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* Merge tag 'kbuild-v5.1-2' of ↵Linus Torvalds2019-03-1739-70/+4
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull more Kbuild updates from Masahiro Yamada: - add more Build-Depends to Debian source package - prefix header search paths with $(srctree)/ - make modpost show verbose section mismatch warnings - avoid hard-coded CROSS_COMPILE for h8300 - fix regression for Debian make-kpkg command - add semantic patch to detect missing put_device() - fix some warnings of 'make deb-pkg' - optimize NOSTDINC_FLAGS evaluation - add warnings about redundant generic-y - clean up Makefiles and scripts * tag 'kbuild-v5.1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: kconfig: remove stale lxdialog/.gitignore kbuild: force all architectures except um to include mandatory-y kbuild: warn redundant generic-y Revert "modsign: Abort modules_install when signing fails" kbuild: Make NOSTDINC_FLAGS a simply expanded variable kbuild: deb-pkg: avoid implicit effects coccinelle: semantic code search for missing put_device() kbuild: pkg: grep include/config/auto.conf instead of $KCONFIG_CONFIG kbuild: deb-pkg: introduce is_enabled and if_enabled_echo to builddeb kbuild: deb-pkg: add CONFIG_ prefix to kernel config options kbuild: add workaround for Debian make-kpkg kbuild: source include/config/auto.conf instead of ${KCONFIG_CONFIG} unicore32: simplify linker script generation for decompressor h8300: use cc-cross-prefix instead of hardcoding h8300-unknown-linux- kbuild: move archive command to scripts/Makefile.lib modpost: always show verbose warning for section mismatch ia64: prefix header search path with $(srctree)/ libfdt: prefix header search paths with $(srctree)/ deb-pkg: generate correct build dependencies
| * kbuild: force all architectures except um to include mandatory-yMasahiro Yamada2019-03-1724-43/+0
| | | | | | | | | | | | | | | | | | | | | | | | Currently, every arch/*/include/uapi/asm/Kbuild explicitly includes the common Kbuild.asm file. Factor out the duplicated include directives to scripts/Makefile.asm-generic so that no architecture would opt out of the mandatory-y mechanism. um is not forced to include mandatory-y since it is a very exceptional case which does not support UAPI. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
| * kbuild: warn redundant generic-yMasahiro Yamada2019-03-1711-13/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The generic-y is redundant under the following condition: - arch has its own implementation - the same header is added to generated-y - the same header is added to mandatory-y If a redundant generic-y is found, the warning like follows is displayed: scripts/Makefile.asm-generic:20: redundant generic-y found in arch/arm/include/asm/Kbuild: timex.h I fixed up arch Kbuild files found by this. Suggested-by: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
| * unicore32: simplify linker script generation for decompressorMasahiro Yamada2019-03-142-4/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | When I was searching for unneeded $(KCONFIG_CONFIG) usages, I noticed this strange build dependency. It can use $(call if_changed,...) in case ZTEXTADDR and ZBSSADDR are changed, but even a simpler way is to use the pattern rule in scripts/Makefile.build. This is what arch/arm/boot/compressed/Makefile does. I did only build test. I confirmed equivalent vmlinux.lds was generated. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
| * h8300: use cc-cross-prefix instead of hardcoding h8300-unknown-linux-Masahiro Yamada2019-03-141-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It believe it is a bad idea to hardcode a specific compiler prefix that may or may not be installed on a user's system. It is annoying when testing features that should not require compilers at all. For example, mrproper, headers_install, etc. should work without any compiler. They look like follows on my machine. $ make ARCH=h8300 mrproper ./scripts/gcc-version.sh: line 26: h8300-unknown-linux-gcc: command not found ./scripts/gcc-version.sh: line 27: h8300-unknown-linux-gcc: command not found make: h8300-unknown-linux-gcc: Command not found make: h8300-unknown-linux-gcc: Command not found [ a bunch of the same error messages continue ] $ make ARCH=h8300 headers_install ./scripts/gcc-version.sh: line 26: h8300-unknown-linux-gcc: command not found ./scripts/gcc-version.sh: line 27: h8300-unknown-linux-gcc: command not found make: h8300-unknown-linux-gcc: Command not found HOSTCC scripts/basic/fixdep make: h8300-unknown-linux-gcc: Command not found WRAP arch/h8300/include/generated/uapi/asm/kvm_para.h [ snip ] The solution is to delete this line, or to use cc-cross-prefix like some architectures do. I chose the latter as a moderate fixup. I added an alternative 'h8300-linux-' because it is available at: https://mirrors.edge.kernel.org/pub/tools/crosstool/files/bin/x86_64/8.1.0/ Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
| * kbuild: move archive command to scripts/Makefile.libMasahiro Yamada2019-03-141-3/+0
| | | | | | | | | | | | | | | | | | scripts/Makefile.build and arch/s390/boot/Makefile use the same command (thin archiving with symbol table creation). Avoid the code duplication, and move it to scripts/Makefile.lib. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
| * ia64: prefix header search path with $(srctree)/Masahiro Yamada2019-03-144-6/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, the Kbuild core manipulates header search paths in a crazy way [1]. To fix this mess, I want all Makefiles to add explicit $(srctree)/ to the search paths in the srctree. Some Makefiles are already written in that way, but not all. The goal of this work is to make the notation consistent, and finally get rid of the gross hacks. Having whitespaces after -I does not matter since commit 48f6e3cf5bc6 ("kbuild: do not drop -I without parameter"). I removed some header search paths because I was able to build ia64 without them. [1]: https://patchwork.kernel.org/patch/9632347/ Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
* | Merge branch 'x86-asm-for-linus' of ↵Linus Torvalds2019-03-173-125/+0
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 asm updates from Thomas Gleixner: "Two cleanup patches removing dead conditionals and unused code" * 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/asm: Remove unused __constant_c_x_memset() macro and inlines x86/asm: Remove dead __GNUC__ conditionals
| * | x86/asm: Remove unused __constant_c_x_memset() macro and inlinesRasmus Villemoes2019-01-121-84/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Nothing refers to the __constant_c_x_memset() macro anymore. Remove it and the two referenced static inline functions. Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: x86-ml <x86@kernel.org> Link: https://lkml.kernel.org/r/20190111084931.24601-2-linux@rasmusvillemoes.dk
| * | x86/asm: Remove dead __GNUC__ conditionalsRasmus Villemoes2019-01-123-41/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The minimum supported gcc version is >= 4.6, so these can be removed. Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: x86-ml <x86@kernel.org> Link: https://lkml.kernel.org/r/20190111084931.24601-1-linux@rasmusvillemoes.dk
* | | Merge branch 'perf-urgent-for-linus' of ↵Linus Torvalds2019-03-172-4/+4
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull perf fixes from Thomas Gleixner: "Three fixes for the fallout from the TSX errata workaround: - Prevent memory corruption caused by a unchecked out of bound array index. - Two trivial fixes to address compiler warnings" * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf/x86/intel: Make dev_attr_allow_tsx_force_abort static perf/x86: Fixup typo in stub functions perf/x86/intel: Fix memory corruption
| * | | perf/x86/intel: Make dev_attr_allow_tsx_force_abort statickbuild test robot2019-03-171-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fixes: 400816f60c54 ("perf/x86/intel: Implement support for TSX Force Abort") Signed-off-by: kbuild test robot <lkp@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org> Cc: kbuild-all@01.org Cc: Borislav Petkov <bp@alien8.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20190313184243.GA10820@lkp-sb-ep06
| * | | perf/x86: Fixup typo in stub functionsPeter Zijlstra2019-03-151-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Guenter reported a build warning for CONFIG_CPU_SUP_INTEL=n: > With allmodconfig-CONFIG_CPU_SUP_INTEL, this patch results in: > > In file included from arch/x86/events/amd/core.c:8:0: > arch/x86/events/amd/../perf_event.h:1036:45: warning: ‘struct cpu_hw_event’ declared inside parameter list will not be visible outside of this definition or declaration > static inline int intel_cpuc_prepare(struct cpu_hw_event *cpuc, int cpu) While harmless (an unsed pointer is an unused pointer, no matter the type) it needs fixing. Reported-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Fixes: d01b1f96a82e ("perf/x86/intel: Make cpuc allocations consistent") Link: http://lkml.kernel.org/r/20190315081410.GR5996@hirez.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | perf/x86/intel: Fix memory corruptionPeter Zijlstra2019-03-151-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Through: validate_event() x86_pmu.get_event_constraints(.idx=-1) tfa_get_event_constraints() dyn_constraint() cpuc->constraint_list[-1] is used, which is an obvious out-of-bound access. In this case, simply skip the TFA constraint code, there is no event constraint with just PMC3, therefore the code will never result in the empty set. Fixes: 400816f60c54 ("perf/x86/intel: Implement support for TSX Force Abort") Reported-by: Tony Jones <tonyj@suse.com> Reported-by: "DSouza, Nelson" <nelson.dsouza@intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Tony Jones <tonyj@suse.com> Tested-by: "DSouza, Nelson" <nelson.dsouza@intel.com> Cc: eranian@google.com Cc: jolsa@redhat.com Cc: stable@kernel.org Link: https://lkml.kernel.org/r/20190314130705.441549378@infradead.org
* | | | Merge tag 'pidfd-v5.1-rc1' of ↵Linus Torvalds2019-03-162-0/+2
|\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux Pull pidfd system call from Christian Brauner: "This introduces the ability to use file descriptors from /proc/<pid>/ as stable handles on struct pid. Even if a pid is recycled the handle will not change. For a start these fds can be used to send signals to the processes they refer to. With the ability to use /proc/<pid> fds as stable handles on struct pid we can fix a long-standing issue where after a process has exited its pid can be reused by another process. If a caller sends a signal to a reused pid it will end up signaling the wrong process. With this patchset we enable a variety of use cases. One obvious example is that we can now safely delegate an important part of process management - sending signals - to processes other than the parent of a given process by sending file descriptors around via scm rights and not fearing that the given process will have been recycled in the meantime. It also allows for easy testing whether a given process is still alive or not by sending signal 0 to a pidfd which is quite handy. There has been some interest in this feature e.g. from systems management (systemd, glibc) and container managers. I have requested and gotten comments from glibc to make sure that this syscall is suitable for their needs as well. In the future I expect it to take on most other pid-based signal syscalls. But such features are left for the future once they are needed. This has been sitting in linux-next for quite a while and has not caused any issues. It comes with selftests which verify basic functionality and also test that a recycled pid cannot be signaled via a pidfd. Jon has written about a prior version of this patchset. It should cover the basic functionality since not a lot has changed since then: https://lwn.net/Articles/773459/ The commit message for the syscall itself is extensively documenting the syscall, including it's functionality and extensibility" * tag 'pidfd-v5.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux: selftests: add tests for pidfd_send_signal() signal: add pidfd_send_signal() syscall
| * | | | signal: add pidfd_send_signal() syscallChristian Brauner2019-03-052-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The kill() syscall operates on process identifiers (pid). After a process has exited its pid can be reused by another process. If a caller sends a signal to a reused pid it will end up signaling the wrong process. This issue has often surfaced and there has been a push to address this problem [1]. This patch uses file descriptors (fd) from proc/<pid> as stable handles on struct pid. Even if a pid is recycled the handle will not change. The fd can be used to send signals to the process it refers to. Thus, the new syscall pidfd_send_signal() is introduced to solve this problem. Instead of pids it operates on process fds (pidfd). /* prototype and argument /* long pidfd_send_signal(int pidfd, int sig, siginfo_t *info, unsigned int flags); /* syscall number 424 */ The syscall number was chosen to be 424 to align with Arnd's rework in his y2038 to minimize merge conflicts (cf. [25]). In addition to the pidfd and signal argument it takes an additional siginfo_t and flags argument. If the siginfo_t argument is NULL then pidfd_send_signal() is equivalent to kill(<positive-pid>, <signal>). If it is not NULL pidfd_send_signal() is equivalent to rt_sigqueueinfo(). The flags argument is added to allow for future extensions of this syscall. It currently needs to be passed as 0. Failing to do so will cause EINVAL. /* pidfd_send_signal() replaces multiple pid-based syscalls */ The pidfd_send_signal() syscall currently takes on the job of rt_sigqueueinfo(2) and parts of the functionality of kill(2), Namely, when a positive pid is passed to kill(2). It will however be possible to also replace tgkill(2) and rt_tgsigqueueinfo(2) if this syscall is extended. /* sending signals to threads (tid) and process groups (pgid) */ Specifically, the pidfd_send_signal() syscall does currently not operate on process groups or threads. This is left for future extensions. In order to extend the syscall to allow sending signal to threads and process groups appropriately named flags (e.g. PIDFD_TYPE_PGID, and PIDFD_TYPE_TID) should be added. This implies that the flags argument will determine what is signaled and not the file descriptor itself. Put in other words, grouping in this api is a property of the flags argument not a property of the file descriptor (cf. [13]). Clarification for this has been requested by Eric (cf. [19]). When appropriate extensions through the flags argument are added then pidfd_send_signal() can additionally replace the part of kill(2) which operates on process groups as well as the tgkill(2) and rt_tgsigqueueinfo(2) syscalls. How such an extension could be implemented has been very roughly sketched in [14], [15], and [16]. However, this should not be taken as a commitment to a particular implementation. There might be better ways to do it. Right now this is intentionally left out to keep this patchset as simple as possible (cf. [4]). /* naming */ The syscall had various names throughout iterations of this patchset: - procfd_signal() - procfd_send_signal() - taskfd_send_signal() In the last round of reviews it was pointed out that given that if the flags argument decides the scope of the signal instead of different types of fds it might make sense to either settle for "procfd_" or "pidfd_" as prefix. The community was willing to accept either (cf. [17] and [18]). Given that one developer expressed strong preference for the "pidfd_" prefix (cf. [13]) and with other developers less opinionated about the name we should settle for "pidfd_" to avoid further bikeshedding. The "_send_signal" suffix was chosen to reflect the fact that the syscall takes on the job of multiple syscalls. It is therefore intentional that the name is not reminiscent of neither kill(2) nor rt_sigqueueinfo(2). Not the fomer because it might imply that pidfd_send_signal() is a replacement for kill(2), and not the latter because it is a hassle to remember the correct spelling - especially for non-native speakers - and because it is not descriptive enough of what the syscall actually does. The name "pidfd_send_signal" makes it very clear that its job is to send signals. /* zombies */ Zombies can be signaled just as any other process. No special error will be reported since a zombie state is an unreliable state (cf. [3]). However, this can be added as an extension through the @flags argument if the need ever arises. /* cross-namespace signals */ The patch currently enforces that the signaler and signalee either are in the same pid namespace or that the signaler's pid namespace is an ancestor of the signalee's pid namespace. This is done for the sake of simplicity and because it is unclear to what values certain members of struct siginfo_t would need to be set to (cf. [5], [6]). /* compat syscalls */ It became clear that we would like to avoid adding compat syscalls (cf. [7]). The compat syscall handling is now done in kernel/signal.c itself by adding __copy_siginfo_from_user_generic() which lets us avoid compat syscalls (cf. [8]). It should be noted that the addition of __copy_siginfo_from_user_any() is caused by a bug in the original implementation of rt_sigqueueinfo(2) (cf. 12). With upcoming rework for syscall handling things might improve significantly (cf. [11]) and __copy_siginfo_from_user_any() will not gain any additional callers. /* testing */ This patch was tested on x64 and x86. /* userspace usage */ An asciinema recording for the basic functionality can be found under [9]. With this patch a process can be killed via: #define _GNU_SOURCE #include <errno.h> #include <fcntl.h> #include <signal.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/stat.h> #include <sys/syscall.h> #include <sys/types.h> #include <unistd.h> static inline int do_pidfd_send_signal(int pidfd, int sig, siginfo_t *info, unsigned int flags) { #ifdef __NR_pidfd_send_signal return syscall(__NR_pidfd_send_signal, pidfd, sig, info, flags); #else return -ENOSYS; #endif } int main(int argc, char *argv[]) { int fd, ret, saved_errno, sig; if (argc < 3) exit(EXIT_FAILURE); fd = open(argv[1], O_DIRECTORY | O_CLOEXEC); if (fd < 0) { printf("%s - Failed to open \"%s\"\n", strerror(errno), argv[1]); exit(EXIT_FAILURE); } sig = atoi(argv[2]); printf("Sending signal %d to process %s\n", sig, argv[1]); ret = do_pidfd_send_signal(fd, sig, NULL, 0); saved_errno = errno; close(fd); errno = saved_errno; if (ret < 0) { printf("%s - Failed to send signal %d to process %s\n", strerror(errno), sig, argv[1]); exit(EXIT_FAILURE); } exit(EXIT_SUCCESS); } /* Q&A * Given that it seems the same questions get asked again by people who are * late to the party it makes sense to add a Q&A section to the commit * message so it's hopefully easier to avoid duplicate threads. * * For the sake of progress please consider these arguments settled unless * there is a new point that desperately needs to be addressed. Please make * sure to check the links to the threads in this commit message whether * this has not already been covered. */ Q-01: (Florian Weimer [20], Andrew Morton [21]) What happens when the target process has exited? A-01: Sending the signal will fail with ESRCH (cf. [22]). Q-02: (Andrew Morton [21]) Is the task_struct pinned by the fd? A-02: No. A reference to struct pid is kept. struct pid - as far as I understand - was created exactly for the reason to not require to pin struct task_struct (cf. [22]). Q-03: (Andrew Morton [21]) Does the entire procfs directory remain visible? Just one entry within it? A-03: The same thing that happens right now when you hold a file descriptor to /proc/<pid> open (cf. [22]). Q-04: (Andrew Morton [21]) Does the pid remain reserved? A-04: No. This patchset guarantees a stable handle not that pids are not recycled (cf. [22]). Q-05: (Andrew Morton [21]) Do attempts to signal that fd return errors? A-05: See {Q,A}-01. Q-06: (Andrew Morton [22]) Is there a cleaner way of obtaining the fd? Another syscall perhaps. A-06: Userspace can already trivially retrieve file descriptors from procfs so this is something that we will need to support anyway. Hence, there's no immediate need to add another syscalls just to make pidfd_send_signal() not dependent on the presence of procfs. However, adding a syscalls to get such file descriptors is planned for a future patchset (cf. [22]). Q-07: (Andrew Morton [21] and others) This fd-for-a-process sounds like a handy thing and people may well think up other uses for it in the future, probably unrelated to signals. Are the code and the interface designed to permit such future applications? A-07: Yes (cf. [22]). Q-08: (Andrew Morton [21] and others) Now I think about it, why a new syscall? This thing is looking rather like an ioctl? A-08: This has been extensively discussed. It was agreed that a syscall is preferred for a variety or reasons. Here are just a few taken from prior threads. Syscalls are safer than ioctl()s especially when signaling to fds. Processes are a core kernel concept so a syscall seems more appropriate. The layout of the syscall with its four arguments would require the addition of a custom struct for the ioctl() thereby causing at least the same amount or even more complexity for userspace than a simple syscall. The new syscall will replace multiple other pid-based syscalls (see description above). The file-descriptors-for-processes concept introduced with this syscall will be extended with other syscalls in the future. See also [22], [23] and various other threads already linked in here. Q-09: (Florian Weimer [24]) What happens if you use the new interface with an O_PATH descriptor? A-09: pidfds opened as O_PATH fds cannot be used to send signals to a process (cf. [2]). Signaling processes through pidfds is the equivalent of writing to a file. Thus, this is not an operation that operates "purely at the file descriptor level" as required by the open(2) manpage. See also [4]. /* References */ [1]: https://lore.kernel.org/lkml/20181029221037.87724-1-dancol@google.com/ [2]: https://lore.kernel.org/lkml/874lbtjvtd.fsf@oldenburg2.str.redhat.com/ [3]: https://lore.kernel.org/lkml/20181204132604.aspfupwjgjx6fhva@brauner.io/ [4]: https://lore.kernel.org/lkml/20181203180224.fkvw4kajtbvru2ku@brauner.io/ [5]: https://lore.kernel.org/lkml/20181121213946.GA10795@mail.hallyn.com/ [6]: https://lore.kernel.org/lkml/20181120103111.etlqp7zop34v6nv4@brauner.io/ [7]: https://lore.kernel.org/lkml/36323361-90BD-41AF-AB5B-EE0D7BA02C21@amacapital.net/ [8]: https://lore.kernel.org/lkml/87tvjxp8pc.fsf@xmission.com/ [9]: https://asciinema.org/a/IQjuCHew6bnq1cr78yuMv16cy [11]: https://lore.kernel.org/lkml/F53D6D38-3521-4C20-9034-5AF447DF62FF@amacapital.net/ [12]: https://lore.kernel.org/lkml/87zhtjn8ck.fsf@xmission.com/ [13]: https://lore.kernel.org/lkml/871s6u9z6u.fsf@xmission.com/ [14]: https://lore.kernel.org/lkml/20181206231742.xxi4ghn24z4h2qki@brauner.io/ [15]: https://lore.kernel.org/lkml/20181207003124.GA11160@mail.hallyn.com/ [16]: https://lore.kernel.org/lkml/20181207015423.4miorx43l3qhppfz@brauner.io/ [17]: https://lore.kernel.org/lkml/CAGXu5jL8PciZAXvOvCeCU3wKUEB_dU-O3q0tDw4uB_ojMvDEew@mail.gmail.com/ [18]: https://lore.kernel.org/lkml/20181206222746.GB9224@mail.hallyn.com/ [19]: https://lore.kernel.org/lkml/20181208054059.19813-1-christian@brauner.io/ [20]: https://lore.kernel.org/lkml/8736rebl9s.fsf@oldenburg.str.redhat.com/ [21]: https://lore.kernel.org/lkml/20181228152012.dbf0508c2508138efc5f2bbe@linux-foundation.org/ [22]: https://lore.kernel.org/lkml/20181228233725.722tdfgijxcssg76@brauner.io/ [23]: https://lwn.net/Articles/773459/ [24]: https://lore.kernel.org/lkml/8736rebl9s.fsf@oldenburg.str.redhat.com/ [25]: https://lore.kernel.org/lkml/CAK8P3a0ej9NcJM8wXNPbcGUyOUZYX+VLoDFdbenW3s3114oQZw@mail.gmail.com/ Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Jann Horn <jannh@google.com> Cc: Andy Lutomirsky <luto@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Florian Weimer <fweimer@redhat.com> Signed-off-by: Christian Brauner <christian@brauner.io> Reviewed-by: Tycho Andersen <tycho@tycho.ws> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: David Howells <dhowells@redhat.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Serge Hallyn <serge@hallyn.com> Acked-by: Aleksa Sarai <cyphar@cyphar.com>
* | | | | Merge tag 'devdax-for-5.1' of ↵Linus Torvalds2019-03-161-0/+1
|\ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm Pull device-dax updates from Dan Williams: "New device-dax infrastructure to allow persistent memory and other "reserved" / performance differentiated memories, to be assigned to the core-mm as "System RAM". Some users want to use persistent memory as additional volatile memory. They are willing to cope with potential performance differences, for example between DRAM and 3D Xpoint, and want to use typical Linux memory management apis rather than a userspace memory allocator layered over an mmap() of a dax file. The administration model is to decide how much Persistent Memory (pmem) to use as System RAM, create a device-dax-mode namespace of that size, and then assign it to the core-mm. The rationale for device-dax is that it is a generic memory-mapping driver that can be layered over any "special purpose" memory, not just pmem. On subsequent boots udev rules can be used to restore the memory assignment. One implication of using pmem as RAM is that mlock() no longer keeps data off persistent media. For this reason it is recommended to enable NVDIMM Security (previously merged for 5.0) to encrypt pmem contents at rest. We considered making this recommendation an actively enforced requirement, but in the end decided to leave it as a distribution / administrator policy to allow for emulation and test environments that lack security capable NVDIMMs. Summary: - Replace the /sys/class/dax device model with /sys/bus/dax, and include a compat driver so distributions can opt-in to the new ABI. - Allow for an alternative driver for the device-dax address-range - Introduce the 'kmem' driver to hotplug / assign a device-dax address-range to the core-mm. - Arrange for the device-dax target-node to be onlined so that the newly added memory range can be uniquely referenced by numa apis" NOTE! I'm not entirely happy with the whole "PMEM as RAM" model because we currently have special - and very annoying rules in the kernel about accessing PMEM only with the "MC safe" accessors, because machine checks inside the regular repeat string copy functions can be fatal in some (not described) circumstances. And apparently the PMEM modules can cause that a lot more than regular RAM. The argument is that this happens because PMEM doesn't necessarily get scrubbed at boot like RAM does, but that is planned to be added for the user space tooling. Quoting Dan from another email: "The exposure can be reduced in the volatile-RAM case by scanning for and clearing errors before it is onlined as RAM. The userspace tooling for that can be in place before v5.1-final. There's also runtime notifications of errors via acpi_nfit_uc_error_notify() from background scrubbers on the DIMM devices. With that mechanism the kernel could proactively clear newly discovered poison in the volatile case, but that would be additional development more suitable for v5.2. I understand the concern, and the need to highlight this issue by tapping the brakes on feature development, but I don't see PMEM as RAM making the situation worse when the exposure is also there via DAX in the PMEM case. Volatile-RAM is arguably a safer use case since it's possible to repair pages where the persistent case needs active application coordination" * tag 'devdax-for-5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: device-dax: "Hotplug" persistent memory for use like normal RAM mm/resource: Let walk_system_ram_range() search child resources mm/memory-hotplug: Allow memory resources to be children mm/resource: Move HMM pr_debug() deeper into resource code mm/resource: Return real error codes from walk failures device-dax: Add a 'modalias' attribute to DAX 'bus' devices device-dax: Add a 'target_node' attribute device-dax: Auto-bind device after successful new_id acpi/nfit, device-dax: Identify differentiated memory with a unique numa-node device-dax: Add /sys/class/dax backwards compatibility device-dax: Add support for a dax override driver device-dax: Move resource pinning+mapping into the common driver device-dax: Introduce bus + driver model device-dax: Start defining a dax bus model device-dax: Remove multi-resource infrastructure device-dax: Kill dax_region base device-dax: Kill dax_region ida
| * | | | | acpi/nfit, device-dax: Identify differentiated memory with a unique numa-nodeDan Williams2019-01-061-0/+1
| | |_|/ / | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Persistent memory, as described by the ACPI NFIT (NVDIMM Firmware Interface Table), is the first known instance of a memory range described by a unique "target" proximity domain. Where "initiator" and "target" proximity domains is an approach that the ACPI HMAT (Heterogeneous Memory Attributes Table) uses to described the unique performance properties of a memory range relative to a given initiator (e.g. CPU or DMA device). Currently the numa-node for a /dev/pmemX block-device or /dev/daxX.Y char-device follows the traditional notion of 'numa-node' where the attribute conveys the closest online numa-node. That numa-node attribute is useful for cpu-binding and memory-binding processes *near* the device. However, when the memory range backing a 'pmem', or 'dax' device is onlined (memory hot-add) the memory-only-numa-node representing that address needs to be differentiated from the set of online nodes. In other words, the numa-node association of the device depends on whether you can bind processes *near* the cpu-numa-node in the offline device-case, or bind process *on* the memory-range directly after the backing address range is onlined. Allow for the case that platform firmware describes persistent memory with a unique proximity domain, i.e. when it is distinct from the proximity of DRAM and CPUs that are on the same socket. Plumb the Linux numa-node translation of that proximity through the libnvdimm region device to namespaces that are in device-dax mode. With this in place the proposed kmem driver [1] can optionally discover a unique numa-node number for the address range as it transitions the memory from an offline state managed by a device-driver to an online memory range managed by the core-mm. [1]: https://lore.kernel.org/lkml/20181022201317.8558C1D8@viggo.jf.intel.com Reported-by: Fan Du <fan.du@intel.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: "Oliver O'Halloran" <oohall@gmail.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Jérôme Glisse <jglisse@redhat.com> Reviewed-by: Yang Shi <yang.shi@linux.alibaba.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* | | | | Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsiLinus Torvalds2019-03-161-3/+4
|\ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull more SCSI updates from James Bottomley: "This is the final round of mostly small fixes and performance improvements to our initial submit. The main regression fix is the ia64 simscsi build failure which was missed in the serial number elimination conversion" * tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (24 commits) scsi: ia64: simscsi: use request tag instead of serial_number scsi: aacraid: Fix performance issue on logical drives scsi: lpfc: Fix error codes in lpfc_sli4_pci_mem_setup() scsi: libiscsi: Hold back_lock when calling iscsi_complete_task scsi: hisi_sas: Change SERDES_CFG init value to increase reliability of HiLink scsi: hisi_sas: Send HARD RESET to clear the previous affiliation of STP target port scsi: hisi_sas: Set PHY linkrate when disconnected scsi: hisi_sas: print PHY RX errors count for later revision of v3 hw scsi: hisi_sas: Fix a timeout race of driver internal and SMP IO scsi: hisi_sas: Change return variable type in phy_up_v3_hw() scsi: qla2xxx: check for kstrtol() failure scsi: lpfc: fix 32-bit format string warning scsi: lpfc: fix unused variable warning scsi: target: tcmu: Switch to bitmap_zalloc() scsi: libiscsi: fall back to sendmsg for slab pages scsi: qla2xxx: avoid printf format warning scsi: lpfc: resolve static checker warning in lpfc_sli4_hba_unset scsi: lpfc: Correct __lpfc_sli_issue_iocb_s4 lockdep check scsi: ufs: hisi: fix ufs_hba_variant_ops passing scsi: qla2xxx: Fix panic in qla_dfs_tgt_counters_show ...
| * | | | | scsi: ia64: simscsi: use request tag instead of serial_numberHannes Reinecke2019-03-151-3/+4
| |/ / / / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Use the request tag for logging instead of the scsi command serial number. Signed-off-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> [jejb: fix commit oneliner] Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
* | | | | Merge tag 'powerpc-5.1-2' of ↵Linus Torvalds2019-03-166-10/+22
|\ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux Pull powerpc fixes from Michael Ellerman: "One fix to prevent runtime allocation of 16GB pages when running in a VM (as opposed to bare metal), because it doesn't work. A small fix to our recently added KCOV support to exempt some more code from being instrumented. Plus a few minor build fixes, a small dead code removal and a defconfig update. Thanks to: Alexey Kardashevskiy, Aneesh Kumar K.V, Christophe Leroy, Jason Yan, Joel Stanley, Mahesh Salgaonkar, Mathieu Malaterre" * tag 'powerpc-5.1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: powerpc/64s: Include <asm/nmi.h> header file to fix a warning powerpc/powernv: Fix compile without CONFIG_TRACEPOINTS powerpc/mm: Disable kcov for SLB routines powerpc: remove dead code in head_fsl_booke.S powerpc/configs: Sync skiroot defconfig powerpc/hugetlb: Don't do runtime allocation of 16G pages in LPAR configuration
| * | | | | powerpc/64s: Include <asm/nmi.h> header file to fix a warningMathieu Malaterre2019-03-131-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Make sure to include <asm/nmi.h> to provide the following prototype: hv_nmi_check_nonrecoverable. Remove the following warning treated as error (W=1): arch/powerpc/kernel/traps.c:393:6: error: no previous prototype for 'hv_nmi_check_nonrecoverable' Fixes: ccd477028a20 ("powerpc/64s: Fix HV NMI vs HV interrupt recoverability test") Signed-off-by: Mathieu Malaterre <malat@debian.org> Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
| * | | | | powerpc/powernv: Fix compile without CONFIG_TRACEPOINTSAlexey Kardashevskiy2019-03-131-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The functions returns s64 but the return statement is missing. This adds the missing return statement. Fixes: 75d9fc7fd94e ("powerpc/powernv: move OPAL call wrapper tracing and interrupt handling to C") Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
| * | | | | powerpc/mm: Disable kcov for SLB routinesMahesh Salgaonkar2019-03-121-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The kcov instrumentation inside SLB routines causes duplicate SLB entries to be added resulting into SLB multihit machine checks. Disable kcov instrumentation on slb.o Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Acked-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
| * | | | | powerpc: remove dead code in head_fsl_booke.SJason Yan2019-03-051-7/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This code is dead. Just remove it. Signed-off-by: Jason Yan <yanaijie@huawei.com> Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
| * | | | | powerpc/configs: Sync skiroot defconfigJoel Stanley2019-03-051-3/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This updates the skiroot defconfig with the version from the OpenPower firmwre build tree. Important changes are the addition of QED and E1000E ethernet drivers. Signed-off-by: Joel Stanley <joel@jms.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
| * | | | | powerpc/hugetlb: Don't do runtime allocation of 16G pages in LPAR configurationAneesh Kumar K.V2019-03-051-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We added runtime allocation of 16G pages in commit 4ae279c2c96a ("powerpc/mm/hugetlb: Allow runtime allocation of 16G.") That was done to enable 16G allocation on PowerNV and KVM config. In case of KVM config, we mostly would have the entire guest RAM backed by 16G hugetlb pages for this to work. PAPR do support partial backing of guest RAM with hugepages via ibm,expected#pages node of memory node in the device tree. This means rest of the guest RAM won't be backed by 16G contiguous pages in the host and hence a hash page table insertion can fail in such case. An example error message will look like hash-mmu: mm: Hashing failure ! EA=0x7efc00000000 access=0x8000000000000006 current=readback hash-mmu: trap=0x300 vsid=0x67af789 ssize=1 base psize=14 psize 14 pte=0xc000000400000386 readback[12260]: unhandled signal 7 at 00007efc00000000 nip 00000000100012d0 lr 000000001000127c code 2 This patch address that by preventing runtime allocation of 16G hugepages in LPAR config. To allocate 16G hugetlb one need to kernel command line hugepagesz=16G hugepages=<number of 16G pages> With radix translation mode we don't run into this issue. This change will prevent runtime allocation of 16G hugetlb pages on kvm with hash translation mode. However, with the current upstream it was observed that 16G hugetlbfs backed guest doesn't boot at all. We observe boot failure with the below message: [131354.647546] KVM: map_vrma at 0 failed, ret=-4 That means this patch is not resulting in an observable regression. Once we fix the boot issue with 16G hugetlb backed memory, we need to use ibm,expected#pages memory node attribute to indicate 16G page reservation to the guest. This will also enable partial backing of guest RAM with 16G pages. Fixes: 4ae279c2c96a ("powerpc/mm/hugetlb: Allow runtime allocation of 16G.") Cc: stable@vger.kernel.org # v4.14+ Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* | | | | | Merge branch 'for-linus-5.1-rc1' of ↵Linus Torvalds2019-03-152-6/+3
|\ \ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml Pull UML updates from Richard Weinberger: "Bugfix for the UML block device driver" * 'for-linus-5.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml: um: Fix for a possible OOPS in ubd initialization um: Remove duplicated include from vector_user.c
| * | | | | | um: Fix for a possible OOPS in ubd initializationAnton Ivanov2019-03-061-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If the ubd device failed to allocate a queue during initialization it tried call blk_cleanup_queue resulting in an oops. This patch simplifies the cleanup logic and ensures that blk_queue_cleanup is called only if there is a valid queue. Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Anton Ivanov <anton.ivanov@cambridgegreys.com> Signed-off-by: Richard Weinberger <richard@nod.at>
| * | | | | | um: Remove duplicated include from vector_user.cYueHaibing2019-03-061-3/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Remove duplicated include. Signed-off-by: YueHaibing <yuehaibing@huawei.com> Reviewed-by: Anton Ivanov <anton.ivanov@cambridgegreys.com> Acked-by: Anton Ivanov <anton.ivanov@cambridgegreys.com> Signed-off-by: Richard Weinberger <richard@nod.at>
* | | | | | | Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds2019-03-1569-825/+1718
|\ \ \ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull KVM updates from Paolo Bonzini: "ARM: - some cleanups - direct physical timer assignment - cache sanitization for 32-bit guests s390: - interrupt cleanup - introduction of the Guest Information Block - preparation for processor subfunctions in cpu models PPC: - bug fixes and improvements, especially related to machine checks and protection keys x86: - many, many cleanups, including removing a bunch of MMU code for unnecessary optimizations - AVIC fixes Generic: - memcg accounting" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (147 commits) kvm: vmx: fix formatting of a comment KVM: doc: Document the life cycle of a VM and its resources MAINTAINERS: Add KVM selftests to existing KVM entry Revert "KVM/MMU: Flush tlb directly in the kvm_zap_gfn_range()" KVM: PPC: Book3S: Add count cache flush parameters to kvmppc_get_cpu_char() KVM: PPC: Fix compilation when KVM is not enabled KVM: Minor cleanups for kvm_main.c KVM: s390: add debug logging for cpu model subfunctions KVM: s390: implement subfunction processor calls arm64: KVM: Fix architecturally invalid reset value for FPEXC32_EL2 KVM: arm/arm64: Remove unused timer variable KVM: PPC: Book3S: Improve KVM reference counting KVM: PPC: Book3S HV: Fix build failure without IOMMU support Revert "KVM: Eliminate extra function calls in kvm_get_dirty_log_protect()" x86: kvmguest: use TSC clocksource if invariant TSC is exposed KVM: Never start grow vCPU halt_poll_ns from value below halt_poll_ns_grow_start KVM: Expose the initial start value in grow_halt_poll_ns() as a module parameter KVM: grow_halt_poll_ns() should never shrink vCPU halt_poll_ns KVM: x86/mmu: Consolidate kvm_mmu_zap_all() and kvm_mmu_zap_mmio_sptes() KVM: x86/mmu: WARN if zapping a MMIO spte results in zapping children ...
| * | | | | | | kvm: vmx: fix formatting of a commentPaolo Bonzini2019-03-151-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Eliminate a gratuitous conflict with 5.0. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * | | | | | | Merge tag 'kvm-ppc-next-5.1-3' of ↵Paolo Bonzini2019-03-153-5/+17
| |\ \ \ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc into HEAD Third PPC KVM update for 5.1 - Tell userspace about whether a particular hardware workaround for one of the Spectre vulnerabilities is available, so that userspace can inform the guest.
| | * | | | | | | KVM: PPC: Book3S: Add count cache flush parameters to kvmppc_get_cpu_char()Suraj Jitindar Singh2019-03-012-4/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add KVM_PPC_CPU_CHAR_BCCTR_FLUSH_ASSIST & KVM_PPC_CPU_BEHAV_FLUSH_COUNT_CACHE to the characteristics returned from the H_GET_CPU_CHARACTERISTICS H-CALL, as queried from either the hypervisor or the device tree. Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
| | * | | | | | | KVM: PPC: Fix compilation when KVM is not enabledPaul Mackerras2019-02-271-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Compiling with CONFIG_PPC_POWERNV=y and KVM disabled currently gives an error like this: CC arch/powerpc/kernel/dbell.o In file included from arch/powerpc/kernel/dbell.c:20:0: arch/powerpc/include/asm/kvm_ppc.h: In function ‘xics_on_xive’: arch/powerpc/include/asm/kvm_ppc.h:625:9: error: implicit declaration of function ‘xive_enabled’ [-Werror=implicit-function-declaration] return xive_enabled() && cpu_has_feature(CPU_FTR_HVMODE); ^ cc1: all warnings being treated as errors scripts/Makefile.build:276: recipe for target 'arch/powerpc/kernel/dbell.o' failed make[3]: *** [arch/powerpc/kernel/dbell.o] Error 1 Fix this by making the xics_on_xive() definition conditional on the same symbol (CONFIG_KVM_BOOK3S_64_HANDLER) that determines whether we include <asm/xive.h> or not, since that's the header that defines xive_enabled(). Fixes: 03f953329bd8 ("KVM: PPC: Book3S: Allow XICS emulation to work in nested hosts using XIVE") Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
| * | | | | | | | Revert "KVM/MMU: Flush tlb directly in the kvm_zap_gfn_range()"Ben Gardon2019-03-151-13/+3
| |/ / / / / / / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This reverts commit 71883a62fcd6c70639fa12cda733378b4d997409. The above commit contains an optimization to kvm_zap_gfn_range which uses gfn-limited TLB flushes, if enabled. If using these limited flushes, kvm_zap_gfn_range passes lock_flush_tlb=false to slot_handle_level_range which creates a race when the function unlocks to call cond_resched. See an example of this race below: CPU 0 CPU 1 CPU 3 // zap_direct_gfn_range mmu_lock() // *ptep == pte_1 *ptep = 0 if (lock_flush_tlb) flush_tlbs() mmu_unlock() // In invalidate range // MMU notifier mmu_lock() if (pte != 0) *ptep = 0 flush = true if (flush) flush_remote_tlbs() mmu_unlock() return // Host MM reallocates // page previously // backing guest memory. // Guest accesses // invalid page // through pte_1 // in its TLB!! Tested: Ran all kvm-unit-tests on a Intel Haswell machine with and without this patch. The patch introduced no new failures. Signed-off-by: Ben Gardon <bgardon@google.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * | | | | | | Merge tag 'kvmarm-for-v5.1' of ↵Paolo Bonzini2019-02-2223-115/+277
| |\ \ \ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into kvm-next KVM/arm updates for Linux v5.1 - A number of pre-nested code rework - Direct physical timer assignment on VHE systems - kvm_call_hyp type safety enforcement - Set/Way cache sanitisation for 32bit guests - Build system cleanups - A bunch of janitorial fixes
| | * | | | | | | arm64: KVM: Fix architecturally invalid reset value for FPEXC32_EL2Dave Martin2019-02-221-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Due to what looks like a typo dating back to the original addition of FPEXC32_EL2 handling, KVM currently initialises this register to an architecturally invalid value. As a result, the VECITR field (RES1) in bits [10:8] is initialised with 0, and the two reserved (RES0) bits [6:5] are initialised with 1. (In the Common VFP Subarchitecture as specified by ARMv7-A, these two bits were IMP DEF. ARMv8-A removes them.) This patch changes the reset value from 0x70 to 0x700, which reflects the architectural constraints and is presumably what was originally intended. Cc: <stable@vger.kernel.org> # 4.12.x- Cc: Christoffer Dall <christoffer.dall@arm.com> Fixes: 62a89c44954f ("arm64: KVM: 32bit handling of coprocessor traps") Signed-off-by: Dave Martin <Dave.Martin@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
| | * | | | | | | KVM: arm64: Fix comment for KVM_PHYS_SHIFTZenghui Yu2019-02-191-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since Suzuki K Poulose's work on Dynamic IPA support, KVM_PHYS_SHIFT will be used only when machine_type's bits[7:0] equal to 0 (by default). Thus the outdated comment should be fixed. Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Zenghui Yu <yuzenghui@huawei.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
| | * | | | | | | KVM: arm/arm64: Prefix header search paths with $(srctree)/Masahiro Yamada2019-02-192-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, the Kbuild core manipulates header search paths in a crazy way [1]. To fix this mess, I want all Makefiles to add explicit $(srctree)/ to the search paths in the srctree. Some Makefiles are already written in that way, but not all. The goal of this work is to make the notation consistent, and finally get rid of the gross hacks. Having whitespaces after -I does not matter since commit 48f6e3cf5bc6 ("kbuild: do not drop -I without parameter"). [1]: https://patchwork.kernel.org/patch/9632347/ Acked-by: Christoffer Dall <christoffer.dall@arm.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
| | * | | | | | | KVM: arm/arm64: Remove -I. header search pathsMasahiro Yamada2019-02-192-4/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The header search path -I. in kernel Makefiles is very suspicious; it allows the compiler to search for headers in the top of $(srctree), where obviously no header file exists. I was able to build without these extra header search paths. Acked-by: Christoffer Dall <christoffer.dall@arm.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
| | * | | | | | | arm64: KVM: Describe data or unified caches as having 1 set and 1 wayArd Biesheuvel2019-02-192-1/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On SMP ARM systems, cache maintenance by set/way should only ever be done in the context of onlining or offlining CPUs, which is typically done by bare metal firmware and never in a virtual machine. For this reason, we trap set/way cache maintenance operations and replace them with conditional flushing of the entire guest address space. Due to this trapping, the set/way arguments passed into the set/way ops are completely ignored, and thus irrelevant. This also means that the set/way geometry is equally irrelevant, and we can simply report it as 1 set and 1 way, so that legacy 32-bit ARM system software (i.e., the kind that only receives odd fixes) doesn't take a performance hit due to the trapping when iterating over the cachelines. Acked-by: Christoffer Dall <christoffer.dall@arm.com> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
| | * | | | | | | arm64: KVM: Expose sanitised cache type register to guestArd Biesheuvel2019-02-193-2/+61
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We currently permit CPUs in the same system to deviate in the exact topology of the caches, and we subsequently hide this fact from user space by exposing a sanitised value of the cache type register CTR_EL0. However, guests running under KVM see the bare value of CTR_EL0, which could potentially result in issues with, e.g., JITs or other pieces of code that are sensitive to misreported cache line sizes. So let's start trapping cache ID instructions if there is a mismatch, and expose the sanitised version of CTR_EL0 to guests. Note that CTR_EL0 is treated as an invariant to KVM user space, so update that part as well. Acked-by: Christoffer Dall <christoffer.dall@arm.com> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
| | * | | | | | | KVM: arm/arm64: Move kvm_is_write_fault to header fileChristoffer Dall2019-02-192-0/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Move this little function to the header files for arm/arm64 so other code can make use of it directly. Signed-off-by: Christoffer Dall <christoffer.dall@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
| | * | | | | | | KVM: arm/arm64: arch_timer: Assign the phys timer on VHE systemsChristoffer Dall2019-02-191-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | VHE systems don't have to emulate the physical timer, we can simply assign the EL1 physical timer directly to the VM as the host always uses the EL2 timers. In order to minimize the amount of cruft, AArch32 gets definitions for the physical timer too, but is should be generally unused on this architecture. Co-written with Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
| | * | | | | | | KVM: arm/arm64: consolidate arch timer trap handlersAndre Przywara2019-02-193-49/+51
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | At the moment we have separate system register emulation handlers for each timer register. Actually they are quite similar, and we rely on kvm_arm_timer_[gs]et_reg() for the actual emulation anyways, so let's just merge all of those handlers into one function, which just marshalls the arguments and then hands off to a set of common accessors. This makes extending the emulation to include EL2 timers much easier. Signed-off-by: Andre Przywara <andre.przywara@arm.com> [Fixed 32-bit VM breakage and reduced to reworking existing code] Signed-off-by: Christoffer Dall <christoffer.dall@arm.com> [Fixed 32bit host, general cleanup] Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
| | * | | | | | | KVM: arm64: Reuse sys_reg() macro when searching the trap tableMarc Zyngier2019-02-191-13/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Instead of having an open-coded macro, reuse the sys_reg() macro that does the exact same thing (the encoding is slightly different, but the ordering property is the same). Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Acked-by: Christoffer Dall <christoffer.dall@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
| | * | | | | | | KVM: arm64: Fix ICH_ELRSR_EL2 sysreg namingMarc Zyngier2019-02-192-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We previously incorrectly named the define for this system register. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
| | * | | | | | | KVM: arm/arm64: Factor out VMID into struct kvm_vmidChristoffer Dall2019-02-197-16/+34
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In preparation for nested virtualization where we are going to have more than a single VMID per VM, let's factor out the VMID data into a separate VMID data structure and change the VMID allocator to operate on this new structure instead of using a struct kvm. This also means that udate_vttbr now becomes update_vmid, and that the vttbr itself is generated on the fly based on the stage 2 page table base address and the vmid. We cache the physical address of the pgd when allocating the pgd to avoid doing the calculation on every entry to the guest and to avoid calling into potentially non-hyp-mapped code from hyp/EL2. If we wanted to merge the VMID allocator with the arm64 ASID allocator at some point in the future, it should actually become easier to do that after this patch. Note that to avoid mapping the kvm_vmid_bits variable into hyp, we simply forego the masking of the vmid value in kvm_get_vttbr and rely on update_vmid to always assign a valid vmid value (within the supported range). Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> [maz: minor cleanups] Reviewed-by: Julien Thierry <julien.thierry@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
| | * | | | | | | arm/arm64: KVM: Statically configure the host's view of MPIDRMarc Zyngier2019-02-194-2/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We currently eagerly save/restore MPIDR. It turns out to be slightly pointless: - On the host, this value is known as soon as we're scheduled on a physical CPU - In the guest, this value cannot change, as it is set by KVM (and this is a read-only register) The result of the above is that we can perfectly avoid the eager saving of MPIDR_EL1, and only keep the restore. We just have to setup the host contexts appropriately at boot time. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Acked-by: Christoffer Dall <christoffer.dall@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>