.

Reviewed-by: Javier Martinez Canillas 
Acked-by: Khalid Azzi 
Acked-by: Helge Deller 
Signed-off-by: Arnd Bergmann 
Link: https://lore.kernel.org/r/20231009211845.3136536-6-arnd@kernel.org
Signed-off-by: Greg Kroah-Hartman