[ Upstream commit d5a9597d6916a76663085db984cb8fe97f0a5c56 ]
Today, all possible serial lines (ssl*=) as well as all
possible consoles (con*=) each share a single interrupt
(with a fixed number) with others of the same type.
Now, if you have two lines, say ssl0 and ssl1, and one
of them is connected to an fd you cannot read (e.g. a
file), but the other gets a read interrupt, then both
of them get the interrupt since it's shared. Then, the
read() call will return EOF, since it's a file being
written and there's nothing to read (at least not at
the current offset, at the end).
Unfortunately, this is treated as a read error, and we
close this line, losing all the possible output.
It might be possible to work around this and make the
IRQ sharing work, however, now that we have dynamically
allocated IRQs that are easy to use, simply use that to
achieve separating between the events; then there's no
interrupt for that line and we never attempt the read
in the first place, thus not closing the line.
This manifested itself in the wifi hostap/hwsim tests
where the parallel script communicates via one serial
console and the kernel messages go to another (a file)
and sending data on the communication console caused
the kernel messages to stop flowing into the file.
Reported-by: Jouni Malinen <j@w1.fi>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-By: anton ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 365719035526e8eda214a1cedb2e1c96e969a0d7 upstream.
If DMA (PCI over virtio) is enabled, then some drivers may
enable CONFIG_DMA_OPS as well, and then we pull in the x86
definition of get_arch_dma_ops(), which uses the dma_ops
symbol, which isn't defined.
Since we don't have real DMA ops nor any kind of IOMMU fix
this in the simplest possible way: pull in the asm-generic
file instead of inheriting the x86 one. It's not clear why
those drivers that do (e.g. VDPA) "select DMA_OPS", and if
they'd even work with this, but chances are nobody will be
wanting to do that anyway, so fixing the build failure is
good enough.
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Fixes: 68f5d3f3b6 ("um: add PCI over virtio emulation driver")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Cc: stable@vger.kernel.org
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 9f13fb0cd11ed2327abff69f6501a2c124c88b5a upstream.
In the event that random_get_entropy() can't access a cycle counter or
similar, falling back to returning 0 is really not the best we can do.
Instead, at least calling random_get_entropy_fallback() would be
preferable, because that always needs to return _something_, even
falling back to jiffies eventually. It's not as though
random_get_entropy_fallback() is super high precision or guaranteed to
be entropic, but basically anything that's not zero all the time is
better than returning zero all the time.
This is accomplished by just including the asm-generic code like on
other architectures, which means we can get rid of the empty stub
function here.
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Richard Weinberger <richard@nod.at>
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit e3a33af812c611d99756e2ec61e9d7068d466bdf ]
Due to dropped inclusion of asm-generic/xor.h, xor_block_8regs symbol is
missing with CONFIG64 and break compilation, as the asm/xor_64.h also did
not include it. The patch recreate the logic from arch/x86, which check
whether AVX is available and add fallbacks for 32bit and 64bit config of
um.
A very minor additional "fix" is, the return of the macro parameter
instead of NULL, as this is the original intent of the macro, but
this does not change the actual behavior.
Fixes: c0ecca6604 ("um: enable the use of optimized xor routines in UML")
Signed-off-by: Benjamin Beichler <benjamin.beichler@uni-rostock.de>
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 077b7320942b64b0da182aefd83c374462a65535 ]
The function names init_registers() and restore_registers() are used
in several net/ethernet/ and gpu/drm/ drivers for other purposes (not
calls to UML functions), so rename them.
This fixes multiple build errors.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: linux-um@lists.infradead.org
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit bbe33504d4a7fdab9011211e55e262c869b3f6cc ]
Rename set_signals() as there's at least one driver that
uses the same name and can now be built on UM due to PCI
support, and thus we can get symbol conflicts.
Also rename set_signals_trace() to be consistent.
Reported-by: kernel test robot <lkp@intel.com>
Fixes: 68f5d3f3b6 ("um: add PCI over virtio emulation driver")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 5f8539e2ff962e25b57742ca7106456403abbc94 ]
Many places in the kernel use 'udelay' as an identifier, and
are broken with the current "#define udelay um_udelay". Fix
this by adding an argument to the macro, and do the same to
'ndelay' as well, just in case.
Fixes: 0bc8fb4dda ("um: Implement ndelay/udelay in time-travel mode")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Pull Kbuild updates from Masahiro Yamada:
- Add -s option (strict mode) to merge_config.sh to make it fail when
any symbol is redefined.
- Show a warning if a different compiler is used for building external
modules.
- Infer --target from ARCH for CC=clang to let you cross-compile the
kernel without CROSS_COMPILE.
- Make the integrated assembler default (LLVM_IAS=1) for CC=clang.
- Add <linux/stdarg.h> to the kernel source instead of borrowing
<stdarg.h> from the compiler.
- Add Nick Desaulniers as a Kbuild reviewer.
- Drop stale cc-option tests.
- Fix the combination of CONFIG_TRIM_UNUSED_KSYMS and CONFIG_LTO_CLANG
to handle symbols in inline assembly.
- Show a warning if 'FORCE' is missing for if_changed rules.
- Various cleanups
* tag 'kbuild-v5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (39 commits)
kbuild: redo fake deps at include/ksym/*.h
kbuild: clean up objtool_args slightly
modpost: get the *.mod file path more simply
checkkconfigsymbols.py: Fix the '--ignore' option
kbuild: merge vmlinux_link() between ARCH=um and other architectures
kbuild: do not remove 'linux' link in scripts/link-vmlinux.sh
kbuild: merge vmlinux_link() between the ordinary link and Clang LTO
kbuild: remove stale *.symversions
kbuild: remove unused quiet_cmd_update_lto_symversions
gen_compile_commands: extract compiler command from a series of commands
x86: remove cc-option-yn test for -mtune=
arc: replace cc-option-yn uses with cc-option
s390: replace cc-option-yn uses with cc-option
ia64: move core-y in arch/ia64/Makefile to arch/ia64/Kbuild
sparc: move the install rule to arch/sparc/Makefile
security: remove unneeded subdir-$(CONFIG_...)
kbuild: sh: remove unused install script
kbuild: Fix 'no symbols' warning when CONFIG_TRIM_UNUSD_KSYMS=y
kbuild: Switch to 'f' variants of integrated assembler flag
kbuild: Shuffle blank line to improve comment meaning
...
Pull printk updates from Petr Mladek:
- Optionally, provide an index of possible printk messages via
<debugfs>/printk/index/. It can be used when monitoring important
kernel messages on a farm of various hosts. The monitor has to be
updated when some messages has changed or are not longer available by
a newly deployed kernel.
- Add printk.console_no_auto_verbose boot parameter. It allows to
generate crash dump even with slow consoles in a reasonable time
frame.
- Remove printk_safe buffers. The messages are always stored directly
to the main logbuffer, even in NMI or recursive context. Also it
allows to serialize syslog operations by a mutex instead of a spin
lock.
- Misc clean up and build fixes.
* tag 'printk-for-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux:
printk/index: Fix -Wunused-function warning
lib/nmi_backtrace: Serialize even messages about idle CPUs
printk: Add printk.console_no_auto_verbose boot parameter
printk: Remove console_silent()
lib/test_scanf: Handle n_bits == 0 in random tests
printk: syslog: close window between wait and read
printk: convert @syslog_lock to mutex
printk: remove NMI tracking
printk: remove safe buffers
printk: track/limit recursion
lib/nmi_backtrace: explicitly serialize banner and regs
printk: Move the printk() kerneldoc comment to its new home
printk/index: Fix warning about missing prototypes
MIPS/asm/printk: Fix build failure caused by printk
printk: index: Add indexing support to dev_printk
printk: Userspace format indexing support
printk: Rework parse_prefix into printk_parse_prefix
printk: Straighten out log_flags into printk_info_flags
string_helpers: Escape double quotes in escape_special
printk/console: Check consistent sequence number when handling race in console_unlock()
Delete/fixup few includes in anticipation of global -isystem compile
option removal.
Note: crypto/aegis128-neon-inner.c keeps <stddef.h> due to redefinition
of uintptr_t error (one definition comes from <stddef.h>, another from
<linux/types.h>).
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
As these are now in asm-generic, it's no longer necessary to
declare them in the architecture.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
This is a preparation for changing over architectures to the
generic implementation one at a time. As there are no callers
of either __strncpy_from_user() or __strnlen_user(), fold these
into the strncpy_from_user() and strnlen_user() functions to make
each implementation independent of the others.
Many of these implementations have known bugs, but the intention
here is to not change behavior at all and stay compatible with
those bugs for the moment.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
We have a number of systems industry-wide that have a subset of their
functionality that works as follows:
1. Receive a message from local kmsg, serial console, or netconsole;
2. Apply a set of rules to classify the message;
3. Do something based on this classification (like scheduling a
remediation for the machine), rinse, and repeat.
As a couple of examples of places we have this implemented just inside
Facebook, although this isn't a Facebook-specific problem, we have this
inside our netconsole processing (for alarm classification), and as part
of our machine health checking. We use these messages to determine
fairly important metrics around production health, and it's important
that we get them right.
While for some kinds of issues we have counters, tracepoints, or metrics
with a stable interface which can reliably indicate the issue, in order
to react to production issues quickly we need to work with the interface
which most kernel developers naturally use when developing: printk.
Most production issues come from unexpected phenomena, and as such
usually the code in question doesn't have easily usable tracepoints or
other counters available for the specific problem being mitigated. We
have a number of lines of monitoring defence against problems in
production (host metrics, process metrics, service metrics, etc), and
where it's not feasible to reliably monitor at another level, this kind
of pragmatic netconsole monitoring is essential.
As one would expect, monitoring using printk is rather brittle for a
number of reasons -- most notably that the message might disappear
entirely in a new version of the kernel, or that the message may change
in some way that the regex or other classification methods start to
silently fail.
One factor that makes this even harder is that, under normal operation,
many of these messages are never expected to be hit. For example, there
may be a rare hardware bug which one wants to detect if it was to ever
happen again, but its recurrence is not likely or anticipated. This
precludes using something like checking whether the printk in question
was printed somewhere fleetwide recently to determine whether the
message in question is still present or not, since we don't anticipate
that it should be printed anywhere, but still need to monitor for its
future presence in the long-term.
This class of issue has happened on a number of occasions, causing
unhealthy machines with hardware issues to remain in production for
longer than ideal. As a recent example, some monitoring around
blk_update_request fell out of date and caused semi-broken machines to
remain in production for longer than would be desirable.
Searching through the codebase to find the message is also extremely
fragile, because many of the messages are further constructed beyond
their callsite (eg. btrfs_printk and other module-specific wrappers,
each with their own functionality). Even if they aren't, guessing the
format and formulation of the underlying message based on the aesthetics
of the message emitted is not a recipe for success at scale, and our
previous issues with fleetwide machine health checking demonstrate as
much.
This provides a solution to the issue of silently changed or deleted
printks: we record pointers to all printk format strings known at
compile time into a new .printk_index section, both in vmlinux and
modules. At runtime, this can then be iterated by looking at
<debugfs>/printk/index/<module>, which emits the following format, both
readable by humans and able to be parsed by machines:
$ head -1 vmlinux; shuf -n 5 vmlinux
# <level[,flags]> filename:line function "format"
<5> block/blk-settings.c:661 disk_stack_limits "%s: Warning: Device %s is misaligned\n"
<4> kernel/trace/trace.c:8296 trace_create_file "Could not create tracefs '%s' entry\n"
<6> arch/x86/kernel/hpet.c:144 _hpet_print_config "hpet: %s(%d):\n"
<6> init/do_mounts.c:605 prepare_namespace "Waiting for root device %s...\n"
<6> drivers/acpi/osl.c:1410 acpi_no_auto_serialize_setup "ACPI: auto-serialization disabled\n"
This mitigates the majority of cases where we have a highly-specific
printk which we want to match on, as we can now enumerate and check
whether the format changed or the printk callsite disappeared entirely
in userspace. This allows us to catch changes to printks we monitor
earlier and decide what to do about it before it becomes problematic.
There is no additional runtime cost for printk callers or printk itself,
and the assembly generated is exactly the same.
Signed-off-by: Chris Down <chris@chrisdown.name>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kees Cook <keescook@chromium.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Tested-by: Petr Mladek <pmladek@suse.com>
Reported-by: kernel test robot <lkp@intel.com>
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Acked-by: Jessica Yu <jeyu@kernel.org> # for module.{c,h}
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/e42070983637ac5e384f17fbdbe86d19c7b212a5.1623775748.git.chris@chrisdown.name
Pull UML updates from Richard Weinberger:
- Support for optimized routines based on the host CPU
- Support for PCI via virtio
- Various fixes
* tag 'for-linus-5.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml:
um: remove unneeded semicolon in um_arch.c
um: Remove the repeated declaration
um: fix error return code in winch_tramp()
um: fix error return code in slip_open()
um: Fix stack pointer alignment
um: implement flush_cache_vmap/flush_cache_vunmap
um: add a UML specific futex implementation
um: enable the use of optimized xor routines in UML
um: Add support for host CPU flags and alignment
um: allow not setting extra rpaths in the linux binary
um: virtio/pci: enable suspend/resume
um: add PCI over virtio emulation driver
um: irqs: allow invoking time-travel handler multiple times
um: time-travel/signals: fix ndelay() in interrupt
um: expose time-travel mode to userspace side
um: export signals_enabled directly
um: remove unused smp_sigio_handler() declaration
lib: add iomem emulation (logic_iomem)
um: allow disabling NO_IOMEM
vmalloc() heavy workloads in UML are extremely slow, due to
flushing the entire kernel VM space (flush_tlb_kernel_vm())
on the first segfault.
Implement flush_cache_vmap() to avoid that, and while at it
also add flush_cache_vunmap() since it's trivial.
This speeds up my vmalloc() heavy test of copying files out
from /sys/kernel/debug/gcov/ by 30x (from 30s to 1s.)
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
The generic asm futex implementation emulates atomic access to
memory by doing a get_user followed by put_user. These translate
to two mapping operations on UML with paging enabled in the
meantime. This, in turn may end up changing interrupts,
invoking the signal loop, etc.
This replaces the generic implementation by a mapping followed
by an operation on the mapped segment.
Signed-off-by: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
This patch enables the use of optimized xor routines from the x86
tree as well as the necessary fpu api shims so they can work on
UML.
Signed-off-by: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
1. Reflect host cpu flags into the UML instance so they can
be used to select the correct implementations for xor, crypto, etc.
2. Reflect host cache alignment into UML instance. This is
important when running 32 bit on a 64 bit host as 32 bit by
default aligns to 32 while the actual alignment should be 64.
Ditto for some Xeons which align at 128.
Signed-off-by: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
The UM virtual PCI devices currently cannot be suspended properly
since the virtio driver already disables VQs well before the PCI
bus's suspend_noirq wants to complete the transition by writing to
PCI config space.
After trying around for a long time with moving the devices on the
DPM list, trying to create dependencies between them, etc. I gave
up and instead added UML specific cross-driver API that lets the
virt-pci code enable not suspending/resuming VQs for its devices.
This then allows the PCI bus suspend_noirq to still talk to the
device, and suspend/resume works properly.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
To support testing of PCI/PCIe drivers in UML, add a PCI bus
support driver. This driver uses virtio, which in UML is really
just vhost-user, to talk to devices, and adds the devices to
the virtual PCI bus in the system.
Since virtio already allows DMA/bus mastering this really isn't
all that hard, of course we need the logic_iomem infrastructure
that was added by a previous patch.
The protocol to talk to the device is has a few fairly simple
messages for reading to/writing from config and IO spaces, and
messages for the device to send the various interrupts (INT#,
MSI/MSI-X and while suspended PME#).
Note that currently no offical virtio device ID is assigned for
this protocol, as a consequence this patch requires defining it
in the Kconfig, with a default that makes the driver refuse to
work at all.
Finally, in order to add support for MSI/MSI-X interrupts, some
small changes are needed in the UML IRQ code, it needs to have
more interrupts, changing NR_IRQS from 64 to 128 if this driver
is enabled, but not actually use them for anything so that the
generic IRQ domain/MSI infrastructure can allocate IRQ numbers.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
We should be able to ndelay() from any context, even from an
interrupt context! However, this is broken (not functionally,
but locking-wise) in time-travel because we'll get into the
time-travel code and enable interrupts to handle messages on
other time-travel aware subsystems (only virtio for now).
Luckily, I've already reworked the time-travel aware signal
(interrupt) delivery for suspend/resume to have a time travel
handler, which runs directly in the context of the signal and
not from the Linux interrupt.
In order to fix this time-travel issue then, we need to do a
few things:
1) rework the signal handling code to call time-travel handlers
(only) if interrupts are disabled but signals aren't blocked,
instead of marking it only pending there. This is needed to
not deadlock other communication.
2) rework time-travel to not enable interrupts while it's
waiting for a message;
3) rework time-travel to not (just) disable interrupts but
rather block signals at a lower level while it needs them
disabled for communicating with the controller.
Finally, since now we can actually spend even virtual time
in interrupts-disabled sections, the delay warning when we
deliver a time-travel delayed interrupt is no longer valid,
things can (and should) now get delayed.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
This will be necessary in the userspace side to fix the
signal/interrupt handling in time-travel=ext mode, which
is the next patch.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Use signals_enabled instead of always jumping through
a function call to read it, there's not much point in
that.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Adjust the kconfig a little to allow disabling NO_IOMEM in UML. To
make an "allyesconfig" with CONFIG_NO_IOMEM=n build, adjust a few
Kconfig things elsewhere and add dummy asm/fb.h and asm/vga.h files.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Use the common kernel style to eliminate a warning:
./arch/um/include/asm/pgtable.h:305:47: warning: suggest braces around empty body in ‘do’ statement [-Wempty-body]
#define update_mmu_cache(vma,address,ptep) do ; while (0)
^
mm/filemap.c:3212:3: note: in expansion of macro ‘update_mmu_cache’
update_mmu_cache(vma, addr, vmf->pte);
^~~~~~~~~~~~~~~~
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: linux-um@lists.infradead.org
Signed-off-by: Richard Weinberger <richard@nod.at>
Pull x86 irq entry updates from Thomas Gleixner:
"The irq stack switching was moved out of the ASM entry code in course
of the entry code consolidation. It ended up being suboptimal in
various ways.
This reworks the X86 irq stack handling:
- Make the stack switching inline so the stackpointer manipulation is
not longer at an easy to find place.
- Get rid of the unnecessary indirect call.
- Avoid the double stack switching in interrupt return and reuse the
interrupt stack for softirq handling.
- A objtool fix for CONFIG_FRAME_POINTER=y builds where it got
confused about the stack pointer manipulation"
* tag 'x86-entry-2021-02-24' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
objtool: Fix stack-swizzle for FRAME_POINTER=y
um: Enforce the usage of asm-generic/softirq_stack.h
x86/softirq/64: Inline do_softirq_own_stack()
softirq: Move do_softirq_own_stack() to generic asm header
softirq: Move __ARCH_HAS_DO_SOFTIRQ to Kconfig
x86: Select CONFIG_HAVE_IRQ_EXIT_ON_IRQ_STACK
x86/softirq: Remove indirection in do_softirq_own_stack()
x86/entry: Use run_sysvec_on_irqstack_cond() for XEN upcall
x86/entry: Convert device interrupts to inline stack switching
x86/entry: Convert system vectors to irq stack macro
x86/irq: Provide macro for inlining irq stack switching
x86/apic: Split out spurious handling code
x86/irq/64: Adjust the per CPU irq stack pointer by 8
x86/irq: Sanitize irq stack tracking
x86/entry: Fix instrumentation annotation
The recent rework of the X86 irq stack switching mechanism broke UM as UM
pulls in the X86 specific variant of softirq_stack.h.
Enforce the usage of the asm-generic variant.
Fixes: 72f40a2823 ("x86/softirq/64: Inline do_softirq_own_stack()")
Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Richard Weinberger <richard@nod.at>
This will get the (no-op) definition of irq_canonicalize()
which some code might want. We could define that ourselves,
but it seems like we'd likely want generic extensions in
the future, if any.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
This may be needed for size_t if something doesn't get
it included elsewhere before including <asm/io.h>, so
add the include.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Add a pseudo RTC that simply is able to send an alarm signal
waking up the system at a given time in the future.
Since apparently timerfd_create() FDs don't support SIGIO, we
use the sigio-creating helper thread, which just learned to do
suspend/resume properly in the previous patch.
For time-travel mode, OTOH, just add an event at the specified
time in the future, and that's already sufficient to wake up
the system at that point in time since suspend will just be in
an "endless wait".
For s2idle support also call pm_system_wakeup().
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
This mostly reverts the old commit 3963333fe6 ("uml: cover stubs
with a VMA") which had added a VMA to the existing PTEs. However,
there's no real reason to have the PTEs in the first place and the
VMA cannot be 'fixed' in place, which leads to bugs that userspace
could try to unmap them and be forcefully killed, or such. Also,
there's a bit of an ugly hole in userspace's address space.
Simplify all this: just install the stub code/page at the top of
the (inner) address space, i.e. put it just above TASK_SIZE. The
pages are simply hard-coded to be mapped in the userspace process
we use to implement an mm context, and they're out of reach of the
inner mmap/munmap/mprotect etc. since they're above TASK_SIZE.
Getting rid of the VMA also makes vma_merge() no longer hit one of
the VM_WARN_ON()s there because we installed a VMA while the code
assumes the stack VMA is the first one.
It also removes a lockdep warning about mmap_sem usage since we no
longer have uml_setup_stubs() and thus no longer need to do any
manipulation that would require mmap_sem in activate_mm().
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
The userspace stacks mostly have a stack (and in the case of the
syscall stub we can just set their stack pointer) that points to
the location of the stub data page already.
Rework the stubs to use the stack pointer to derive the start of
the data page, rather than requiring it to be hard-coded.
In the clone stub, also integrate the int3 into the stack remap,
since we really must not use the stack while we remap it.
This prepares for putting the stub at a variable location that's
not part of the normal address space of the userspace processes
running inside the UML machine.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
If the two are mixed up, then it looks as though the parent
returned an error if the child failed (before) the mmap(),
and then the resulting process never gets killed. Fix this
by splitting the child and parent errors, reporting and
using them appropriately.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
In some cases we can get to fix_range_common() with mmap_sem held,
and in others we get there without it being held. For example, we
get there with it held from sys_mprotect(), and without it held
from fork_handler().
Avoid any issues in this and simply defer killing the task until
it runs the next time. Do it on the mm so that another task that
shares the same mm can't continue running afterwards.
Cc: stable@vger.kernel.org
Fixes: 468f65976a ("um: Fix hung task in fix_range_common()")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
powerpc was the last provider of arch_remap() and the last
user of mm-arch-hooks.h.
Since commit 526a9c4a72 ("powerpc/vdso: Provide vdso_remap()"),
arch_remap() hence mm-arch-hooks.h are not used anymore.
Remove them.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Richard Weinberger <richard@nod.at>
In external time-travel mode, where time is controlled via the
controller application socket, interrupt handling is a little
tricky. For example on virtio, the following happens:
* we receive a message (that requires an ACK) on the vhost-user socket
* we add a time-travel event to handle the interrupt
(this causes communication on the time socket)
* we ACK the original vhost-user message
* we then handle the interrupt once the event is triggered
This protocol ensures that the sender of the interrupt only continues
to run in the simulation when the time-travel event has been added.
So far, this was only done in the virtio driver, but it was actually
wrong, because only virtqueue interrupts were handled this way, and
config change interrupts were handled immediately. Additionally, the
messages were actually handled in the real Linux interrupt handler,
but Linux interrupt handlers are part of the simulation and shouldn't
run while there's no time event.
To really do this properly and only handle all kinds of interrupts in
the time-travel event when we are scheduled to run in the simulation,
rework this to plug in to the lower interrupt layers in UML directly:
Add a um_request_irq_tt() function that let's a time-travel aware
driver request an interrupt with an additional timetravel_handler()
that is called outside of the context of the simulation, to handle
the message only. It then adds an event to the time-travel calendar
if necessary, and no "real" Linux code runs outside of the time
simulation.
This also hooks in with suspend/resume properly now, since this new
timetravel_handler() can run while Linux is suspended and interrupts
are disabled, and decide to wake up (or not) the system based on the
message it received. Importantly in this case, it ACKs the message
before the system even resumes and interrupts are re-enabled, thus
allowing the simulation to progress properly.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
This reverts commit 963285b0b4 ("um: support some of
ARCH_HAS_SET_MEMORY"), as it turns out that it's not only not
working (due to um never using the protection bits in the
page tables) but also corrupts the page tables if used on a
non-vmalloc page, since um never allocates proper page tables
for the 'physmem' in the first place.
Fixing all this will take more effort, so for now revert it.
Reported-by: Benjamin Berg <benjamin@sipsolutions.net>
Fixes: 963285b0b4 ("um: support some of ARCH_HAS_SET_MEMORY")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
This reverts commit ef4459a6da ("um: allocate a guard page to
helper threads"), it's broken in multiple ways:
1) the free no longer matches the alloc; and
2) more importantly, the set_memory_ro() causes allocation of
page tables for the normal memory that doesn't have any,
and that later causes corruption and crashes (usually but
not always in vfree()).
We could fix the first bug and use vmalloc() to work around the
second, but set_memory_ro() actually doesn't do anything either
so I'll just revert that as well.
Reported-by: Benjamin Berg <benjamin@sipsolutions.net>
Fixes: ef4459a6da ("um: allocate a guard page to helper threads")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Pull UML updates from Richard Weinberger:
- IRQ handling cleanups
- Support for suspend
- Various fixes for UML specific drivers: ubd, vector, xterm
* tag 'for-linus-5.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml: (32 commits)
um: Fix build w/o CONFIG_PM_SLEEP
um: time-travel: Correct time event IRQ delivery
um: irq/sigio: Support suspend/resume handling of workaround IRQs
um: time-travel: Actually apply "free-until" optimisation
um: chan_xterm: Fix fd leak
um: tty: Fix handling of close in tty lines
um: Monitor error events in IRQ controller
um: allocate a guard page to helper threads
um: support some of ARCH_HAS_SET_MEMORY
um: time-travel: avoid multiple identical propagations
um: Fetch registers only for signals which need them
um: Support suspend to RAM
um: Allow PM with suspend-to-idle
um: time: Fix read_persistent_clock64() in time-travel
um: Simplify os_idle_sleep() and sleep longer
um: Simplify IRQ handling code
um: Remove IRQ_NONE type
um: irq: Reduce irq_reg allocation
um: irq: Clean up and rename struct irq_fd
um: Clean up alarm IRQ chip name
...
Pull TIF_NOTIFY_SIGNAL updates from Jens Axboe:
"This sits on top of of the core entry/exit and x86 entry branch from
the tip tree, which contains the generic and x86 parts of this work.
Here we convert the rest of the archs to support TIF_NOTIFY_SIGNAL.
With that done, we can get rid of JOBCTL_TASK_WORK from task_work and
signal.c, and also remove a deadlock work-around in io_uring around
knowing that signal based task_work waking is invoked with the sighand
wait queue head lock.
The motivation for this work is to decouple signal notify based
task_work, of which io_uring is a heavy user of, from sighand. The
sighand lock becomes a huge contention point, particularly for
threaded workloads where it's shared between threads. Even outside of
threaded applications it's slower than it needs to be.
Roman Gershman <romger@amazon.com> reported that his networked
workload dropped from 1.6M QPS at 80% CPU to 1.0M QPS at 100% CPU
after io_uring was changed to use TIF_NOTIFY_SIGNAL. The time was all
spent hammering on the sighand lock, showing 57% of the CPU time there
[1].
There are further cleanups possible on top of this. One example is
TIF_PATCH_PENDING, where a patch already exists to use
TIF_NOTIFY_SIGNAL instead. Hopefully this will also lead to more
consolidation, but the work stands on its own as well"
[1] https://github.com/axboe/liburing/issues/215
* tag 'tif-task_work.arch-2020-12-14' of git://git.kernel.dk/linux-block: (28 commits)
io_uring: remove 'twa_signal_ok' deadlock work-around
kernel: remove checking for TIF_NOTIFY_SIGNAL
signal: kill JOBCTL_TASK_WORK
io_uring: JOBCTL_TASK_WORK is no longer used by task_work
task_work: remove legacy TWA_SIGNAL path
sparc: add support for TIF_NOTIFY_SIGNAL
riscv: add support for TIF_NOTIFY_SIGNAL
nds32: add support for TIF_NOTIFY_SIGNAL
ia64: add support for TIF_NOTIFY_SIGNAL
h8300: add support for TIF_NOTIFY_SIGNAL
c6x: add support for TIF_NOTIFY_SIGNAL
alpha: add support for TIF_NOTIFY_SIGNAL
xtensa: add support for TIF_NOTIFY_SIGNAL
arm: add support for TIF_NOTIFY_SIGNAL
microblaze: add support for TIF_NOTIFY_SIGNAL
hexagon: add support for TIF_NOTIFY_SIGNAL
csky: add support for TIF_NOTIFY_SIGNAL
openrisc: add support for TIF_NOTIFY_SIGNAL
sh: add support for TIF_NOTIFY_SIGNAL
um: add support for TIF_NOTIFY_SIGNAL
...
Pull asm-generic mmu-context cleanup from Arnd Bergmann:
"This is a cleanup series from Nicholas Piggin, preparing for later
changes. The asm/mmu_context.h header are generalized and common code
moved to asm-gneneric/mmu_context.h.
This saves a bit of code and makes it easier to change in the future"
* tag 'asm-generic-mmu-context-5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic: (25 commits)
h8300: Fix generic mmu_context build
m68k: mmu_context: Fix Sun-3 build
xtensa: use asm-generic/mmu_context.h for no-op implementations
x86: use asm-generic/mmu_context.h for no-op implementations
um: use asm-generic/mmu_context.h for no-op implementations
sparc: use asm-generic/mmu_context.h for no-op implementations
sh: use asm-generic/mmu_context.h for no-op implementations
s390: use asm-generic/mmu_context.h for no-op implementations
riscv: use asm-generic/mmu_context.h for no-op implementations
powerpc: use asm-generic/mmu_context.h for no-op implementations
parisc: use asm-generic/mmu_context.h for no-op implementations
openrisc: use asm-generic/mmu_context.h for no-op implementations
nios2: use asm-generic/mmu_context.h for no-op implementations
nds32: use asm-generic/mmu_context.h for no-op implementations
mips: use asm-generic/mmu_context.h for no-op implementations
microblaze: use asm-generic/mmu_context.h for no-op implementations
m68k: use asm-generic/mmu_context.h for no-op implementations
ia64: use asm-generic/mmu_context.h for no-op implementations
hexagon: use asm-generic/mmu_context.h for no-op implementations
csky: use asm-generic/mmu_context.h for no-op implementations
...
Pull irq updates from Thomas Gleixner:
"Generic interrupt and irqchips subsystem updates. Unusually, there is
not a single completely new irq chip driver, just new DT bindings and
extensions of existing drivers to accomodate new variants!
Core:
- Consolidation and robustness changes for irq time accounting
- Cleanup and consolidation of irq stats
- Remove the fasteoi IPI flow which has been proved useless
- Provide an interface for converting legacy interrupt mechanism into
irqdomains
Drivers:
- Preliminary support for managed interrupts on platform devices
- Correctly identify allocation of MSIs proxyied by another device
- Generalise the Ocelot support to new SoCs
- Improve GICv4.1 vcpu entry, matching the corresponding KVM
optimisation
- Work around spurious interrupts on Qualcomm PDC
- Random fixes and cleanups"
* tag 'irq-core-2020-12-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (54 commits)
irqchip/qcom-pdc: Fix phantom irq when changing between rising/falling
driver core: platform: Add devm_platform_get_irqs_affinity()
ACPI: Drop acpi_dev_irqresource_disabled()
resource: Add irqresource_disabled()
genirq/affinity: Add irq_update_affinity_desc()
irqchip/gic-v3-its: Flag device allocation as proxied if behind a PCI bridge
irqchip/gic-v3-its: Tag ITS device as shared if allocating for a proxy device
platform-msi: Track shared domain allocation
irqchip/ti-sci-intr: Fix freeing of irqs
irqchip/ti-sci-inta: Fix printing of inta id on probe success
drivers/irqchip: Remove EZChip NPS interrupt controller
Revert "genirq: Add fasteoi IPI flow"
irqchip/hip04: Make IPIs use handle_percpu_devid_irq()
irqchip/bcm2836: Make IPIs use handle_percpu_devid_irq()
irqchip/armada-370-xp: Make IPIs use handle_percpu_devid_irq()
irqchip/gic, gic-v3: Make SGIs use handle_percpu_devid_irq()
irqchip/ocelot: Add support for Jaguar2 platforms
irqchip/ocelot: Add support for Serval platforms
irqchip/ocelot: Add support for Luton platforms
irqchip/ocelot: prepare to support more SoC
...
