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2024-01-05um: Rely on PTRACE_SETREGSET to set FS/GS base registersBenjamin Berg
These registers are saved/restored together with the other general registers using ptrace. In arch_set_tls we then just need to set the register and it will be synced back normally. Most of this logic was introduced in commit f355559cf7845 ("[PATCH] uml: x86_64 thread fixes"). However, at least today we can rely on ptrace to restore the base registers for us. As such, only the part of the patch that tracks the FS register for use as thread local storage is actually needed. Signed-off-by: Benjamin Berg <benjamin@sipsolutions.net> Signed-off-by: Richard Weinberger <richard@nod.at>
2022-07-18um: seed rng using host OS rngJason A. Donenfeld
UML generally does not provide access to special CPU instructions like RDRAND, and execution tends to be rather deterministic, with no real hardware interrupts, making good randomness really very hard, if not all together impossible. Not only is this a security eyebrow raiser, but it's also quite annoying when trying to do various pieces of UML-based automation that takes a long time to boot, if ever. Fix this by trivially calling getrandom() in the host and using that seed as "bootloader randomness", which initializes the rng immediately at UML boot. The old behavior can be restored the same way as on any other arch, by way of CONFIG_TRUST_BOOTLOADER_RANDOMNESS=n or random.trust_bootloader=0. So seen from that perspective, this just makes UML act like other archs, which is positive in its own right. Additionally, wire up arch_get_random_{int,long}() in the same way, so that reseeds can also make use of the host RNG, controllable by CONFIG_TRUST_CPU_RANDOMNESS and random.trust_cpu, per usual. Cc: stable@vger.kernel.org Acked-by: Johannes Berg <johannes@sipsolutions.net> Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-03-11um: Fix WRITE_ZEROES in the UBD DriverFrédéric Danis
Call to fallocate with FALLOC_FL_PUNCH_HOLE on a device backed by a sparse file can end up by missing data, zeroes data range, if the underlying file is used with a tool like bmaptool which will referenced only used spaces. Signed-off-by: Frédéric Danis <frederic.danis@collabora.com> Acked-by: Anton Ivanov <anton.ivanov@cambridgegreys.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2021-12-21um: header debriding - os.hAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Richard Weinberger <richard@nod.at>
2021-12-21um: rename set_signals() to um_set_signals()Johannes Berg
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: 68f5d3f3b654 ("um: add PCI over virtio emulation driver") Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2021-08-19isystem: trim/fixup stdarg.h and other headersAlexey Dobriyan
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>
2021-06-17um: Remove the repeated declarationShaokun Zhang
Function 'os_flush_stdout' is declared twice, so remove the repeated declaration. Cc: Jeff Dike <jdike@addtoit.com> Cc: Richard Weinberger <richard@nod.at> Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2021-06-17um: Add support for host CPU flags and alignmentAnton Ivanov
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>
2021-06-17um: time-travel/signals: fix ndelay() in interruptJohannes Berg
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>
2021-06-17um: export signals_enabled directlyJohannes Berg
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>
2020-12-13um: time-travel: Correct time event IRQ deliveryJohannes Berg
Lockdep (on 5.10-rc) points out that we're delivering IRQs while IRQs are not even enabled, which clearly shouldn't happen. Defer the time event IRQ delivery until they actually are enabled. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2020-12-13um: irq/sigio: Support suspend/resume handling of workaround IRQsJohannes Berg
If the sigio workaround needed to be applied to a file descriptor, set_irq_wake() wouldn't work for it since it would get polled by the thread instead of causing SIGIO, and thus could never really cause a wakeup, since the thread notification FD wasn't marked as being able to wake up the system. Fix this by marking the thread's notification FD explicitly as a wake source FD, i.e. not suppressing SIGIO for it in suspend. In order to not cause spurious wakeups, we then need to remove all FDs that shouldn't wake up the system from the polling thread. In order to do this, add unlocked versions of ignore_sigio_fd() and add_sigio_fd() (nothing else is happening in suspend, so this is fine), and also modify ignore_sigio_fd() to return -ENOENT if the FD wasn't originally in there. This doesn't matter because nothing else currently checks the return value, but the irq code needs to know which ones to restore the workaround for. All told, this lets us use a timerfd for the RTC clock in the next patch, which doesn't send SIGIO. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2020-12-13um: Support suspend to RAMJohannes Berg
With all the previous bits in place, we can now also support suspend to RAM, in the sense that everything is suspended, not just most, including userspace, processes like in s2idle. Since um_idle_sleep() now waits forever, we can simply call that to "suspend" the system. As before, you can wake it up using SIGUSR1 since we're just in a pause() call that only needs to return. In order to implement selective resume from certain devices, and not have any arbitrary device interrupt wake up, suspend interrupts by removing SIGIO notification (O_ASYNC) from all the FDs that are not supposed to wake up the system. However, swap out the handler so we don't actually handle the SIGIO as an interrupt. Since we're in pause(), the mere act of receiving SIGIO wakes us up, and then after things have been restored enough, re-set O_ASYNC for all previously suspended FDs, reinstall the proper SIGIO handler, and send SIGIO to self to process anything that might now be pending. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2020-12-13um: Allow PM with suspend-to-idleJohannes Berg
In order to be able to experiment with suspend in UML, add the minimal work to be able to suspend (s2idle) an instance of UML, and be able to wake it back up from that state with the USR1 signal sent to the main UML process. 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>
2020-12-13um: Simplify os_idle_sleep() and sleep longerJohannes Berg
There really is no reason to pass the amount of time we should sleep, especially since it's just hard-coded to one second. Additionally, one second isn't really all that long, and as we are expecting to be woken up by a signal, we can sleep longer and avoid doing some work every second, so replace the current clock_nanosleep() with just an empty select() that can _only_ be woken up by a signal. We can also remove the deliver_alarm() since we don't need to do that when we got e.g. SIGIO that woke us up, and if we got SIGALRM the signal handler will actually (have) run, so it's just unnecessary extra work. Similarly, in time-travel mode, just program the wakeup event from idle to be S64_MAX, which is basically the most you could ever simulate to. Of course, you should already have an event in the list that's earlier and will cause a wakeup, normally that's the regular timer interrupt, though in suspend it may (later) also be an RTC event. Since actually getting to this point would be a bug and you can't ever get out again, panic() on it in the time control code. 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>
2020-12-13um: Remove IRQ_NONE typeJohannes Berg
We don't actually use this in um_request_irq(), so it can never be assigned. It's also not clear what that would be useful for, so just remove it. This results in quite a number of cleanups, all the way to removing the "SIGIO on close" startup check, since the data it assigns (pty_close_sigio) is not used anymore. While at it, also make this an enum so we get a minimum of type checking, and remove the IRQ_NONE hack in virtio since we now no longer have the name twice. Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com> 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>
2020-03-29um: Implement time-travel=extJohannes Berg
This implements synchronized time-travel mode which - using a special application on a unix socket - lets multiple machines take part in a time-travelling simulation together. The protocol for the unix domain socket is defined in the new file include/uapi/linux/um_timetravel.h. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2019-12-18um: ubd: use 64-bit time_t where possibleArnd Bergmann
The ubd code suffers from a possible y2038 overflow on 32-bit architectures, both for the cow header and the os_file_modtime() function. Replace time_t with time64_t to extend the ubd_kern side as much as possible. Whether this makes a difference for the user side depends on the host libc implementation that may use either 32-bit or 64-bit time_t. For the cow file format, the header contains an unsigned 32-bit timestamp, which is good until y2106, passing this through a 'long long' gives us a consistent interpretation between 32-bit and 64-bit um kernels. Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2019-09-15um: Add SPDX headers for files in arch/um/includeAlex Dewar
Convert files to use SPDX header. All files are licensed under the GPLv2. Signed-off-by: Alex Dewar <alex.dewar@gmx.co.uk> Signed-off-by: Richard Weinberger <richard@nod.at>
2019-09-15um: drivers: Add virtio vhost-user driverErel Geron
This module allows virtio devices to be used over a vhost-user socket. Signed-off-by: Erel Geron <erelx.geron@intel.com> Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2019-09-15um: Implement TRACE_IRQFLAGS_SUPPORTJohannes Berg
UML enables TRACE_IRQFLAGS_SUPPORT but doesn't actually implement it. It seems to have been added for lockdep support, but that can't actually really work well without IRQ flags tracing, as is also very noisily reported when enabling CONFIG_DEBUG_LOCKDEP. Implement it now. Fixes: 711553efa5b8 ("[PATCH] uml: declare in Kconfig our partial LOCKDEP support") Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2019-07-02um: Pass nsecs to os timer functionsJohannes Berg
This makes the code clearer and lets the time travel patch have the actual time used for these functions in just one place. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2019-07-02um: Timer code cleanupJohannes Berg
There are some unused functions, and some others that have unused arguments; clean up the timer code a bit. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2019-07-02um: fix os_timer_one_shot()Johannes Berg
os_timer_one_shot() gets passed a value "unsigned long delta", so must not have an "int ticks" as that actually ends up being -1, and thus triggering a timer over and over again. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2018-12-27um: Add support for DISCARD in the UBD DriverAnton Ivanov
Support for DISCARD and WRITE_ZEROES in the ubd driver using fallocate. DISCARD is enabled by default and can be disabled using a new UBD command line flag. If the underlying fs on which the UBD image is stored does not support DISCARD the support for both DISCARD and WRITE_ZEROES is turned off. Signed-off-by: Anton Ivanov <anton.ivanov@cambridgegreys.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2018-02-19Epoll based IRQ controllerAnton Ivanov
1. Removes the need to walk the IRQ/Device list to determine who triggered the IRQ. 2. Improves scalability (up to several times performance improvement for cases with 10s of devices). 3. Improves UML baseline IO performance for one disk + one NIC use case by up to 10%. 4. Introduces write poll triggered IRQs. 5. Prerequisite for introducing high performance mmesg family of functions in network IO. 6. Fixes RNG shutdown which was leaking a file descriptor Signed-off-by: Anton Ivanov <anton.ivanov@cambridgegreys.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2017-09-13um: Fix FP register size for XSTATE/XSAVEThomas Meyer
Hard code max size. Taken from https://sourceware.org/git/?p=binutils-gdb.git;a=blob;f=gdb/common/x86-xstate.h Signed-off-by: Thomas Meyer <thomas@m3y3r.de> Signed-off-by: Richard Weinberger <richard@nod.at>
2017-07-05um: Add os_warn() for pre-boot warning/error messagesMasami Hiramatsu
Add os_warn() for printing out pre-boot warning/error messages in stderr. The messages via os_warn() are not suppressed by quiet option. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Richard Weinberger <richard@nod.at>
2017-07-05um: Add os_info() for pre-boot information messagesMasami Hiramatsu
Add os_info() for printing out pre-boot information level messages in stderr. The messages via os_info() are suppressed by "quiet" kernel command line. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Richard Weinberger <richard@nod.at>
2017-03-20x86/arch_prctl/64: Rename do_arch_prctl() to do_arch_prctl_64()Kyle Huey
In order to introduce new arch_prctls that are not 64 bit only, rename the existing 64 bit implementation to do_arch_prctl_64(). Also rename the second argument of that function from 'addr' to 'arg2', because it will no longer always be an address. Signed-off-by: Kyle Huey <khuey@kylehuey.com> Reviewed-by: Andy Lutomirski <luto@kernel.org> Cc: Grzegorz Andrejczuk <grzegorz.andrejczuk@intel.com> Cc: kvm@vger.kernel.org Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: linux-kselftest@vger.kernel.org Cc: Nadav Amit <nadav.amit@gmail.com> Cc: Robert O'Callahan <robert@ocallahan.org> Cc: Richard Weinberger <richard@nod.at> Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: Len Brown <len.brown@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: user-mode-linux-devel@lists.sourceforge.net Cc: Jeff Dike <jdike@addtoit.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: user-mode-linux-user@lists.sourceforge.net Cc: David Matlack <dmatlack@google.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Dmitry Safonov <dsafonov@virtuozzo.com> Cc: linux-fsdevel@vger.kernel.org Cc: Paolo Bonzini <pbonzini@redhat.com> Link: http://lkml.kernel.org/r/20170320081628.18952-5-khuey@kylehuey.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-03-20x86/arch_prctl: Rename 'code' argument to 'option'Kyle Huey
The x86 specific arch_prctl() arbitrarily changed prctl's 'option' to 'code'. Before adding new options, rename it. Signed-off-by: Kyle Huey <khuey@kylehuey.com> Cc: Grzegorz Andrejczuk <grzegorz.andrejczuk@intel.com> Cc: kvm@vger.kernel.org Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: linux-kselftest@vger.kernel.org Cc: Nadav Amit <nadav.amit@gmail.com> Cc: Robert O'Callahan <robert@ocallahan.org> Cc: Richard Weinberger <richard@nod.at> Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: Len Brown <len.brown@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: user-mode-linux-devel@lists.sourceforge.net Cc: Jeff Dike <jdike@addtoit.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: user-mode-linux-user@lists.sourceforge.net Cc: David Matlack <dmatlack@google.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Dmitry Safonov <dsafonov@virtuozzo.com> Cc: linux-fsdevel@vger.kernel.org Cc: Paolo Bonzini <pbonzini@redhat.com> Link: http://lkml.kernel.org/r/20170320081628.18952-3-khuey@kylehuey.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-01-10um: Fix ptrace GETREGS/SETREGS bugsMickaël Salaün
This fix two related bugs: * PTRACE_GETREGS doesn't get the right orig_ax (syscall) value * PTRACE_SETREGS can't set the orig_ax value (erased by initial value) Get rid of the now useless and error-prone get_syscall(). Fix inconsistent behavior in the ptrace implementation for i386 when updating orig_eax automatically update the syscall number as well. This is now updated in handle_syscall(). Signed-off-by: Mickaël Salaün <mic@digikod.net> Cc: Jeff Dike <jdike@addtoit.com> Cc: Richard Weinberger <richard@nod.at> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Kees Cook <keescook@chromium.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Will Drewry <wad@chromium.org> Cc: Thomas Meyer <thomas@m3y3r.de> Cc: Nicolas Iooss <nicolas.iooss_linux@m4x.org> Cc: Anton Ivanov <aivanov@brocade.com> Cc: Meredydd Luff <meredydd@senatehouse.org> Cc: David Drysdale <drysdale@google.com> Signed-off-by: Richard Weinberger <richard@nod.at> Acked-by: Kees Cook <keescook@chromium.org>
2016-01-10um: Update UBD to use pread/pwrite family of functionsAnton Ivanov
This decreases the number of syscalls per read/write by half. Signed-off-by: Anton Ivanov <aivanov@brocade.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2015-11-06um: Switch clocksource to hrtimersAnton Ivanov
UML is using an obsolete itimer call for all timers and "polls" for kernel space timer firing in its userspace portion resulting in a long list of bugs and incorrect behaviour(s). It also uses ITIMER_VIRTUAL for its timer which results in the timer being dependent on it running and the cpu load. This patch fixes this by moving to posix high resolution timers firing off CLOCK_MONOTONIC and relaying the timer correctly to the UML userspace. Fixes: - crashes when hosts suspends/resumes - broken userspace timers - effecive ~40Hz instead of what they should be. Note - this modifies skas behavior by no longer setting an itimer per clone(). Timer events are relayed instead. - kernel network packet scheduling disciplines - tcp behaviour especially under load - various timer related corner cases Finally, overall responsiveness of userspace is better. Signed-off-by: Thomas Meyer <thomas@m3y3r.de> Signed-off-by: Anton Ivanov <aivanov@brocade.com> [rw: massaged commit message] Signed-off-by: Richard Weinberger <richard@nod.at>
2015-11-06um: Store syscall number after syscall_trace_enter()Richard Weinberger
To support changing syscall numbers we have to store it after syscall_trace_enter(). Signed-off-by: Richard Weinberger <richard@nod.at>
2015-05-31um: Move syscall() declaration into os.hRichard Weinberger
Signed-off-by: Richard Weinberger <richard@nod.at>
2015-04-13um: Remove SKAS3/4 supportRichard Weinberger
Before we had SKAS0 UML had two modes of operation TT (tracing thread) and SKAS3/4 (separated kernel address space). TT was known to be insecure and got removed a long time ago. SKAS3/4 required a few (3 or 4) patches on the host side which never went mainline. The last host patch is 10 years old. With SKAS0 mode (separated kernel address space using 0 host patches), default since 2005, SKAS3/4 is obsolete and can be removed. Signed-off-by: Richard Weinberger <richard@nod.at>
2014-04-20um: Memory corruption on startupAnton Ivanov
The reverse case of this race (you must msync before read) is well known. This is the not so common one. It can be triggered only on systems which do a lot of task switching and only at UML startup. If you are starting 200+ UMLs ~ 0.5% will always die without this fix. Signed-off-by: Anton Ivanov <antivano@cisco.com> [rw: minor whitespace fixes] Signed-off-by: Richard Weinberger <richard@nod.at>
2013-11-17um: Make stack trace reliable against kernel mode faultsRichard Weinberger
As UML uses an alternative signal stack we cannot use the current stack pointer for stack dumping if UML itself dies by SIGSEGV. To bypass this issue we save regs taken from mcontext in our segv handler into thread_struct and use these regs to obtain the stack pointer in show_stack(). Signed-off-by: Richard Weinberger <richard@nod.at>
2013-09-07um: Cleanup SIGTERM handlingRichard Weinberger
Richard reported that some UML processes survive if the UML main process receives a SIGTERM. This issue was caused by a wrongly placed signal(SIGTERM, SIG_DFL) in init_new_thread_signals(). It disabled the UML exit handler accidently for some processes. The correct solution is to disable the fatal handler for all UML helper threads/processes. Such that last_ditch_exit() does not get called multiple times and all processes can exit due to SIGTERM. Reported-and-tested-by: Richard W.M. Jones <rjones@redhat.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2013-09-07um: ubd: Add REQ_FLUSH suppportRichard Weinberger
UML's block device driver does not support write barriers, to support this this patch adds REQ_FLUSH suppport. Every time the block layer sends a REQ_FLUSH we fsync() now our backing file to guarantee data consistency. Reported-and-tested-by: Richard W.M. Jones <rjones@redhat.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2013-09-07um: Implement probe_kernel_read()Richard Weinberger
UML needs it's own probe_kernel_read() to handle kernel mode faults correctly. The implementation uses mincore() on the host side to detect whether a page is owned by the UML kernel process. This fixes also a possible crash when sysrq-t is used. Starting with 3.10 sysrq-t calls probe_kernel_read() to read details from the kernel workers. As kernel worker are completely async pointers may turn NULL while reading them. Cc: <stian@nixia.no> Cc: <tj@kernel.org> Cc: <stable@vger.kernel.org> # 3.10.x Signed-off-by: Richard Weinberger <richard@nod.at>
2012-10-13Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal Pull third pile of kernel_execve() patches from Al Viro: "The last bits of infrastructure for kernel_thread() et.al., with alpha/arm/x86 use of those. Plus sanitizing the asm glue and do_notify_resume() on alpha, fixing the "disabled irq while running task_work stuff" breakage there. At that point the rest of kernel_thread/kernel_execve/sys_execve work can be done independently for different architectures. The only pending bits that do depend on having all architectures converted are restrictred to fs/* and kernel/* - that'll obviously have to wait for the next cycle. I thought we'd have to wait for all of them done before we start eliminating the longjump-style insanity in kernel_execve(), but it turned out there's a very simple way to do that without flagday-style changes." * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal: alpha: switch to saner kernel_execve() semantics arm: switch to saner kernel_execve() semantics x86, um: convert to saner kernel_execve() semantics infrastructure for saner ret_from_kernel_thread semantics make sure that kernel_thread() callbacks call do_exit() themselves make sure that we always have a return path from kernel_execve() ppc: eeh_event should just use kthread_run() don't bother with kernel_thread/kernel_execve for launching linuxrc alpha: get rid of switch_stack argument of do_work_pending() alpha: don't bother passing switch_stack separately from regs alpha: take SIGPENDING/NOTIFY_RESUME loop into signal.c alpha: simplify TIF_NEED_RESCHED handling
2012-10-12x86, um: convert to saner kernel_execve() semanticsAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-10-09um: get rid of pointless include "..." where include <...> will doAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Richard Weinberger <richard@nod.at>
2011-11-02um: merge os-Linux/tls.c into arch/x86/um/os-Linux/tls.cAl Viro
it's i386-specific; moreover, analogs on other targets have incompatible interface - PTRACE_GET_THREAD_AREA does exist elsewhere, but struct user_desc does *not* Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Richard Weinberger <richard@nod.at>
2011-11-02um: fill the handlers array at build timeAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Richard Weinberger <richard@nod.at>
2011-11-02um: simplify set_handler()Al Viro
For one thing, we always block the same signals (IRQ ones - IO, WINCH, VTALRM), so there's no need to pass sa_mask elements in arguments. For another, the flags depend only on whether it's an IRQ signal or not (we add SA_RESTART for them). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Richard Weinberger <richard@nod.at>
2011-11-02um: kill dead code around uaccessAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Richard Weinberger <richard@nod.at>
2011-05-25um: add earlyprintk supportRichard Weinberger
User Mode Linux can also benefit from earlyprintk. UML's earlyprintk writes kernel messages directly to stdout. Signed-off-by: Richard Weinberger <richard@nod.at> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>