linux.git/arch/powerpc/platforms/pseries/pseries.h, branch vsnprintf

powerpc/pseries: Fix scv instruction crash with kexec

2024-06-28T12:05:44+00:00

kexec on pseries disables AIL (reloc_on_exc), required for scv
instruction support, before other CPUs have been shut down. This means
they can execute scv instructions after AIL is disabled, which causes an
interrupt at an unexpected entry location that crashes the kernel.

Change the kexec sequence to disable AIL after other CPUs have been
brought down.

As a refresher, the real-mode scv interrupt vector is 0x17000, and the
fixed-location head code probably couldn't easily deal with implementing
such high addresses so it was just decided not to support that interrupt
at all.

Fixes: 7fa95f9adaee ("powerpc/64s: system call support for scv/rfscv instructions")
Cc: stable@vger.kernel.org # v5.9+
Reported-by: Sourabh Jain 
Closes: https://lore.kernel.org/3b4b2943-49ad-4619-b195-bc416f1d1409@linux.ibm.com
Signed-off-by: Nicholas Piggin 
Tested-by: Gautam Menghani 
Tested-by: Sourabh Jain 
Link: https://msgid.link/20240625134047.298759-1-npiggin@gmail.com
Signed-off-by: Michael Ellerman

powerpc/rtas: Move post_mobility_fixup() declaration to pseries

2023-11-21T01:06:50+00:00

This is a pseries-specific function declaration that doesn't belong in
rtas.h. Move it to the pseries platform code and adjust
pseries/suspend.c accordingly.

Signed-off-by: Nathan Lynch 
Signed-off-by: Michael Ellerman 
Link: https://msgid.link/20231106-rtas-trivial-v1-5-61847655c51f@linux.ibm.com

powerpc/mm: Cleanup memory block size probing

2023-08-18T07:03:15+00:00

Parse the device tree in early init to find the memory block size to be
used by the kernel. Consolidate the memory block size device tree parsing
to one helper and use that on both powernv and pseries. We still want to
use machine-specific callback because on all machine types other than
powernv and pseries we continue to return MIN_MEMORY_BLOCK_SIZE.

pseries_memory_block_size used to look for the second memory
block (memory@x) to determine the memory_block_size value. This patch
changed that to look at all memory blocks and make sure we can map them all
correctly using the computed memory block size value.

Add workaround to force 256MB memory block size if device driver managed
memory such as GPU memory is present. This helps to add GPU memory
that is not aligned to 1G.

Co-developed-by: Reza Arbab 
Signed-off-by: Reza Arbab 
Signed-off-by: "Aneesh Kumar K.V" 
Signed-off-by: Michael Ellerman 
Link: https://msgid.link/20230801044447.11275-1-aneesh.kumar@linux.ibm.com

powerpc/pseries: Initialise CPU hotplug callbacks earlier

2023-08-02T12:43:42+00:00

As part of the generic HOTPLUG_SMT code, there is support for disabling
secondary SMT threads at boot time, by passing "nosmt" on the kernel
command line.

The way that is implemented is the secondary threads are brought partly
online, and then taken back offline again. That is done to support x86
CPUs needing certain initialisation done on all threads. However powerpc
has similar needs, see commit d70a54e2d085 ("powerpc/powernv: Ignore
smt-enabled on Power8 and later").

For that to work the powerpc CPU hotplug callbacks need to be registered
before secondary CPUs are brought online, otherwise __cpu_disable()
fails due to smp_ops->cpu_disable being NULL.

So split the basic initialisation into pseries_cpu_hotplug_init() which
can be called early from setup_arch(). The DLPAR related initialisation
can still be done later, because it needs to do allocations.

Signed-off-by: Michael Ellerman 
Link: https://msgid.link/20230705145143.40545-9-ldufour@linux.ibm.com

powerpc/iommu: Add iommu_ops to report capabilities and allow blocking domains

2023-03-14T13:51:46+00:00

Up until now PPC64 managed to avoid using iommu_ops. The VFIO driver
uses a SPAPR TCE sub-driver and all iommu_ops uses were kept in the
Type1 VFIO driver. Recent development added 2 uses of iommu_ops to the
generic VFIO which broke POWER:
- a coherency capability check;
- blocking IOMMU domain - iommu_group_dma_owner_claimed()/...

This adds a simple iommu_ops which reports support for cache coherency
and provides a basic support for blocking domains. No other domain types
are implemented so the default domain is NULL.

Since now iommu_ops controls the group ownership, this takes it out of
VFIO.

This adds an IOMMU device into a pci_controller (=PHB) and registers it
in the IOMMU subsystem, iommu_ops is registered at this point. This
setup is done in postcore_initcall_sync.

This replaces iommu_group_add_device() with iommu_probe_device() as the
former misses necessary steps in connecting PCI devices to IOMMU
devices. This adds a comment about why explicit iommu_probe_device() is
still needed.

The previous discussion is here:
https://lore.kernel.org/r/20220707135552.3688927-1-aik@ozlabs.ru/
https://lore.kernel.org/r/20220701061751.1955857-1-aik@ozlabs.ru/

Fixes: e8ae0e140c05 ("vfio: Require that devices support DMA cache coherence")
Fixes: 70693f470848 ("vfio: Set DMA ownership for VFIO devices")
Signed-off-by: Alexey Kardashevskiy
Signed-off-by: Timothy Pearson
Acked-by: Alex Williamson
[mpe: Fix CONFIG_IOMMU_API=n build]
Signed-off-by: Michael Ellerman
Link: https://msgid.link/2000135730.16998523.1678123860135.JavaMail.zimbra@raptorengineeringinc.com

powerpc/pseries: wire up rng during setup_arch()

2022-06-18T00:19:10+00:00

The platform's RNG must be available before random_init() in order to be
useful for initial seeding, which in turn means that it needs to be
called from setup_arch(), rather than from an init call. Fortunately,
each platform already has a setup_arch function pointer, which means
it's easy to wire this up. This commit also removes some noisy log
messages that don't add much.

Fixes: a489043f4626 ("powerpc/pseries: Implement arch_get_random_long() based on H_RANDOM")
Cc: stable@vger.kernel.org # v3.13+
Signed-off-by: Jason A. Donenfeld 
Reviewed-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20220611151015.548325-4-Jason@zx2c4.com

powerpc/kasan: Disable address sanitization in kexec paths

2022-05-22T05:58:29+00:00

The kexec code paths involve code that necessarily run in real mode, as
CPUs are disabled and control is transferred to the new kernel. Disable
address sanitization for the kexec code and the functions called in real
mode on CPUs being disabled.

[paulus@ozlabs.org: combined a few work-in-progress commits of
 Daniel's and wrote the commit message.]

Signed-off-by: Daniel Axtens 
Signed-off-by: Paul Mackerras 
[mpe: Move pseries_machine_kexec() into kexec.c so setup.c can be instrumented]
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/YoTFSQ2TUSEaDdVC@cleo

powerpc/mce: Avoid using irq_work_queue() in realmode

2022-03-07T13:05:00+00:00

In realmode mce handler we use irq_work_queue() to defer
the processing of mce events, irq_work_queue() can only
be called when translation is enabled because it touches
memory outside RMA, hence we enable translation before
calling irq_work_queue and disable on return, though it
is not safe to do in realmode.

To avoid this, program the decrementer and call the event
processing functions from timer handler.

Signed-off-by: Ganesh Goudar 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20220120121931.517974-1-ganeshgr@linux.ibm.com

powerpc/pseries: Add __init attribute to eligible functions

2021-12-23T11:33:15+00:00

Some functions defined in 'arch/powerpc/platforms/pseries' are
deserving of an `__init` macro attribute. These functions are only
called by other initialization functions and therefore should inherit
the attribute.
Also, change function declarations in header files to include `__init`.

Signed-off-by: Nick Child 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20211216220035.605465-13-nick.child@ibm.com

powerpc/64s: Move hash MMU support code under CONFIG_PPC_64S_HASH_MMU

2021-12-09T11:41:13+00:00

Compiling out hash support code when CONFIG_PPC_64S_HASH_MMU=n saves
128kB kernel image size (90kB text) on powernv_defconfig minus KVM,
350kB on pseries_defconfig minus KVM, 40kB on a tiny config.

Signed-off-by: Nicholas Piggin 
[mpe: Fixup defined(ARCH_HAS_MEMREMAP_COMPAT_ALIGN), which needs CONFIG.
      Fix radix_enabled() use in setup_initial_memory_limit(). Add some
      stubs to reduce number of ifdefs.]
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20211201144153.2456614-18-npiggin@gmail.com