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fb13b11d |
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11-Mar-2024 |
André Rösti <an.roesti@gmail.com> |
entry: Respect changes to system call number by trace_sys_enter() When a probe is registered at the trace_sys_enter() tracepoint, and that probe changes the system call number, the old system call still gets executed. This worked correctly until commit b6ec41346103 ("core/entry: Report syscall correctly for trace and audit"), which removed the re-evaluation of the syscall number after the trace point. Restore the original semantics by re-evaluating the system call number after trace_sys_enter(). The performance impact of this re-evaluation is minimal because it only takes place when a trace point is active, and compared to the actual trace point overhead the read from a cache hot variable is negligible. Fixes: b6ec41346103 ("core/entry: Report syscall correctly for trace and audit") Signed-off-by: André Rösti <an.roesti@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20240311211704.7262-1-an.roesti@gmail.com
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221a1640 |
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18-Dec-2023 |
Sven Schnelle <svens@linux.ibm.com> |
entry: Move syscall_enter_from_user_mode() to header file To allow inlining of syscall_enter_from_user_mode(), move it to entry-common.h. Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20231218074520.1998026-4-svens@linux.ibm.com
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#
caf4062e |
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18-Dec-2023 |
Sven Schnelle <svens@linux.ibm.com> |
entry: Move enter_from_user_mode() to header file To allow inlining of enter_from_user_mode(), move it to entry-common.h. Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20231218074520.1998026-3-svens@linux.ibm.com
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d6801947 |
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18-Dec-2023 |
Sven Schnelle <svens@linux.ibm.com> |
entry: Move exit to usermode functions to header file To allow inlining, move exit_to_user_mode() to entry-common.h. Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20231218074520.1998026-2-svens@linux.ibm.com
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1dfe3a5a |
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21-Aug-2023 |
Mark Rutland <mark.rutland@arm.com> |
entry: Remove empty addr_limit_user_check() Back when set_fs() was a generic API for altering the address limit, addr_limit_user_check() was a safety measure to prevent userspace being able to issue syscalls with an unbound limit. With the the removal of set_fs() as a generic API, the last user of addr_limit_user_check() was removed in commit: b5a5a01d8e9a44ec ("arm64: uaccess: remove addr_limit_user_check()") ... as since that commit, no architecture defines TIF_FSCHECK, and hence addr_limit_user_check() always expands to nothing. Remove addr_limit_user_check(), updating the comment in exit_to_user_mode_prepare() to no longer refer to it. At the same time, the comment is reworded to be a little more generic so as to cover kmap_assert_nomap() in addition to lockdep_sys_exit(). No functional change. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20230821163526.2319443-1-mark.rutland@arm.com
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#
b4165140 |
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15-Mar-2023 |
Frederic Weisbecker <frederic@kernel.org> |
entry/rcu: Check TIF_RESCHED _after_ delayed RCU wake-up RCU sometimes needs to perform a delayed wake up for specific kthreads handling offloaded callbacks (RCU_NOCB). These wakeups are performed by timers and upon entry to idle (also to guest and to user on nohz_full). However the delayed wake-up on kernel exit is actually performed after the thread flags are fetched towards the fast path check for work to do on exit to user. As a result, and if there is no other pending work to do upon that kernel exit, the current task will resume to userspace with TIF_RESCHED set and the pending wake up ignored. Fix this with fetching the thread flags _after_ the delayed RCU-nocb kthread wake-up. Fixes: 47b8ff194c1f ("entry: Explicitly flush pending rcuog wakeup before last rescheduling point") Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20230315194349.10798-3-joel@joelfernandes.org
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#
f87d2867 |
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25-Feb-2023 |
Josh Poimboeuf <jpoimboe@kernel.org> |
entry: Fix noinstr warning in __enter_from_user_mode() __enter_from_user_mode() is triggering noinstr warnings with CONFIG_DEBUG_PREEMPT due to its call of preempt_count_add() via ct_state(). The preemption disable isn't needed as interrupts are already disabled. And the context_tracking_enabled() check in ct_state() also isn't needed as that's already being done by the CT_WARN_ON(). Just use __ct_state() instead. Fixes the following warnings: vmlinux.o: warning: objtool: enter_from_user_mode+0xba: call to preempt_count_add() leaves .noinstr.text section vmlinux.o: warning: objtool: syscall_enter_from_user_mode+0xf9: call to preempt_count_add() leaves .noinstr.text section vmlinux.o: warning: objtool: syscall_enter_from_user_mode_prepare+0xc7: call to preempt_count_add() leaves .noinstr.text section vmlinux.o: warning: objtool: irqentry_enter_from_user_mode+0xba: call to preempt_count_add() leaves .noinstr.text section Fixes: 171476775d32 ("context_tracking: Convert state to atomic_t") Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/d8955fa6d68dc955dda19baf13ae014ae27926f5.1677369694.git.jpoimboe@kernel.org
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#
6cae637f |
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15-Sep-2022 |
Alexander Potapenko <glider@google.com> |
entry: kmsan: introduce kmsan_unpoison_entry_regs() struct pt_regs passed into IRQ entry code is set up by uninstrumented asm functions, therefore KMSAN may not notice the registers are initialized. kmsan_unpoison_entry_regs() unpoisons the contents of struct pt_regs, preventing potential false positives. Unlike kmsan_unpoison_memory(), it can be called under kmsan_in_runtime(), which is often the case in IRQ entry code. Link: https://lkml.kernel.org/r/20220915150417.722975-41-glider@google.com Signed-off-by: Alexander Potapenko <glider@google.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Christoph Hellwig <hch@lst.de> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Eric Biggers <ebiggers@google.com> Cc: Eric Biggers <ebiggers@kernel.org> Cc: Eric Dumazet <edumazet@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Ilya Leoshkevich <iii@linux.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Kees Cook <keescook@chromium.org> Cc: Marco Elver <elver@google.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Petr Mladek <pmladek@suse.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vegard Nossum <vegard.nossum@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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#
493c1822 |
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08-Jun-2022 |
Frederic Weisbecker <frederic@kernel.org> |
context_tracking: Take NMI eqs entrypoints over RCU The RCU dynticks counter is going to be merged into the context tracking subsystem. Prepare with moving the NMI extended quiescent states entrypoints to context tracking. For now those are dumb redirection to existing RCU calls. Acked-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Uladzislau Rezki <uladzislau.rezki@sony.com> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Nicolas Saenz Julienne <nsaenz@kernel.org> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Xiongfeng Wang <wangxiongfeng2@huawei.com> Cc: Yu Liao <liaoyu15@huawei.com> Cc: Phil Auld <pauld@redhat.com> Cc: Paul Gortmaker<paul.gortmaker@windriver.com> Cc: Alex Belits <abelits@marvell.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Nicolas Saenz Julienne <nsaenzju@redhat.com> Tested-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
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#
6f0e6c15 |
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08-Jun-2022 |
Frederic Weisbecker <frederic@kernel.org> |
context_tracking: Take IRQ eqs entrypoints over RCU The RCU dynticks counter is going to be merged into the context tracking subsystem. Prepare with moving the IRQ extended quiescent states entrypoints to context tracking. For now those are dumb redirection to existing RCU calls. [ paulmck: Apply Stephen Rothwell feedback from -next. ] [ paulmck: Apply Nathan Chancellor feedback. ] Acked-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Uladzislau Rezki <uladzislau.rezki@sony.com> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Nicolas Saenz Julienne <nsaenz@kernel.org> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Xiongfeng Wang <wangxiongfeng2@huawei.com> Cc: Yu Liao <liaoyu15@huawei.com> Cc: Phil Auld <pauld@redhat.com> Cc: Paul Gortmaker<paul.gortmaker@windriver.com> Cc: Alex Belits <abelits@marvell.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Nicolas Saenz Julienne <nsaenzju@redhat.com> Tested-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
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#
8b023acc |
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14-Mar-2022 |
Nick Desaulniers <ndesaulniers@google.com> |
lockdep: Fix -Wunused-parameter for _THIS_IP_ While looking into a bug related to the compiler's handling of addresses of labels, I noticed some uses of _THIS_IP_ seemed unused in lockdep. Drive by cleanup. -Wunused-parameter: kernel/locking/lockdep.c:1383:22: warning: unused parameter 'ip' kernel/locking/lockdep.c:4246:48: warning: unused parameter 'ip' kernel/locking/lockdep.c:4844:19: warning: unused parameter 'ip' Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Waiman Long <longman@redhat.com> Link: https://lore.kernel.org/r/20220314221909.2027027-1-ndesaulniers@google.com
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#
6d97af48 |
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04-May-2022 |
Sven Schnelle <svens@linux.ibm.com> |
entry: Rename arch_check_user_regs() to arch_enter_from_user_mode() arch_check_user_regs() is used at the moment to verify that struct pt_regs contains valid values when entering the kernel from userspace. s390 needs a place in the generic entry code to modify a cpu data structure when switching from userspace to kernel mode. As arch_check_user_regs() is exactly this, rename it to arch_enter_from_user_mode(). When entering the kernel from userspace, arch_check_user_regs() is used to verify that struct pt_regs contains valid values. Note that the NMI codepath doesn't call this function. s390 needs a place in the generic entry code to modify a cpu data structure when switching from userspace to kernel mode. As arch_check_user_regs() is exactly this, rename it to arch_enter_from_user_mode(). Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andy Lutomirski <luto@kernel.org> Link: https://lore.kernel.org/r/20220504062351.2954280-2-tmricht@linux.ibm.com Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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0a70045e |
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30-Mar-2022 |
Sven Schnelle <svens@linux.ibm.com> |
entry: Fix compile error in dynamic_irqentry_exit_cond_resched() kernel/entry/common.c: In function ‘dynamic_irqentry_exit_cond_resched’: kernel/entry/common.c:409:14: error: implicit declaration of function ‘static_key_unlikely’; did you mean ‘static_key_enable’? [-Werror=implicit-function-declaration] 409 | if (!static_key_unlikely(&sk_dynamic_irqentry_exit_cond_resched)) | ^~~~~~~~~~~~~~~~~~~ | static_key_enable static_key_unlikely() should be static_branch_unlikely(). Fixes: 99cf983cc8bca ("sched/preempt: Add PREEMPT_DYNAMIC using static keys") Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Mark Rutland <mark.rutland@arm.com> Link: https://lore.kernel.org/r/20220330084328.1805665-1-svens@linux.ibm.com
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7dd5ad2d |
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31-Mar-2022 |
Thomas Gleixner <tglx@linutronix.de> |
Revert "signal, x86: Delay calling signals in atomic on RT enabled kernels" Revert commit bf9ad37dc8a. It needs to be better encapsulated and generalized. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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03248add |
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08-Feb-2022 |
Eric W. Biederman <ebiederm@xmission.com> |
resume_user_mode: Move to resume_user_mode.h Move set_notify_resume and tracehook_notify_resume into resume_user_mode.h. While doing that rename tracehook_notify_resume to resume_user_mode_work. Update all of the places that included tracehook.h for these functions to include resume_user_mode.h instead. Update all of the callers of tracehook_notify_resume to call resume_user_mode_work. Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lkml.kernel.org/r/20220309162454.123006-12-ebiederm@xmission.com Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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8ba62d37 |
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09-Feb-2022 |
Eric W. Biederman <ebiederm@xmission.com> |
task_work: Call tracehook_notify_signal from get_signal on all architectures Always handle TIF_NOTIFY_SIGNAL in get_signal. With commit 35d0b389f3b2 ("task_work: unconditionally run task_work from get_signal()") always calling task_work_run all of the work of tracehook_notify_signal is already happening except clearing TIF_NOTIFY_SIGNAL. Factor clear_notify_signal out of tracehook_notify_signal and use it in get_signal so that get_signal only needs one call of task_work_run. To keep the semantics in sync update xfer_to_guest_mode_work (which does not call get_signal) to call tracehook_notify_signal if either _TIF_SIGPENDING or _TIF_NOTIFY_SIGNAL. Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lkml.kernel.org/r/20220309162454.123006-8-ebiederm@xmission.com Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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0cfcb2b9 |
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26-Jan-2022 |
Eric W. Biederman <ebiederm@xmission.com> |
ptrace: Remove arch_syscall_{enter,exit}_tracehook These functions are alwasy one-to-one wrappers around ptrace_report_syscall_entry and ptrace_report_syscall_exit. So directly call the functions they are wrapping instead. Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lkml.kernel.org/r/20220309162454.123006-4-ebiederm@xmission.com Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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153474ba |
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27-Jan-2022 |
Eric W. Biederman <ebiederm@xmission.com> |
ptrace: Create ptrace_report_syscall_{entry,exit} in ptrace.h Rename tracehook_report_syscall_{entry,exit} to ptrace_report_syscall_{entry,exit} and place them in ptrace.h There is no longer any generic tracehook infractructure so make these ptrace specific functions ptrace specific. Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lkml.kernel.org/r/20220309162454.123006-3-ebiederm@xmission.com Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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99cf983c |
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14-Feb-2022 |
Mark Rutland <mark.rutland@arm.com> |
sched/preempt: Add PREEMPT_DYNAMIC using static keys Where an architecture selects HAVE_STATIC_CALL but not HAVE_STATIC_CALL_INLINE, each static call has an out-of-line trampoline which will either branch to a callee or return to the caller. On such architectures, a number of constraints can conspire to make those trampolines more complicated and potentially less useful than we'd like. For example: * Hardware and software control flow integrity schemes can require the addition of "landing pad" instructions (e.g. `BTI` for arm64), which will also be present at the "real" callee. * Limited branch ranges can require that trampolines generate or load an address into a register and perform an indirect branch (or at least have a slow path that does so). This loses some of the benefits of having a direct branch. * Interaction with SW CFI schemes can be complicated and fragile, e.g. requiring that we can recognise idiomatic codegen and remove indirections understand, at least until clang proves more helpful mechanisms for dealing with this. For PREEMPT_DYNAMIC, we don't need the full power of static calls, as we really only need to enable/disable specific preemption functions. We can achieve the same effect without a number of the pain points above by using static keys to fold early returns into the preemption functions themselves rather than in an out-of-line trampoline, effectively inlining the trampoline into the start of the function. For arm64, this results in good code generation. For example, the dynamic_cond_resched() wrapper looks as follows when enabled. When disabled, the first `B` is replaced with a `NOP`, resulting in an early return. | <dynamic_cond_resched>: | bti c | b <dynamic_cond_resched+0x10> // or `nop` | mov w0, #0x0 | ret | mrs x0, sp_el0 | ldr x0, [x0, #8] | cbnz x0, <dynamic_cond_resched+0x8> | paciasp | stp x29, x30, [sp, #-16]! | mov x29, sp | bl <preempt_schedule_common> | mov w0, #0x1 | ldp x29, x30, [sp], #16 | autiasp | ret ... compared to the regular form of the function: | <__cond_resched>: | bti c | mrs x0, sp_el0 | ldr x1, [x0, #8] | cbz x1, <__cond_resched+0x18> | mov w0, #0x0 | ret | paciasp | stp x29, x30, [sp, #-16]! | mov x29, sp | bl <preempt_schedule_common> | mov w0, #0x1 | ldp x29, x30, [sp], #16 | autiasp | ret Any architecture which implements static keys should be able to use this to implement PREEMPT_DYNAMIC with similar cost to non-inlined static calls. Since this is likely to have greater overhead than (inlined) static calls, PREEMPT_DYNAMIC is only defaulted to enabled when HAVE_PREEMPT_DYNAMIC_CALL is selected. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Ard Biesheuvel <ardb@kernel.org> Acked-by: Frederic Weisbecker <frederic@kernel.org> Link: https://lore.kernel.org/r/20220214165216.2231574-6-mark.rutland@arm.com
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4624a14f |
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14-Feb-2022 |
Mark Rutland <mark.rutland@arm.com> |
sched/preempt: Simplify irqentry_exit_cond_resched() callers Currently callers of irqentry_exit_cond_resched() need to be aware of whether the function should be indirected via a static call, leading to ugly ifdeffery in callers. Save them the hassle with a static inline wrapper that does the right thing. The raw_irqentry_exit_cond_resched() will also be useful in subsequent patches which will add conditional wrappers for preemption functions. Note: in arch/x86/entry/common.c, xen_pv_evtchn_do_upcall() always calls irqentry_exit_cond_resched() directly, even when PREEMPT_DYNAMIC is in use. I believe this is a latent bug (which this patch corrects), but I'm not entirely certain this wasn't deliberate. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Ard Biesheuvel <ardb@kernel.org> Acked-by: Frederic Weisbecker <frederic@kernel.org> Link: https://lore.kernel.org/r/20220214165216.2231574-4-mark.rutland@arm.com
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#
bf9ad37d |
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14-Jul-2015 |
Oleg Nesterov <oleg@redhat.com> |
signal, x86: Delay calling signals in atomic on RT enabled kernels On x86_64 we must disable preemption before we enable interrupts for stack faults, int3 and debugging, because the current task is using a per CPU debug stack defined by the IST. If we schedule out, another task can come in and use the same stack and cause the stack to be corrupted and crash the kernel on return. When CONFIG_PREEMPT_RT is enabled, spinlock_t locks become sleeping, and one of these is the spin lock used in signal handling. Some of the debug code (int3) causes do_trap() to send a signal. This function calls a spinlock_t lock that has been converted to a sleeping lock. If this happens, the above issues with the corrupted stack is possible. Instead of calling the signal right away, for PREEMPT_RT and x86, the signal information is stored on the stacks task_struct and TIF_NOTIFY_RESUME is set. Then on exit of the trap, the signal resume code will send the signal when preemption is enabled. [ rostedt: Switched from #ifdef CONFIG_PREEMPT_RT to ARCH_RT_DELAYS_SIGNAL_SEND and added comments to the code. ] [bigeasy: Add on 32bit as per Yang Shi, minor rewording. ] [ tglx: Use a config option ] Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/Ygq5aBB/qMQw6aP5@linutronix.de
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#
6ce89512 |
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29-Nov-2021 |
Mark Rutland <mark.rutland@arm.com> |
entry: Snapshot thread flags Some thread flags can be set remotely, and so even when IRQs are disabled, the flags can change under our feet. Generally this is unlikely to cause a problem in practice, but it is somewhat unsound, and KCSAN will legitimately warn that there is a data race. To avoid such issues, a snapshot of the flags has to be taken prior to using them. Some places already use READ_ONCE() for that, others do not. Convert them all to the new flag accessor helpers. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Paul E. McKenney <paulmck@kernel.org> Link: https://lore.kernel.org/r/20211129130653.2037928-3-mark.rutland@arm.com
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a68de80f |
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01-Sep-2021 |
Sean Christopherson <seanjc@google.com> |
entry: rseq: Call rseq_handle_notify_resume() in tracehook_notify_resume() Invoke rseq_handle_notify_resume() from tracehook_notify_resume() now that the two function are always called back-to-back by architectures that have rseq. The rseq helper is stubbed out for architectures that don't support rseq, i.e. this is a nop across the board. Note, tracehook_notify_resume() is horribly named and arguably does not belong in tracehook.h as literally every line of code in it has nothing to do with tracing. But, that's been true since commit a42c6ded827d ("move key_repace_session_keyring() into tracehook_notify_resume()") first usurped tracehook_notify_resume() back in 2012. Punt cleaning that mess up to future patches. No functional change intended. Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210901203030.1292304-3-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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#
f268c373 |
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27-May-2021 |
Frederic Weisbecker <frederic@kernel.org> |
tick/nohz: Only check for RCU deferred wakeup on user/guest entry when needed Checking for and processing RCU-nocb deferred wakeup upon user/guest entry is only relevant when nohz_full runs on the local CPU, otherwise the periodic tick should take care of it. Make sure we don't needlessly pollute these fast-paths as a -3% performance regression on a will-it-scale.per_process_ops has been reported so far. Fixes: 47b8ff194c1f (entry: Explicitly flush pending rcuog wakeup before last rescheduling point) Fixes: 4ae7dc97f726 (entry/kvm: Explicitly flush pending rcuog wakeup before last rescheduling point) Reported-by: kernel test robot <oliver.sang@intel.com> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Paul E. McKenney <paulmck@kernel.org> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20210527113441.465489-1-frederic@kernel.org
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#
97258ce9 |
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21-Mar-2021 |
Ingo Molnar <mingo@kernel.org> |
entry: Fix typos in comments Fix 3 single-word typos in the generic syscall entry code. Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
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0c89d87d |
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10-Apr-2021 |
Zhouyi Zhou <zhouzhouyi@gmail.com> |
preempt/dynamic: Fix typo in macro conditional statement Commit 40607ee97e4e ("preempt/dynamic: Provide irqentry_exit_cond_resched() static call") tried to provide irqentry_exit_cond_resched() static call in irqentry_exit, but has a typo in macro conditional statement. Fixes: 40607ee97e4e ("preempt/dynamic: Provide irqentry_exit_cond_resched() static call") Signed-off-by: Zhouyi Zhou <zhouzhouyi@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20210410073523.5493-1-zhouzhouyi@gmail.com
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47b8ff19 |
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31-Jan-2021 |
Frederic Weisbecker <frederic@kernel.org> |
entry: Explicitly flush pending rcuog wakeup before last rescheduling point Following the idle loop model, cleanly check for pending rcuog wakeup before the last rescheduling point on resuming to user mode. This way we can avoid to do it from rcu_user_enter() with the last resort self-IPI hack that enforces rescheduling. Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20210131230548.32970-5-frederic@kernel.org
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40607ee9 |
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18-Jan-2021 |
Peter Zijlstra (Intel) <peterz@infradead.org> |
preempt/dynamic: Provide irqentry_exit_cond_resched() static call Provide static call to control IRQ preemption (called in CONFIG_PREEMPT) so that we can override its behaviour when preempt= is overriden. Since the default behaviour is full preemption, its call is initialized to provide IRQ preemption when preempt= isn't passed. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/20210118141223.123667-8-frederic@kernel.org
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6342adca |
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03-Feb-2021 |
Gabriel Krisman Bertazi <krisman@collabora.com> |
entry: Ensure trap after single-step on system call return Commit 299155244770 ("entry: Drop usage of TIF flags in the generic syscall code") introduced a bug on architectures using the generic syscall entry code, in which processes stopped by PTRACE_SYSCALL do not trap on syscall return after receiving a TIF_SINGLESTEP. The reason is that the meaning of TIF_SINGLESTEP flag is overloaded to cause the trap after a system call is executed, but since the above commit, the syscall call handler only checks for the SYSCALL_WORK flags on the exit work. Split the meaning of TIF_SINGLESTEP such that it only means single-step mode, and create a new type of SYSCALL_WORK to request a trap immediately after a syscall in single-step mode. In the current implementation, the SYSCALL_WORK flag shadows the TIF_SINGLESTEP flag for simplicity. Update x86 to flip this bit when a tracer enables single stepping. Fixes: 299155244770 ("entry: Drop usage of TIF flags in the generic syscall code") Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Kyle Huey <me@kylehuey.com> Link: https://lore.kernel.org/r/87h7mtc9pr.fsf_-_@collabora.com
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41c1a06d |
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23-Jan-2021 |
Yuxuan Shui <yshuiv7@gmail.com> |
entry: Unbreak single step reporting behaviour The move of TIF_SYSCALL_EMU to SYSCALL_WORK_SYSCALL_EMU broke single step reporting. The original code reported the single step when TIF_SINGLESTEP was set and TIF_SYSCALL_EMU was not set. The SYSCALL_WORK conversion got the logic wrong and now the reporting only happens when both bits are set. Restore the original behaviour. [ tglx: Massaged changelog and dropped the pointless double negation ] Fixes: 64eb35f701f0 ("ptrace: Migrate TIF_SYSCALL_EMU to use SYSCALL_WORK flag") Signed-off-by: Yuxuan Shui <yshuiv7@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Gabriel Krisman Bertazi <krisman@collabora.com> Link: https://lore.kernel.org/r/877do3gaq9.fsf@m5Zedd9JOGzJrf0
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c6156e1d |
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01-Dec-2020 |
Sven Schnelle <svens@linux.ibm.com> |
entry: Add syscall_exit_to_user_mode_work() This is the same as syscall_exit_to_user_mode() but without calling exit_to_user_mode(). This can be used if there is an architectural reason to avoid the combo function, e.g. restarting a syscall without returning to userspace. Before returning to user space the caller has to invoke exit_to_user_mode(). [ tglx: Amended comments ] Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20201201142755.31931-6-svens@linux.ibm.com
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#
310de1a6 |
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01-Dec-2020 |
Sven Schnelle <svens@linux.ibm.com> |
entry: Add exit_to_user_mode() wrapper Called from architecture specific code when syscall_exit_to_user_mode() is not suitable. It simply calls __exit_to_user_mode(). This way __exit_to_user_mode() can still be inlined because it is declared static __always_inline. [ tglx: Amended comments and moved it to a different place in the header ] Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20201201142755.31931-5-svens@linux.ibm.com
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96e2fbcc |
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01-Dec-2020 |
Sven Schnelle <svens@linux.ibm.com> |
entry_Add_enter_from_user_mode_wrapper To be called from architecture specific code if the combo interfaces are not suitable. It simply calls __enter_from_user_mode(). This way __enter_from_user_mode will still be inlined because it is declared static __always_inline. [ tglx: Amend comments and move it to a different location in the header ] Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20201201142755.31931-4-svens@linux.ibm.com
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bb793562 |
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01-Dec-2020 |
Sven Schnelle <svens@linux.ibm.com> |
entry: Rename exit_to_user_mode() In order to make this function publicly available rename it so it can still be inlined. An additional exit_to_user_mode() function will be added with a later commit. Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20201201142755.31931-3-svens@linux.ibm.com
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6666bb71 |
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01-Dec-2020 |
Sven Schnelle <svens@linux.ibm.com> |
entry: Rename enter_from_user_mode() In order to make this function publicly available rename it so it can still be inlined. An additional enter_from_user_mode() function will be added with a later commit. Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20201201142755.31931-2-svens@linux.ibm.com
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11894468 |
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27-Nov-2020 |
Gabriel Krisman Bertazi <krisman@collabora.com> |
entry: Support Syscall User Dispatch on common syscall entry Syscall User Dispatch (SUD) must take precedence over seccomp and ptrace, since the use case is emulation (it can be invoked with a different ABI) such that seccomp filtering by syscall number doesn't make sense in the first place. In addition, either the syscall is dispatched back to userspace, in which case there is no resource for to trace, or the syscall will be executed, and seccomp/ptrace will execute next. Since SUD runs before tracepoints, it needs to be a SYSCALL_WORK_EXIT as well, just to prevent a trace exit event when dispatch was triggered. For that, the on_syscall_dispatch() examines context to skip the tracepoint, audit and other work. [ tglx: Add a comment on the exit side ] Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Andy Lutomirski <luto@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20201127193238.821364-5-krisman@collabora.com
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5fbda3ec |
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18-Nov-2020 |
Thomas Gleixner <tglx@linutronix.de> |
sched: highmem: Store local kmaps in task struct Instead of storing the map per CPU provide and use per task storage. That prepares for local kmaps which are preemptible. The context switch code is preparatory and not yet in use because kmap_atomic() runs with preemption disabled. Will be made usable in the next step. The context switch logic is safe even when an interrupt happens after clearing or before restoring the kmaps. The kmap index in task struct is not modified so any nesting kmap in an interrupt will use unused indices and on return the counter is the same as before. Also add an assert into the return to user space code. Going back to user space with an active kmap local is a nono. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20201118204007.372935758@linutronix.de
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29915524 |
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15-Nov-2020 |
Gabriel Krisman Bertazi <krisman@collabora.com> |
entry: Drop usage of TIF flags in the generic syscall code Now that the flags migration in the common syscall entry code is complete and the code relies exclusively on thread_info::syscall_work, clean up the accesses to TI flags in that path. Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Andy Lutomirski <luto@kernel.org> Link: https://lore.kernel.org/r/20201116174206.2639648-10-krisman@collabora.com
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64eb35f7 |
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15-Nov-2020 |
Gabriel Krisman Bertazi <krisman@collabora.com> |
ptrace: Migrate TIF_SYSCALL_EMU to use SYSCALL_WORK flag On architectures using the generic syscall entry code the architecture independent syscall work is moved to flags in thread_info::syscall_work. This removes architecture dependencies and frees up TIF bits. Define SYSCALL_WORK_SYSCALL_EMU, use it in the generic entry code and convert the code which uses the TIF specific helper functions to use the new *_syscall_work() helpers which either resolve to the new mode for users of the generic entry code or to the TIF based functions for the other architectures. Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Andy Lutomirski <luto@kernel.org> Link: https://lore.kernel.org/r/20201116174206.2639648-8-krisman@collabora.com
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64c19ba2 |
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15-Nov-2020 |
Gabriel Krisman Bertazi <krisman@collabora.com> |
ptrace: Migrate to use SYSCALL_TRACE flag On architectures using the generic syscall entry code the architecture independent syscall work is moved to flags in thread_info::syscall_work. This removes architecture dependencies and frees up TIF bits. Define SYSCALL_WORK_SYSCALL_TRACE, use it in the generic entry code and convert the code which uses the TIF specific helper functions to use the new *_syscall_work() helpers which either resolve to the new mode for users of the generic entry code or to the TIF based functions for the other architectures. Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Andy Lutomirski <luto@kernel.org> Link: https://lore.kernel.org/r/20201116174206.2639648-7-krisman@collabora.com
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524666cb |
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15-Nov-2020 |
Gabriel Krisman Bertazi <krisman@collabora.com> |
tracepoints: Migrate to use SYSCALL_WORK flag On architectures using the generic syscall entry code the architecture independent syscall work is moved to flags in thread_info::syscall_work. This removes architecture dependencies and frees up TIF bits. Define SYSCALL_WORK_SYSCALL_TRACEPOINT, use it in the generic entry code and convert the code which uses the TIF specific helper functions to use the new *_syscall_work() helpers which either resolve to the new mode for users of the generic entry code or to the TIF based functions for the other architectures. Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Andy Lutomirski <luto@kernel.org> Link: https://lore.kernel.org/r/20201116174206.2639648-6-krisman@collabora.com
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23d67a54 |
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15-Nov-2020 |
Gabriel Krisman Bertazi <krisman@collabora.com> |
seccomp: Migrate to use SYSCALL_WORK flag On architectures using the generic syscall entry code the architecture independent syscall work is moved to flags in thread_info::syscall_work. This removes architecture dependencies and frees up TIF bits. Define SYSCALL_WORK_SECCOMP, use it in the generic entry code and convert the code which uses the TIF specific helper functions to use the new *_syscall_work() helpers which either resolve to the new mode for users of the generic entry code or to the TIF based functions for the other architectures. Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Andy Lutomirski <luto@kernel.org> Link: https://lore.kernel.org/r/20201116174206.2639648-5-krisman@collabora.com
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b86678cf |
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15-Nov-2020 |
Gabriel Krisman Bertazi <krisman@collabora.com> |
entry: Wire up syscall_work in common entry code Prepare the common entry code to use the SYSCALL_WORK flags. They will be defined in subsequent patches for each type of syscall work. SYSCALL_WORK_ENTRY/EXIT are defined for the transition, as they will replace the TIF_ equivalent defines. Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Andy Lutomirski <luto@kernel.org> Link: https://lore.kernel.org/r/20201116174206.2639648-4-krisman@collabora.com
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78a56e04 |
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04-Nov-2020 |
Ira Weiny <ira.weiny@intel.com> |
entry: Fix spelling/typo errors in irq entry code s/reguired/required/ s/Interupts/Interrupts/ s/quiescient/quiescent/ s/assemenbly/assembly/ Signed-off-by: Ira Weiny <ira.weiny@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20201104230157.3378023-1-ira.weiny@intel.com
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#
b6be002b |
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02-Nov-2020 |
Thomas Gleixner <tglx@linutronix.de> |
x86/entry: Move nmi entry/exit into common code Lockdep state handling on NMI enter and exit is nothing specific to X86. It's not any different on other architectures. Also the extra state type is not necessary, irqentry_state_t can carry the necessary information as well. Move it to common code and extend irqentry_state_t to carry lockdep state. [ Ira: Make exit_rcu and lockdep a union as they are mutually exclusive between the IRQ and NMI exceptions, and add kernel documentation for struct irqentry_state_t ] Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ira Weiny <ira.weiny@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20201102205320.1458656-7-ira.weiny@intel.com
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9d820f68 |
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04-Nov-2020 |
Thomas Gleixner <tglx@linutronix.de> |
entry: Fix the incorrect ordering of lockdep and RCU check When an exception/interrupt hits kernel space and the kernel is not currently in the idle task then RCU must be watching. irqentry_enter() validates this via rcu_irq_enter_check_tick(), which in turn invokes lockdep when taking a lock. But at that point lockdep does not yet know about the fact that interrupts have been disabled by the CPU, which triggers a lockdep splat complaining about inconsistent state. Invoking trace_hardirqs_off() before rcu_irq_enter_check_tick() defeats the point of rcu_irq_enter_check_tick() because trace_hardirqs_off() uses RCU. So use the same sequence as for the idle case and tell lockdep about the irq state change first, invoke the RCU check and then do the lockdep and tracer update. Fixes: a5497bab5f72 ("entry: Provide generic interrupt entry/exit code") Reported-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Mark Rutland <mark.rutland@arm.com> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/87y2jhl19s.fsf@nanos.tec.linutronix.de
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45ff5105 |
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28-Oct-2020 |
Ira Weiny <ira.weiny@intel.com> |
entry: Fixup irqentry_enter() comment irq_enter_from_user_mode() was changed to irqentry_enter_from_user_mode(). Update the comment within irqentry_enter() to reflect this change. Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ira Weiny <ira.weiny@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20201028163632.965518-1-ira.weiny@intel.com
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12db8b69 |
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26-Oct-2020 |
Jens Axboe <axboe@kernel.dk> |
entry: Add support for TIF_NOTIFY_SIGNAL Add TIF_NOTIFY_SIGNAL handling in the generic entry code, which if set, will return true if signal_pending() is used in a wait loop. That causes an exit of the loop so that notify_signal tracehooks can be run. If the wait loop is currently inside a system call, the system call is restarted once task_work has been processed. In preparation for only having arch_do_signal() handle syscall restarts if _TIF_SIGPENDING isn't set, rename it to arch_do_signal_or_restart(). Pass in a boolean that tells the architecture specific signal handler if it should attempt to get a signal, or just process a potential syscall restart. For !CONFIG_GENERIC_ENTRY archs, add the TIF_NOTIFY_SIGNAL handling to get_signal(). This is done to minimize the needed architecture changes to support this feature. Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Link: https://lore.kernel.org/r/20201026203230.386348-3-axboe@kernel.dk
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3c532798 |
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03-Oct-2020 |
Jens Axboe <axboe@kernel.dk> |
tracehook: clear TIF_NOTIFY_RESUME in tracehook_notify_resume() All the callers currently do this, clean it up and move the clearing into tracehook_notify_resume() instead. Reviewed-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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900ffe39 |
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19-Sep-2020 |
Kees Cook <keescook@chromium.org> |
x86/entry: Fix typo in comments for syscall_enter_from_user_mode() Just to help myself and others with finding the correct function names, fix a typo for "usermode" vs "user_mode". Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20200919080936.259819-1-keescook@chromium.org
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b6ec4134 |
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11-Sep-2020 |
Kees Cook <keescook@chromium.org> |
core/entry: Report syscall correctly for trace and audit On v5.8 when doing seccomp syscall rewrites (e.g. getpid into getppid as seen in the seccomp selftests), trace (and audit) correctly see the rewritten syscall on entry and exit: seccomp_bpf-1307 [000] .... 22974.874393: sys_enter: NR 110 (... seccomp_bpf-1307 [000] .N.. 22974.874401: sys_exit: NR 110 = 1304 With mainline we see a mismatched enter and exit (the original syscall is incorrectly visible on entry): seccomp_bpf-1030 [000] .... 21.806766: sys_enter: NR 39 (... seccomp_bpf-1030 [000] .... 21.806767: sys_exit: NR 110 = 1027 When ptrace or seccomp change the syscall, this needs to be visible to trace and audit at that time as well. Update the syscall earlier so they see the correct value. Fixes: d88d59b64ca3 ("core/entry: Respect syscall number rewrites") Reported-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20200912005826.586171-1-keescook@chromium.org
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4facb95b |
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01-Sep-2020 |
Thomas Gleixner <tglx@linutronix.de> |
x86/entry: Unbreak 32bit fast syscall Andy reported that the syscall treacing for 32bit fast syscall fails: # ./tools/testing/selftests/x86/ptrace_syscall_32 ... [RUN] SYSEMU [FAIL] Initial args are wrong (nr=224, args=10 11 12 13 14 4289172732) ... [RUN] SYSCALL [FAIL] Initial args are wrong (nr=29, args=0 0 0 0 0 4289172732) The eason is that the conversion to generic entry code moved the retrieval of the sixth argument (EBP) after the point where the syscall entry work runs, i.e. ptrace, seccomp, audit... Unbreak it by providing a split up version of syscall_enter_from_user_mode(). - syscall_enter_from_user_mode_prepare() establishes state and enables interrupts - syscall_enter_from_user_mode_work() runs the entry work Replace the call to syscall_enter_from_user_mode() in the 32bit fast syscall C-entry with the split functions and stick the EBP retrieval between them. Fixes: 27d6b4d14f5c ("x86/entry: Use generic syscall entry function") Reported-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/87k0xdjbtt.fsf@nanos.tec.linutronix.de
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7f2a53c2 |
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17-Aug-2020 |
Paul E. McKenney <paulmck@kernel.org> |
rcu: Remove unused __rcu_is_watching() function The x86/entry work removed all uses of __rcu_is_watching(), therefore this commit removes it entirely. Cc: Andy Lutomirski <luto@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: <x86@kernel.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
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d88d59b6 |
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19-Aug-2020 |
Thomas Gleixner <tglx@linutronix.de> |
core/entry: Respect syscall number rewrites The transcript of the x86 entry code to the generic version failed to reload the syscall number from ptregs after ptrace and seccomp have run, which both can modify the syscall number in ptregs. It returns the original syscall number instead which is obviously not the right thing to do. Reload the syscall number to fix that. Fixes: 142781e108b1 ("entry: Provide generic syscall entry functionality") Reported-by: Kyle Huey <me@kylehuey.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Kyle Huey <me@kylehuey.com> Tested-by: Kees Cook <keescook@chromium.org> Acked-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/87blj6ifo8.fsf@nanos.tec.linutronix.de
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aadfc2f9 |
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25-Jul-2020 |
Ingo Molnar <mingo@kernel.org> |
entry: Correct 'noinstr' attributes The noinstr attribute is to be specified before the return type in the same way 'inline' is used. Similar cases were recently fixed for x86 in commit 7f6fa101dfac ("x86: Correct noinstr qualifiers"), but the generic entry code was based on the the original version and did not carry the fix over. Fixes: a5497bab5f72 ("entry: Provide generic interrupt entry/exit code") Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20200725091951.744848-3-mingo@kernel.org
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a5497bab |
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22-Jul-2020 |
Thomas Gleixner <tglx@linutronix.de> |
entry: Provide generic interrupt entry/exit code Like the syscall entry/exit code interrupt/exception entry after the real low level ASM bits should not be different accross architectures. Provide a generic version based on the x86 code. irqentry_enter() is called after the low level entry code and irqentry_exit() must be invoked right before returning to the low level code which just contains the actual return logic. The code before irqentry_enter() and irqentry_exit() must not be instrumented. Code after irqentry_enter() and before irqentry_exit() can be instrumented. irqentry_enter() invokes irqentry_enter_from_user_mode() if the interrupt/exception came from user mode. If if entered from kernel mode it handles the kernel mode variant of establishing state for lockdep, RCU and tracing depending on the kernel context it interrupted (idle, non-idle). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20200722220519.723703209@linutronix.de
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a9f3a74a |
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22-Jul-2020 |
Thomas Gleixner <tglx@linutronix.de> |
entry: Provide generic syscall exit function Like syscall entry all architectures have similar and pointlessly different code to handle pending work before returning from a syscall to user space. 1) One-time syscall exit work: - rseq syscall exit - audit - syscall tracing - tracehook (single stepping) 2) Preparatory work - Exit to user mode loop (common TIF handling). - Architecture specific one time work arch_exit_to_user_mode_prepare() - Address limit and lockdep checks 3) Final transition (lockdep, tracing, context tracking, RCU). Invokes arch_exit_to_user_mode() to handle e.g. speculation mitigations Provide a generic version based on the x86 code which has all the RCU and instrumentation protections right. Provide a variant for interrupt return to user mode as well which shares the above #2 and #3 work items. After syscall_exit_to_user_mode() and irqentry_exit_to_user_mode() the architecture code just has to return to user space. The code after returning from these functions must not be instrumented. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lkml.kernel.org/r/20200722220519.613977173@linutronix.de
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142781e1 |
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22-Jul-2020 |
Thomas Gleixner <tglx@linutronix.de> |
entry: Provide generic syscall entry functionality On syscall entry certain work needs to be done: - Establish state (lockdep, context tracking, tracing) - Conditional work (ptrace, seccomp, audit...) This code is needlessly duplicated and different in all architectures. Provide a generic version based on the x86 implementation which has all the RCU and instrumentation bits right. As interrupt/exception entry from user space needs parts of the same functionality, provide a function for this as well. syscall_enter_from_user_mode() and irqentry_enter_from_user_mode() must be called right after the low level ASM entry. The calling code must be non-instrumentable. After the functions returns state is correct and the subsequent functions can be instrumented. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Kees Cook <keescook@chromium.org> Link: https://lkml.kernel.org/r/20200722220519.513463269@linutronix.de
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