lttng-context-interruptible.c

   1 /* SPDX-License-Identifier: (GPL-2.0 or LGPL-2.1)
   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 <wrapper/ringbuffer/frontend_types.h>
  16 #include <wrapper/vmalloc.h>
  17 #include <lttng-tracer.h>
  18
  19 /*
  20  * Interruptible at value -1 means "unknown".
  21  */
  22
  23 static
  24 size_t interruptible_get_size(size_t offset)
  25 {
  26         size_t size = 0;
  27
  28         size += lib_ring_buffer_align(offset, lttng_alignof(int8_t));
  29         size += sizeof(int8_t);
  30         return size;
  31 }
  32
  33 static
  34 void interruptible_record(struct lttng_ctx_field *field,
  35                 struct lib_ring_buffer_ctx *ctx,
  36                 struct lttng_channel *chan)
  37 {
  38         struct lttng_probe_ctx *lttng_probe_ctx = ctx->priv;
  39         int8_t interruptible = lttng_probe_ctx->interruptible;
  40
  41         lib_ring_buffer_align_ctx(ctx, lttng_alignof(interruptible));
  42         chan->ops->event_write(ctx, &interruptible, sizeof(interruptible));
  43 }
  44
  45 static
  46 void interruptible_get_value(struct lttng_ctx_field *field,
  47                 struct lttng_probe_ctx *lttng_probe_ctx,
  48                 union lttng_ctx_value *value)
  49 {
  50         int8_t interruptible = lttng_probe_ctx->interruptible;
  51
  52         value->s64 = interruptible;
  53 }
  54
  55 int lttng_add_interruptible_to_ctx(struct lttng_ctx **ctx)
  56 {
  57         struct lttng_ctx_field *field;
  58
  59         field = lttng_append_context(ctx);
  60         if (!field)
  61                 return -ENOMEM;
  62         if (lttng_find_context(*ctx, "interruptible")) {
  63                 lttng_remove_context_field(ctx, field);
  64                 return -EEXIST;
  65         }
  66         field->event_field.name = "interruptible";
  67         field->event_field.type.atype = atype_integer;
  68         field->event_field.type.u.basic.integer.size = sizeof(int8_t) * CHAR_BIT;
  69         field->event_field.type.u.basic.integer.alignment = lttng_alignof(int8_t) * CHAR_BIT;
  70         field->event_field.type.u.basic.integer.signedness = lttng_is_signed_type(int8_t);
  71         field->event_field.type.u.basic.integer.reverse_byte_order = 0;
  72         field->event_field.type.u.basic.integer.base = 10;
  73         field->event_field.type.u.basic.integer.encoding = lttng_encode_none;
  74         field->get_size = interruptible_get_size;
  75         field->record = interruptible_record;
  76         field->get_value = interruptible_get_value;
  77         lttng_context_update(*ctx);
  78         wrapper_vmalloc_sync_all();
  79         return 0;
  80 }
  81 EXPORT_SYMBOL_GPL(lttng_add_interruptible_to_ctx);