src/lttng-context-interruptible.c

   1 /* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
   2  *
   3  * lttng-context-interruptible.c
   4  *
   5  * LTTng interruptible context.
   6  *
   7  * Copyright (C) 2009-2015 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   8  */
   9
  10 #include <linux/module.h>
  11 #include <linux/slab.h>
  12 #include <linux/sched.h>
  13 #include <linux/irqflags.h>
  14 #include <lttng/events.h>
  15 #include <lttng/events-internal.h>
  16 #include <ringbuffer/frontend_types.h>
  17 #include <wrapper/vmalloc.h>
  18 #include <lttng/tracer.h>
  19
  20 /*
  21  * Interruptible at value -1 means "unknown".
  22  */
  23
  24 static
  25 size_t interruptible_get_size(void *priv, struct lttng_kernel_probe_ctx *probe_ctx, size_t offset)
  26 {
  27         size_t size = 0;
  28
  29         size += lib_ring_buffer_align(offset, lttng_alignof(int8_t));
  30         size += sizeof(int8_t);
  31         return size;
  32 }
  33
  34 static
  35 void interruptible_record(void *priv, struct lttng_kernel_probe_ctx *probe_ctx,
  36                 struct lttng_kernel_ring_buffer_ctx *ctx,
  37                 struct lttng_channel *chan)
  38 {
  39         struct lttng_kernel_probe_ctx *lttng_probe_ctx = ctx->probe_ctx;
  40         int8_t interruptible = lttng_probe_ctx->interruptible;
  41
  42         lib_ring_buffer_align_ctx(ctx, lttng_alignof(interruptible));
  43         chan->ops->event_write(ctx, &interruptible, sizeof(interruptible));
  44 }
  45
  46 static
  47 void interruptible_get_value(void *priv,
  48                 struct lttng_kernel_probe_ctx *lttng_probe_ctx,
  49                 struct lttng_ctx_value *value)
  50 {
  51         int8_t interruptible = lttng_probe_ctx->interruptible;
  52
  53         value->u.s64 = interruptible;
  54 }
  55
  56 static const struct lttng_kernel_ctx_field *ctx_field = lttng_kernel_static_ctx_field(
  57         lttng_kernel_static_event_field("interruptible",
  58                 lttng_kernel_static_type_integer_from_type(int8_t, __BYTE_ORDER, 10),
  59                 false, false, false),
  60         interruptible_get_size,
  61         interruptible_record,
  62         interruptible_get_value,
  63         NULL, NULL);
  64
  65 int lttng_add_interruptible_to_ctx(struct lttng_kernel_ctx **ctx)
  66 {
  67         int ret;
  68
  69         if (lttng_kernel_find_context(*ctx, ctx_field->event_field->name))
  70                 return -EEXIST;
  71         ret = lttng_kernel_context_append(ctx, ctx_field);
  72         wrapper_vmalloc_sync_mappings();
  73         return ret;
  74 }
  75 EXPORT_SYMBOL_GPL(lttng_add_interruptible_to_ctx);