linux/init, branch v4.16-rc2

membarrier: Provide core serializing command, *_SYNC_CORE

2018-02-05T20:35:03Z

Provide core serializing membarrier command to support memory reclaim by JIT. Each architecture needs to explicitly opt into that support by documenting in their architecture code how they provide the core serializing instructions required when returning from the membarrier IPI, and after the scheduler has updated the curr->mm pointer (before going back to user-space). They should then select ARCH_HAS_MEMBARRIER_SYNC_CORE to enable support for that command on their architecture. Architectures selecting this feature need to either document that they issue core serializing instructions when returning to user-space, or implement their architecture-specific sync_core_before_usermode(). Signed-off-by: Mathieu Desnoyers Acked-by: Thomas Gleixner Acked-by: Peter Zijlstra (Intel) Cc: Andrea Parri Cc: Andrew Hunter Cc: Andy Lutomirski Cc: Avi Kivity Cc: Benjamin Herrenschmidt Cc: Boqun Feng Cc: Dave Watson Cc: David Sehr Cc: Greg Hackmann Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Maged Michael Cc: Michael Ellerman Cc: Paul E. McKenney Cc: Paul Mackerras Cc: Russell King Cc: Will Deacon Cc: linux-api@vger.kernel.org Cc: linux-arch@vger.kernel.org Link: http://lkml.kernel.org/r/20180129202020.8515-9-mathieu.desnoyers@efficios.com Signed-off-by: Ingo Molnar

locking: Introduce sync_core_before_usermode()

2018-02-05T20:34:50Z

Introduce an architecture function that ensures the current CPU issues a core serializing instruction before returning to usermode. This is needed for the membarrier "sync_core" command. Architectures defining the sync_core_before_usermode() static inline need to select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE. Signed-off-by: Mathieu Desnoyers Acked-by: Thomas Gleixner Acked-by: Peter Zijlstra (Intel) Cc: Andrea Parri Cc: Andrew Hunter Cc: Andy Lutomirski Cc: Arnd Bergmann Cc: Avi Kivity Cc: Benjamin Herrenschmidt Cc: Boqun Feng Cc: Dave Watson Cc: David Sehr Cc: Greg Hackmann Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Maged Michael Cc: Michael Ellerman Cc: Paul E. McKenney Cc: Paul Mackerras Cc: Russell King Cc: Will Deacon Cc: linux-api@vger.kernel.org Cc: linux-arch@vger.kernel.org Link: http://lkml.kernel.org/r/20180129202020.8515-7-mathieu.desnoyers@efficios.com Signed-off-by: Ingo Molnar

powerpc, membarrier: Skip memory barrier in switch_mm()

2018-02-05T20:34:02Z

Allow PowerPC to skip the full memory barrier in switch_mm(), and only issue the barrier when scheduling into a task belonging to a process that has registered to use expedited private. Threads targeting the same VM but which belong to different thread groups is a tricky case. It has a few consequences: It turns out that we cannot rely on get_nr_threads(p) to count the number of threads using a VM. We can use (atomic_read(&mm->mm_users) == 1 && get_nr_threads(p) == 1) instead to skip the synchronize_sched() for cases where the VM only has a single user, and that user only has a single thread. It also turns out that we cannot use for_each_thread() to set thread flags in all threads using a VM, as it only iterates on the thread group. Therefore, test the membarrier state variable directly rather than relying on thread flags. This means membarrier_register_private_expedited() needs to set the MEMBARRIER_STATE_PRIVATE_EXPEDITED flag, issue synchronize_sched(), and only then set MEMBARRIER_STATE_PRIVATE_EXPEDITED_READY which allows private expedited membarrier commands to succeed. membarrier_arch_switch_mm() now tests for the MEMBARRIER_STATE_PRIVATE_EXPEDITED flag. Signed-off-by: Mathieu Desnoyers Acked-by: Thomas Gleixner Acked-by: Peter Zijlstra (Intel) Cc: Alan Stern Cc: Alexander Viro Cc: Andrea Parri Cc: Andrew Hunter Cc: Andy Lutomirski Cc: Avi Kivity Cc: Benjamin Herrenschmidt Cc: Boqun Feng Cc: Dave Watson Cc: David Sehr Cc: Greg Hackmann Cc: Linus Torvalds Cc: Maged Michael Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Paul E. McKenney Cc: Paul Mackerras Cc: Russell King Cc: Will Deacon Cc: linux-api@vger.kernel.org Cc: linux-arch@vger.kernel.org Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/20180129202020.8515-3-mathieu.desnoyers@efficios.com Signed-off-by: Ingo Molnar

Merge tag 'init_task-20180117' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

2018-01-29T17:08:34Z

Pull init_task initializer cleanups from David Howells: "It doesn't seem useful to have the init_task in a header file rather than in a normal source file. We could consolidate init_task handling instead and expand out various macros. Here's a series of patches that consolidate init_task handling: (1) Make THREAD_SIZE available to vmlinux.lds for cris, hexagon and openrisc. (2) Alter the INIT_TASK_DATA linker script macro to set init_thread_union and init_stack rather than defining these in C. Insert init_task and init_thread_into into the init_stack area in the linker script as appropriate to the configuration, with different section markers so that they end up correctly ordered. We can then get merge ia64's init_task.c into the main one. We then have a bunch of single-use INIT_*() macros that seem only to be macros because they used to be used per-arch. We can then expand these in place of the user and get rid of a few lines and a lot of backslashes. (3) Expand INIT_TASK() in place. (4) Expand in place various small INIT_*() macros that are defined conditionally. Expand them and surround them by #if[n]def/#endif in the .c file as it takes fewer lines. (5) Expand INIT_SIGNALS() and INIT_SIGHAND() in place. (6) Expand INIT_STRUCT_PID in place. These macros can then be discarded" * tag 'init_task-20180117' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs: Expand INIT_STRUCT_PID and remove Expand the INIT_SIGNALS and INIT_SIGHAND macros and remove Expand various INIT_* macros and remove Expand INIT_TASK() in init/init_task.c and remove Construct init thread stack in the linker script rather than by union openrisc: Make THREAD_SIZE available to vmlinux.lds hexagon: Make THREAD_SIZE available to vmlinux.lds cris: Make THREAD_SIZE available to vmlinux.lds

Expand the INIT_SIGNALS and INIT_SIGHAND macros and remove

2018-01-17T11:30:16Z

There doesn't seem to be any need to have the INIT_SIGNALS and INIT_SIGHAND macros, so expand them in their single places of use and remove them. Signed-off-by: David Howells Tested-by: Tony Luck Tested-by: Will Deacon (arm64) Tested-by: Palmer Dabbelt Acked-by: Thomas Gleixner

Expand various INIT_* macros and remove

2018-01-17T11:30:16Z

Expand various INIT_* macros into the single places they're used in init/init_task.c and remove them. Signed-off-by: David Howells Tested-by: Tony Luck Tested-by: Will Deacon (arm64) Tested-by: Palmer Dabbelt Acked-by: Thomas Gleixner

Expand INIT_TASK() in init/init_task.c and remove

2018-01-17T11:30:16Z

It's no longer necessary to have an INIT_TASK() macro, and this can be expanded into the one place it is now used and removed. Signed-off-by: David Howells Tested-by: Tony Luck Tested-by: Will Deacon (arm64) Tested-by: Palmer Dabbelt Acked-by: Thomas Gleixner

Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2018-01-12T18:23:59Z

Pull scheduler fixes from Ingo Molnar: "A Kconfig fix, a build fix and a membarrier bug fix" * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: membarrier: Disable preemption when calling smp_call_function_many() sched/isolation: Make CONFIG_CPU_ISOLATION=y depend on SMP or COMPILE_TEST ia64, sched/cputime: Fix build error if CONFIG_VIRT_CPU_ACCOUNTING_NATIVE=y

Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf

2018-01-10T16:17:21Z

Daniel Borkmann says: ==================== pull-request: bpf 2018-01-09 The following pull-request contains BPF updates for your *net* tree. The main changes are: 1) Prevent out-of-bounds speculation in BPF maps by masking the index after bounds checks in order to fix spectre v1, and add an option BPF_JIT_ALWAYS_ON into Kconfig that allows for removing the BPF interpreter from the kernel in favor of JIT-only mode to make spectre v2 harder, from Alexei. 2) Remove false sharing of map refcount with max_entries which was used in spectre v1, from Daniel. 3) Add a missing NULL psock check in sockmap in order to fix a race, from John. 4) Fix test_align BPF selftest case since a recent change in verifier rejects the bit-wise arithmetic on pointers earlier but test_align update was missing, from Alexei. ==================== Signed-off-by: David S. Miller

Construct init thread stack in the linker script rather than by union

2018-01-09T23:21:02Z

Construct the init thread stack in the linker script rather than doing it by means of a union so that ia64's init_task.c can be got rid of. The following symbols are then made available from INIT_TASK_DATA() linker script macro: init_thread_union init_stack INIT_TASK_DATA() also expands the region to THREAD_SIZE to accommodate the size of the init stack. init_thread_union is given its own section so that it can be placed into the stack space in the right order. I'm assuming that the ia64 ordering is correct and that the task_struct is first and the thread_info second. Signed-off-by: David Howells Tested-by: Tony Luck Tested-by: Will Deacon (arm64) Tested-by: Palmer Dabbelt Acked-by: Thomas Gleixner