[18.04] kpatch - Add livepatch hook support for ppc64le

------- Comment From <email address hidden> 2018-01-09 01:37 EDT-------
Livepatch modules created using kpatch tools also requires Kernel changes. The required kernel bits are merged into powerpc/next branch, attaching the kernel patches.
1. https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/commit/?id=1ea61ea23985c0f15c027e4c0ac022
2. https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/commit/?id=b9eab08d012fa093947b230f9a8725
3. https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/commit/?id=a443bf6e8a7674b86221f4922cae82

------- Comment on attachment From <email address hidden> 2018-01-09 01:39 EDT-------

Livepatch re-uses module loader function apply_relocate_add() to write
relocations, instead of managing them by arch-dependent
klp_write_module_reloc() function.

apply_relocate_add() doesn't understand livepatch symbols (marked with
SHN_LIVEPATCH symbol section index) and assumes them to be local
symbols by default for R_PPC64_REL24 relocation type. It fails with an
error, when trying to calculate offset with local_entry_offset():

  module_64: kpatch_meminfo: REL24 -1152921504897399800 out of range!

Whereas livepatch symbols are essentially SHN_UNDEF, should be called
via stub used for global calls. This issue can be fixed by teaching
apply_relocate_add() to handle both SHN_UNDEF/SHN_LIVEPATCH symbols
via the same stub. This patch extends SHN_UNDEF code to handle
livepatch symbols too.

------- Comment on attachment From <email address hidden> 2018-01-09 01:40 EDT-------

When attempting to load a livepatch module, I got the following error:

  module_64: patch_module: Expect noop after relocate, got 3c820000

The error was triggered by the following code in
unregister_netdevice_queue():

  14c: 00 00 00 48 b 14c <unregister_netdevice_queue+0x14c>
                         14c: R_PPC64_REL24 net_set_todo
  150: 00 00 82 3c addis r4,r2,0

GCC didn't insert a nop after the branch to net_set_todo() because it's
a sibling call, so it never returns. The nop isn't needed after the
branch in that case.

------- Comment on attachment From <email address hidden> 2018-01-09 01:41 EDT-------

Print the function address associated with the restore_r2() error to
make it easier to debug the problem.

Also clarify the wording a bit.

Before:

  module_64: patch_foo: Expect noop after relocate, got 3c820000

After:

  module_64: patch_foo: Expected nop after call, got 7c630034 at netdev_has_upper_dev+0x54/0xb0 [patch_foo]

Note: This patch is optional, it improves the debugging message.

------- Comment on attachment From <email address hidden> 2018-01-09 01:40 EDT-------

When attempting to load a livepatch module, I got the following error:

  module_64: patch_module: Expect noop after relocate, got 3c820000

The error was triggered by the following code in
unregister_netdevice_queue():

  14c: 00 00 00 48 b 14c <unregister_netdevice_queue+0x14c>
                         14c: R_PPC64_REL24 net_set_todo
  150: 00 00 82 3c addis r4,r2,0

GCC didn't insert a nop after the branch to net_set_todo() because it's
a sibling call, so it never returns. The nop isn't needed after the
branch in that case.

------- Comment on attachment From <email address hidden> 2018-01-09 01:41 EDT-------

Print the function address associated with the restore_r2() error to
make it easier to debug the problem.

Also clarify the wording a bit.

Before:

  module_64: patch_foo: Expect noop after relocate, got 3c820000

After:

  module_64: patch_foo: Expected nop after call, got 7c630034 at netdev_has_upper_dev+0x54/0xb0 [patch_foo]

Note: This patch is optional, it improves the debugging message.

This bug was fixed in the package linux - 4.15.0-12.13

---------------
linux (4.15.0-12.13) bionic; urgency=medium

  * linux: 4.15.0-12.13 -proposed tracker (LP: #1754059)

  * CONFIG_EFI=y on armhf (LP: #1726362)
    - [Config] CONFIG_EFI=y on armhf, reconcile secureboot EFI settings

  * ppc64el: Support firmware disable of RFI flush (LP: #1751994)
    - powerpc/pseries: Support firmware disable of RFI flush
    - powerpc/powernv: Support firmware disable of RFI flush

  * [Feature] CFL/CNL (PCH:CNP-H): New GPIO Commit added (GPIO Driver needed)
    (LP: #1751714)
    - gpio / ACPI: Drop unnecessary ACPI GPIO to Linux GPIO translation
    - pinctrl: intel: Allow custom GPIO base for pad groups
    - pinctrl: cannonlake: Align GPIO number space with Windows

  * [Feature] Add xHCI debug device support in the driver (LP: #1730832)
    - usb: xhci: Make some static functions global
    - usb: xhci: Add DbC support in xHCI driver
    - [Config] USB_XHCI_DBGCAP=y for commit mainline dfba2174dc42.

  * [SRU] Lenovo E41 Mic mute hotkey is not responding (LP: #1753347)
    - platform/x86: ideapad-laptop: Increase timeout to wait for EC answer

  * headset mic can't be detected on two Dell machines (LP: #1748807)
    - ALSA: hda - Fix a wrong FIXUP for alc289 on Dell machines

  * hisi_sas: Add disk LED support (LP: #1752695)
    - scsi: hisi_sas: directly attached disk LED feature for v2 hw

  * [Feature] [Graphics]Whiskey Lake (Coffelake-U 4+2) new PCI Device ID adds
    (LP: #1742561)
    - drm/i915/cfl: Adding more Coffee Lake PCI IDs.

  * [Bug] [USB Function][CFL-CNL PCH]Stall Error and USB Transaction Error in
    trace, Disable of device-initiated U1/U2 failed and rebind failed: -517
    during suspend/resume with usb storage. (LP: #1730599)
    - usb: Don't print a warning if interface driver rebind is deferred at resume

  * retpoline: ignore %cs:0xNNN constant indirections (LP: #1752655)
    - [Packaging] retpoline -- elide %cs:0xNNNN constants on i386
    - [Config] retpoline -- clean up i386 retpoline files

  * hisilicon hibmc regression due to ea642c3216cb ("drm/ttm: add io_mem_pfn
    callback") (LP: #1738334)
    - drm/ttm: add ttm_bo_io_mem_pfn to check io_mem_pfn

  * [Asus UX360UA] battery status in unity-panel is not changing when battery is
    being charged (LP: #1661876) // AC adapter status not detected on Asus
    ZenBook UX410UAK (LP: #1745032)
    - ACPI / battery: Add quirk for Asus UX360UA and UX410UAK

  * ASUS UX305LA - Battery state not detected correctly (LP: #1482390)
    - ACPI / battery: Add quirk for Asus GL502VSK and UX305LA

  * [18.04 FEAT] Automatically detect layer2 setting in the qeth device driver
    (LP: #1747639)
    - s390/diag: add diag26c support for VNIC info
    - s390/qeth: support early setup for z/VM NICs

  * Bionic update to v4.15.7 stable release (LP: #1752317)
    - netfilter: drop outermost socket lock in getsockopt()
    - arm64: mm: don't write garbage into TTBR1_EL1 register
    - kconfig.h: Include compiler types to avoid missed struct attributes
    - MIPS: boot: Define __ASSEMBLY__ for its.S build
    - xtensa: fix high memory/reserved memory collision
    - scsi: ibmvfc: fix misde...