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2022-03-28Merge tag 'char-misc-5.18-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc Pull char/misc and other driver updates from Greg KH: "Here is the big set of char/misc and other small driver subsystem updates for 5.18-rc1. Included in here are merges from driver subsystems which contain: - iio driver updates and new drivers - fsi driver updates - fpga driver updates - habanalabs driver updates and support for new hardware - soundwire driver updates and new drivers - phy driver updates and new drivers - coresight driver updates - icc driver updates Individual changes include: - mei driver updates - interconnect driver updates - new PECI driver subsystem added - vmci driver updates - lots of tiny misc/char driver updates All of these have been in linux-next for a while with no reported problems" * tag 'char-misc-5.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (556 commits) firmware: google: Properly state IOMEM dependency kgdbts: fix return value of __setup handler firmware: sysfb: fix platform-device leak in error path firmware: stratix10-svc: add missing callback parameter on RSU arm64: dts: qcom: add non-secure domain property to fastrpc nodes misc: fastrpc: Add dma handle implementation misc: fastrpc: Add fdlist implementation misc: fastrpc: Add helper function to get list and page misc: fastrpc: Add support to secure memory map dt-bindings: misc: add fastrpc domain vmid property misc: fastrpc: check before loading process to the DSP misc: fastrpc: add secure domain support dt-bindings: misc: add property to support non-secure DSP misc: fastrpc: Add support to get DSP capabilities misc: fastrpc: add support for FASTRPC_IOCTL_MEM_MAP/UNMAP misc: fastrpc: separate fastrpc device from channel context dt-bindings: nvmem: brcm,nvram: add basic NVMEM cells dt-bindings: nvmem: make "reg" property optional nvmem: brcm_nvram: parse NVRAM content into NVMEM cells nvmem: dt-bindings: Fix the error of dt-bindings check ...
2022-03-17configs/debug: restore DEBUG_INFO=y for overridingQian Cai
Previously, I failed to realize that Kees' patch [1] has not been merged into the mainline yet, and dropped DEBUG_INFO=y too eagerly from the mainline. As the results, "make debug.config" won't be able to flip DEBUG_INFO=n from the existing .config. This should close the gaps of a few weeks before Kees' patch is there, and work regardless of their merging status anyway. Link: https://lore.kernel.org/all/20220125075126.891825-1-keescook@chromium.org/ [1] Link: https://lkml.kernel.org/r/20220308153524.8618-1-quic_qiancai@quicinc.com Signed-off-by: Qian Cai <quic_qiancai@quicinc.com> Reported-by: Daniel Thompson <daniel.thompson@linaro.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Cc: Kees Cook <keescook@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-03-05configs/debug: set CONFIG_DEBUG_INFO=y properlyQian Cai
CONFIG_DEBUG_INFO can't be set by user directly, so set CONFIG_DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT=y instead. Otherwise, we end up with no debuginfo in vmlinux which is a big no-no for kernel debugging. Link: https://lkml.kernel.org/r/20220301202920.18488-1-quic_qiancai@quicinc.com Signed-off-by: Qian Cai <quic_qiancai@quicinc.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-02-25config: android-recommended: Disable BPF_UNPRIV_DEFAULT_OFF for netdMarijn Suijten
AOSP's `netd` process fails to start on Android S: E ClatdController: getClatEgress4MapFd() failure: Operation not permitted I netd : Initializing ClatdController: 410us E netd : Failed to start trafficcontroller: (Status[code: 1, msg: "Pinned map not accessible or does not exist: (/sys/fs/bpf/map_netd_cookie_tag_map): Operation not permitted"]) E netd : CRITICAL: sleeping 60 seconds, netd exiting with failure, crash loop likely! And on Android R: I ClatdController: 4.9+ kernel and device shipped with P - clat ebpf might work. E ClatdController: getClatEgressMapFd() failure: Operation not permitted I netd : Initializing ClatdController: 1409us E netd : Failed to start trafficcontroller: (Status[code: 1, msg: "Pinned map not accessible or does not exist: (/sys/fs/bpf/map_netd_cookie_tag_map): Operation not permitted"]) These permission issues are caused by 08389d888287 ("bpf: Add kconfig knob for disabling unpriv bpf by default") because AOSP does not provide netd the `SYS_ADMIN` capability, and also has no userspace support for the `BPF` capability yet. Cc: Amit Pundir <amit.pundir@linaro.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Suggested-by: John Stultz <john.stultz@linaro.org> [John suggested this in https://linaro.atlassian.net/browse/ACK-107?focusedCommentId=117382] Signed-off-by: Marijn Suijten <marijn.suijten@somainline.org> Link: https://lore.kernel.org/r/20220202100528.190794-2-marijn.suijten@somainline.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-02-25config: android-recommended: Don't explicitly disable CONFIG_AIOMarijn Suijten
Android nowadays (for a couple years already) requires AIO for at least its `adb` "Android Debug Bridge" [1]. Without this config option (`default y`) it simply refuses start, making users unable to connect to their phone for debugging purposes when using these kernel fragments. [1]: https://cs.android.com/android/_/android/platform/packages/modules/adb/+/a2cb8de5e68067a5e1d002886d5f3b42d91371e1 Cc: Amit Pundir <amit.pundir@linaro.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: John Stultz <john.stultz@linaro.org> Signed-off-by: Marijn Suijten <marijn.suijten@somainline.org> Link: https://lore.kernel.org/r/20220202100528.190794-1-marijn.suijten@somainline.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-01-20configs: introduce debug.config for CI-like setupQian Cai
Some general debugging features like kmemleak, KASAN, lockdep, UBSAN etc help fix many viruses like a microscope. On the other hand, those features are scatter around and mixed up with more situational debugging options making them difficult to consume properly. This cold help amplify the general debugging/testing efforts and help establish sensitive default values for those options across the broad. This could also help different distros to collaborate on maintaining debug-flavored kernels. The config is based on years' experiences running daily CI inside the largest enterprise Linux distro company to seek regressions on linux-next builds on different bare-metal and virtual platforms. It can be used for example, $ make ARCH=arm64 defconfig debug.config Since KASAN and KCSAN can't be enabled together, we will need to create a separate one for KCSAN later as well. Link: https://lkml.kernel.org/r/20211115134754.7334-1-quic_qiancai@quicinc.com Signed-off-by: Qian Cai <quic_qiancai@quicinc.com> Acked-by: Paul E. McKenney <paulmck@kernel.org> Cc: Marco Elver <elver@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Daniel Thompson <daniel.thompson@linaro.org> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Naresh Kamboju <naresh.kamboju@linaro.org> Cc: "Stephen Rothwell" <sfr@canb.auug.org.au> Cc: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-05-07drivers/char: remove /dev/kmem for goodDavid Hildenbrand
Patch series "drivers/char: remove /dev/kmem for good". Exploring /dev/kmem and /dev/mem in the context of memory hot(un)plug and memory ballooning, I started questioning the existence of /dev/kmem. Comparing it with the /proc/kcore implementation, it does not seem to be able to deal with things like a) Pages unmapped from the direct mapping (e.g., to be used by secretmem) -> kern_addr_valid(). virt_addr_valid() is not sufficient. b) Special cases like gart aperture memory that is not to be touched -> mem_pfn_is_ram() Unless I am missing something, it's at least broken in some cases and might fault/crash the machine. Looks like its existence has been questioned before in 2005 and 2010 [1], after ~11 additional years, it might make sense to revive the discussion. CONFIG_DEVKMEM is only enabled in a single defconfig (on purpose or by mistake?). All distributions disable it: in Ubuntu it has been disabled for more than 10 years, in Debian since 2.6.31, in Fedora at least starting with FC3, in RHEL starting with RHEL4, in SUSE starting from 15sp2, and OpenSUSE has it disabled as well. 1) /dev/kmem was popular for rootkits [2] before it got disabled basically everywhere. Ubuntu documents [3] "There is no modern user of /dev/kmem any more beyond attackers using it to load kernel rootkits.". RHEL documents in a BZ [5] "it served no practical purpose other than to serve as a potential security problem or to enable binary module drivers to access structures/functions they shouldn't be touching" 2) /proc/kcore is a decent interface to have a controlled way to read kernel memory for debugging puposes. (will need some extensions to deal with memory offlining/unplug, memory ballooning, and poisoned pages, though) 3) It might be useful for corner case debugging [1]. KDB/KGDB might be a better fit, especially, to write random memory; harder to shoot yourself into the foot. 4) "Kernel Memory Editor" [4] hasn't seen any updates since 2000 and seems to be incompatible with 64bit [1]. For educational purposes, /proc/kcore might be used to monitor value updates -- or older kernels can be used. 5) It's broken on arm64, and therefore, completely disabled there. Looks like it's essentially unused and has been replaced by better suited interfaces for individual tasks (/proc/kcore, KDB/KGDB). Let's just remove it. [1] https://lwn.net/Articles/147901/ [2] https://www.linuxjournal.com/article/10505 [3] https://wiki.ubuntu.com/Security/Features#A.2Fdev.2Fkmem_disabled [4] https://sourceforge.net/projects/kme/ [5] https://bugzilla.redhat.com/show_bug.cgi?id=154796 Link: https://lkml.kernel.org/r/20210324102351.6932-1-david@redhat.com Link: https://lkml.kernel.org/r/20210324102351.6932-2-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Alexander A. Klimov" <grandmaster@al2klimov.de> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Alexandre Belloni <alexandre.belloni@bootlin.com> Cc: Andrew Lunn <andrew@lunn.ch> Cc: Andrey Zhizhikin <andrey.zhizhikin@leica-geosystems.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Brian Cain <bcain@codeaurora.org> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Chris Zankel <chris@zankel.net> Cc: Corentin Labbe <clabbe@baylibre.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: Greentime Hu <green.hu@gmail.com> Cc: Gregory Clement <gregory.clement@bootlin.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Helge Deller <deller@gmx.de> Cc: Hillf Danton <hdanton@sina.com> Cc: huang ying <huang.ying.caritas@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com> Cc: James Troup <james.troup@canonical.com> Cc: Jiaxun Yang <jiaxun.yang@flygoat.com> Cc: Jonas Bonn <jonas@southpole.se> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kairui Song <kasong@redhat.com> Cc: Krzysztof Kozlowski <krzk@kernel.org> Cc: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com> Cc: Liviu Dudau <liviu.dudau@arm.com> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Cc: Luc Van Oostenryck <luc.vanoostenryck@gmail.com> Cc: Luis Chamberlain <mcgrof@kernel.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Matt Turner <mattst88@gmail.com> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Mike Rapoport <rppt@kernel.org> Cc: Mikulas Patocka <mpatocka@redhat.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Niklas Schnelle <schnelle@linux.ibm.com> Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com> Cc: openrisc@lists.librecores.org Cc: Palmer Dabbelt <palmerdabbelt@google.com> Cc: Paul Mackerras <paulus@samba.org> Cc: "Pavel Machek (CIP)" <pavel@denx.de> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org> Cc: Pierre Morel <pmorel@linux.ibm.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Richard Henderson <rth@twiddle.net> Cc: Rich Felker <dalias@libc.org> Cc: Robert Richter <rric@kernel.org> Cc: Rob Herring <robh@kernel.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com> Cc: sparclinux@vger.kernel.org Cc: Stafford Horne <shorne@gmail.com> Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Sudeep Holla <sudeep.holla@arm.com> Cc: Theodore Dubois <tblodt@icloud.com> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Viresh Kumar <viresh.kumar@linaro.org> Cc: William Cohen <wcohen@redhat.com> Cc: Xiaoming Ni <nixiaoming@huawei.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-04-14kconfig: do not use allnoconfig_y optionMasahiro Yamada
allnoconfig_y is an ugly hack that sets a symbol to 'y' by allnoconfig. allnoconfig does not mean a minimal set of CONFIG options because a bunch of prompts are hidden by 'if EMBEDDED' or 'if EXPERT', but I do not like to hack Kconfig this way. Use the pre-existing feature, KCONFIG_ALLCONFIG, to provide a one liner config fragment. CONFIG_EMBEDDED=y is still forced when allnoconfig is invoked as a part of tinyconfig. No change in the .config file produced by 'make tinyconfig'. The output of 'make allnoconfig' will be changed; we will get CONFIG_EMBEDDED=n because allnoconfig literally sets all symbols to n. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-01-06staging: ION: remove some references to CONFIG_IONMatthias Maennich
With commit e722a295cf49 ("staging: ion: remove from the tree"), ION and its corresponding config CONFIG_ION is gone. Remove stale references from drivers/staging/media/atomisp/pci and from the recommended Android kernel config. Fixes: e722a295cf49 ("staging: ion: remove from the tree") Cc: Hridya Valsaraju <hridya@google.com> Cc: Rob Herring <robh@kernel.org> Cc: linux-media@vger.kernel.org Cc: devel@driverdev.osuosl.org Signed-off-by: Matthias Maennich <maennich@google.com> Link: https://lore.kernel.org/r/20210106155201.2845319-1-maennich@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-12-09Input: gtco - remove driverDmitry Torokhov
The driver has its own HID descriptor parsing code, that had and still has several issues discovered by syzbot and other tools. Ideally we should move the driver over to the HID subsystem, so that it uses proven parsing code. However the devices in question are EOL, and GTCO is not willing to extend resources for that, so let's simply remove the driver. Note that our HID support has greatly improved over the last 10 years, we may also consider reverting 6f8d9e26e7de ("hid-core.c: Adds all GTCO CalComp Digitizers and InterWrite School Products to blacklist") and see if GTCO devices actually work with normal HID drivers. Link: https://lore.kernel.org/r/X8wbBtO5KidME17K@google.com Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
2020-04-07compiler: remove CONFIG_OPTIMIZE_INLINING entirelyMasahiro Yamada
Commit ac7c3e4ff401 ("compiler: enable CONFIG_OPTIMIZE_INLINING forcibly") made this always-on option. We released v5.4 and v5.5 including that commit. Remove the CONFIG option and clean up the code now. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: David Miller <davem@davemloft.net> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20200220110807.32534-2-masahiroy@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-24kvm_config: add CONFIG_VIRTIO_MENULénaïc Huard
Make sure that make kvmconfig enables all the virtio drivers even if it is preceded by a make allnoconfig. Signed-off-by: Lénaïc Huard <lenaic@lhuard.fr> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2018-06-15kconfig: tinyconfig: remove stale stack protector fixupsMasahiro Yamada
Prior to commit 2a61f4747eea ("stack-protector: test compiler capability in Kconfig and drop AUTO mode"), the stack protector was configured by the choice of NONE, REGULAR, STRONG, AUTO. tiny.config needed to explicitly set NONE because the default value of choice, AUTO, did not produce the tiniest kernel. Now that there are only two boolean symbols, STACKPROTECTOR and STACKPROTECTOR_STRONG, they are naturally disabled by "make allnoconfig", which "make tinyconfig" is based on. Remove unnecessary lines from the tiny.config fragment file. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-06-14Kbuild: rename CC_STACKPROTECTOR[_STRONG] config variablesLinus Torvalds
The changes to automatically test for working stack protector compiler support in the Kconfig files removed the special STACKPROTECTOR_AUTO option that picked the strongest stack protector that the compiler supported. That was all a nice cleanup - it makes no sense to have the AUTO case now that the Kconfig phase can just determine the compiler support directly. HOWEVER. It also meant that doing "make oldconfig" would now _disable_ the strong stackprotector if you had AUTO enabled, because in a legacy config file, the sane stack protector configuration would look like CONFIG_HAVE_CC_STACKPROTECTOR=y # CONFIG_CC_STACKPROTECTOR_NONE is not set # CONFIG_CC_STACKPROTECTOR_REGULAR is not set # CONFIG_CC_STACKPROTECTOR_STRONG is not set CONFIG_CC_STACKPROTECTOR_AUTO=y and when you ran this through "make oldconfig" with the Kbuild changes, it would ask you about the regular CONFIG_CC_STACKPROTECTOR (that had been renamed from CONFIG_CC_STACKPROTECTOR_REGULAR to just CONFIG_CC_STACKPROTECTOR), but it would think that the STRONG version used to be disabled (because it was really enabled by AUTO), and would disable it in the new config, resulting in: CONFIG_HAVE_CC_STACKPROTECTOR=y CONFIG_CC_HAS_STACKPROTECTOR_NONE=y CONFIG_CC_STACKPROTECTOR=y # CONFIG_CC_STACKPROTECTOR_STRONG is not set CONFIG_CC_HAS_SANE_STACKPROTECTOR=y That's dangerously subtle - people could suddenly find themselves with the weaker stack protector setup without even realizing. The solution here is to just rename not just the old RECULAR stack protector option, but also the strong one. This does that by just removing the CC_ prefix entirely for the user choices, because it really is not about the compiler support (the compiler support now instead automatially impacts _visibility_ of the options to users). This results in "make oldconfig" actually asking the user for their choice, so that we don't have any silent subtle security model changes. The end result would generally look like this: CONFIG_HAVE_CC_STACKPROTECTOR=y CONFIG_CC_HAS_STACKPROTECTOR_NONE=y CONFIG_STACKPROTECTOR=y CONFIG_STACKPROTECTOR_STRONG=y CONFIG_CC_HAS_SANE_STACKPROTECTOR=y where the "CC_" versions really are about internal compiler infrastructure, not the user selections. Acked-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-02-10Merge tag 'kvm-4.16-1' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds
Pull KVM updates from Radim Krčmář: "ARM: - icache invalidation optimizations, improving VM startup time - support for forwarded level-triggered interrupts, improving performance for timers and passthrough platform devices - a small fix for power-management notifiers, and some cosmetic changes PPC: - add MMIO emulation for vector loads and stores - allow HPT guests to run on a radix host on POWER9 v2.2 CPUs without requiring the complex thread synchronization of older CPU versions - improve the handling of escalation interrupts with the XIVE interrupt controller - support decrement register migration - various cleanups and bugfixes. s390: - Cornelia Huck passed maintainership to Janosch Frank - exitless interrupts for emulated devices - cleanup of cpuflag handling - kvm_stat counter improvements - VSIE improvements - mm cleanup x86: - hypervisor part of SEV - UMIP, RDPID, and MSR_SMI_COUNT emulation - paravirtualized TLB shootdown using the new KVM_VCPU_PREEMPTED bit - allow guests to see TOPOEXT, GFNI, VAES, VPCLMULQDQ, and more AVX512 features - show vcpu id in its anonymous inode name - many fixes and cleanups - per-VCPU MSR bitmaps (already merged through x86/pti branch) - stable KVM clock when nesting on Hyper-V (merged through x86/hyperv)" * tag 'kvm-4.16-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (197 commits) KVM: PPC: Book3S: Add MMIO emulation for VMX instructions KVM: PPC: Book3S HV: Branch inside feature section KVM: PPC: Book3S HV: Make HPT resizing work on POWER9 KVM: PPC: Book3S HV: Fix handling of secondary HPTEG in HPT resizing code KVM: PPC: Book3S PR: Fix broken select due to misspelling KVM: x86: don't forget vcpu_put() in kvm_arch_vcpu_ioctl_set_sregs() KVM: PPC: Book3S PR: Fix svcpu copying with preemption enabled KVM: PPC: Book3S HV: Drop locks before reading guest memory kvm: x86: remove efer_reload entry in kvm_vcpu_stat KVM: x86: AMD Processor Topology Information x86/kvm/vmx: do not use vm-exit instruction length for fast MMIO when running nested kvm: embed vcpu id to dentry of vcpu anon inode kvm: Map PFN-type memory regions as writable (if possible) x86/kvm: Make it compile on 32bit and with HYPYERVISOR_GUEST=n KVM: arm/arm64: Fixup userspace irqchip static key optimization KVM: arm/arm64: Fix userspace_irqchip_in_use counting KVM: arm/arm64: Fix incorrect timer_is_pending logic MAINTAINERS: update KVM/s390 maintainers MAINTAINERS: add Halil as additional vfio-ccw maintainer MAINTAINERS: add David as a reviewer for KVM/s390 ...
2018-02-06Makefile: introduce CONFIG_CC_STACKPROTECTOR_AUTOKees Cook
Nearly all modern compilers support a stack-protector option, and nearly all modern distributions enable the kernel stack-protector, so enabling this by default in kernel builds would make sense. However, Kconfig does not have knowledge of available compiler features, so it isn't safe to force on, as this would unconditionally break builds for the compilers or architectures that don't have support. Instead, this introduces a new option, CONFIG_CC_STACKPROTECTOR_AUTO, which attempts to discover the best possible stack-protector available, and will allow builds to proceed even if the compiler doesn't support any stack-protector. This option is made the default so that kernels built with modern compilers will be protected-by-default against stack buffer overflows, avoiding things like the recent BlueBorne attack. Selection of a specific stack-protector option remains available, including disabling it. Additionally, tiny.config is adjusted to use CC_STACKPROTECTOR_NONE, since that's the option with the least code size (and it used to be the default, so we have to explicitly choose it there now). Link: http://lkml.kernel.org/r/1510076320-69931-4-git-send-email-keescook@chromium.org Signed-off-by: Kees Cook <keescook@chromium.org> Tested-by: Laura Abbott <labbott@redhat.com> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Josh Triplett <josh@joshtriplett.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-02-01Merge branch 'x86/hyperv' of ↵Radim Krčmář
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Topic branch for stable KVM clockource under Hyper-V. Thanks to Christoffer Dall for resolving the ARM conflict.
2018-01-16kvm_config: add CONFIG_S390_GUESTChristian Borntraeger
make kvmconfig currently does not select CONFIG_S390_GUEST. Since the virtio-ccw transport depends on CONFIG_S390_GUEST, we want to add CONFIG_S390_GUEST to kvmconfig. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Acked-by: Cornelia Huck <cohuck@redhat.com>
2017-12-04PM: Provide a config snippet for disabling PMMark Brown
A frequent source of build problems is poor handling of optional PM support, almost all development is done with the PM options enabled but they can be turned off. Currently few if any of the build test services do this as standard as there is no standard config for it and the use of selects and def_bool means that simply setting CONFIG_PM=n doesn't do what is expected. To make this easier provide a fragement that can be used with KCONFIG_ALLCONFIG to force PM off. CONFIG_XEN is disabled as Xen uses hibernation callbacks which end up turning on power management on architectures with Xen. Some cpuidle implementations on ARM select PM so CONFIG_CPU_IDLE is disabled, and some ARM architectures unconditionally enable PM so they are also disabled. Signed-off-by: Mark Brown <broonie@kernel.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-08-22ANDROID: binder: add hwbinder,vndbinder to BINDER_DEVICES.Martijn Coenen
These will be required going forward. Signed-off-by: Martijn Coenen <maco@android.com> Cc: stable <stable@vger.kernel.org> # 4.11+ Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-09config: android-base: disable CONFIG_NFSD and CONFIG_NFS_FSRoberto Pereira
Disable Network file system support. Reviewed-at: https://android-review.googlesource.com/#/c/409559/ Signed-off-by: Roberto Pereira <rpere@google.com> [AmitP: cherry-picked this change from Android common kernel and updated commit message] Signed-off-by: Amit Pundir <amit.pundir@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-09config: android-base: add CGROUP_BPFChenbo Feng
Add CONFIG_CGROUP_BPF as a default configuration in android base config since it is used to replace XT_QTAGUID in future. Reviewed-at: https://android-review.googlesource.com/#/c/400374/ Signed-off-by: Chenbo Feng <fengc@google.com> [AmitP: cherry-picked this change from Android common kernel] Signed-off-by: Amit Pundir <amit.pundir@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-09config: android-base: add CONFIG_MODULES optionGreg Kroah-Hartman
This adds CONFIG_MODULES, CONFIG_MODULE_UNLOAD, and CONFIG_MODVERSIONS which are required by the O release. Reviewed-at: https://android-review.googlesource.com/#/c/364554/ Signed-off-by: Greg Kroah-Hartman <gregkh@google.com> [AmitP: cherry-picked this change from Android common kernel] Signed-off-by: Amit Pundir <amit.pundir@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-09config: android-base: add CONFIG_IKCONFIG optionGreg Kroah-Hartman
This adds CONFIG_IKCONFIG and CONFIG_IKCONFIG_PROC options, which are a requirement for the O release. Reviewed-at: https://android-review.googlesource.com/#/c/364553/ Signed-off-by: Greg Kroah-Hartman <gregkh@google.com> [AmitP: cherry-picked this change from Android common kernel] Signed-off-by: Amit Pundir <amit.pundir@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-09config: android-recommended: enable CONFIG_CPU_SW_DOMAIN_PANSami Tolvanen
Enable CPU domain PAN to ensure that normal kernel accesses are unable to access userspace addresses. Reviewed-at: https://android-review.googlesource.com/#/c/334035/ Signed-off-by: Sami Tolvanen <samitolvanen@google.com> [AmitP: cherry-picked this change from Android common kernel, updated the commit message and re-placed the CONFIG_STRICT_KERNEL_RWX config in sorted order] Signed-off-by: Amit Pundir <amit.pundir@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-09config: android-base: disable CONFIG_USELIB and CONFIG_FHANDLEMax Shi
Turn off the two kernel configs to disable related system ABI. Reviewed-at: https://android-review.googlesource.com/#/c/264976/ Signed-off-by: Max Shi <meixuanshi@google.com> [AmitP: cherry-picked this change from Android common kernel] Signed-off-by: Amit Pundir <amit.pundir@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-09config: android-recommended: enable CONFIG_ARM64_SW_TTBR0_PANSami Tolvanen
Enable PAN emulation using TTBR0_EL1 switching. Reviewed-at: https://android-review.googlesource.com/#/c/325997/ Signed-off-by: Sami Tolvanen <samitolvanen@google.com> [AmitP: cherry-picked this change from Android common kernel and updated the commit message] Signed-off-by: Amit Pundir <amit.pundir@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-09config: android-recommended: enable fstack-protector-strongJeff Vander Stoep
If compiler has stack protector support, set CONFIG_CC_STACKPROTECTOR_STRONG. Reviewed-at: https://android-review.googlesource.com/#/c/238388/ Signed-off-by: Jeff Vander Stoep <jeffv@google.com> [AmitP: cherry-picked this change from Android common kernel] Signed-off-by: Amit Pundir <amit.pundir@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-27config: android-base: enable hardened usercopy and kernel ASLRAmit Pundir
Enable CONFIG_HARDENED_USERCOPY and CONFIG_RANDOMIZE_BASE in Android base config fragment. Reviewed at https://android-review.googlesource.com/#/c/283659/ Reviewed at https://android-review.googlesource.com/#/c/278133/ Link: http://lkml.kernel.org/r/1481113148-29204-2-git-send-email-amit.pundir@linaro.org Signed-off-by: Amit Pundir <amit.pundir@linaro.org> Cc: Rob Herring <rob.herring@linaro.org> Cc: John Stultz <john.stultz@linaro.org> Cc: Daniel Micay <danielmicay@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-27config: android-recommended: disable aio supportDaniel Micay
The aio interface adds substantial attack surface for a feature that's not being exposed by Android at all. It's unlikely that anyone is using the kernel feature directly either. This feature is rarely used even on servers. The glibc POSIX aio calls really use thread pools. The lack of widespread usage also means this is relatively poorly audited/tested. The kernel's aio rarely provides performance benefits over using a thread pool and is quite incomplete in terms of system call coverage along with having edge cases where blocking can occur. Part of the performance issue is the fact that it only supports direct io, not buffered io. The existing API is considered fundamentally flawed and it's unlikely it will be expanded, but rather replaced: https://marc.info/?l=linux-aio&m=145255815216051&w=2 Since ext4 encryption means no direct io support, kernel aio isn't even going to work properly on Android devices using file-based encryption. Reviewed-at: https://android-review.googlesource.com/#/c/292158/ Link: http://lkml.kernel.org/r/1481113148-29204-1-git-send-email-amit.pundir@linaro.org Signed-off-by: Daniel Micay <danielmicay@gmail.com> Signed-off-by: Amit Pundir <amit.pundir@linaro.org> Cc: Rob Herring <rob.herring@linaro.org> Cc: John Stultz <john.stultz@linaro.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-07arch: Rename CONFIG_DEBUG_RODATA and CONFIG_DEBUG_MODULE_RONXLaura Abbott
Both of these options are poorly named. The features they provide are necessary for system security and should not be considered debug only. Change the names to CONFIG_STRICT_KERNEL_RWX and CONFIG_STRICT_MODULE_RWX to better describe what these options do. Signed-off-by: Laura Abbott <labbott@redhat.com> Acked-by: Jessica Yu <jeyu@redhat.com> Signed-off-by: Kees Cook <keescook@chromium.org>
2016-10-11config: android: enable CONFIG_SECCOMPRob Herring
As of Android N, SECCOMP is required. Without it, we will get mediaextractor error: E /system/bin/mediaextractor: libminijail: prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER): Invalid argument Link: http://lkml.kernel.org/r/20160908185934.18098-3-robh@kernel.org Signed-off-by: Rob Herring <robh@kernel.org> Acked-by: John Stultz <john.stultz@linaro.org> Cc: Amit Pundir <amit.pundir@linaro.org> Cc: Dmitry Shmidt <dimitrysh@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-11config: android: set SELinux as default security modeRob Herring
Android won't boot without SELinux enabled, so make it the default. Link: http://lkml.kernel.org/r/20160908185934.18098-2-robh@kernel.org Signed-off-by: Rob Herring <robh@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-11config: android: move device mapper options to recommendedRob Herring
CONFIG_MD is in recommended, but other dependent options like DM_CRYPT and DM_VERITY options are in base. The result is the options in base don't get enabled when applying both base and recommended fragments. Move all the options to recommended. Link: http://lkml.kernel.org/r/20160908185934.18098-1-robh@kernel.org Signed-off-by: Rob Herring <robh@kernel.org> Acked-by: John Stultz <john.stultz@linaro.org> Cc: Amit Pundir <amit.pundir@linaro.org> Cc: Dmitry Shmidt <dimitrysh@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-11config/android: Remove CONFIG_IPV6_PRIVACYBorislav Petkov
Option is long gone, see commit 5d9efa7ee99e ("ipv6: Remove privacy config option.") Link: http://lkml.kernel.org/r/20160811170340.9859-1-bp@alien8.de Signed-off-by: Borislav Petkov <bp@suse.de> Cc: Rob Herring <robh@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-06Merge tag 'kvm-4.9-1' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds
Pull KVM updates from Radim Krčmář: "All architectures: - move `make kvmconfig` stubs from x86 - use 64 bits for debugfs stats ARM: - Important fixes for not using an in-kernel irqchip - handle SError exceptions and present them to guests if appropriate - proxying of GICV access at EL2 if guest mappings are unsafe - GICv3 on AArch32 on ARMv8 - preparations for GICv3 save/restore, including ABI docs - cleanups and a bit of optimizations MIPS: - A couple of fixes in preparation for supporting MIPS EVA host kernels - MIPS SMP host & TLB invalidation fixes PPC: - Fix the bug which caused guests to falsely report lockups - other minor fixes - a small optimization s390: - Lazy enablement of runtime instrumentation - up to 255 CPUs for nested guests - rework of machine check deliver - cleanups and fixes x86: - IOMMU part of AMD's AVIC for vmexit-less interrupt delivery - Hyper-V TSC page - per-vcpu tsc_offset in debugfs - accelerated INS/OUTS in nVMX - cleanups and fixes" * tag 'kvm-4.9-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (140 commits) KVM: MIPS: Drop dubious EntryHi optimisation KVM: MIPS: Invalidate TLB by regenerating ASIDs KVM: MIPS: Split kernel/user ASID regeneration KVM: MIPS: Drop other CPU ASIDs on guest MMU changes KVM: arm/arm64: vgic: Don't flush/sync without a working vgic KVM: arm64: Require in-kernel irqchip for PMU support KVM: PPC: Book3s PR: Allow access to unprivileged MMCR2 register KVM: PPC: Book3S PR: Support 64kB page size on POWER8E and POWER8NVL KVM: PPC: Book3S: Remove duplicate setting of the B field in tlbie KVM: PPC: BookE: Fix a sanity check KVM: PPC: Book3S HV: Take out virtual core piggybacking code KVM: PPC: Book3S: Treat VTB as a per-subcore register, not per-thread ARM: gic-v3: Work around definition of gic_write_bpr1 KVM: nVMX: Fix the NMI IDT-vectoring handling KVM: VMX: Enable MSR-BASED TPR shadow even if APICv is inactive KVM: nVMX: Fix reload apic access page warning kvmconfig: add virtio-gpu to config fragment config: move x86 kvm_guest.config to a common location arm64: KVM: Remove duplicating init code for setting VMID ARM: KVM: Support vgic-v3 ...
2016-09-23kvmconfig: add virtio-gpu to config fragmentRob Herring
virtio-gpu is used for VMs, so add it to the kvm config. Signed-off-by: Rob Herring <robh@kernel.org> Cc: Christoffer Dall <christoffer.dall@linaro.org> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: kvmarm@lists.cs.columbia.edu Cc: kvm@vger.kernel.org [expanded "frag" to "fragment" in summary] Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2016-09-23config: move x86 kvm_guest.config to a common locationRob Herring
kvm_guest.config is useful for KVM guests on other arches, and nothing in it appears to be x86 specific, so just move the whole file. Kbuild will find it in either location. Signed-off-by: Rob Herring <robh@kernel.org> Cc: Christoffer Dall <christoffer.dall@linaro.org> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: kvmarm@lists.cs.columbia.edu Cc: kvm@vger.kernel.org Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2016-09-01kconfig: tinyconfig: provide whole choice blocks to avoid warningsArnd Bergmann
Using "make tinyconfig" produces a couple of annoying warnings that show up for build test machines all the time: .config:966:warning: override: NOHIGHMEM changes choice state .config:965:warning: override: SLOB changes choice state .config:963:warning: override: KERNEL_XZ changes choice state .config:962:warning: override: CC_OPTIMIZE_FOR_SIZE changes choice state .config:933:warning: override: SLOB changes choice state .config:930:warning: override: CC_OPTIMIZE_FOR_SIZE changes choice state .config:870:warning: override: SLOB changes choice state .config:868:warning: override: KERNEL_XZ changes choice state .config:867:warning: override: CC_OPTIMIZE_FOR_SIZE changes choice state I've made a previous attempt at fixing them and we discussed a number of alternatives. I tried changing the Makefile to use "merge_config.sh -n $(fragment-list)" but couldn't get that to work properly. This is yet another approach, based on the observation that we do want to see a warning for conflicting 'choice' options, and that we can simply make them non-conflicting by listing all other options as disabled. This is a trivial patch that we can apply independent of plans for other changes. Link: http://lkml.kernel.org/r/20160829214952.1334674-2-arnd@arndb.de Link: https://storage.kernelci.org/mainline/v4.7-rc6/x86-tinyconfig/build.log https://patchwork.kernel.org/patch/9212749/ Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-02config: add android config fragmentsRob Herring
Copy the config fragments from the AOSP common kernel android-4.4 branch. It is becoming possible to run mainline kernels with Android, but the kernel defconfigs don't work as-is and debugging missing config options is a pain. Adding the config fragments into the kernel tree, makes configuring a mainline kernel as simple as: make ARCH=arm multi_v7_defconfig android-base.config android-recommended.config The following non-upstream config options were removed: CONFIG_NETFILTER_XT_MATCH_QTAGUID CONFIG_NETFILTER_XT_MATCH_QUOTA2 CONFIG_NETFILTER_XT_MATCH_QUOTA2_LOG CONFIG_PPPOLAC CONFIG_PPPOPNS CONFIG_SECURITY_PERF_EVENTS_RESTRICT CONFIG_USB_CONFIGFS_F_MTP CONFIG_USB_CONFIGFS_F_PTP CONFIG_USB_CONFIGFS_F_ACC CONFIG_USB_CONFIGFS_F_AUDIO_SRC CONFIG_USB_CONFIGFS_UEVENT CONFIG_INPUT_KEYCHORD CONFIG_INPUT_KEYRESET Link: http://lkml.kernel.org/r/1466708235-28593-1-git-send-email-robh@kernel.org Signed-off-by: Rob Herring <robh@kernel.org> Cc: Amit Pundir <amit.pundir@linaro.org> Cc: John Stultz <john.stultz@linaro.org> Cc: Dmitry Shmidt <dimitrysh@google.com> Cc: Rom Lemarchand <romlem@android.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-16kconfig: add xenconfig defconfig helperLuis R. Rodriguez
This lets you build a kernel which can support xen dom0 or xen guests on i386, x86-64 and arm64 by just using: make xenconfig You can start from an allnoconfig and then switch to xenconfig. This also splits out the options which are available currently to be built with x86 and 'make ARCH=arm64' under a shared config. Technically xen supports a dom0 kernel and also a guest kernel configuration but upon review with the xen team since we don't have many dom0 options its best to just combine these two into one. A few generic notes: we enable both of these: CONFIG_INET=y CONFIG_BINFMT_ELF=y although technically not required given you likely will end up with a pretty useless system otherwise. A few architectural differences worth noting: $ make allnoconfig; make xenconfig > /dev/null ; \ grep XEN .config > 64-bit-config $ make ARCH=i386 allnoconfig; make ARCH=i386 xenconfig > /dev/null; \ grep XEN .config > 32-bit-config $ make ARCH=arm64 allnoconfig; make ARCH=arm64 xenconfig > /dev/null; \ grep XEN .config > arm64-config Since the options are already split up with a generic config and architecture specific configs you anything on the x86 configs are known to only work right now on x86. For instance arm64 doesn't support MEMORY_HOTPLUG yet as such although we try to enabe it generically arm64 doesn't have it yet, so we leave the xen specific kconfig option XEN_BALLOON_MEMORY_HOTPLUG on x86's config file to set expecations correctly. Then on x86 we have differences between i386 and x86-64. The difference between 64-bit-config and 32-bit-config is you don't get XEN_MCE_LOG as this is only supported on 64-bit. You also do not get on i386 XEN_BALLOON_MEMORY_HOTPLUG, there does not seem to be any technical reasons to not allow this but I gave up after a few attempts. Cc: Josh Triplett <josh@joshtriplett.org> Cc: Borislav Petkov <bp@suse.de> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Michal Marek <mmarek@suse.cz> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: penberg@kernel.org Cc: levinsasha928@gmail.com Cc: mtosatti@redhat.com Cc: fengguang.wu@intel.com Cc: David Vrabel <david.vrabel@citrix.com> Cc: Ian Campbell <Ian.Campbell@citrix.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: xen-devel@lists.xenproject.org Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Acked-by: Julien Grall <julien.grall@linaro.org> Acked-by: Michal Marek <mmarek@suse.cz> Acked-by: David Rientjes <rientjes@google.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2014-08-08x86: Add "make tinyconfig" to configure the tiniest possible kernelJosh Triplett
Since commit 5d2acfc7b974bbd3858b4dd3f2cdc6362dd8843a ("kconfig: make allnoconfig disable options behind EMBEDDED and EXPERT") in 3.15-rc1, "make allnoconfig" disables every possible config option. However, a few configuration options (CC_OPTIMIZE_FOR_SIZE, OPTIMIZE_INLINING) produce a smaller kernel when turned on, and a few choices exist (compression, highmem, allocator) for which a non-default option produces a smaller kernel. Add a "tinyconfig" option, which starts from allnoconfig and then sets these options to configure the tiniest possible kernel. This provides a better baseline for embedded systems or efforts to reduce kernel size. Signed-off-by: Josh Triplett <josh@joshtriplett.org>