linux.git/arch/arm64/kernel/machine_kexec.c, branch v5.5

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

2019-06-19T15:09:55+00:00

Based on 2 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner 
Reviewed-by: Enrico Weigelt 
Reviewed-by: Kate Stewart 
Reviewed-by: Allison Randal 
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman

arm64: kdump: no need to mark crashkernel pages manually PG_reserved

2019-03-06T05:07:19+00:00

The crashkernel is reserved via memblock_reserve().  memblock_free_all()
will call free_low_memory_core_early(), which will go over all reserved
memblocks, marking the pages as PG_reserved.

So manually marking pages as PG_reserved is not necessary, they are
already in the desired state (otherwise they would have been handed over
to the buddy as free pages and bad things would happen).

Link: http://lkml.kernel.org/r/20190114125903.24845-8-david@redhat.com
Signed-off-by: David Hildenbrand 
Reviewed-by: Matthias Brugger 
Reviewed-by: Bhupesh Sharma 
Cc: Catalin Marinas 
Cc: Will Deacon 
Cc: James Morse 
Cc: David Hildenbrand 
Cc: Mark Rutland 
Cc: Dave Kleikamp 
Cc: Mike Rapoport 
Cc: Michal Hocko 
Cc: Florian Fainelli 
Cc: Stefan Agner 
Cc: Laura Abbott 
Cc: Greg Hackmann 
Cc: Johannes Weiner 
Cc: Kristina Martsenko 
Cc: CHANDAN VN 
Cc: AKASHI Takahiro 
Cc: Logan Gunthorpe 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

arm64: kexec: no need to ClearPageReserved()

2019-03-06T05:07:19+00:00

This will be done by free_reserved_page().

Link: http://lkml.kernel.org/r/20190114125903.24845-7-david@redhat.com
Signed-off-by: David Hildenbrand 
Acked-by: James Morse 
Reviewed-by: Bhupesh Sharma 
Cc: Catalin Marinas 
Cc: Will Deacon 
Cc: James Morse 
Cc: Marc Zyngier 
Cc: Dave Kleikamp 
Cc: Mark Rutland 
Cc: Michal Hocko 
Cc: Matthew Wilcox 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

arm64: kexec_file: invoke the kernel without purgatory

2018-12-06T14:38:53+00:00

On arm64, purgatory would do almost nothing. So just invoke secondary
kernel directly by jumping into its entry code.

While, in this case, cpu_soft_restart() must be called with dtb address
in the fifth argument, the behavior still stays compatible with kexec_load
case as long as the argument is null.

Signed-off-by: AKASHI Takahiro 
Reviewed-by: James Morse 
Cc: Catalin Marinas 
Cc: Will Deacon 
Signed-off-by: Will Deacon

arm64: kernel: arch_crash_save_vmcoreinfo() should depend on CONFIG_CRASH_CORE

2018-09-11T10:08:49+00:00

Since commit 23c85094fe18 ("proc/kcore: add vmcoreinfo note to /proc/kcore")
the kernel has exported the vmcoreinfo PT_NOTE on /proc/kcore as well
as /proc/vmcore.

arm64 only exposes it's additional arch information via
arch_crash_save_vmcoreinfo() if built with CONFIG_KEXEC, as kdump was
previously the only user of vmcoreinfo.

Move this weak function to a separate file that is built at the same
time as its caller in kernel/crash_core.c. This ensures values like
'kimage_voffset' are always present in the vmcoreinfo PT_NOTE.

CC: AKASHI Takahiro 
Reviewed-by: Bhupesh Sharma 
Signed-off-by: James Morse 
Signed-off-by: Will Deacon

arm64: kexec: Add comment to explain use of __flush_icache_range()

2018-07-31T11:10:38+00:00

Now that we understand the deadlock arising from flush_icache_range()
on the kexec crash kernel path, add a comment to justify the use of
__flush_icache_range() here.

Reported-by: Dave Kleikamp 
Signed-off-by: Will Deacon

arm64, kaslr: export offset in VMCOREINFO ELF notes

2018-07-31T09:27:01+00:00

Include KASLR offset in arm64 VMCOREINFO ELF notes to assist in
debugging. vmcore parsing in user-space already expects this value in
the notes and we are providing it for portability of those existing
tools with x86.

Ideally we would like core code to do this (so that way this
information won't be missed when an architecture adds KASLR support),
but mips has CONFIG_RANDOMIZE_BASE, and doesn't provide kaslr_offset(),
so I am not sure if this is needed for mips (and other such similar arch
cases in future). So, lets keep this architecture specific for now.

As an example of a user-space use-case, consider the
makedumpfile user-space utility which will need fixup to use this
KASLR offset to work with cases where we need to find a way to
translate symbol address from vmlinux to kernel run time address
in case of KASLR boot on arm64.

I have already submitted the makedumpfile user-space patch upstream
and the maintainer has suggested to wait for the kernel changes to be
included (see [0]).

I tested this on my qualcomm amberwing board both for KASLR and
non-KASLR boot cases:

Without this patch:
   # cat > scrub.conf << EOF
   [vmlinux]
   erase jiffies
   erase init_task.utime
   for tsk in init_task.tasks.next within task_struct:tasks
       erase tsk.utime
   endfor
   EOF

  # makedumpfile --split -d 31 -x vmlinux --config scrub.conf vmcore dumpfile_{1,2,3}
  readpage_elf: Attempt to read non-existent page at 0xffffa8a5bf180000.
  readmem: type_addr: 1, addr:ffffa8a5bf180000, size:8
  vaddr_to_paddr_arm64: Can't read pgd
  readmem: Can't convert a virtual address(ffff0000092a542c) to physical
  address.
  readmem: type_addr: 0, addr:ffff0000092a542c, size:390
  check_release: Can't get the address of system_utsname

After this patch check_release() is ok, and also we are able to erase
symbol from vmcore (I checked this with kernel 4.18.0-rc4+):

  # makedumpfile --split -d 31 -x vmlinux --config scrub.conf vmcore dumpfile_{1,2,3}
  The kernel version is not supported.
  The makedumpfile operation may be incomplete.
  Checking for memory holes                         : [100.0 %] \
  Checking for memory holes                         : [100.0 %] |
  Checking foExcluding unnecessary pages                       : [100.0 %]
  \
  Excluding unnecessary pages                       : [100.0 %] \

  The dumpfiles are saved to dumpfile_1, dumpfile_2, and dumpfile_3.

  makedumpfile Completed.

[0] https://www.spinics.net/lists/kexec/msg21195.html

Cc: Ard Biesheuvel 
Cc: Will Deacon 
Cc: Mark Rutland 
Cc: Catalin Marinas 
Cc: James Morse 
Acked-by: James Morse 
Signed-off-by: Bhupesh Sharma 
Signed-off-by: Will Deacon

arm64: kexec: machine_kexec should call __flush_icache_range

2018-07-30T16:58:11+00:00

machine_kexec flushes the reboot_code_buffer from the icache
after stopping the other cpus.

Commit 3b8c9f1cdfc5 ("arm64: IPI each CPU after invalidating the I-cache
for kernel mappings") added an IPI call to flush_icache_range, which
causes a hang here, so replace the call with __flush_icache_range

Signed-off-by: Dave Kleikamp 
Cc: AKASHI Takahiro 
Cc: Catalin Marinas 
Cc: Will Deacon 
Signed-off-by: Will Deacon

arm64: kexec: always reset to EL2 if present

2018-07-04T17:34:24+00:00

Currently machine_kexec() doesn't reset to EL2 in the case of a
crashdump kernel. This leaves potentially dodgy state active at EL2, and
means that if the crashdump kernel attempts to online secondary CPUs,
these will be booted as mismatched ELs.

Let's reset to EL2, as we do in all other cases, and simplify things. If
EL2 state is corrupt, things are already sufficiently bad that kdump is
unlikely to work, and it's best-effort regardless.

Cc: Catalin Marinas 
Cc: James Morse 
Acked-by: Marc Zyngier 
Signed-off-by: Mark Rutland 
Signed-off-by: Will Deacon

arm64: explicitly mask all exceptions

2017-11-02T15:55:40+00:00

There are a few places where we want to mask all exceptions. Today we
do this in a piecemeal fashion, typically we expect the caller to
have masked irqs and the arch code masks debug exceptions, ignoring
serror which is probably masked.

Make it clear that 'mask all exceptions' is the intention by adding
helpers to do exactly that.

This will let us unmask SError without having to add 'oh and SError'
to these paths.

Signed-off-by: James Morse 
Reviewed-by: Julien Thierry 
Reviewed-by: Catalin Marinas 
Signed-off-by: Will Deacon