Pull pci fixes from Bjorn Helgaas:

 - Update kernel-parameters doc to describe "pcie_aspm=off" more
   accurately (Bjorn Helgaas)

 - Restore the parent's (not the child's) ASPM state to the parent
   during resume, which fixes a reboot during resume (Kai-Heng Feng)

* tag 'pci-v6.9-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/pci/pci:
  PCI/ASPM: Restore parent state to parent, child state to child
  PCI/ASPM: Clarify that pcie_aspm=off means leave ASPM untouched

Previously we claimed "pcie_aspm=off" meant that ASPM would be disabled,
which is wrong.

Correct this to say that with "pcie_aspm=off", Linux doesn't touch any ASPM
configuration at all.  ASPM may have been enabled by firmware, and that
will be left unchanged.  See "aspm_support_enabled".

Link: https://lore.kernel.org/r/20240429191821.691726-1-helgaas@kernel.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: David E. Box <david.e.box@linux.intel.com>

Pull x86 fixes from Ingo Molnar:

 - Make the CPU_MITIGATIONS=n interaction with conflicting
   mitigation-enabling boot parameters a bit saner.

 - Re-enable CPU mitigations by default on non-x86

 - Fix TDX shared bit propagation on mprotect()

 - Fix potential show_regs() system hang when PKE initialization
   is not fully finished yet.

 - Add the 0x10-0x1f model IDs to the Zen5 range

 - Harden #VC instruction emulation some more

* tag 'x86-urgent-2024-04-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  cpu: Ignore "mitigations" kernel parameter if CPU_MITIGATIONS=n
  cpu: Re-enable CPU mitigations by default for !X86 architectures
  x86/tdx: Preserve shared bit on mprotect()
  x86/cpu: Fix check for RDPKRU in __show_regs()
  x86/CPU/AMD: Add models 0x10-0x1f to the Zen5 range
  x86/sev: Check for MWAITX and MONITORX opcodes in the #VC handler

Explicitly disallow enabling mitigations at runtime for kernels that were
built with CONFIG_CPU_MITIGATIONS=n, as some architectures may omit code
entirely if mitigations are disabled at compile time.

E.g. on x86, a large pile of Kconfigs are buried behind CPU_MITIGATIONS,
and trying to provide sane behavior for retroactively enabling mitigations
is extremely difficult, bordering on impossible.  E.g. page table isolation
and call depth tracking require build-time support, BHI mitigations will
still be off without additional kernel parameters, etc.

  [ bp: Touchups. ]

Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20240420000556.2645001-3-seanjc@google.com

Pull documentation fixes from Jonathan Corbet:
 "A set of updates from Thorsten to his (new) guide to verifying bugs
  and tracking down regressions"

* tag 'docs-6.9-fixes2' of git://git.lwn.net/linux:
  docs: verify/bisect: stable regressions: first stable, then mainline
  docs: verify/bisect: describe how to use a build host
  docs: verify/bisect: explain testing reverts, patches and newer code
  docs: verify/bisect: proper headlines and more spacing
  docs: verify/bisect: add and fetch stable branches ahead of time
  docs: verify/bisect: use git switch, tag kernel, and various fixes

Rearrange the instructions so that readers facing a regression within a
stable or longterm series first test its latest release before testing
mainline. This is less scary for some people. It also reduces the chance
that something goes sideways for readers that compile their first
kernel, as mainline can cause slightly more trouble.

Signed-off-by: Thorsten Leemhuis <linux@leemhuis.info>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/efd3cb9c68db450091021326bf9c334553df0ec2.1712647788.git.linux@leemhuis.info

Describe how to build kernels on another system (with and without
cross-compiling), as building locally can be quite painfully on some
slow systems. This is done in an add-on section, as it would make the
step-by-step guide to complicated if this special case would be
described there.

Signed-off-by: Thorsten Leemhuis <linux@leemhuis.info>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/288160cb4769e46a3280250ca71da0abc4aa002d.1712647788.git.linux@leemhuis.info

Rename 'Supplementary tasks' to 'Complementary tasks' while introducing
a section 'Optional tasks: test reverts, patches, or later versions':
the latter is something readers occasionally will have to do after
reporting a bug and thus is best covered here.

Signed-off-by: Thorsten Leemhuis <linux@leemhuis.info>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/dacf26a4c48e9e8f04ecbc77e0a74c9b2a6a1103.1712647788.git.linux@leemhuis.info

Various small improvements and fixes:

* Separate ref links from their target with a space for better
  readability.

* Add a proper heading for the note at the end of the step-by-step
  guide.

* Use proper 3rd and 4th level headlines in the reference section and
  add short intros for the 2nd level headlines that lacked one.

Signed-off-by: Thorsten Leemhuis <linux@leemhuis.info>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/f59f0f235a2192ed93899a7338153e4cb71075f0.1712647788.git.linux@leemhuis.info

Add and fetch all required stable branches ahead of time. This fixes a
bug, as readers that wanted to bisect a regression within a stable or
longterm series otherwise did not have them available at the right time.
This way also matches the flow somewhat better and avoids some "if you
haven't already added it" phrases that otherwise become necessary in
future changes.

Signed-off-by: Thorsten Leemhuis <linux@leemhuis.info>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/57dcf312959476abe6151bf3d35eb79e3e9a83d1.1712647788.git.linux@leemhuis.info