As explained by commit daf00ae71d ("powerpc/traps: restore
recoverability of machine_check interrupts"), die() can't be called from
within nmi_enter to nicely kill a process context that was interrupted.
nmi_exit must be called first.
This adds a function die_mce which takes care of this for machine check
handlers.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210130130852.2952424-24-npiggin@gmail.com
This simplifies code, and it is also useful when introducing
interrupt handler wrappers when introducing wrapper functionality
that doesn't cope with asm entry code calling into more than one
handler function.
32-bit and 64e still have some such cases, which limits some ways
they can use interrupt wrappers.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210130130852.2952424-15-npiggin@gmail.com
Make mm fault handlers all just take the pt_regs * argument and load
DAR/DSISR from that. Make those that return a value return long.
This is done to make the function signatures match other handlers, which
will help with a future patch to add wrappers. Explicit arguments could
be added for performance but that would require more wrapper macro
variants.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210130130852.2952424-7-npiggin@gmail.com
handle_page_fault() has some code dedicated to book3s/32 to
call do_break() when the DSI is a DABR match.
On other platforms, do_break() is handled separately.
Do the same for book3s/32, do it earlier in the process of DSI.
This change also avoid doing the test on ISI.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210130130852.2952424-4-npiggin@gmail.com
Interrupts that occur in kernel mode expect that context tracking
is set to kernel. Enabling local irqs before context tracking
switches from guest to host means interrupts can come in and trigger
warnings about wrong context, and possibly worse.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210130130852.2952424-3-npiggin@gmail.com
When replaying pending soft-masked interrupts when an interrupt returns
to an irqs-enabled context, there is a special case required if this was
an asynchronous interrupt to avoid unbounded interrupt recursion.
This case was not tested for in the case the asynchronous interrupt hit
in user context, because a subsequent nested interrupt would by definition
hit in kernel mode, which then exits via the kernel path which does test
this case.
There is no reason to allow this for such interrupts. While recursion is
bounded at the next level, it's simpler and uses less stack to apply the
replay logic consistently.
This also expands the comment which was really pretty poor and didn't
explain the problem (I can say that because I wrote it).
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210130130852.2952424-2-npiggin@gmail.com
Make powernv, pseries, powermac and maple use ppc_mc.discover_phbs.
These platforms need to be done together because they all depend on
pci_dn's being created from the DT. The pci_dn contains a pointer to
the relevant pci_controller so they need to be created after the
pci_controller structures are available, but before PCI devices are
scanned. Currently this ordering is provided by initcalls and the
sequence is:
1. PHBs are discovered (setup_arch) (early boot, pre-initcalls)
2. pci_dn are created from the unflattended DT (core initcall)
3. PHBs are scanned pcibios_init() (subsys initcall)
The new ppc_md.discover_phbs() function is also a core_initcall so we
can't guarantee ordering between the creation of pci_controllers and
the creation of pci_dn's which require a pci_controller. We could use
the postcore, or core_sync initcall levels, but it's cleaner to just
move the pci_dn setup into the per-PHB inits which occur inside of
.discover_phb() for these platforms. This brings the boot-time path in
line with the PHB hotplug path that is used for pseries DLPAR
operations too.
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
[mpe: Squash powermac & maple in to avoid breakage those platforms,
convert memblock allocs to use kmalloc to avoid warnings]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201103043523.916109-2-oohall@gmail.com
EXPORT_UNUSED_SYMBOL* is not actually used anywhere. Remove the
unused functionality as we generally just remove unused code anyway.
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
The static inline get_cxl_module function is entirely unused since commit
8bf6b91a51 ("Revert "powerpc/powernv: Add support for the cxl kernel
api on the real phb"), so remove it.
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Andrew Donnellan <ajd@linux.ibm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
Pull powerpc fixes from Michael Ellerman:
- A fix for a change we made to __kernel_sigtramp_rt64() which confused
glibc's backtrace logic, and also changed the semantics of that
symbol, which was arguably an ABI break.
- A fix for a stack overwrite in our VSX instruction emulation.
- A couple of fixes for the Makefile logic in the new C VDSO.
Thanks to Masahiro Yamada, Naveen N. Rao, Raoni Fassina Firmino, and
Ravi Bangoria.
* tag 'powerpc-5.11-7' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
powerpc/64/signal: Fix regression in __kernel_sigtramp_rt64() semantics
powerpc/vdso64: remove meaningless vgettimeofday.o build rule
powerpc/vdso: fix unnecessary rebuilds of vgettimeofday.o
powerpc/sstep: Fix array out of bound warning
This fix the bad fault reported by KUAP when io_wqe_worker access userspace.
Bug: Read fault blocked by KUAP!
WARNING: CPU: 1 PID: 101841 at arch/powerpc/mm/fault.c:229 __do_page_fault+0x6b4/0xcd0
NIP [c00000000009e7e4] __do_page_fault+0x6b4/0xcd0
LR [c00000000009e7e0] __do_page_fault+0x6b0/0xcd0
..........
Call Trace:
[c000000016367330] [c00000000009e7e0] __do_page_fault+0x6b0/0xcd0 (unreliable)
[c0000000163673e0] [c00000000009ee3c] do_page_fault+0x3c/0x120
[c000000016367430] [c00000000000c848] handle_page_fault+0x10/0x2c
--- interrupt: 300 at iov_iter_fault_in_readable+0x148/0x6f0
..........
NIP [c0000000008e8228] iov_iter_fault_in_readable+0x148/0x6f0
LR [c0000000008e834c] iov_iter_fault_in_readable+0x26c/0x6f0
interrupt: 300
[c0000000163677e0] [c0000000007154a0] iomap_write_actor+0xc0/0x280
[c000000016367880] [c00000000070fc94] iomap_apply+0x1c4/0x780
[c000000016367990] [c000000000710330] iomap_file_buffered_write+0xa0/0x120
[c0000000163679e0] [c00800000040791c] xfs_file_buffered_aio_write+0x314/0x5e0 [xfs]
[c000000016367a90] [c0000000006d74bc] io_write+0x10c/0x460
[c000000016367bb0] [c0000000006d80e4] io_issue_sqe+0x8d4/0x1200
[c000000016367c70] [c0000000006d8ad0] io_wq_submit_work+0xc0/0x250
[c000000016367cb0] [c0000000006e2578] io_worker_handle_work+0x498/0x800
[c000000016367d40] [c0000000006e2cdc] io_wqe_worker+0x3fc/0x4f0
[c000000016367da0] [c0000000001cb0a4] kthread+0x1c4/0x1d0
[c000000016367e10] [c00000000000dbf0] ret_from_kernel_thread+0x5c/0x6c
The kernel consider thread AMR value for kernel thread to be
AMR_KUAP_BLOCKED. Hence access to userspace is denied. This
of course not correct and we should allow userspace access after
kthread_use_mm(). To be precise, kthread_use_mm() should inherit the
AMR value of the operating address space. But, the AMR value is
thread-specific and we inherit the address space and not thread
access restrictions. Because of this ignore AMR value when accessing
userspace via kernel thread.
current_thread_amr/iamr() are updated, because we use them in the
below stack.
....
[ 530.710838] CPU: 13 PID: 5587 Comm: io_wqe_worker-0 Tainted: G D 5.11.0-rc6+ #3
....
NIP [c0000000000aa0c8] pkey_access_permitted+0x28/0x90
LR [c0000000004b9278] gup_pte_range+0x188/0x420
--- interrupt: 700
[c00000001c4ef3f0] [0000000000000000] 0x0 (unreliable)
[c00000001c4ef490] [c0000000004bd39c] gup_pgd_range+0x3ac/0xa20
[c00000001c4ef5a0] [c0000000004bdd44] internal_get_user_pages_fast+0x334/0x410
[c00000001c4ef620] [c000000000852028] iov_iter_get_pages+0xf8/0x5c0
[c00000001c4ef6a0] [c0000000007da44c] bio_iov_iter_get_pages+0xec/0x700
[c00000001c4ef770] [c0000000006a325c] iomap_dio_bio_actor+0x2ac/0x4f0
[c00000001c4ef810] [c00000000069cd94] iomap_apply+0x2b4/0x740
[c00000001c4ef920] [c0000000006a38b8] __iomap_dio_rw+0x238/0x5c0
[c00000001c4ef9d0] [c0000000006a3c60] iomap_dio_rw+0x20/0x80
[c00000001c4ef9f0] [c008000001927a30] xfs_file_dio_aio_write+0x1f8/0x650 [xfs]
[c00000001c4efa60] [c0080000019284dc] xfs_file_write_iter+0xc4/0x130 [xfs]
[c00000001c4efa90] [c000000000669984] io_write+0x104/0x4b0
[c00000001c4efbb0] [c00000000066cea4] io_issue_sqe+0x3d4/0xf50
[c00000001c4efc60] [c000000000670200] io_wq_submit_work+0xb0/0x2f0
[c00000001c4efcb0] [c000000000674268] io_worker_handle_work+0x248/0x4a0
[c00000001c4efd30] [c0000000006746e8] io_wqe_worker+0x228/0x2a0
[c00000001c4efda0] [c00000000019d994] kthread+0x1b4/0x1c0
Fixes: 48a8ab4eeb ("powerpc/book3s64/pkeys: Don't update SPRN_AMR when in kernel mode.")
Reported-by: Zorro Lang <zlang@redhat.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210206025634.521979-1-aneesh.kumar@linux.ibm.com
On many powerpc platforms the discovery and initalisation of
pci_controllers (PHBs) happens inside of setup_arch(). This is very early
in boot (pre-initcalls) and means that we're initialising the PHB long
before many basic kernel services (slab allocator, debugfs, a real ioremap)
are available.
On PowerNV this causes an additional problem since we map the PHB registers
with ioremap(). As of commit d538aadc27 ("powerpc/ioremap: warn on early
use of ioremap()") a warning is printed because we're using the "incorrect"
API to setup and MMIO mapping in searly boot. The kernel does provide
early_ioremap(), but that is not intended to create long-lived MMIO
mappings and a seperate warning is printed by generic code if
early_ioremap() mappings are "leaked."
This is all fixable with dumb hacks like using early_ioremap() to setup
the initial mapping then replacing it with a real ioremap later on in
boot, but it does raise the question: Why the hell are we setting up the
PHB's this early in boot?
The old and wise claim it's due to "hysterical rasins." Aside from amused
grapes there doesn't appear to be any real reason to maintain the current
behaviour. Already most of the newer embedded platforms perform PHB
discovery in an arch_initcall and between the end of setup_arch() and the
start of initcalls none of the generic kernel code does anything PCI
related. On powerpc scanning PHBs occurs in a subsys_initcall so it should
be possible to move the PHB discovery to a core, postcore or arch initcall.
This patch adds the ppc_md.discover_phbs hook and a core_initcall stub that
calls it. The core_initcalls are the earliest to be called so this will
any possibly issues with dependency between initcalls. This isn't just an
academic issue either since on pseries and PowerNV EEH init occurs in an
arch_initcall and depends on the pci_controllers being available, similarly
the creation of pci_dns occurs at core_initcall_sync (i.e. between core and
postcore initcalls). These problems need to be addressed seperately.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
[mpe: Make discover_phbs() static]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201103043523.916109-1-oohall@gmail.com
Commit 0138ba5783 ("powerpc/64/signal: Balance return predictor
stack in signal trampoline") changed __kernel_sigtramp_rt64() VDSO and
trampoline code, and introduced a regression in the way glibc's
backtrace()[1] detects the signal-handler stack frame. Apart from the
practical implications, __kernel_sigtramp_rt64() was a VDSO function
with the semantics that it is a function you can call from userspace
to end a signal handling. Now this semantics are no longer valid.
I believe the aforementioned change affects all releases since 5.9.
This patch tries to fix both the semantics and practical aspect of
__kernel_sigtramp_rt64() returning it to the previous code, whilst
keeping the intended behaviour of 0138ba5783 by adding a new symbol
to serve as the jump target from the kernel to the trampoline. Now the
trampoline has two parts, a new entry point and the old return point.
[1] https://lists.ozlabs.org/pipermail/linuxppc-dev/2021-January/223194.html
Fixes: 0138ba5783 ("powerpc/64/signal: Balance return predictor stack in signal trampoline")
Cc: stable@vger.kernel.org # v5.9+
Signed-off-by: Raoni Fassina Firmino <raoni@linux.ibm.com>
Acked-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Minor tweaks to change log formatting, add stable tag]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210201200505.iz46ubcizipnkcxe@work-tp
Current PERF_SAMPLE_WEIGHT sample type is very useful to expresses the
cost of an action represented by the sample. This allows the profiler
to scale the samples to be more informative to the programmer. It could
also help to locate a hotspot, e.g., when profiling by memory latencies,
the expensive load appear higher up in the histograms. But current
PERF_SAMPLE_WEIGHT sample type is solely determined by one factor. This
could be a problem, if users want two or more factors to contribute to
the weight. For example, Golden Cove core PMU can provide both the
instruction latency and the cache Latency information as factors for the
memory profiling.
For current X86 platforms, although meminfo::latency is defined as a
u64, only the lower 32 bits include the valid data in practice (No
memory access could last than 4G cycles). The higher 32 bits can be used
to store new factors.
Add a new sample type, PERF_SAMPLE_WEIGHT_STRUCT, to indicate the new
sample weight structure. It shares the same space as the
PERF_SAMPLE_WEIGHT sample type.
Users can apply either the PERF_SAMPLE_WEIGHT sample type or the
PERF_SAMPLE_WEIGHT_STRUCT sample type to retrieve the sample weight, but
they cannot apply both sample types simultaneously.
Currently, only X86 and PowerPC use the PERF_SAMPLE_WEIGHT sample type.
- For PowerPC, there is nothing changed for the PERF_SAMPLE_WEIGHT
sample type. There is no effect for the new PERF_SAMPLE_WEIGHT_STRUCT
sample type. PowerPC can re-struct the weight field similarly later.
- For X86, the same value will be dumped for the PERF_SAMPLE_WEIGHT
sample type or the PERF_SAMPLE_WEIGHT_STRUCT sample type for now.
The following patches will apply the new factors for the
PERF_SAMPLE_WEIGHT_STRUCT sample type.
The field in the union perf_sample_weight should be shared among
different architectures. A generic name is required, but it's hard to
abstract a name that applies to all architectures. For example, on X86,
the fields are to store all kinds of latency. While on PowerPC, it
stores MMCRA[TECX/TECM], which should not be latency. So a general name
prefix 'var$NUM' is used here.
Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/1611873611-156687-2-git-send-email-kan.liang@linux.intel.com
Pull powerpc fix from Michael Ellerman:
"One fix for a bug in our soft interrupt masking, which could lead to
interrupt replaying recursing, causing spurious interrupts.
Thanks to Nicholas Piggin"
* tag 'powerpc-5.11-6' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
powerpc/64s: prevent recursive replay_soft_interrupts causing superfluous interrupt
The pnv_phb->initialized flag is an odd beast. It was added back in 2012 in
commit db1266c852 ("powerpc/powernv: Skip check on PE if necessary") to
allow devices to be enabled even if the device had not yet been assigned to
a PE. Allowing the device to be enabled before the PE is configured may
cause spurious EEH events since none of the IOMMU context has been setup.
I'm not entirely sure why this was ever necessary. My best guess is that it
was an workaround for a bug or some other undesireable behaviour from the
PCI core. Either way, it's unnecessary now since as of commit dc3d8f85bb
("powerpc/powernv/pci: Re-work bus PE configuration") we can guarantee that
the PE will be configured before the PCI core will allow drivers to bind to
the device.
It's also worth pointing out that the ->initialized flag is only set in
pnv_pci_ioda_create_dbgfs(). That function has its entire body wrapped
in #ifdef CONFIG_DEBUG_FS. As a result, for kernels built without debugfs
(i.e. petitboot) the other checks in pnv_pci_enable_device_hook() are
bypassed entirely.
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200902013657.1753830-1-oohall@gmail.com
