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2020-08-15all arch: remove system call sys_sysctlXiaoming Ni2-2/+2
Since commit 61a47c1ad3a4dc ("sysctl: Remove the sysctl system call"), sys_sysctl is actually unavailable: any input can only return an error. We have been warning about people using the sysctl system call for years and believe there are no more users. Even if there are users of this interface if they have not complained or fixed their code by now they probably are not going to, so there is no point in warning them any longer. So completely remove sys_sysctl on all architectures. [nixiaoming@huawei.com: s390: fix build error for sys_call_table_emu] Link: http://lkml.kernel.org/r/20200618141426.16884-1-nixiaoming@huawei.com Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Will Deacon <will@kernel.org> [arm/arm64] Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Aleksa Sarai <cyphar@cyphar.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andi Kleen <ak@linux.intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Bin Meng <bin.meng@windriver.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: chenzefeng <chenzefeng2@huawei.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Christian Brauner <christian@brauner.io> Cc: Chris Zankel <chris@zankel.net> Cc: David Howells <dhowells@redhat.com> Cc: David S. Miller <davem@davemloft.net> Cc: Diego Elio Pettenò <flameeyes@flameeyes.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Dominik Brodowski <linux@dominikbrodowski.net> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Helge Deller <deller@gmx.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Iurii Zaikin <yzaikin@google.com> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Kars de Jong <jongk@linux-m68k.org> Cc: Kees Cook <keescook@chromium.org> Cc: Krzysztof Kozlowski <krzk@kernel.org> Cc: Luis Chamberlain <mcgrof@kernel.org> Cc: Marco Elver <elver@google.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Martin K. Petersen <martin.petersen@oracle.com> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Matt Turner <mattst88@gmail.com> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Simek <monstr@monstr.eu> Cc: Miklos Szeredi <mszeredi@redhat.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Cc: Nick Piggin <npiggin@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Olof Johansson <olof@lixom.net> Cc: Paul Burton <paulburton@kernel.org> Cc: "Paul E. McKenney" <paulmck@kernel.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com> Cc: Richard Henderson <rth@twiddle.net> Cc: Rich Felker <dalias@libc.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Sami Tolvanen <samitolvanen@google.com> Cc: Sargun Dhillon <sargun@sargun.me> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Sudeep Holla <sudeep.holla@arm.com> Cc: Sven Schnelle <svens@stackframe.org> Cc: Thiago Jung Bauermann <bauerman@linux.ibm.com> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Zhou Yanjie <zhouyanjie@wanyeetech.com> Link: http://lkml.kernel.org/r/20200616030734.87257-1-nixiaoming@huawei.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-14Merge tag 'for-linus-5.9-rc1b-tag' of ↵Linus Torvalds2-137/+2
git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip Pull more xen updates from Juergen Gross: - Remove support for running as 32-bit Xen PV-guest. 32-bit PV guests are rarely used, are lacking security fixes for Meltdown, and can be easily replaced by PVH mode. Another series for doing more cleanup will follow soon (removal of 32-bit-only pvops functionality). - Fixes and additional features for the Xen display frontend driver. * tag 'for-linus-5.9-rc1b-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: drm/xen-front: Pass dumb buffer data offset to the backend xen: Sync up with the canonical protocol definition in Xen drm/xen-front: Add YUYV to supported formats drm/xen-front: Fix misused IS_ERR_OR_NULL checks xen/gntdev: Fix dmabuf import with non-zero sgt offset x86/xen: drop tests for highmem in pv code x86/xen: eliminate xen-asm_64.S x86/xen: remove 32-bit Xen PV guest support
2020-08-11x86/xen: remove 32-bit Xen PV guest supportJuergen Gross2-137/+2
Xen is requiring 64-bit machines today and since Xen 4.14 it can be built without 32-bit PV guest support. There is no need to carry the burden of 32-bit PV guest support in the kernel any longer, as new guests can be either HVM or PVH, or they can use a 64 bit kernel. Remove the 32-bit Xen PV support from the kernel. Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Juergen Gross <jgross@suse.com>
2020-08-10Merge tag 'kbuild-v5.9' of ↵Linus Torvalds1-2/+2
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: - run the checker (e.g. sparse) after the compiler - remove unneeded cc-option tests for old compiler flags - fix tar-pkg to install dtbs - introduce ccflags-remove-y and asflags-remove-y syntax - allow to trace functions in sub-directories of lib/ - introduce hostprogs-always-y and userprogs-always-y syntax - various Makefile cleanups * tag 'kbuild-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: kbuild: stop filtering out $(GCC_PLUGINS_CFLAGS) from cc-option base kbuild: include scripts/Makefile.* only when relevant CONFIG is enabled kbuild: introduce hostprogs-always-y and userprogs-always-y kbuild: sort hostprogs before passing it to ifneq kbuild: move host .so build rules to scripts/gcc-plugins/Makefile kbuild: Replace HTTP links with HTTPS ones kbuild: trace functions in subdirectories of lib/ kbuild: introduce ccflags-remove-y and asflags-remove-y kbuild: do not export LDFLAGS_vmlinux kbuild: always create directories of targets powerpc/boot: add DTB to 'targets' kbuild: buildtar: add dtbs support kbuild: remove cc-option test of -ffreestanding kbuild: remove cc-option test of -fno-stack-protector Revert "kbuild: Create directory for target DTB" kbuild: run the checker after the compiler
2020-08-06Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextLinus Torvalds3-4/+11
Pull networking updates from David Miller: 1) Support 6Ghz band in ath11k driver, from Rajkumar Manoharan. 2) Support UDP segmentation in code TSO code, from Eric Dumazet. 3) Allow flashing different flash images in cxgb4 driver, from Vishal Kulkarni. 4) Add drop frames counter and flow status to tc flower offloading, from Po Liu. 5) Support n-tuple filters in cxgb4, from Vishal Kulkarni. 6) Various new indirect call avoidance, from Eric Dumazet and Brian Vazquez. 7) Fix BPF verifier failures on 32-bit pointer arithmetic, from Yonghong Song. 8) Support querying and setting hardware address of a port function via devlink, use this in mlx5, from Parav Pandit. 9) Support hw ipsec offload on bonding slaves, from Jarod Wilson. 10) Switch qca8k driver over to phylink, from Jonathan McDowell. 11) In bpftool, show list of processes holding BPF FD references to maps, programs, links, and btf objects. From Andrii Nakryiko. 12) Several conversions over to generic power management, from Vaibhav Gupta. 13) Add support for SO_KEEPALIVE et al. to bpf_setsockopt(), from Dmitry Yakunin. 14) Various https url conversions, from Alexander A. Klimov. 15) Timestamping and PHC support for mscc PHY driver, from Antoine Tenart. 16) Support bpf iterating over tcp and udp sockets, from Yonghong Song. 17) Support 5GBASE-T i40e NICs, from Aleksandr Loktionov. 18) Add kTLS RX HW offload support to mlx5e, from Tariq Toukan. 19) Fix the ->ndo_start_xmit() return type to be netdev_tx_t in several drivers. From Luc Van Oostenryck. 20) XDP support for xen-netfront, from Denis Kirjanov. 21) Support receive buffer autotuning in MPTCP, from Florian Westphal. 22) Support EF100 chip in sfc driver, from Edward Cree. 23) Add XDP support to mvpp2 driver, from Matteo Croce. 24) Support MPTCP in sock_diag, from Paolo Abeni. 25) Commonize UDP tunnel offloading code by creating udp_tunnel_nic infrastructure, from Jakub Kicinski. 26) Several pci_ --> dma_ API conversions, from Christophe JAILLET. 27) Add FLOW_ACTION_POLICE support to mlxsw, from Ido Schimmel. 28) Add SK_LOOKUP bpf program type, from Jakub Sitnicki. 29) Refactor a lot of networking socket option handling code in order to avoid set_fs() calls, from Christoph Hellwig. 30) Add rfc4884 support to icmp code, from Willem de Bruijn. 31) Support TBF offload in dpaa2-eth driver, from Ioana Ciornei. 32) Support XDP_REDIRECT in qede driver, from Alexander Lobakin. 33) Support PCI relaxed ordering in mlx5 driver, from Aya Levin. 34) Support TCP syncookies in MPTCP, from Flowian Westphal. 35) Fix several tricky cases of PMTU handling wrt. briding, from Stefano Brivio. * git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (2056 commits) net: thunderx: initialize VF's mailbox mutex before first usage usb: hso: remove bogus check for EINPROGRESS usb: hso: no complaint about kmalloc failure hso: fix bailout in error case of probe ip_tunnel_core: Fix build for archs without _HAVE_ARCH_IPV6_CSUM selftests/net: relax cpu affinity requirement in msg_zerocopy test mptcp: be careful on subflow creation selftests: rtnetlink: make kci_test_encap() return sub-test result selftests: rtnetlink: correct the final return value for the test net: dsa: sja1105: use detected device id instead of DT one on mismatch tipc: set ub->ifindex for local ipv6 address ipv6: add ipv6_dev_find() net: openvswitch: silence suspicious RCU usage warning Revert "vxlan: fix tos value before xmit" ptp: only allow phase values lower than 1 period farsync: switch from 'pci_' to 'dma_' API wan: wanxl: switch from 'pci_' to 'dma_' API hv_netvsc: do not use VF device if link is down dpaa2-eth: Fix passing zero to 'PTR_ERR' warning net: macb: Properly handle phylink on at91sam9x ...
2020-08-05Merge tag 'x86-fsgsbase-2020-08-04' of ↵Linus Torvalds2-32/+147
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 fsgsbase from Thomas Gleixner: "Support for FSGSBASE. Almost 5 years after the first RFC to support it, this has been brought into a shape which is maintainable and actually works. This final version was done by Sasha Levin who took it up after Intel dropped the ball. Sasha discovered that the SGX (sic!) offerings out there ship rogue kernel modules enabling FSGSBASE behind the kernels back which opens an instantanious unpriviledged root hole. The FSGSBASE instructions provide a considerable speedup of the context switch path and enable user space to write GSBASE without kernel interaction. This enablement requires careful handling of the exception entries which go through the paranoid entry path as they can no longer rely on the assumption that user GSBASE is positive (as enforced via prctl() on non FSGSBASE enabled systemn). All other entries (syscalls, interrupts and exceptions) can still just utilize SWAPGS unconditionally when the entry comes from user space. Converting these entries to use FSGSBASE has no benefit as SWAPGS is only marginally slower than WRGSBASE and locating and retrieving the kernel GSBASE value is not a free operation either. The real benefit of RD/WRGSBASE is the avoidance of the MSR reads and writes. The changes come with appropriate selftests and have held up in field testing against the (sanitized) Graphene-SGX driver" * tag 'x86-fsgsbase-2020-08-04' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (21 commits) x86/fsgsbase: Fix Xen PV support x86/ptrace: Fix 32-bit PTRACE_SETREGS vs fsbase and gsbase selftests/x86/fsgsbase: Add a missing memory constraint selftests/x86/fsgsbase: Fix a comment in the ptrace_write_gsbase test selftests/x86: Add a syscall_arg_fault_64 test for negative GSBASE selftests/x86/fsgsbase: Test ptracer-induced GS base write with FSGSBASE selftests/x86/fsgsbase: Test GS selector on ptracer-induced GS base write Documentation/x86/64: Add documentation for GS/FS addressing mode x86/elf: Enumerate kernel FSGSBASE capability in AT_HWCAP2 x86/cpu: Enable FSGSBASE on 64bit by default and add a chicken bit x86/entry/64: Handle FSGSBASE enabled paranoid entry/exit x86/entry/64: Introduce the FIND_PERCPU_BASE macro x86/entry/64: Switch CR3 before SWAPGS in paranoid entry x86/speculation/swapgs: Check FSGSBASE in enabling SWAPGS mitigation x86/process/64: Use FSGSBASE instructions on thread copy and ptrace x86/process/64: Use FSBSBASE in switch_to() if available x86/process/64: Make save_fsgs_for_kvm() ready for FSGSBASE x86/fsgsbase/64: Enable FSGSBASE instructions in helper functions x86/fsgsbase/64: Add intrinsics for FSGSBASE instructions x86/cpu: Add 'unsafe_fsgsbase' to enable CR4.FSGSBASE ...
2020-08-05Merge tag 'x86-entry-2020-08-04' of ↵Linus Torvalds3-597/+39
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 conversion to generic entry code from Thomas Gleixner: "The conversion of X86 syscall, interrupt and exception entry/exit handling to the generic code. Pretty much a straight-forward 1:1 conversion plus the consolidation of the KVM handling of pending work before entering guest mode" * tag 'x86-entry-2020-08-04' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/kvm: Use __xfer_to_guest_mode_work_pending() in kvm_run_vcpu() x86/kvm: Use generic xfer to guest work function x86/entry: Cleanup idtentry_enter/exit x86/entry: Use generic interrupt entry/exit code x86/entry: Cleanup idtentry_entry/exit_user x86/entry: Use generic syscall exit functionality x86/entry: Use generic syscall entry function x86/ptrace: Provide pt_regs helper for entry/exit x86/entry: Move user return notifier out of loop x86/entry: Consolidate 32/64 bit syscall entry x86/entry: Consolidate check_user_regs() x86: Correct noinstr qualifiers x86/idtentry: Remove stale comment
2020-08-05Merge tag 'close-range-v5.9' of ↵Linus Torvalds2-0/+2
git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux Pull close_range() implementation from Christian Brauner: "This adds the close_range() syscall. It allows to efficiently close a range of file descriptors up to all file descriptors of a calling task. This is coordinated with the FreeBSD folks which have copied our version of this syscall and in the meantime have already merged it in April 2019: https://reviews.freebsd.org/D21627 https://svnweb.freebsd.org/base?view=revision&revision=359836 The syscall originally came up in a discussion around the new mount API and making new file descriptor types cloexec by default. During this discussion, Al suggested the close_range() syscall. First, it helps to close all file descriptors of an exec()ing task. This can be done safely via (quoting Al's example from [1] verbatim): /* that exec is sensitive */ unshare(CLONE_FILES); /* we don't want anything past stderr here */ close_range(3, ~0U); execve(....); The code snippet above is one way of working around the problem that file descriptors are not cloexec by default. This is aggravated by the fact that we can't just switch them over without massively regressing userspace. For a whole class of programs having an in-kernel method of closing all file descriptors is very helpful (e.g. demons, service managers, programming language standard libraries, container managers etc.). Second, it allows userspace to avoid implementing closing all file descriptors by parsing through /proc/<pid>/fd/* and calling close() on each file descriptor and other hacks. From looking at various large(ish) userspace code bases this or similar patterns are very common in service managers, container runtimes, and programming language runtimes/standard libraries such as Python or Rust. In addition, the syscall will also work for tasks that do not have procfs mounted and on kernels that do not have procfs support compiled in. In such situations the only way to make sure that all file descriptors are closed is to call close() on each file descriptor up to UINT_MAX or RLIMIT_NOFILE, OPEN_MAX trickery. Based on Linus' suggestion close_range() also comes with a new flag CLOSE_RANGE_UNSHARE to more elegantly handle file descriptor dropping right before exec. This would usually be expressed in the sequence: unshare(CLONE_FILES); close_range(3, ~0U); as pointed out by Linus it might be desirable to have this be a part of close_range() itself under a new flag CLOSE_RANGE_UNSHARE which gets especially handy when we're closing all file descriptors above a certain threshold. Test-suite as always included" * tag 'close-range-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux: tests: add CLOSE_RANGE_UNSHARE tests close_range: add CLOSE_RANGE_UNSHARE tests: add close_range() tests arch: wire-up close_range() open: add close_range()
2020-08-05Merge tag 'threads-v5.9' of ↵Linus Torvalds1-3/+2
git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux Pull thread updates from Christian Brauner: "This contains the changes to add the missing support for attaching to time namespaces via pidfds. Last cycle setns() was changed to support attaching to multiple namespaces atomically. This requires all namespaces to have a point of no return where they can't fail anymore. Specifically, <namespace-type>_install() is allowed to perform permission checks and install the namespace into the new struct nsset that it has been given but it is not allowed to make visible changes to the affected task. Once <namespace-type>_install() returns, anything that the given namespace type additionally requires to be setup needs to ideally be done in a function that can't fail or if it fails the failure must be non-fatal. For time namespaces the relevant functions that fell into this category were timens_set_vvar_page() and vdso_join_timens(). The latter could still fail although it didn't need to. This function is only implemented for vdso_join_timens() in current mainline. As discussed on-list (cf. [1]), in order to make setns() support time namespaces when attaching to multiple namespaces at once properly we changed vdso_join_timens() to always succeed. So vdso_join_timens() replaces the mmap_write_lock_killable() with mmap_read_lock(). Please note that arm is about to grow vdso support for time namespaces (possibly this merge window). We've synced on this change and arm64 also uses mmap_read_lock(), i.e. makes vdso_join_timens() a function that can't fail. Once the changes here and the arm64 changes have landed, vdso_join_timens() should be turned into a void function so it's obvious to callers and implementers on other architectures that the expectation is that it can't fail. We didn't do this right away because it would've introduced unnecessary merge conflicts between the two trees for no major gain. As always, tests included" [1]: https://lore.kernel.org/lkml/20200611110221.pgd3r5qkjrjmfqa2@wittgenstein * tag 'threads-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux: tests: add CLONE_NEWTIME setns tests nsproxy: support CLONE_NEWTIME with setns() timens: add timens_commit() helper timens: make vdso_join_timens() always succeed
2020-08-05Merge branch 'exec-linus' of ↵Linus Torvalds2-2/+2
git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace Pull execve updates from Eric Biederman: "During the development of v5.7 I ran into bugs and quality of implementation issues related to exec that could not be easily fixed because of the way exec is implemented. So I have been diggin into exec and cleaning up what I can. This cycle I have been looking at different ideas and different implementations to see what is possible to improve exec, and cleaning the way exec interfaces with in kernel users. Only cleaning up the interfaces of exec with rest of the kernel has managed to stabalize and make it through review in time for v5.9-rc1 resulting in 2 sets of changes this cycle. - Implement kernel_execve - Make the user mode driver code a better citizen With kernel_execve the code size got a little larger as the copying of parameters from userspace and copying of parameters from userspace is now separate. The good news is kernel threads no longer need to play games with set_fs to use exec. Which when combined with the rest of Christophs set_fs changes should security bugs with set_fs much more difficult" * 'exec-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (23 commits) exec: Implement kernel_execve exec: Factor bprm_stack_limits out of prepare_arg_pages exec: Factor bprm_execve out of do_execve_common exec: Move bprm_mm_init into alloc_bprm exec: Move initialization of bprm->filename into alloc_bprm exec: Factor out alloc_bprm exec: Remove unnecessary spaces from binfmts.h umd: Stop using split_argv umd: Remove exit_umh bpfilter: Take advantage of the facilities of struct pid exit: Factor thread_group_exited out of pidfd_poll umd: Track user space drivers with struct pid bpfilter: Move bpfilter_umh back into init data exec: Remove do_execve_file umh: Stop calling do_execve_file umd: Transform fork_usermode_blob into fork_usermode_driver umd: Rename umd_info.cmdline umd_info.driver_name umd: For clarity rename umh_info umd_info umh: Separate the user mode driver and the user mode helper support umh: Remove call_usermodehelper_setup_file. ...
2020-07-26Merge branch 'locking/nmi' into x86/entryIngo Molnar1-0/+34
Resolve conflicts with ongoing lockdep work that fixed the NMI entry code. Conflicts: arch/x86/entry/common.c arch/x86/include/asm/idtentry.h Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-07-26Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netDavid S. Miller2-5/+13
The UDP reuseport conflict was a little bit tricky. The net-next code, via bpf-next, extracted the reuseport handling into a helper so that the BPF sk lookup code could invoke it. At the same time, the logic for reuseport handling of unconnected sockets changed via commit efc6b6f6c3113e8b203b9debfb72d81e0f3dcace which changed the logic to carry on the reuseport result into the rest of the lookup loop if we do not return immediately. This requires moving the reuseport_has_conns() logic into the callers. While we are here, get rid of inline directives as they do not belong in foo.c files. The other changes were cases of more straightforward overlapping modifications. Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-25Merge tag 'v5.8-rc6' into locking/core, to pick up fixesIngo Molnar2-5/+13
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-07-24x86/entry: Cleanup idtentry_enter/exitThomas Gleixner1-3/+3
Remove the temporary defines and fixup all references. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lkml.kernel.org/r/20200722220520.855839271@linutronix.de
2020-07-24x86/entry: Use generic interrupt entry/exit codeThomas Gleixner1-166/+1
Replace the x86 code with the generic variant. Use temporary defines for idtentry_* which will be cleaned up in the next step. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20200722220520.711492752@linutronix.de
2020-07-24x86/entry: Use generic syscall exit functionalityThomas Gleixner3-218/+7
Replace the x86 variant with the generic version. Provide the relevant architecture specific helper functions and defines. Use a temporary define for idtentry_exit_user which will be cleaned up seperately. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Kees Cook <keescook@chromium.org> Link: https://lkml.kernel.org/r/20200722220520.494648601@linutronix.de
2020-07-24x86/entry: Use generic syscall entry functionThomas Gleixner1-173/+8
Replace the syscall entry work handling with the generic version. Provide the necessary helper inlines to handle the real architecture specific parts, e.g. ptrace. Use a temporary define for idtentry_enter_user which will be cleaned up seperately. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lkml.kernel.org/r/20200722220520.376213694@linutronix.de
2020-07-24x86/entry: Move user return notifier out of loopThomas Gleixner1-4/+4
Guests and user space share certain MSRs. KVM sets these MSRs to guest values once and does not set them back to user space values on every VM exit to spare the costly MSR operations. User return notifiers ensure that these MSRs are set back to the correct values before returning to user space in exit_to_usermode_loop(). There is no reason to evaluate the TIF flag indicating that user return notifiers need to be invoked in the loop. The important point is that they are invoked before returning to user space. Move the invocation out of the loop into the section which does the last preperatory steps before returning to user space. That section is not preemptible and runs with interrupts disabled until the actual return. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20200722220520.159112003@linutronix.de
2020-07-24x86/entry: Consolidate 32/64 bit syscall entryThomas Gleixner1-52/+41
64bit and 32bit entry code have the same open coded syscall entry handling after the bitwidth specific bits. Move it to a helper function and share the code. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20200722220520.051234096@linutronix.de
2020-07-24x86/entry: Consolidate check_user_regs()Thomas Gleixner1-15/+9
The user register sanity check is sprinkled all over the place. Move it into enter_from_user_mode(). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lkml.kernel.org/r/20200722220519.943016204@linutronix.de
2020-07-24Merge branch 'core/entry' into x86/entryThomas Gleixner1-3/+11
Pick up generic entry code to migrate x86 over.
2020-07-21exec: Implement kernel_execveEric W. Biederman2-2/+2
To allow the kernel not to play games with set_fs to call exec implement kernel_execve. The function kernel_execve takes pointers into kernel memory and copies the values pointed to onto the new userspace stack. The calls with arguments from kernel space of do_execve are replaced with calls to kernel_execve. The calls do_execve and do_execveat are made static as there are now no callers outside of exec. The comments that mention do_execve are updated to refer to kernel_execve or execve depending on the circumstances. In addition to correcting the comments, this makes it easy to grep for do_execve and verify it is not used. Inspired-by: https://lkml.kernel.org/r/20200627072704.2447163-1-hch@lst.de Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lkml.kernel.org/r/87wo365ikj.fsf@x220.int.ebiederm.org Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2020-07-20net: remove compat_sys_{get,set}sockoptChristoph Hellwig3-4/+11
Now that the ->compat_{get,set}sockopt proto_ops methods are gone there is no good reason left to keep the compat syscalls separate. This fixes the odd use of unsigned int for the compat_setsockopt optlen and the missing sock_use_custom_sol_socket. It would also easily allow running the eBPF hooks for the compat syscalls, but such a large change in behavior does not belong into a consolidation patch like this one. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-19x86/entry: Actually disable stack protectorKees Cook1-3/+11
Some builds of GCC enable stack protector by default. Simply removing the arguments is not sufficient to disable stack protector, as the stack protector for those GCC builds must be explicitly disabled. Remove the argument removals and add -fno-stack-protector. Additionally include missed x32 argument updates, and adjust whitespace for readability. Fixes: 20355e5f73a7 ("x86/entry: Exclude low level entry code from sanitizing") Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/202006261333.585319CA6B@keescook
2020-07-10lockdep: Remove lockdep_hardirq{s_enabled,_context}() argumentPeter Zijlstra1-1/+1
Now that the macros use per-cpu data, we no longer need the argument. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/20200623083721.571835311@infradead.org
2020-07-10x86/entry: Fix NMI vs IRQ state trackingPeter Zijlstra1-4/+38
While the nmi_enter() users did trace_hardirqs_{off_prepare,on_finish}() there was no matching lockdep_hardirqs_*() calls to complete the picture. Introduce idtentry_{enter,exit}_nmi() to enable proper IRQ state tracking across the NMIs. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/20200623083721.216740948@infradead.org
2020-07-10Merge branch 'x86/urgent' into x86/entry to pick up upstream fixes.Thomas Gleixner1-2/+2
2020-07-09x86/entry/common: Make prepare_exit_to_usermode() staticThomas Gleixner1-1/+1
No users outside this file anymore. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Andy Lutomirski <luto@kernel.org> Link: https://lkml.kernel.org/r/20200708192934.301116609@linutronix.de
2020-07-09x86/entry: Mark check_user_regs() noinstrThomas Gleixner1-1/+1
It's called from the non-instrumentable section. Fixes: c9c26150e61d ("x86/entry: Assert that syscalls are on the right stack") Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Andy Lutomirski <luto@kernel.org> Link: https://lkml.kernel.org/r/20200708192934.191497962@linutronix.de
2020-07-08timens: make vdso_join_timens() always succeedChristian Brauner1-3/+2
As discussed on-list (cf. [1]), in order to make setns() support time namespaces when attaching to multiple namespaces at once properly we need to tweak vdso_join_timens() to always succeed. So switch vdso_join_timens() to using a read lock and replacing mmap_write_lock_killable() to mmap_read_lock() as we discussed. Last cycle setns() was changed to support attaching to multiple namespaces atomically. This requires all namespaces to have a point of no return where they can't fail anymore. Specifically, <namespace-type>_install() is allowed to perform permission checks and install the namespace into the new struct nsset that it has been given but it is not allowed to make visible changes to the affected task. Once <namespace-type>_install() returns anything that the given namespace type requires to be setup in addition needs to ideally be done in a function that can't fail or if it fails the failure is not fatal. For time namespaces the relevant functions that fall into this category are timens_set_vvar_page() and vdso_join_timens(). Currently the latter can fail but doesn't need to. With this we can go on to implement a timens_commit() helper in a follow up patch to be used by setns(). [1]: https://lore.kernel.org/lkml/20200611110221.pgd3r5qkjrjmfqa2@wittgenstein Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> Reviewed-by: Andrei Vagin <avagin@gmail.com> Cc: Will Deacon <will@kernel.org> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Dmitry Safonov <dima@arista.com> Cc: linux-arm-kernel@lists.infradead.org Link: https://lore.kernel.org/r/20200706154912.3248030-2-christian.brauner@ubuntu.com
2020-07-07kbuild: remove cc-option test of -fno-stack-protectorMasahiro Yamada1-2/+2
Some Makefiles already pass -fno-stack-protector unconditionally. For example, arch/arm64/kernel/vdso/Makefile, arch/x86/xen/Makefile. No problem report so far about hard-coding this option. So, we can assume all supported compilers know -fno-stack-protector. GCC 4.8 and Clang support this option (https://godbolt.org/z/_HDGzN) Get rid of cc-option from -fno-stack-protector. Remove CONFIG_CC_HAS_STACKPROTECTOR_NONE, which is always 'y'. Note: arch/mips/vdso/Makefile adds -fno-stack-protector twice, first unconditionally, and second conditionally. I removed the second one. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Ard Biesheuvel <ardb@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2020-07-06x86/entry: Rename idtentry_enter/exit_cond_rcu() to idtentry_enter/exit()Andy Lutomirski1-22/+28
They were originally called _cond_rcu because they were special versions with conditional RCU handling. Now they're the standard entry and exit path, so the _cond_rcu part is just confusing. Drop it. Also change the signature to make them more extensible and more foolproof. No functional change -- it's pure refactoring. Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/247fc67685263e0b673e1d7f808182d28ff80359.1593795633.git.luto@kernel.org
2020-07-04x86/entry, selftests: Further improve user entry sanity checksAndy Lutomirski1-0/+19
Chasing down a Xen bug caused me to realize that the new entry sanity checks are still fairly weak. Add some more checks. Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/881de09e786ab93ce56ee4a2437ba2c308afe7a9.1593795633.git.luto@kernel.org
2020-07-04x86/entry/compat: Clear RAX high bits on Xen PV SYSENTERAndy Lutomirski1-9/+10
Move the clearing of the high bits of RAX after Xen PV joins the SYSENTER path so that Xen PV doesn't skip it. Arguably this code should be deleted instead, but that would belong in the merge window. Fixes: ffae641f5747 ("x86/entry/64/compat: Fix Xen PV SYSENTER frame setup") Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/9d33b3f3216dcab008070f1c28b6091ae7199969.1593795633.git.luto@kernel.org
2020-07-01x86/entry/64/compat: Fix Xen PV SYSENTER frame setupAndy Lutomirski1-0/+1
The SYSENTER frame setup was nonsense. It worked by accident because the normal code into which the Xen asm jumped (entry_SYSENTER_32/compat) threw away SP without touching the stack. entry_SYSENTER_compat was recently modified such that it relied on having a valid stack pointer, so now the Xen asm needs to invoke it with a valid stack. Fix it up like SYSCALL: use the Xen-provided frame and skip the bare metal prologue. Fixes: 1c3e5d3f60e2 ("x86/entry: Make entry_64_compat.S objtool clean") Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Link: https://lkml.kernel.org/r/947880c41ade688ff4836f665d0c9fcaa9bd1201.1593191971.git.luto@kernel.org
2020-07-01x86/entry: Move SYSENTER's regs->sp and regs->flags fixups into CAndy Lutomirski3-9/+19
The SYSENTER asm (32-bit and compat) contains fixups for regs->sp and regs->flags. Move the fixups into C and fix some comments while at it. This is a valid cleanup all by itself, and it also simplifies the subsequent patch that will fix Xen PV SYSENTER. Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/fe62bef67eda7fac75b8f3dbafccf571dc4ece6b.1593191971.git.luto@kernel.org
2020-07-01x86/entry: Assert that syscalls are on the right stackAndy Lutomirski1-3/+15
Now that the entry stack is a full page, it's too easy to regress the system call entry code and end up on the wrong stack without noticing. Assert that all system calls (SYSCALL64, SYSCALL32, SYSENTER, and INT80) are on the right stack and have pt_regs in the right place. Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/52059e42bb0ab8551153d012d68f7be18d72ff8e.1593191971.git.luto@kernel.org
2020-06-18x86/entry/64: Handle FSGSBASE enabled paranoid entry/exitChang S. Bae2-26/+91
Without FSGSBASE, user space cannot change GSBASE other than through a PRCTL. The kernel enforces that the user space GSBASE value is postive as negative values are used for detecting the kernel space GSBASE value in the paranoid entry code. If FSGSBASE is enabled, user space can set arbitrary GSBASE values without kernel intervention, including negative ones, which breaks the paranoid entry assumptions. To avoid this, paranoid entry needs to unconditionally save the current GSBASE value independent of the interrupted context, retrieve and write the kernel GSBASE and unconditionally restore the saved value on exit. The restore happens either in paranoid_exit or in the special exit path of the NMI low level code. All other entry code pathes which use unconditional SWAPGS are not affected as they do not depend on the actual content. [ tglx: Massaged changelogs and comments ] Suggested-by: H. Peter Anvin <hpa@zytor.com> Suggested-by: Andy Lutomirski <luto@kernel.org> Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/1557309753-24073-13-git-send-email-chang.seok.bae@intel.com Link: https://lkml.kernel.org/r/20200528201402.1708239-12-sashal@kernel.org
2020-06-18x86/entry/64: Introduce the FIND_PERCPU_BASE macroChang S. Bae1-0/+34
GSBASE is used to find per-CPU data in the kernel. But when GSBASE is unknown, the per-CPU base can be found from the per_cpu_offset table with a CPU NR. The CPU NR is extracted from the limit field of the CPUNODE entry in GDT, or by the RDPID instruction. This is a prerequisite for using FSGSBASE in the low level entry code. Also, add the GAS-compatible RDPID macro as binutils 2.23 do not support it. Support is added in version 2.27. [ tglx: Massaged changelog ] Suggested-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/1557309753-24073-12-git-send-email-chang.seok.bae@intel.com Link: https://lkml.kernel.org/r/20200528201402.1708239-11-sashal@kernel.org
2020-06-18x86/entry/64: Switch CR3 before SWAPGS in paranoid entryChang S. Bae1-8/+24
When FSGSBASE is enabled, the GSBASE handling in paranoid entry will need to retrieve the kernel GSBASE which requires that the kernel page table is active. As the CR3 switch to the kernel page tables (PTI is active) does not depend on kernel GSBASE, move the CR3 switch in front of the GSBASE handling. Comment the EBX content while at it. No functional change. [ tglx: Rewrote changelog and comments ] Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/1557309753-24073-11-git-send-email-chang.seok.bae@intel.com Link: https://lkml.kernel.org/r/20200528201402.1708239-10-sashal@kernel.org
2020-06-17arch: wire-up close_range()Christian Brauner2-0/+2
This wires up the close_range() syscall into all arches at once. Suggested-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Cc: Jann Horn <jannh@google.com> Cc: David Howells <dhowells@redhat.com> Cc: Dmitry V. Levin <ldv@altlinux.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Florian Weimer <fweimer@redhat.com> Cc: linux-api@vger.kernel.org Cc: linux-alpha@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-ia64@vger.kernel.org Cc: linux-m68k@lists.linux-m68k.org Cc: linux-mips@vger.kernel.org Cc: linux-parisc@vger.kernel.org Cc: linuxppc-dev@lists.ozlabs.org Cc: linux-s390@vger.kernel.org Cc: linux-sh@vger.kernel.org Cc: sparclinux@vger.kernel.org Cc: linux-xtensa@linux-xtensa.org Cc: linux-arch@vger.kernel.org Cc: x86@kernel.org
2020-06-13Merge tag 'x86-entry-2020-06-12' of ↵Linus Torvalds7-1106/+761
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 entry updates from Thomas Gleixner: "The x86 entry, exception and interrupt code rework This all started about 6 month ago with the attempt to move the Posix CPU timer heavy lifting out of the timer interrupt code and just have lockless quick checks in that code path. Trivial 5 patches. This unearthed an inconsistency in the KVM handling of task work and the review requested to move all of this into generic code so other architectures can share. Valid request and solved with another 25 patches but those unearthed inconsistencies vs. RCU and instrumentation. Digging into this made it obvious that there are quite some inconsistencies vs. instrumentation in general. The int3 text poke handling in particular was completely unprotected and with the batched update of trace events even more likely to expose to endless int3 recursion. In parallel the RCU implications of instrumenting fragile entry code came up in several discussions. The conclusion of the x86 maintainer team was to go all the way and make the protection against any form of instrumentation of fragile and dangerous code pathes enforcable and verifiable by tooling. A first batch of preparatory work hit mainline with commit d5f744f9a2ac ("Pull x86 entry code updates from Thomas Gleixner") That (almost) full solution introduced a new code section '.noinstr.text' into which all code which needs to be protected from instrumentation of all sorts goes into. Any call into instrumentable code out of this section has to be annotated. objtool has support to validate this. Kprobes now excludes this section fully which also prevents BPF from fiddling with it and all 'noinstr' annotated functions also keep ftrace off. The section, kprobes and objtool changes are already merged. The major changes coming with this are: - Preparatory cleanups - Annotating of relevant functions to move them into the noinstr.text section or enforcing inlining by marking them __always_inline so the compiler cannot misplace or instrument them. - Splitting and simplifying the idtentry macro maze so that it is now clearly separated into simple exception entries and the more interesting ones which use interrupt stacks and have the paranoid handling vs. CR3 and GS. - Move quite some of the low level ASM functionality into C code: - enter_from and exit to user space handling. The ASM code now calls into C after doing the really necessary ASM handling and the return path goes back out without bells and whistels in ASM. - exception entry/exit got the equivivalent treatment - move all IRQ tracepoints from ASM to C so they can be placed as appropriate which is especially important for the int3 recursion issue. - Consolidate the declaration and definition of entry points between 32 and 64 bit. They share a common header and macros now. - Remove the extra device interrupt entry maze and just use the regular exception entry code. - All ASM entry points except NMI are now generated from the shared header file and the corresponding macros in the 32 and 64 bit entry ASM. - The C code entry points are consolidated as well with the help of DEFINE_IDTENTRY*() macros. This allows to ensure at one central point that all corresponding entry points share the same semantics. The actual function body for most entry points is in an instrumentable and sane state. There are special macros for the more sensitive entry points, e.g. INT3 and of course the nasty paranoid #NMI, #MCE, #DB and #DF. They allow to put the whole entry instrumentation and RCU handling into safe places instead of the previous pray that it is correct approach. - The INT3 text poke handling is now completely isolated and the recursion issue banned. Aside of the entry rework this required other isolation work, e.g. the ability to force inline bsearch. - Prevent #DB on fragile entry code, entry relevant memory and disable it on NMI, #MC entry, which allowed to get rid of the nested #DB IST stack shifting hackery. - A few other cleanups and enhancements which have been made possible through this and already merged changes, e.g. consolidating and further restricting the IDT code so the IDT table becomes RO after init which removes yet another popular attack vector - About 680 lines of ASM maze are gone. There are a few open issues: - An escape out of the noinstr section in the MCE handler which needs some more thought but under the aspect that MCE is a complete trainwreck by design and the propability to survive it is low, this was not high on the priority list. - Paravirtualization When PV is enabled then objtool complains about a bunch of indirect calls out of the noinstr section. There are a few straight forward ways to fix this, but the other issues vs. general correctness were more pressing than parawitz. - KVM KVM is inconsistent as well. Patches have been posted, but they have not yet been commented on or picked up by the KVM folks. - IDLE Pretty much the same problems can be found in the low level idle code especially the parts where RCU stopped watching. This was beyond the scope of the more obvious and exposable problems and is on the todo list. The lesson learned from this brain melting exercise to morph the evolved code base into something which can be validated and understood is that once again the violation of the most important engineering principle "correctness first" has caused quite a few people to spend valuable time on problems which could have been avoided in the first place. The "features first" tinkering mindset really has to stop. With that I want to say thanks to everyone involved in contributing to this effort. Special thanks go to the following people (alphabetical order): Alexandre Chartre, Andy Lutomirski, Borislav Petkov, Brian Gerst, Frederic Weisbecker, Josh Poimboeuf, Juergen Gross, Lai Jiangshan, Macro Elver, Paolo Bonzin,i Paul McKenney, Peter Zijlstra, Vitaly Kuznetsov, and Will Deacon" * tag 'x86-entry-2020-06-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (142 commits) x86/entry: Force rcu_irq_enter() when in idle task x86/entry: Make NMI use IDTENTRY_RAW x86/entry: Treat BUG/WARN as NMI-like entries x86/entry: Unbreak __irqentry_text_start/end magic x86/entry: __always_inline CR2 for noinstr lockdep: __always_inline more for noinstr x86/entry: Re-order #DB handler to avoid *SAN instrumentation x86/entry: __always_inline arch_atomic_* for noinstr x86/entry: __always_inline irqflags for noinstr x86/entry: __always_inline debugreg for noinstr x86/idt: Consolidate idt functionality x86/idt: Cleanup trap_init() x86/idt: Use proper constants for table size x86/idt: Add comments about early #PF handling x86/idt: Mark init only functions __init x86/entry: Rename trace_hardirqs_off_prepare() x86/entry: Clarify irq_{enter,exit}_rcu() x86/entry: Remove DBn stacks x86/entry: Remove debug IDT frobbing x86/entry: Optimize local_db_save() for virt ...
2020-06-12x86/entry: Force rcu_irq_enter() when in idle taskThomas Gleixner1-7/+28
The idea of conditionally calling into rcu_irq_enter() only when RCU is not watching turned out to be not completely thought through. Paul noticed occasional premature end of grace periods in RCU torture testing. Bisection led to the commit which made the invocation of rcu_irq_enter() conditional on !rcu_is_watching(). It turned out that this conditional breaks RCU assumptions about the idle task when the scheduler tick happens to be a nested interrupt. Nested interrupts can happen when the first interrupt invokes softirq processing on return which enables interrupts. If that nested tick interrupt does not invoke rcu_irq_enter() then the RCU's irq-nesting checks will believe that this interrupt came directly from idle, which will cause RCU to report a quiescent state. Because this interrupt instead came from a softirq handler which might have been executing an RCU read-side critical section, this can cause the grace period to end prematurely. Change the condition from !rcu_is_watching() to is_idle_task(current) which enforces that interrupts in the idle task unconditionally invoke rcu_irq_enter() independent of the RCU state. This is also correct vs. user mode entries in NOHZ full scenarios because user mode entries bring RCU out of EQS and force the RCU irq nesting state accounting to nested. As only the first interrupt can enter from user mode a nested tick interrupt will enter from kernel mode and as the nesting state accounting is forced to nesting it will not do anything stupid even if rcu_irq_enter() has not been invoked. Fixes: 3eeec3858488 ("x86/entry: Provide idtentry_entry/exit_cond_rcu()") Reported-by: "Paul E. McKenney" <paulmck@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: "Paul E. McKenney" <paulmck@kernel.org> Reviewed-by: "Paul E. McKenney" <paulmck@kernel.org> Acked-by: Andy Lutomirski <luto@kernel.org> Acked-by: Frederic Weisbecker <frederic@kernel.org> Link: https://lkml.kernel.org/r/87wo4cxubv.fsf@nanos.tec.linutronix.de
2020-06-11Rebase locking/kcsan to locking/urgentThomas Gleixner1-0/+6
Merge the state of the locking kcsan branch before the read/write_once() and the atomics modifications got merged. Squash the fallout of the rebase on top of the read/write once and atomic fallback work into the merge. The history of the original branch is preserved in tag locking-kcsan-2020-06-02. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2020-06-11x86/entry: Unbreak __irqentry_text_start/end magicThomas Gleixner2-2/+20
The entry rework moved interrupt entry code from the irqentry to the noinstr section which made the irqentry section empty. This breaks boundary checks which rely on the __irqentry_text_start/end markers to find out whether a function in a stack trace is interrupt/exception entry code. This affects the function graph tracer and filter_irq_stacks(). As the IDT entry points are all sequentialy emitted this is rather simple to unbreak by injecting __irqentry_text_start/end as global labels. To make this work correctly: - Remove the IRQENTRY_TEXT section from the x86 linker script - Define __irqentry so it breaks the build if it's used - Adjust the entry mirroring in PTI - Remove the redundant kprobes and unwinder bound checks Reported-by: Qian Cai <cai@lca.pw> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2020-06-11x86/entry: Rename trace_hardirqs_off_prepare()Peter Zijlstra1-3/+3
The typical pattern for trace_hardirqs_off_prepare() is: ENTRY lockdep_hardirqs_off(); // because hardware ... do entry magic instrumentation_begin(); trace_hardirqs_off_prepare(); ... do actual work trace_hardirqs_on_prepare(); lockdep_hardirqs_on_prepare(); instrumentation_end(); ... do exit magic lockdep_hardirqs_on(); which shows that it's named wrong, rename it to trace_hardirqs_off_finish(), as it concludes the hardirq_off transition. Also, given that the above is the only correct order, make the traditional all-in-one trace_hardirqs_off() follow suit. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20200529213321.415774872@infradead.org
2020-06-11x86/entry: Remove DBn stacksPeter Zijlstra1-17/+0
Both #DB itself, as all other IST users (NMI, #MC) now clear DR7 on entry. Combined with not allowing breakpoints on entry/noinstr/NOKPROBE text and no single step (EFLAGS.TF) inside the #DB handler should guarantee no nested #DB. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20200529213321.303027161@infradead.org
2020-06-11x86/entry: Remove the TRACE_IRQS cruftThomas Gleixner2-21/+1
No more users. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Andy Lutomirski <luto@kernel.org> Link: https://lore.kernel.org/r/20200521202120.523289762@linutronix.de
2020-06-11x86/entry: Move paranoid irq tracing out of ASM codeThomas Gleixner1-13/+0
The last step to remove the irq tracing cruft from ASM. Ignore #DF as the maschine is going to die anyway. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Andy Lutomirski <luto@kernel.org> Link: https://lore.kernel.org/r/20200521202120.414043330@linutronix.de
2020-06-11x86/entry/64: Remove TRACE_IRQS_*_DEBUGThomas Gleixner1-45/+3
Since INT3/#BP no longer runs on an IST, this workaround is no longer required. Tested by running lockdep+ftrace as described in the initial commit: 5963e317b1e9 ("ftrace/x86: Do not change stacks in DEBUG when calling lockdep") Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Acked-by: Andy Lutomirski <luto@kernel.org> Link: https://lore.kernel.org/r/20200521202120.319418546@linutronix.de