linux-stable.git/drivers/pci/hotplug/pnv_php.c, branch v5.4.285

pci/hotplug/pnv_php: Fix hotplug driver crash on Powernv

2024-09-12T09:03:54+00:00

[ Upstream commit 335e35b748527f0c06ded9eebb65387f60647fda ]

The hotplug driver for powerpc (pci/hotplug/pnv_php.c) causes a kernel
crash when we try to hot-unplug/disable the PCIe switch/bridge from
the PHB.

The crash occurs because although the MSI data structure has been
released during disable/hot-unplug path and it has been assigned
with NULL, still during unregistration the code was again trying to
explicitly disable the MSI which causes the NULL pointer dereference and
kernel crash.

The patch fixes the check during unregistration path to prevent invoking
pci_disable_msi/msix() since its data structure is already freed.

Reported-by: Timothy Pearson 
Closes: https://lore.kernel.org/all/1981605666.2142272.1703742465927.JavaMail.zimbra@raptorengineeringinc.com/
Acked-by: Bjorn Helgaas 
Tested-by: Shawn Anastasio 
Signed-off-by: Krishna Kumar 
Signed-off-by: Michael Ellerman 
Link: https://msgid.link/20240701074513.94873-2-krishnak@linux.ibm.com
Signed-off-by: Sasha Levin

pci-hotplug/pnv_php: Add attention indicator support

2019-09-05T04:22:39+00:00

pnv_php is generally used with PCIe bridges which provide a native
interface for setting the attention and power indicator LEDs. Wire up
those interfaces even if firmware does not have support for them (yet...)

Signed-off-by: Oliver O'Halloran 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20190903101605.2890-11-oohall@gmail.com

pci-hotplug/pnv_php: Add support for IODA3 Power9 PHBs

2019-09-05T04:22:39+00:00

Currently we check that an IODA2 compatible PHB is upstream of this slot.
This is mainly to avoid pnv_php creating slots for the various "virtual
PHBs" that we create for NVLink. There's no real need for this restriction
so allow it on IODA3.

Signed-off-by: Oliver O'Halloran 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20190903101605.2890-10-oohall@gmail.com

pci-hotplug/pnv_php: Add a reset_slot() callback

2019-09-05T04:22:39+00:00

When performing EEH recovery of devices in a hotplug slot we need to use
the slot driver's ->reset_slot() callback to prevent spurious hotplug
events due to spurious DLActive and PresDet change interrupts. Add a
reset_slot() callback to pnv_php so we can handle recovery of devices
in pnv_php managed slots.

Signed-off-by: Oliver O'Halloran 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20190903101605.2890-9-oohall@gmail.com

Merge tag 'powerpc-4.20-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

2018-10-26T21:36:21+00:00

Pull powerpc updates from Michael Ellerman:
"Notable changes:

- A large series to rewrite our SLB miss handling, replacing a lot of
fairly complicated asm with much fewer lines of C.

- Following on from that, we now maintain a cache of SLB entries for
each process and preload them on context switch. Leading to a 27%
speedup for our context switch benchmark on Power9.

- Improvements to our handling of SLB multi-hit errors. We now print
more debug information when they occur, and try to continue running
by flushing the SLB and reloading, rather than treating them as
fatal.

- Enable THP migration on 64-bit Book3S machines (eg. Power7/8/9).

- Add support for physical memory up to 2PB in the linear mapping on
64-bit Book3S. We only support up to 512TB as regular system
memory, otherwise the percpu allocator runs out of vmalloc space.

- Add stack protector support for 32 and 64-bit, with a per-task
canary.

- Add support for PTRACE_SYSEMU and PTRACE_SYSEMU_SINGLESTEP.

- Support recognising "big cores" on Power9, where two SMT4 cores are
presented to us as a single SMT8 core.

- A large series to cleanup some of our ioremap handling and PTE
flags.

- Add a driver for the PAPR SCM (storage class memory) interface,
allowing guests to operate on SCM devices (acked by Dan).

- Changes to our ftrace code to handle very large kernels, where we
need to use a trampoline to get to ftrace_caller().

And many other smaller enhancements and cleanups.

Thanks to: Alan Modra, Alistair Popple, Aneesh Kumar K.V, Anton
Blanchard, Aravinda Prasad, Bartlomiej Zolnierkiewicz, Benjamin
Herrenschmidt, Breno Leitao, Cédric Le Goater, Christophe Leroy,
Christophe Lombard, Dan Carpenter, Daniel Axtens, Finn Thain, Gautham
R. Shenoy, Gustavo Romero, Haren Myneni, Hari Bathini, Jia Hongtao,
Joel Stanley, John Allen, Laurent Dufour, Madhavan Srinivasan, Mahesh
Salgaonkar, Mark Hairgrove, Masahiro Yamada, Michael Bringmann,
Michael Neuling, Michal Suchanek, Murilo Opsfelder Araujo, Nathan
Fontenot, Naveen N. Rao, Nicholas Piggin, Nick Desaulniers, Oliver
O'Halloran, Paul Mackerras, Petr Vorel, Rashmica Gupta, Reza Arbab,
Rob Herring, Sam Bobroff, Samuel Mendoza-Jonas, Scott Wood, Stan
Johnson, Stephen Rothwell, Stewart Smith, Suraj Jitindar Singh, Tyrel
Datwyler, Vaibhav Jain, Vasant Hegde, YueHaibing, zhong jiang"

* tag 'powerpc-4.20-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (221 commits)
Revert "selftests/powerpc: Fix out-of-tree build errors"
powerpc/msi: Fix compile error on mpc83xx
powerpc: Fix stack protector crashes on CPU hotplug
powerpc/traps: restore recoverability of machine_check interrupts
powerpc/64/module: REL32 relocation range check
powerpc/64s/radix: Fix radix__flush_tlb_collapsed_pmd double flushing pmd
selftests/powerpc: Add a test of wild bctr
powerpc/mm: Fix page table dump to work on Radix
powerpc/mm/radix: Display if mappings are exec or not
powerpc/mm/radix: Simplify split mapping logic
powerpc/mm/radix: Remove the retry in the split mapping logic
powerpc/mm/radix: Fix small page at boundary when splitting
powerpc/mm/radix: Fix overuse of small pages in splitting logic
powerpc/mm/radix: Fix off-by-one in split mapping logic
powerpc/ftrace: Handle large kernel configs
powerpc/mm: Fix WARN_ON with THP NUMA migration
selftests/powerpc: Fix out-of-tree build errors
powerpc/time: no steal_time when CONFIG_PPC_SPLPAR is not selected
powerpc/time: Only set CONFIG_ARCH_HAS_SCALED_CPUTIME on PPC64
powerpc/time: isolate scaled cputime accounting in dedicated functions.
...

powerpc/eeh: Cleanup eeh_pe_state_mark()

2018-10-13T11:21:25+00:00

Currently, eeh_pe_state_mark() marks a PE (and it's children) with a
state and then performs additional processing if that state included
EEH_PE_ISOLATED.

The state parameter is always a constant at the call site, so
rearrange eeh_pe_state_mark() into two functions and just call the
appropriate one at each site.

Signed-off-by: Sam Bobroff 
Signed-off-by: Michael Ellerman

PCI: pnv_php: Use kmemdup()

2018-10-02T21:04:40+00:00

Use kmemdup() rather than duplicating its implementation.

Signed-off-by: YueHaibing 
Signed-off-by: Bjorn Helgaas 
Acked-by: Michael Ellerman

PCI: hotplug: Embed hotplug_slot

2018-09-18T22:52:15+00:00

When the PCI hotplug core and its first user, cpqphp, were introduced in
February 2002 with historic commit a8a2069f432c, cpqphp allocated a slot
struct for its internal use plus a hotplug_slot struct to be registered
with the hotplug core and linked the two with pointers:
https://git.kernel.org/tglx/history/c/a8a2069f432c

Nowadays, the predominant pattern in the tree is to embed ("subclass")
such structures in one another and cast to the containing struct with
container_of().  But it wasn't until July 2002 that container_of() was
introduced with historic commit ec4f214232cf:
https://git.kernel.org/tglx/history/c/ec4f214232cf

pnv_php, introduced in 2016, did the right thing and embedded struct
hotplug_slot in its internal struct pnv_php_slot, but all other drivers
cargo-culted cpqphp's design and linked separate structs with pointers.

Embedding structs is preferrable to linking them with pointers because
it requires fewer allocations, thereby reducing overhead and simplifying
error paths.  Casting an embedded struct to the containing struct
becomes a cheap subtraction rather than a dereference.  And having fewer
pointers reduces the risk of them pointing nowhere either accidentally
or due to an attack.

Convert all drivers to embed struct hotplug_slot in their internal slot
struct.  The "private" pointer in struct hotplug_slot thereby becomes
unused, so drop it.

Signed-off-by: Lukas Wunner 
Signed-off-by: Bjorn Helgaas 
Reviewed-by: Rafael J. Wysocki 
Acked-by: Tyrel Datwyler   # drivers/pci/hotplug/rpa*
Acked-by: Sebastian Ott         # drivers/pci/hotplug/s390*
Acked-by: Andy Shevchenko  # drivers/platform/x86
Cc: Len Brown 
Cc: Scott Murray 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Cc: Michael Ellerman 
Cc: Oliver OHalloran 
Cc: Gavin Shan 
Cc: Gerald Schaefer 
Cc: Corentin Chary 
Cc: Darren Hart

PCI: hotplug: Drop hotplug_slot_info

2018-09-18T22:52:15+00:00

Ever since the PCI hotplug core was introduced in 2002, drivers had to
allocate and register a struct hotplug_slot_info for every slot:
https://git.kernel.org/tglx/history/c/a8a2069f432c

Apparently the idea was that drivers furnish the hotplug core with an
up-to-date card presence status, power status, latch status and
attention indicator status as well as notify the hotplug core of changes
thereof.  However only 4 out of 12 hotplug drivers bother to notify the
hotplug core with pci_hp_change_slot_info() and the hotplug core never
made any use of the information:  There is just a single macro in
pci_hotplug_core.c, GET_STATUS(), which uses the hotplug_slot_info if
the driver lacks the corresponding callback in hotplug_slot_ops.  The
macro is called when the user reads the attribute via sysfs.

Now, if the callback isn't defined, the attribute isn't exposed in sysfs
in the first place (see e.g. has_power_file()).  There are only two
situations when the hotplug_slot_info would actually be accessed:

* If the driver defines ->enable_slot or ->disable_slot but not
  ->get_power_status.

* If the driver defines ->set_attention_status but not
  ->get_attention_status.

There is no driver doing the former and just a single driver doing the
latter, namely pnv_php.c.  Amend it with a ->get_attention_status
callback.  With that, the hotplug_slot_info becomes completely unused by
the PCI hotplug core.  But a few drivers use it internally as a cache:

cpcihp uses it to cache the latch_status and adapter_status.
cpqhp uses it to cache the adapter_status.
pnv_php and rpaphp use it to cache the attention_status.
shpchp uses it to cache all four values.

Amend these drivers to cache the information in their private slot
struct.  shpchp's slot struct already contains members to cache the
power_status and adapter_status, so additional members are only needed
for the other two values.  In the case of cpqphp, the cached value is
only accessed in a single place, so instead of caching it, read the
current value from the hardware.

Caution:  acpiphp, cpci, cpqhp, shpchp, asus-wmi and eeepc-laptop
populate the hotplug_slot_info with initial values on probe.  That code
is herewith removed.  There is a theoretical chance that the code has
side effects without which the driver fails to function, e.g. if the
ACPI method to read the adapter status needs to be executed at least
once on probe.  That seems unlikely to me, still maintainers should
review the changes carefully for this possibility.

Rafael adds: "I'm not aware of any case in which it will break anything,
[...] but if that happens, it may be necessary to add the execution of
the control methods in question directly to the initialization part."

Signed-off-by: Lukas Wunner 
Signed-off-by: Bjorn Helgaas 
Reviewed-by: Rafael J. Wysocki 
Acked-by: Tyrel Datwyler   # drivers/pci/hotplug/rpa*
Acked-by: Sebastian Ott         # drivers/pci/hotplug/s390*
Acked-by: Andy Shevchenko  # drivers/platform/x86
Cc: Len Brown 
Cc: Scott Murray 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Cc: Michael Ellerman 
Cc: Oliver OHalloran 
Cc: Gavin Shan 
Cc: Gerald Schaefer 
Cc: Corentin Chary 
Cc: Darren Hart

PCI: hotplug: Constify hotplug_slot_ops

2018-09-18T22:52:15+00:00

Hotplug drivers cannot declare their hotplug_slot_ops const, making them
attractive targets for attackers, because upon registration of a hotplug
slot, __pci_hp_initialize() writes to the "owner" and "mod_name" members
in that struct.

Fix by moving these members to struct hotplug_slot and constify every
driver's hotplug_slot_ops except for pciehp.

pciehp constructs its hotplug_slot_ops at runtime based on the PCIe
port's capabilities, hence cannot declare them const.  It can be
converted to __write_rarely once that's mainlined:
http://www.openwall.com/lists/kernel-hardening/2016/11/16/3

Signed-off-by: Lukas Wunner 
Signed-off-by: Bjorn Helgaas 
Reviewed-by: Rafael J. Wysocki 
Acked-by: Tyrel Datwyler   # drivers/pci/hotplug/rpa*
Acked-by: Andy Shevchenko  # drivers/platform/x86
Cc: Len Brown 
Cc: Scott Murray 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Cc: Michael Ellerman 
Cc: Oliver OHalloran 
Cc: Gavin Shan 
Cc: Sebastian Ott 
Cc: Gerald Schaefer 
Cc: Corentin Chary 
Cc: Darren Hart