Boot fails with GCC latent entropy plugin enabled.
This is due to early boot functions trying to access 'latent_entropy'
global data while the kernel is not relocated at its final
destination yet.
As there is no way to tell GCC to use PTRRELOC() to access it,
disable latent entropy plugin in early_32.o and feature-fixups.o and
code-patching.o
Fixes: 38addce8b6 ("gcc-plugins: Add latent_entropy plugin")
Cc: stable@vger.kernel.org # v4.9+
Reported-by: Erhard Furtner <erhard_f@mailbox.org>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=215217
Link: https://lore.kernel.org/r/2bac55483b8daf5b1caa163a45fa5f9cdbe18be4.1640178426.git.christophe.leroy@csgroup.eu
The purpose of selftests is to check that instructions are
properly formed. Not to check that they properly run.
For that test it uses normal memory, not special test
memory.
In preparation of a future patch enforcing patch_instruction()
to be used only on valid text areas, implement a ppc_inst_write()
instruction which is the complement of ppc_inst_read(). This
new function writes the formated instruction in valid kernel
memory and doesn't bother about icache.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/7cf5335cc07ca9b6f8cdaa20ca9887fce4df3bea.1638446239.git.christophe.leroy@csgroup.eu
Split do_patch_instruction() in two functions, the caller doing the
spin locking and the callee doing everything else.
And remove a few unnecessary initialisations and intermediate
variables.
This allows the callee to return from anywhere in the function.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/dbc85980a0d2a935731b272e8907e8bb1d8fc8c5.1638446239.git.christophe.leroy@csgroup.eu
pXd_offset() doesn't return NULL. When the base is NULL, it
still adds the offset.
Use pXd_none() to check validity instead. It also improves
performance by folding out none existing levels as pXd_none()
always returns 0 in that case.
Such an error is unexpected, use WARN_ON() so that the caller
doesn't have to worry about it, and drop the returned value.
And now that unmap_patch_area() doesn't return error, we can
take into account the error returned by __patch_instruction().
While at it, remove the 'inline' property which is useless.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/299804b117fae35c786c827536c91f25352e279b.1638446239.git.christophe.leroy@csgroup.eu
code-patching has been working for years now, time has come to
remove debugging messages.
Change useful message to KERN_INFO and remove other ones.
Also add KERN_ERR to check() macro and change it into a do/while
to make checkpatch happy.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/3ff9823c0a812a8a145d979a9600a6d4591b80ee.1638446239.git.christophe.leroy@csgroup.eu
The llvm integrated assembler does not recognise the ISA 2.05 tlbiel
version. Work around it by switching to .long when an old arch level
detected.
Signed-off-by: Daniel Axtens <dja@axtens.net>
[aik: did "Eventually do this more smartly"]
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211221055904.555763-7-aik@ozlabs.ru
The dssall ("Data Stream Stop All") instruction is obsolete altogether
with other Data Cache Instructions since ISA 2.03 (year 2006).
LLVM IAS does not support it but PPC970 seems to be using it.
This switches dssall to .long as there is no much point in fixing LLVM.
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211221055904.555763-6-aik@ozlabs.ru
The LLVM integrated assembler really does not like us reassigning things
to the same label:
<instantiation>:7:9: error: invalid reassignment of non-absolute variable 'fs_label'
This happens across a bunch of platforms:
https://github.com/ClangBuiltLinux/linux/issues/1043https://github.com/ClangBuiltLinux/linux/issues/1008https://github.com/ClangBuiltLinux/linux/issues/920https://github.com/ClangBuiltLinux/linux/issues/1050
There is no hope of getting this fixed in LLVM (see
https://github.com/ClangBuiltLinux/linux/issues/1043#issuecomment-641571200
and https://bugs.llvm.org/show_bug.cgi?id=47798#c1 )
so if we want to build with LLVM_IAS, we need to hack
around it ourselves.
For us the big problem comes from this:
\#define USE_FIXED_SECTION(sname) \
fs_label = start_##sname; \
fs_start = sname##_start; \
use_ftsec sname;
\#define USE_TEXT_SECTION()
fs_label = start_text; \
fs_start = text_start; \
.text
and in particular fs_label.
This works around it by not setting those 'variables' and requiring
that users of the variables instead track for themselves what section
they are in. This isn't amazing, by any stretch, but it gets us further
in the compilation.
Note that even though users have to keep track of the section, using
a wrong one produces an error with both binutils and llvm which prevents
from using wrong section at the compile time:
llvm error example:
AS arch/powerpc/kernel/head_64.o
<unknown>:0: error: Cannot represent a difference across sections
make[3]: *** [/home/aik/p/kernels-llvm/llvm/scripts/Makefile.build:388: arch/powerpc/kernel/head_64.o] Error 1
binutils error example:
/home/aik/p/kernels-llvm/llvm/arch/powerpc/kernel/exceptions-64s.S: Assembler messages:
/home/aik/p/kernels-llvm/llvm/arch/powerpc/kernel/exceptions-64s.S:1974: Error: can't resolve `system_call_common' {.text section} - `start_r
eal_vectors' {.head.text.real_vectors section}
make[3]: *** [/home/aik/p/kernels-llvm/llvm/scripts/Makefile.build:388: arch/powerpc/kernel/head_64.o] Error 1
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211221055904.555763-5-aik@ozlabs.ru
LLVM's integrated assembler does not like either -Wa,-mpower4
or -Wa,-many. So just don't pass them if they're not supported.
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211221055904.555763-3-aik@ozlabs.ru
This patch future-proofs the kernel against linker changes that might
put the toc pointer at some location other than .got+0x8000, by
replacing __toc_start+0x8000 with .TOC. throughout. If the kernel's
idea of the toc pointer doesn't agree with the linker, bad things
happen.
prom_init.c code relocating its toc is also changed so that a symbolic
__prom_init_toc_start toc-pointer relative address is calculated
rather than assuming that it is always at toc-pointer - 0x8000. The
length calculations loading values from the toc are also avoided.
It's a little incestuous to do that with unreloc_toc picking up
adjusted values (which is fine in practice, they both adjust by the
same amount if all goes well).
I've also changed the way .got is aligned in vmlinux.lds and
zImage.lds, mostly so that dumping out section info by objdump or
readelf plainly shows the alignment is 256. This linker script
feature was added 2005-09-27, available in FSF binutils releases from
2.17 onwards. Should be safe to use in the kernel, I think.
Finally, put *(.got) before the prom_init.o entry which only needs
*(.toc), so that the GOT header goes in the correct place. I don't
believe this makes any difference for the kernel as it would for
dynamic objects being loaded by ld.so. That change is just to stop
lusers who blindly copy kernel scripts being led astray. Of course,
this change needs the prom_init.c changes.
Some notes on .toc and .got.
.toc is a compiler generated section of addresses. .got is a linker
generated section of addresses, generally built when the linker sees
R_*_*GOT* relocations. In the case of powerpc64 ld.bfd, there are
multiple generated .got sections, one per input object file. So you
can somewhat reasonably write in a linker script an input section
statement like *prom_init.o(.got .toc) to mean "the .got and .toc
section for files matching *prom_init.o". On other architectures that
doesn't make sense, because the linker generally has just one .got
section. Even on powerpc64, note well that the GOT entries for
prom_init.o may be merged with GOT entries from other objects. That
means that if prom_init.o references, say, _end via some GOT
relocation, and some other object also references _end via a GOT
relocation, the GOT entry for _end may be in the range
__prom_init_toc_start to __prom_init_toc_end and if the kernel does
something special to GOT/TOC entries in that range then the value of
_end as seen by objects other than prom_init.o will be affected. On
the other hand the GOT entry for _end may not be in the range
__prom_init_toc_start to __prom_init_toc_end. Which way it turns out
is deterministic but a detail of linker operation that should not be
relied on.
A feature of ld.bfd is that input .toc (and .got) sections matching
one linker input section statement may be sorted, to put entries used
by small-model code first, near the toc base. This is why scripts for
powerpc64 normally use *(.got .toc) rather than *(.got) *(.toc), since
the first form allows more freedom to sort.
Another feature of ld.bfd is that indirect addressing sequences using
the GOT/TOC may be edited by the linker to relative addressing. In
many cases relative addressing would be emitted by gcc for
-mcmodel=medium if you appropriately decorate variable declarations
with non-default visibility.
The original patch is here:
https://lore.kernel.org/linuxppc-dev/20210310034813.GM6042@bubble.grove.modra.org/
Signed-off-by: Alan Modra <amodra@au1.ibm.com>
[aik: removed non-relocatable which is gone in 24d33ac5b8]
[aik: added <=2.24 check]
[aik: because of llvm-as, kernel_toc_addr() uses "mr" instead of global register variable]
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211221055904.555763-2-aik@ozlabs.ru
Make `find_via_cuda` and `find_via_pmu` initialization functions.
Previously, their definitions in `drivers/macintosh/via-cuda.h` include
the `__init` attribute but their alternative definitions in
`arch/powerpc/powermac/sectup./c` and prototypes in `include/linux/
cuda.h` and `include/linux/pmu.h` do not use the `__init` macro. Since,
only initialization functions call `find_via_cuda` and `find_via_pmu`
it is safe to label these functions with `__init`.
Signed-off-by: Nick Child <nick.child@ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211216220035.605465-21-nick.child@ibm.com
Some functions defined in 'arch/powerpc/platforms/512x' 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 <nick.child@ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211216220035.605465-20-nick.child@ibm.com
Some functions defined in 'arch/powerpc/platforms/85xx' 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 <nick.child@ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211216220035.605465-19-nick.child@ibm.com
Some functions defined in 'arch/powerpc/platforms/83xx' 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 <nick.child@ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211216220035.605465-18-nick.child@ibm.com
Some functions defined in 'arch/powerpc/platforms/embedded6xx' 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 <nick.child@ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211216220035.605465-17-nick.child@ibm.com
Some functions defined in 'arch/powerpc/platforms/44x/' are deserving of an
`__init` macro attribute. These functions are only called by other
initialization functions and therefore should inherit the attribute.
Signed-off-by: Nick Child <nick.child@ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211216220035.605465-16-nick.child@ibm.com
Some functions defined in 'arch/powerpc/platforms/4xx' are deserving of an
`__init` macro attribute. These functions are only called by other
initialization functions and therefore should inherit the attribute.
Signed-off-by: Nick Child <nick.child@ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211216220035.605465-15-nick.child@ibm.com
Some functions defined in 'arch/powerpc/platforms/ps3' 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 <nick.child@ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211216220035.605465-14-nick.child@ibm.com
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 <nick.child@ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211216220035.605465-13-nick.child@ibm.com
Some functions defined in 'arch/powerpc/platforms/powernv' 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 <nick.child@ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211216220035.605465-12-nick.child@ibm.com
Some functions defined in 'arch/powerpc/platforms/powermac` 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 <nick.child@ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211216220035.605465-11-nick.child@ibm.com
Some functions defined in 'arch/powerpc/platforms/pasemi' 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 <nick.child@ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211216220035.605465-10-nick.child@ibm.com
The function `Enable_SRAM` defined in 'arch/powerpc/platforms/chrp' is
deserving of an `__init` macro attribute. This function is only called by
other initialization functions and therefore should inherit the attribute.
Signed-off-by: Nick Child <nick.child@ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211216220035.605465-9-nick.child@ibm.com
Some functions defined in 'arch/powerpc/platforms/cell' are deserving of an
`__init` macro attribute. These functions are only called by other
initialization functions and therefore should inherit the attribute.
Signed-off-by: Nick Child <nick.child@ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211216220035.605465-8-nick.child@ibm.com
`xmon_register_spus` defined in 'arch/powerpc/xmon' is deserving of an
`__init` macro attribute. This functions is only called by other
initialization functions and therefore should inherit the attribute.
Also, change the function declaration in the header file to include
`__init`.
Signed-off-by: Nick Child <nick.child@ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211216220035.605465-7-nick.child@ibm.com
Some files functions in 'arch/powerpc/sysdev' 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 <nick.child@ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211216220035.605465-6-nick.child@ibm.com
Some functions defined in 'arch/powerpc/perf' 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 <nick.child@ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211216220035.605465-5-nick.child@ibm.com
Some functions defined in 'arch/powerpc/mm' 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 <nick.child@ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211216220035.605465-4-nick.child@ibm.com
Some functions defined in 'arch/powerpc/lib' 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 <nick.child@ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211216220035.605465-3-nick.child@ibm.com
Some functions defined in `arch/powerpc/kernel` (and one in `arch/powerpc/
kexec`) 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 <nick.child@ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211216220035.605465-2-nick.child@ibm.com
We have a general signal fuzzer, sigfuz, which can modify the MSR & NIP
before sigreturn. But the chance of it hitting a kernel address and also
clearing MSR_PR is fairly slim.
So add a specific test of sigreturn to a kernel address, both with and
without attempting to clear MSR_PR (which the kernel must block).
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211209115944.4062384-1-mpe@ellerman.id.au
"spidev" is not a real device, but a Linux implementation detail. It has
never been documented either. The kernel has WARNed on the use of it for
over 6 years. Time to remove its usage from the tree.
Signed-off-by: Rob Herring <robh@kernel.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211217221400.3667133-1-robh@kernel.org
Return value from ocxl_context_attach() directly instead
of taking this in another redundant variable.
Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Minghao Chi <chi.minghao@zte.com.cn>
Acked-by: Andrew Donnellan <ajd@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211215060438.441918-1-chi.minghao@zte.com.cn
pmd_huge() is defined to false when HUGETLB_PAGE is not configured, but
the vmap code still installs huge PMDs. This leads to false bad PMD
errors when vunmapping because it is not seen as a huge PTE, and the bad
PMD check catches it. The end result may not be much more serious than
some bad pmd warning messages, because the pmd_none_or_clear_bad() does
what we wanted and clears the huge PTE anyway.
Fix this by checking pmd_is_leaf(), which checks for a PTE regardless of
config options. The whole huge/large/leaf stuff is a tangled mess but
that's kernel-wide and not something we can improve much in arch/powerpc
code.
pmd_page(), pud_page(), etc., called by vmalloc_to_page() on huge vmaps
can similarly trigger a false VM_BUG_ON when CONFIG_HUGETLB_PAGE=n, so
those checks are adjusted. The checks were added by commit d6eacedd1f
("powerpc/book3s: Use config independent helpers for page table walk"),
while implementing a similar fix for other page table walking functions.
Fixes: d909f9109c ("powerpc/64s/radix: Enable HAVE_ARCH_HUGE_VMAP")
Cc: stable@vger.kernel.org # v5.3+
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211216103342.609192-1-npiggin@gmail.com
Use the macro 'swap()' defined in 'include/linux/minmax.h' to avoid
opencoding it.
Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: David Yang <davidcomponentone@gmail.com>
Signed-off-by: Yang Guang <yang.guang5@zte.com.cn>
[mpe: Add include of linux/minmax.h]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/71a702c2189b16c152affd8a8cda1d84ce32741c.1639792543.git.yang.guang5@zte.com.cn
Mitigation patching test iterates over a set of mitigations irrespective
of whether a certain mitigation is supported/available in the kernel.
This causes following messages on a kernel where some mitigations
are unavailable:
Spawned threads enabling/disabling mitigations ...
cat: entry_flush: No such file or directory
cat: uaccess_flush: No such file or directory
Waiting for timeout ...
OK
This patch adds a check for available mitigations in the kernel.
Reported-by: Nageswara R Sastry <rnsastry@linux.ibm.com>
Signed-off-by: Sachin Sant <sachinp@linux.vnet.ibm.com>
Tested-by: Nageswara R Sastry <rnsastry@linux.ibm.com>
Reviewed-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/163941374362.36967.18016981579099073379.sendpatchset@1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa
Slab is up at this point, using the bootmem allocator triggers a
warning. Switch to using the regular cpumask allocator.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Tested-by: Sachin Sant <sachinp@linux.vnet.ibm.com>
Reviewed-by: Nathan Lynch <nathanl@linux.ibm.com>
Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211105132923.1582514-1-npiggin@gmail.com
Reading the CFAR register is quite costly (~20 cycles on POWER9). It is
a good idea to have for most synchronous interrupts, but for async ones
it is much less important.
Doorbell, external, and decrementer interrupts are the important
asynchronous ones. HV interrupts can't skip CFAR if KVM HV is possible,
because it might be a guest exit that requires CFAR preserved. But the
important pseries interrupts can avoid loading CFAR.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210922145452.352571-7-npiggin@gmail.com
Move the assertions requiring restart table searches under
CONFIG_PPC_IRQ_SOFT_MASK_DEBUG.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210922145452.352571-6-npiggin@gmail.com
Enabling MSR[EE] in interrupt handlers while interrupts are still soft
masked allows PMIs to profile interrupt handlers to some degree, beyond
what SIAR latching allows.
When perf is not being used, this is almost useless work. It requires an
extra mtmsrd in the irq handler, and it also opens the door to masked
interrupts hitting and requiring replay, which is more expensive than
just taking them directly. This effect can be noticable in high IRQ
workloads.
Avoid enabling MSR[EE] unless perf is currently in use. This saves about
60 cycles (or 8%) on a simple decrementer interrupt microbenchmark.
Replayed interrupts drop from 1.4% of all interrupts taken, to 0.003%.
This does prevent the soft-nmi interrupt being taken in these handlers,
but that's not too reliable anyway. The SMP watchdog will continue to be
the reliable way to catch lockups.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210922145452.352571-5-npiggin@gmail.com
Interrupt code enables MSR[EE] in some irq handlers while keeping local
irqs disabled via soft-mask, allowing PMI interrupts to be taken as
soft-NMI to improve profiling of irq handlers.
When perf is not enabled, there is no point to doing this, it's
additional overhead. So provide a function that can say if PMIs should
be taken promptly if possible.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210922145452.352571-4-npiggin@gmail.com
Christophe Leroy
Alexey Kardashevskiy
Daniel Axtens
Alan Modra
Nick Child
Michael Ellerman
Rob Herring
Minghao Chi
Nicholas Piggin
Yang Guang
Christophe JAILLET
Sachin Sant