Refactoring: combine _lttng_event_unregister common code

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I89111affad4b35b68939c51f2ebd3aec6f4a881b

Refactoring: combine register_event common code

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Icb8d0ba19c7070c86f25b9d54ec6034ffe74ba77

Refactoring: combine lttng_create_syscall_event_if_missing common code

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I392c8dd39a956e2b46ce4dac76112249bccabf7b

Refactoring: syscalls: move lttng_syscalls_create_matching_event_notifiers into registration

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I3c8e7c0f2ebf832e433b0c10b5073e7e469d8329

Refactoring: Rename lttng_channel_syscall_mask to lttng_syscall_table_get_active_mask

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I4740cef4ec6465ba9cbd4d61b097263e01acf4b8

Refactoring: kretprobes: use event common argument types

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I9c272f240b01cf070e45d7663c331e1cbce921b8

Refactoring: kprobes: combine common code between recorder and notifier

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Iea2cf795c5409b0f5dadbadccb9cb2b4cd37acfc

Refactoring: uprobes: combine common code between recorder and notifier

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Ibbd7ddb064ca114e0c9dcf1b88c695167ee087aa

Refactoring: syscalls: combine syscalls register event for notifier/recorder

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I907ac0397d0fdf421702d50ee382eb5e79827921

Refactoring: syscall: combine syscall filter enable/disable recorder/notifier

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: If0e10ade6586073255817f5a8a96f73b5aa92f99

Refactoring: rename lttng_syscalls_register_event to lttng_syscalls_register_event_recorder

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Icc5a6fcfdf951dd9b4661a4485c90ea7e84ad39a

Cleanup: tracepoint probe register/unregister: use parent field

Use the parent field to match the type expected in the probe callback.

This works so far only because parent is the first field of the children
structures.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I05fb3cdc75c1c04abb352cdebdaa90f780d0c789

Refactoring/fix: syscall table unregister/destroy

Combine syscall table unregister/destroy for both channel buffers and
notifier groups.

This fixes an issue within notifier groups where the syscall dispatch
tables are freed before waiting for an RCU grace period.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Ia69f6be86da651022c5d5f4f6bce6e321156c070

Refactoring: rename lttng_channel_create to lttng_channel_buffer_create

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I2d1ca065c5eb03adab3a982d1159c2e472bbc177

Refactoring: channel enable/disable using common type

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Ie86e23937d00a5d53aa3dbadb7666c176f3c0d52

Cleanup: rename event register/unregister for event recorder

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Ifb45adfed7b5c3acef3d5003b123c12b5f2d7a64

Cleanup: rename lttng_syscalls_destroy_event to lttng_syscalls_destroy_channel

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Iabff0107d1280e2d88aa607b3220fa811f80c09c

Cleanup: syscall filter enable/disable event

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I36f683e209a51ef0ca9e3a490f52f2c270f9b297

Cleanup: notifier syscalls: Remove useless zero-init of zeroed memory

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I30f1c97f3d8ca9f6d800c0407f8ef96d3199cf06

Refactoring: combine event enabler destroy for notifier and recorder

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I39ed3d9046604e5ab16f3e565ba72460348f54f5

Refactoring: combine event notifier notifier and recorder enable/disable

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Ia6cffc5bb36b91c5a5c289c1d1b13accb55dcce3

Refactoring: combine filter bytecode attach functions

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Idd9f50a2e2fc38b16732ada4a33dba4ba14258d8

Refactoring: rename lttng_event_enabler to lttng_event_recorder_enabler

To clarify that event recorder is distinct from event notifier, rename
"event enabler" to "event recorder enabler".

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I968d2f7a4efc43dfa7f4a8bb62cc4f963af83b30

Refactoring: syscall tracing: combine common fields into struct lttng_kernel_syscall_table

There was a lot of code duplication between syscall tables associated
with ring buffers and those associated with event notifiers.

Move common fields into a struct lttng_kernel_syscall_table, and add a
syscall_table field in both struct lttng_event_notifier_group and
struct lttng_kernel_channel_common_private.

This allows removing both syscall_entry_event_notifier_probe and
syscall_exit_event_notifier_probe by using the syscall_entry_event_probe
and syscall_exit_event_probe instead for event notifiers as well.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Ifb78755429ebf8699ac4bd3bb66af16bda1d86c4

Rename event/notifier enabler base field to parent

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I06d707d26c4e582fd1b48de9df5d0e32ab950b22

Rename struct lttng_enabler to struct lttng_event_enabler_common

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I7377b74b3ea59af391c77e22ad2d0c977aa09d6c

Use event enabler for event recorder creation for all instrumentation types

Remove special-cases for uprobes, kprobes, kretprobes and use a
temporary event enabler to hold relevant information for event recorder
creation.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Ib353a67d1554c345ba71d31c5632ded3b33b2a92

fix: implicit-int error in EXPORT_SYMBOL_GPL

Add module header to fix error:
error: type defaults to 'int' in declaration of 'EXPORT_SYMBOL_GPL'
[-Werror=implicit-int]

Log:
/workdir/build/workspace/sources/lttng-modules/src/wrapper/random.c:54:1:
warning: data definition has no type or storage class
   54 EXPORT_SYMBOL_GPL(wrapper_get_bootid);
      ^~~~~~~~~~~~~~~~~
/workdir/build/workspace/sources/lttng-modules/src/wrapper/random.c:54:1:
error: type defaults to 'int' in declaration of 'EXPORT_SYMBOL_GPL'
[-Werror=implicit-int]
/workdir/build/workspace/sources/lttng-modules/src/wrapper/random.c:54:1:
warning: parameter names (without types) in function declaration
cc1: some warnings being treated as errors
make[3]: ***
[/workdir/build/tmp/work-shared/qt5222/kernel-source/scripts/Makefile.build:271:
/workdir/build/workspace/sources/lttng-modules/src/wrapper/random.o]

Signed-off-by: Daniel Gomez <daniel@qtec.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: If1b96f6fcc19988b94dc09b12d071f2c61491b83

fix: Revert "Makefile: Enable -Wimplicit-fallthrough for Clang" (v5.15)

Starting with v5.15, "-Wimplicit-fallthrough=5" was added to the build
flags which requires the use of "__attribute__((__fallthrough__))" to
annotate fallthrough case statements.

See upstream commit by the man himself:

  commit d936eb23874433caa3e3d841cfa16f5434b85dcf
  Author: Linus Torvalds <torvalds@linux-foundation.org>
  Date:   Thu Jul 15 18:05:31 2021 -0700

    Revert "Makefile: Enable -Wimplicit-fallthrough for Clang"

    This reverts commit b7eb335e26a9c7f258c96b3962c283c379d3ede0.

    It turns out that the problem with the clang -Wimplicit-fallthrough
    warning is not about the kernel source code, but about clang itself, and
    that the warning is unusable until clang fixes its broken ways.

    In particular, when you enable this warning for clang, you not only get
    warnings about implicit fallthroughs.  You also get this:

       warning: fallthrough annotation in unreachable code [-Wimplicit-fallthrough]

    which is completely broken becasue it

     (a) doesn't even tell you where the problem is (seriously: no line
         numbers, no filename, no nothing).

     (b) is fundamentally broken anyway, because there are perfectly valid
         reasons to have a fallthrough statement even if it turns out that
         it can perhaps not be reached.

    In the kernel, an example of that second case is code in the scheduler:

                    switch (state) {
                    case cpuset:
                            if (IS_ENABLED(CONFIG_CPUSETS)) {
                                    cpuset_cpus_allowed_fallback(p);
                                    state = possible;
                                    break;
                            }
                            fallthrough;
                    case possible:

    where if CONFIG_CPUSETS is enabled you actually never hit the
    fallthrough case at all.  But that in no way makes the fallthrough
    wrong.

    So the warning is completely broken, and enabling it for clang is a very
    bad idea.

    In the meantime, we can keep the gcc option enabled, and make the gcc
    build use

        -Wimplicit-fallthrough=5

    which means that we will at least continue to require a proper
    fallthrough statement, and that gcc won't silently accept the magic
    comment versions. Because gcc does this all correctly, and while the odd
    "=5" part is kind of obscure, it's documented in [1]:

      "-Wimplicit-fallthrough=5 doesn’t recognize any comments as
       fallthrough comments, only attributes disable the warning"

    so if clang ever fixes its bad behavior we can try enabling it there again.

Change-Id: Iea69849592fb69ac04fb9bb28efcd6b8dce8ba88
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

fix: cpu/hotplug: Remove deprecated CPU-hotplug functions. (v5.15)

The CPU-hotplug functions get|put_online_cpus() were deprecated in v4.13
and removed in v5.15.

See upstream commits :

commit 8c854303ce0e38e5bbedd725ff39da7e235865d8
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date:   Tue Aug 3 16:16:21 2021 +0200

    cpu/hotplug: Remove deprecated CPU-hotplug functions.

    No users in tree use the deprecated CPU-hotplug functions anymore.

    Remove them.

Introduced in v4.13 :

  commit 8f553c498e1772cccb39a114da4a498d22992758
  Author: Thomas Gleixner <tglx@linutronix.de>
  Date:   Wed May 24 10:15:12 2017 +0200

    cpu/hotplug: Provide cpus_read|write_[un]lock()

    The counting 'rwsem' hackery of get|put_online_cpus() is going to be
    replaced by percpu rwsem.

    Rename the functions to make it clear that it's locking and not some
    refcount style interface. These new functions will be used for the
    preparatory patches which make the code ready for the percpu rwsem
    conversion.

    Rename all instances in the cpu hotplug code while at it.

Change-Id: I5a37cf5afc075a402b7347989fac637dfa60a1ed
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

fix: sched: Change task_struct::state (v5.14)

See upstream commit:

  commit 2f064a59a11ff9bc22e52e9678bc601404c7cb34
  Author: Peter Zijlstra <peterz@infradead.org>
  Date:   Fri Jun 11 10:28:17 2021 +0200

    sched: Change task_struct::state

    Change the type and name of task_struct::state. Drop the volatile and
    shrink it to an 'unsigned int'. Rename it in order to find all uses
    such that we can use READ_ONCE/WRITE_ONCE as appropriate.

Change-Id: I3a379192d6b977753fe58d4f67833a78dd7a0a47
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

fix: btrfs: pass btrfs_inode to btrfs_writepage_endio_finish_ordered() (v5.14)

See upstream commit:

  commit 38a39ac77e089515acbe85c6c70c3df1e728357d
  Author: Qu Wenruo <wqu@suse.com>
  Date:   Thu Apr 8 20:32:27 2021 +0800

    btrfs: pass btrfs_inode to btrfs_writepage_endio_finish_ordered()

    There is a pretty bad abuse of btrfs_writepage_endio_finish_ordered() in
    end_compressed_bio_write().

    It passes compressed pages to btrfs_writepage_endio_finish_ordered(),
    which is only supposed to accept inode pages.

    Thankfully the important info here is the inode, so let's pass
    btrfs_inode directly into btrfs_writepage_endio_finish_ordered(), and
    make @page parameter optional.

    By this, end_compressed_bio_write() can happily pass page=NULL while
    still getting everything done properly.

    Also, to cooperate with such modification, replace @page parameter for
    trace_btrfs_writepage_end_io_hook() with btrfs_inode.
    Although this removes page_index info, the existing start/len should be
    enough for most usage.

Change-Id: If96e99c2d9533d96d9d1aa6460bb7fd3ac9ed7ab
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

fix: adjust ranges for RHEL 8.4

Change-Id: I9ac44467cca4850fb4051252937542d5a054ccc4
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

fix: adjust ranges for RHEL 8.2 and 8.3

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I0863ac030f9fdfeb0173b843e75396acda21f3b6

Disable x86 error code bitwise enum in default build

Only generate the bitwise enumerations when
CONFIG_LTTNG_EXPERIMENTAL_BITWISE_ENUM is enabled, so the default build
does not generate traces which lead to warnings when viewed with
babeltrace 1.x and babeltrace 2 with default options.

commit 8c7f2a9f2732b11f5cc9798cecb621420cc0e972
Author: Francis Deslauriers <francis.deslauriers@efficios.com>
Date:   Fri Jun 5 18:42:54 2020 -0400

    x86: add error code enum to pagefault tracepoints

Change-Id: I7901fad216b4774a9bbf3665568f357321805871
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Disable mmap bitwise enum in default build

Only generate the bitwise enumerations when
CONFIG_LTTNG_EXPERIMENTAL_BITWISE_ENUM is enabled, so the default build
does not generate traces which lead to warnings when viewed with
babeltrace 1.x and babeltrace 2 with default options.

Original commit:

  commit 3cf55950d0f6aa43eb5ad119bad1dbda69f75a54
  Author: Francis Deslauriers <francis.deslauriers@efficios.com>
  Date:   Fri Jun 5 11:38:14 2020 -0400

    syscalls: Make mmap()'s fields `prot` and `flags` enums

Change-Id: I033f42855c2967356b1e90cd89450eb5100a0f0b
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Disable block rwbs bitwise enum in default build

Only generate the bitwise enumerations when
CONFIG_LTTNG_EXPERIMENTAL_BITWISE_ENUM is enabled, so the default build
does not generate traces which lead to warnings when viewed with
babeltrace 1.x and babeltrace 2 with default options.

Original commit:

  commit 23634515e7271c8c8594ad87a6685232d4eff297
  Author: Geneviève Bastien <gbastien@versatic.net>
  Date:   Tue Feb 11 11:20:27 2020 -0500

    block: Make the rwbs field as a bit field enum

Change-Id: I6c285d1cbfbd88e151d4b0abb52ad9a650764ea2
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Disable sched_switch bitwise enum in default build

Only generate the bitwise enumerations when
CONFIG_LTTNG_EXPERIMENTAL_BITWISE_ENUM is enabled, so the default build
does not generate traces which lead to warnings when viewed with
babeltrace 1.x and babeltrace 2 with default options.

Original commit:

  commit 721caea47b6506f7ad9086c3e9801dc9dfe06b6a
  Author: Geneviève Bastien <gbastien@versatic.net>
  Date:   Wed Feb 12 16:58:25 2020 -0500

    sched: Make the sched_switch task state an enum

Change-Id: Ib19d06365fbed7daa9440d5dfff283c4f89db6ee
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Disable open[at] bitwise enum in default build

Only generate the bitwise enumerations when
CONFIG_LTTNG_EXPERIMENTAL_BITWISE_ENUM is enabled, so the default build
does not generate traces which lead to warnings when viewed with
babeltrace 1.x and babeltrace 2 with default options.

Original commit:

  commit c8dfb72431505d5f01a6f090f3f7427d9ca6fe94
  Author: Geneviève Bastien <gbastien@versatic.net>
  Date:   Wed Mar 11 12:33:04 2020 -0400

    syscalls: Make the flags and mode fields of open[at] enumerations

Use the non-override system call tracing implementation when the enum is
not used.

Change-Id: I2dbebe56eaba6186843dab20264d3378962c7d30
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Disable fcntl bitwise enum in default build

Only generate the bitwise enumerations when
CONFIG_LTTNG_EXPERIMENTAL_BITWISE_ENUM is enabled, so the default build
does not generate traces which lead to warnings when viewed with
babeltrace 1.x and babeltrace 2 with default options.

Original commit:

  commit c1c07d681a68ba37da066d6f0456129957073169
  Author: Geneviève Bastien <gbastien+lttng@versatic.net>
  Date:   Wed Mar 11 12:38:51 2020 -0400

    syscalls: Make the cmd field of fcntl an enum

Use the non-override system call tracing implementation when the enum is
not used.

Change-Id: I4c650d40a14b1c56ada0ed9aae1877364d0c4580
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Disable clone bitwise enum in default build

Only generate the bitwise enumerations when
CONFIG_LTTNG_EXPERIMENTAL_BITWISE_ENUM is enabled, so the default build
does not generate traces which lead to warnings when viewed with
babeltrace 1.x and babeltrace 2 with default options.

Original commit:

  commit d775625e2ba4825b73b5897e7701ad6e2bdba115
  Author: Geneviève Bastien <gbastien@versatic.net>
  Date:   Wed Apr 1 14:31:49 2020 -0400

    syscalls: Make clone()'s `flags` field a 2 enum struct.

Change-Id: Ia67b5fc93b932b8b76330b4965753a43401c1514
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add experimental bitwise enum config option

Only generate the bitwise enumerations when
CONFIG_LTTNG_EXPERIMENTAL_BITWISE_ENUM is enabled, so the default build
does not generate traces which lead to warnings when viewed with
babeltrace 1.x and babeltrace 2 with default options.

Change-Id: Id45c7a78b280a7f35bbeafb80f2f6f5aa1ebbdc9
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add defaults to Kconfig options

Add defaults to the Kconfig options used when building in-tree that
match the default configuration when built out-of-tree.

Change-Id: I436251f1fb4c3e238a013d18d67932565b92ef45
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Cleanup: remove unused EXTCFLAGS from Makefile

Change-Id: I36c4f6f403b03a1aa158863f393049efdc70af04
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Sync `show_inode_state()` macro with upstream stable kernels

The following commit was backported to multiple stable branches:

  commit 5fcd57505c002efc5823a7355e21f48dd02d5a51
  Author: Jan Kara <jack@suse.cz>
  Date:   Fri May 29 16:24:43 2020 +0200

    writeback: Drop I_DIRTY_TIME_EXPIRE

    The only use of I_DIRTY_TIME_EXPIRE is to detect in
    __writeback_single_inode() that inode got there because flush worker
    decided it's time to writeback the dirty inode time stamps (either
    because we are syncing or because of age). However we can detect this
    directly in __writeback_single_inode() and there's no need for the
    strange propagation with I_DIRTY_TIME_EXPIRE flag.

Change-Id: I6e7c0ced13acd4fcd88bcd572d0ba1f9b254c58c
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Sync `show_inode_state()` macro with Ubuntu 4.15 kernel

The following commit changed the `show_inode_state()` macro which
triggered a warning on our CI build:
  commit 63388062bea96e5cd8b8d7abf7b7142f8666ca1f
  Author: Jan Kara <jack@suse.cz>
  Date:   Mon Jan 25 12:37:43 2021 -0800

      writeback: Drop I_DIRTY_TIME_EXPIRE

Also, this commit adds a comment to clarify why we keep these
`#if/#elif` even though we don't use it the macro.

Signed-off-by: Francis Deslauriers <francis.deslauriers@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I2dd53a1a286ab8a431977bda6cde01f700f0c7d9

fix: block: remove disk_part_iter (v5.12)

In v5.12 a refactoring of the genhd code was started and the symbols
related to 'disk_part_iter' were unexported. In v5.13 they were
completely removed.

This patch replaces the short lived compat code that is specific to
v5.12 and replaces it with a generic internal implementation that
iterates directly on the 'disk->part_tbl' xarray which will be used
on v5.12 and up.

This seems like a better option than keeping the compat code that will
only work on v5.12 and make maintenance more complicated. The compat was
backported to the stable branches but isn't yet part of a point release
so can be safely replaced.

See the upstream commits:

  commit 3212135a718b06be38811f2d9a320ae842e76409
  Author: Christoph Hellwig <hch@lst.de>
  Date:   Tue Apr 6 08:23:02 2021 +0200

    block: remove disk_part_iter

    Just open code the xa_for_each in the remaining user.

  commit a33df75c6328bf40078b35f2040d8e54d574c357
  Author: Christoph Hellwig <hch@lst.de>
  Date:   Sun Jan 24 11:02:41 2021 +0100

    block: use an xarray for disk->part_tbl

    Now that no fast path lookups in the partition table are left, there is
    no point in micro-optimizing the data structure for it.  Just use a bog
    standard xarray.

Change-Id: If3497e087fadaa285e135f57aab7e6df157b06c6
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Cleanup: lib ring buffer: rename pagecpy local variable

Rename pagecpy local variable to bytes_left_in_page, which has a clearer
semantic. Also remove the unused pagecpy parameter from slow paths which
was always 0.

Also add a missing __user annotation on @src of
the _lib_ring_buffer_copy_from_user_inatomic prototype.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I22a85cb8e94a65aaa80ca49951479243477ac600

Cleanup: clarify strcpy/strcpy_from_user local variables

The variable name "bytes_left_in_page" is clearer than "pagecpy". Also
the only caller of slow paths always has a 0 pagecpy parameter, so
remove that parameter. Also use a "bool" for src_terminated (no
functional change).

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I38520b8cab54c31dbbb7b9296200b432afb3cee9

Implement ring buffer Pascal string copy

Introduce a new lib_ring_buffer_pstrcpy() to handle copying into a ring
buffer Pascal String, use them for array and sequence of text.

Cover strings copied from both kernel and user-space.

This ensures that when copying from a string input to a ring buffer
utf8/ascii-encoded array or sequence, the source is not read beyond its
null terminating character.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I74996c8c8db6eec39b189693739aa2f980e29816

Move alignment into event write callback

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I7563cdd07163fc22e2269627879a83e871c4eb01

Cleanup: disable page fault after access_ok

The page faults don't need to be disabled for access_ok. Simplify the
fill buffer error paths.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I2e31d308d45efdfede04e2159c37c066749871ae

Fix: increment buffer offset when failing to copy from user-space

Upon failure to copy from user-space due to failing access ok check, the
ring buffer offset is not incremented, which could generate unreadable
traces because we don't account for the padding we write into the ring
buffer.

Note that this typically won't affect a common use-case of copying
strings from user-space, because unless mprotect is invoked within a
narrow race window (between user strlen and user strcpy), the strlen
will fail on access ok when calculating the space to reserve, which will
match what happens on strcpy.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Ic4d9487dd8870a526bae3023bb80f5e6301cec50

Fix: incorrect in/out direction for syscall exit

Syscall exit should fetch the "sc_out" parameters. This issue was
introduced by commit e42c4f49c15b ("Split syscall tracepoint generation in their own files").

Fixes: e42c4f49c15b ("Split syscall tracepoint generation in their own files")
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Ib34912005323ea34b6d11ca9acc5edf491649cdd

Fix: add missing #include for 3.8 kernel

Add the `linux/compat.h` include to fix the following error while
building the modules against a 3.8 kernel for x86-64 kernel:
  error: ‘F_GETLK64’ undeclared here (not in a function)
     ctf_enum_value("F_GETLK64", F_GETLK64)

Also, move the #include directives from the instrumentation headers to
the `lttng-syscalls.h` file.

Signed-off-by: Francis Deslauriers <francis.deslauriers@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I334a14d0b40ec77e0ca0aa3b762197de2050a1ae

Fix: builtin script referring to old directories

Signed-off-by: Francis Deslauriers <francis.deslauriers@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I30fb8abb1a69d6695552947e30cf2b43d3db36b3

events.h API const-ness

Ensure events.h definitions, fields, and arguments referring to const
arrays of pointers are const.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Id1f9a736de72220f7576d9780b82ab7879eac300

Rename struct lib_ring_buffer* to struct lttng_kernel_ring_buffer*

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I61b5a78c6485422ae4a2e2e45e32465db82b3d97

Rename struct channel to struct lttng_kernel_ring_buffer_channel

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Ifb737dfa71c9fdd08b62680f7782328b50a70d61

Refactoring: struct lttng_channel

Split lttng_channel into public/private structures, and introduce
inheritance for common fields which will be shared between the channel
buffer and upcoming channel counter.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I932231c4af9ed1066d010b5be4f75f34842e8484

Fix: missing #include for 3.8 kernel

Change-Id: If13a6615c2bed93d887047b6feaf377107d98cf9
Signed-off-by: Francis Deslauriers <francis.deslauriers@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Introduce struct lttng_kernel_tracepoint_class, enum probe_desc field

Introduce struct lttng_kernel_tracepoint_class to clearly split the
event instance from the class, thus allowing the event instance to refer
to the class through a single symbol. This removes the need to rely on
ARRAY_SIZE() to calculate the size of the event field array (part of the
class) from within the event instance. This refactoring opens the door
to have event class and instance not only in different providers, but
also in providers emitted within different compile units and shared
objects in the future.

While refactoring kprobes, uprobes and kretprobes code, there is a lot
of dynamically allocated memory which can be turned into static data
structures for tp_class, fields and types. This simplification ends up
fixing a few memory leaks as well.

Introduce a probe_desc field in the enumeration descriptor to keep the
same pattern for both tp_class and enumerations.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I221ad33383de48144d0d14b2b461ecb38dfb54ab

Set probe descriptor field in event descriptor

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I8afd12cae160fbd7637fb2f9528309f5245f77cf

Split syscall tracepoint generation in their own files

This commit tracepoint generation of the 4 different types of syscalls
(entry, exit, entry_compat, and exit_compat) each in their own .c file.

The compilation time of the lttng-modules projects is currently
dominated by the compilation of the src/lttng-syscalls.o object.
This is caused by the extensive use of macros to generate tracepoint for
all syscalls. This also uses a lot of memory making the compilation of
the project tedious on system with low memory.

This allows for parallelization of the compilation which offers 2
improvements: Reduction of compilation time and reduction of the memory
usage.

In term of compilation time, on my 4 cpus laptop, I measured a 15sec
(20%) speedup over 10 runs when using all 4 cpus (make -j4).

On a larger machine (16 cpus), I measured 30sec (60%) speedup when using
all 16 cpus.

In term of memory usage, I was able to compile the project on a virtual
machine with 500MB of memory without hitting memory exhaustion errors.

Signed-off-by: Francis Deslauriers <francis.deslauriers@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I025a4c36ef16b935be2a86f5b6649526752a7393

Include `linux/in{,6}.h` closer to where it's used

Signed-off-by: Francis Deslauriers <francis.deslauriers@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I5e2acc1cd081da131ae289506592e74de553133a

Group all syscall enums in one compile unit

Signed-off-by: Francis Deslauriers <francis.deslauriers@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Ic0189984d9bc70ae3f76af08bffd127500adad80

Include `linux/mman.h` for mmap flag enum

Signed-off-by: Francis Deslauriers <francis.deslauriers@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Id891f59aef1bb26b1ed8dff676bbad0f6d9fb69e

Add `struct trace_syscall_table`

Signed-off-by: Francis Deslauriers <francis.deslauriers@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I72181800793e84f001e83caeea8d7b7ae9e8d07c

Define `static_assert()` when not defined by kernel

This macro is useful for build-time assertions. It was added in kernel
v5.1. It uses the C11 _Static_assert macro that was implemented with gcc
4.6. There is support for the _Static_assert in all C modes, including
gnu89.

Since our minimal gcc version is 4.8, we can simply define it manually
if the kernel is older than v5.1.

Kernel commit adding this macro:
  commit 6bab69c65013bed5fce9f101a64a84d0385b3946
  Author: Rasmus Villemoes <linux@rasmusvillemoes.dk>
  Date:   Thu Mar 7 16:27:00 2019 -0800

      build_bug.h: add wrapper for _Static_assert

Signed-off-by: Francis Deslauriers <francis.deslauriers@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I5aa250f60f9dca4f13b8bcc093a006034c28e526

Move event hash tables to private header

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Id4c690c275bace3dee92b5c3c25e09ac4eb3b384

Move forward declarations to private header

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Ibd6fa4f9ec751be8cdb0082c729c3c5662c02d0b

Move lttng_syscall_filter forward declaration to private header

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Ife15ca8d175e33e4282a1dd9fd3dc7e759163c8f

Split ID tracker into public/private structures

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Ic17da38eb96d734110b59656d0fedce1bacd570a

Move id tracker hash node to private header

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I0b0cdb345a24f72a17a84a48a5f28acca72441bb

Split struct lttng_session into public/private structures

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I3c8e5c826268659d78f4c177e846cc93727af1c2

Move struct lttng_metadata_stream to private header

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Ieae3b2c4c2ffe50360a33db1056734d04668af82

Move event notifier and counter structures to private header

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I119a948c39edbe42e22a12d59e8908029d6acad0

Rename struct lib_ring_buffer_ctx to struct lttng_kernel_ring_buffer_ctx

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I81c3ef6dd226f2a27a32b303a096f60927462615

Refactoring: struct lttng_kernel_channel_buffer_ops

Introduce public/private structures for ring buffer channel operations.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I3614d550615a4617541a292fa761bebbdf6a275a

Rename lttng_probe_{,un}register to lttng_kernel_probe_{,un}register

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I62e1d4765d2dd8dcd4a40f3a12e40bbef93a2ead

Move metadata cache structure to internal header

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I99e77d8b6bc1b85dc324feecc81348aeab015030

Move internal APIs to internal header

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Ib8c8f64c00e26d49fa4ba2fdf5c85a7f8fdd2568

Move kprobes, uprobes, kretprobes, syscall structures to internal header

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Id2d352182084cd50998df0a23dcab16d3e7212fc

Move kprobe, kretprobe, uprobe APIs to internal header

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I92c5a245c3e5f12b6d43b73e104a86e55e341817

Remove unused TRACEPOINT_HAS_DATA_ARG

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Ib3af9240f9f995d7e9b6a76310ca8388e01f6c3d

Move enabler APIs to internal header

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Idd0eee625ab10b17a412a6d0d777d64f71801582

Move bytecode structures to internal header

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Ic7931b3fd6d8f4674f7e0a020a4501db4f3ae509

Remove include of internal header from tracepoint-event-impl.h

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I9b504b4d898a9b53c2d1262379fca3e63b7fef2b

Rename struct lttng_probe_ctx to struct lttng_kernel_probe_ctx

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I629b7e447b9842ab863894abd08e4901b439ee17

Rename struct lttng_bytecode_runtime to struct lttng_kernel_bytecode_runtime

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I14051998b44fde8aa94f72c227b89786d40ca4ff

Rename struct lttng_bytecode_node to struct lttng_kernel_bytecode_node

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Ic00142968c7132d3a2b8292d426948dfbe1b0d88

Move context structures and API to internal header

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I1a6cbb26efb8c9fd4b4ef1872dd39b764a1f473b

Move enabler structures to internal header

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I0769e0ea730f5fbf306bce4f5527c81c193cdbe9

Makefile: add .o wildcard target

Signed-off-by: Francis Deslauriers <francis.deslauriers@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Ia421852ef9f778d79d810a36c45daaba27727efb

Fix: Makefile: generation of specific .i file not working

Issue
=====
When trying to get the preprocessed version of the `lttng-syscalls.c` file
I get the following error:
  $ make src/lttng-syscalls.i
    make -C /lib/modules/5.4.0-67-generic/build M=/home/frdeso/projets/lttng/modules/src CONFIG_LTTNG=m CONFIG_LTTNG_CLOCK_PLUGIN_TEST=m src/lttng-syscalls.i
    make[1]: Entering directory '/usr/src/linux-headers-5.4.0-67-generic'
    make[3]: *** No rule to make target '/home/frdeso/projets/lttng/modules/src/src/lttng-syscalls.i'.  Stop.
    make[2]: *** [scripts/Makefile.build:480: __build] Error 2
    make[1]: *** [Makefile:1760: /home/frdeso/projets/lttng/modules/src] Error 2
    make[1]: Leaving directory '/usr/src/linux-headers-5.4.0-67-generic'
    make: *** [Makefile:32: src/lttng-syscalls.i] Error 2

We see that the gcc tries to create the `src/src/lttng-syscalls.i` file
instead of the expected `src/lttng-syscalls.i`.

Fix
===
Remove the `/src` from the `M=` option.

Signed-off-by: Francis Deslauriers <francis.deslauriers@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I4403d32955723239649eb385f877e52cea669720

Fix: refactor preemptible context

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Ia7dd34be0a55baf65bc2ce3981492c26a535c832

Refactoring: context callbacks

Refactor the context callbacks so they take a private pointer as
argument.

Note that the callstack context internally uses a per-cpu stack across
context size calculation and recording to the ring buffer, which
requires that preemption is disabled across those operations.

The get_size_arg and _get_size callbacks are merged into a single
callback.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I7c4146481d35cb9ddef19f2cb5d61e56ebe142be

Remove event id parameter from event_reserve callback

This can be fetched from the event recorder.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I85a4ef493d67c1c374e7f3076569c2c2c2109953

Refactoring: ring buffer context

Split the ring buffer context into:

- Public ring buffer context (initialized by probe),
- Private context (initialized by reserve callback),

Pass event recorder rather than channel as client_ctx for events
generated from instrumentation (calling ring buffer client).

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Iecd23f11c54da4ba58a97c46192f775a0a74bd85

sequence and variant types: use previous field for length/tag if NULL

A common use-case for sequences and variants is to use the field located
immediately prior to the type as length/tag.

The fact that those types need to explicitly contain their length/tag
name ties the sequence/variant type to where it is placed within the
structure fields, preventing re-use of the sequence/variant type.

In order to reduce the memory footprint of the field descriptions and
allow re-use of common field types, special-case the NULL length name
and tag name to use the field prior to the sequence/variant as length.

This allows more efficient type descriptions without reducing the
overall flexibility of sequence/variant layout.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I27053e8541beb4f8f8226e411c71595f7527f533