[lttng-modules.git] / src / lttng-bytecode.c

/* SPDX-License-Identifier: MIT
 *
 * lttng-bytecode.c
 *
 * LTTng modules bytecode code.
 *
 * Copyright (C) 2010-2016 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 */

#include <linux/list.h>
#include <linux/slab.h>

#include <lttng/lttng-bytecode.h>
#include <lttng/events-internal.h>

static const char *opnames[] = {
	[ BYTECODE_OP_UNKNOWN ] = "UNKNOWN",

	[ BYTECODE_OP_RETURN ] = "RETURN",

	/* binary */
	[ BYTECODE_OP_MUL ] = "MUL",
	[ BYTECODE_OP_DIV ] = "DIV",
	[ BYTECODE_OP_MOD ] = "MOD",
	[ BYTECODE_OP_PLUS ] = "PLUS",
	[ BYTECODE_OP_MINUS ] = "MINUS",
	[ BYTECODE_OP_BIT_RSHIFT ] = "BIT_RSHIFT",
	[ BYTECODE_OP_BIT_LSHIFT ] = "BIT_LSHIFT",
	[ BYTECODE_OP_BIT_AND ] = "BIT_AND",
	[ BYTECODE_OP_BIT_OR ] = "BIT_OR",
	[ BYTECODE_OP_BIT_XOR ] = "BIT_XOR",

	/* binary comparators */
	[ BYTECODE_OP_EQ ] = "EQ",
	[ BYTECODE_OP_NE ] = "NE",
	[ BYTECODE_OP_GT ] = "GT",
	[ BYTECODE_OP_LT ] = "LT",
	[ BYTECODE_OP_GE ] = "GE",
	[ BYTECODE_OP_LE ] = "LE",

	/* string binary comparators */
	[ BYTECODE_OP_EQ_STRING ] = "EQ_STRING",
	[ BYTECODE_OP_NE_STRING ] = "NE_STRING",
	[ BYTECODE_OP_GT_STRING ] = "GT_STRING",
	[ BYTECODE_OP_LT_STRING ] = "LT_STRING",
	[ BYTECODE_OP_GE_STRING ] = "GE_STRING",
	[ BYTECODE_OP_LE_STRING ] = "LE_STRING",

	/* s64 binary comparators */
	[ BYTECODE_OP_EQ_S64 ] = "EQ_S64",
	[ BYTECODE_OP_NE_S64 ] = "NE_S64",
	[ BYTECODE_OP_GT_S64 ] = "GT_S64",
	[ BYTECODE_OP_LT_S64 ] = "LT_S64",
	[ BYTECODE_OP_GE_S64 ] = "GE_S64",
	[ BYTECODE_OP_LE_S64 ] = "LE_S64",

	/* double binary comparators */
	[ BYTECODE_OP_EQ_DOUBLE ] = "EQ_DOUBLE",
	[ BYTECODE_OP_NE_DOUBLE ] = "NE_DOUBLE",
	[ BYTECODE_OP_GT_DOUBLE ] = "GT_DOUBLE",
	[ BYTECODE_OP_LT_DOUBLE ] = "LT_DOUBLE",
	[ BYTECODE_OP_GE_DOUBLE ] = "GE_DOUBLE",
	[ BYTECODE_OP_LE_DOUBLE ] = "LE_DOUBLE",

	/* Mixed S64-double binary comparators */
	[ BYTECODE_OP_EQ_DOUBLE_S64 ] = "EQ_DOUBLE_S64",
	[ BYTECODE_OP_NE_DOUBLE_S64 ] = "NE_DOUBLE_S64",
	[ BYTECODE_OP_GT_DOUBLE_S64 ] = "GT_DOUBLE_S64",
	[ BYTECODE_OP_LT_DOUBLE_S64 ] = "LT_DOUBLE_S64",
	[ BYTECODE_OP_GE_DOUBLE_S64 ] = "GE_DOUBLE_S64",
	[ BYTECODE_OP_LE_DOUBLE_S64 ] = "LE_DOUBLE_S64",

	[ BYTECODE_OP_EQ_S64_DOUBLE ] = "EQ_S64_DOUBLE",
	[ BYTECODE_OP_NE_S64_DOUBLE ] = "NE_S64_DOUBLE",
	[ BYTECODE_OP_GT_S64_DOUBLE ] = "GT_S64_DOUBLE",
	[ BYTECODE_OP_LT_S64_DOUBLE ] = "LT_S64_DOUBLE",
	[ BYTECODE_OP_GE_S64_DOUBLE ] = "GE_S64_DOUBLE",
	[ BYTECODE_OP_LE_S64_DOUBLE ] = "LE_S64_DOUBLE",

	/* unary */
	[ BYTECODE_OP_UNARY_PLUS ] = "UNARY_PLUS",
	[ BYTECODE_OP_UNARY_MINUS ] = "UNARY_MINUS",
	[ BYTECODE_OP_UNARY_NOT ] = "UNARY_NOT",
	[ BYTECODE_OP_UNARY_PLUS_S64 ] = "UNARY_PLUS_S64",
	[ BYTECODE_OP_UNARY_MINUS_S64 ] = "UNARY_MINUS_S64",
	[ BYTECODE_OP_UNARY_NOT_S64 ] = "UNARY_NOT_S64",
	[ BYTECODE_OP_UNARY_PLUS_DOUBLE ] = "UNARY_PLUS_DOUBLE",
	[ BYTECODE_OP_UNARY_MINUS_DOUBLE ] = "UNARY_MINUS_DOUBLE",
	[ BYTECODE_OP_UNARY_NOT_DOUBLE ] = "UNARY_NOT_DOUBLE",

	/* logical */
	[ BYTECODE_OP_AND ] = "AND",
	[ BYTECODE_OP_OR ] = "OR",

	/* load field ref */
	[ BYTECODE_OP_LOAD_FIELD_REF ] = "LOAD_FIELD_REF",
	[ BYTECODE_OP_LOAD_FIELD_REF_STRING ] = "LOAD_FIELD_REF_STRING",
	[ BYTECODE_OP_LOAD_FIELD_REF_SEQUENCE ] = "LOAD_FIELD_REF_SEQUENCE",
	[ BYTECODE_OP_LOAD_FIELD_REF_S64 ] = "LOAD_FIELD_REF_S64",
	[ BYTECODE_OP_LOAD_FIELD_REF_DOUBLE ] = "LOAD_FIELD_REF_DOUBLE",

	/* load from immediate operand */
	[ BYTECODE_OP_LOAD_STRING ] = "LOAD_STRING",
	[ BYTECODE_OP_LOAD_S64 ] = "LOAD_S64",
	[ BYTECODE_OP_LOAD_DOUBLE ] = "LOAD_DOUBLE",

	/* cast */
	[ BYTECODE_OP_CAST_TO_S64 ] = "CAST_TO_S64",
	[ BYTECODE_OP_CAST_DOUBLE_TO_S64 ] = "CAST_DOUBLE_TO_S64",
	[ BYTECODE_OP_CAST_NOP ] = "CAST_NOP",

	/* get context ref */
	[ BYTECODE_OP_GET_CONTEXT_REF ] = "GET_CONTEXT_REF",
	[ BYTECODE_OP_GET_CONTEXT_REF_STRING ] = "GET_CONTEXT_REF_STRING",
	[ BYTECODE_OP_GET_CONTEXT_REF_S64 ] = "GET_CONTEXT_REF_S64",
	[ BYTECODE_OP_GET_CONTEXT_REF_DOUBLE ] = "GET_CONTEXT_REF_DOUBLE",

	/* load userspace field ref */
	[ BYTECODE_OP_LOAD_FIELD_REF_USER_STRING ] = "LOAD_FIELD_REF_USER_STRING",
	[ BYTECODE_OP_LOAD_FIELD_REF_USER_SEQUENCE ] = "LOAD_FIELD_REF_USER_SEQUENCE",

	/*
	 * load immediate star globbing pattern (literal string)
	 * from immediate.
	 */
	[ BYTECODE_OP_LOAD_STAR_GLOB_STRING ] = "LOAD_STAR_GLOB_STRING",

	/* globbing pattern binary operator: apply to */
	[ BYTECODE_OP_EQ_STAR_GLOB_STRING ] = "EQ_STAR_GLOB_STRING",
	[ BYTECODE_OP_NE_STAR_GLOB_STRING ] = "NE_STAR_GLOB_STRING",

	/*
	 * Instructions for recursive traversal through composed types.
	 */
	[ BYTECODE_OP_GET_CONTEXT_ROOT ] = "GET_CONTEXT_ROOT",
	[ BYTECODE_OP_GET_APP_CONTEXT_ROOT ] = "GET_APP_CONTEXT_ROOT",
	[ BYTECODE_OP_GET_PAYLOAD_ROOT ] = "GET_PAYLOAD_ROOT",

	[ BYTECODE_OP_GET_SYMBOL ] = "GET_SYMBOL",
	[ BYTECODE_OP_GET_SYMBOL_FIELD ] = "GET_SYMBOL_FIELD",
	[ BYTECODE_OP_GET_INDEX_U16 ] = "GET_INDEX_U16",
	[ BYTECODE_OP_GET_INDEX_U64 ] = "GET_INDEX_U64",

	[ BYTECODE_OP_LOAD_FIELD ] = "LOAD_FIELD",
	[ BYTECODE_OP_LOAD_FIELD_S8 ] = "LOAD_FIELD_S8",
	[ BYTECODE_OP_LOAD_FIELD_S16 ] = "LOAD_FIELD_S16",
	[ BYTECODE_OP_LOAD_FIELD_S32 ] = "LOAD_FIELD_S32",
	[ BYTECODE_OP_LOAD_FIELD_S64 ] = "LOAD_FIELD_S64",
	[ BYTECODE_OP_LOAD_FIELD_U8 ] = "LOAD_FIELD_U8",
	[ BYTECODE_OP_LOAD_FIELD_U16 ] = "LOAD_FIELD_U16",
	[ BYTECODE_OP_LOAD_FIELD_U32 ] = "LOAD_FIELD_U32",
	[ BYTECODE_OP_LOAD_FIELD_U64 ] = "LOAD_FIELD_U64",
	[ BYTECODE_OP_LOAD_FIELD_STRING ] = "LOAD_FIELD_STRING",
	[ BYTECODE_OP_LOAD_FIELD_SEQUENCE ] = "LOAD_FIELD_SEQUENCE",
	[ BYTECODE_OP_LOAD_FIELD_DOUBLE ] = "LOAD_FIELD_DOUBLE",

	[ BYTECODE_OP_UNARY_BIT_NOT ] = "UNARY_BIT_NOT",

	[ BYTECODE_OP_RETURN_S64 ] = "RETURN_S64",
};

const char *lttng_bytecode_print_op(enum bytecode_op op)
{
	if (op >= NR_BYTECODE_OPS)
		return "UNKNOWN";
	else
		return opnames[op];
}

static
int apply_field_reloc(const struct lttng_kernel_event_desc *event_desc,
		struct bytecode_runtime *runtime,
		uint32_t runtime_len,
		uint32_t reloc_offset,
		const char *field_name,
		enum bytecode_op bytecode_op)
{
	const struct lttng_kernel_event_field * const *fields, *field = NULL;
	unsigned int nr_fields, i;
	struct load_op *op;
	uint32_t field_offset = 0;

	dbg_printk("Apply field reloc: %u %s\n", reloc_offset, field_name);

	/* Lookup event by name */
	if (!event_desc)
		return -EINVAL;
	fields = event_desc->tp_class->fields;
	if (!fields)
		return -EINVAL;
	nr_fields = event_desc->tp_class->nr_fields;
	for (i = 0; i < nr_fields; i++) {
		if (fields[i]->nofilter)
			continue;
		if (!strcmp(fields[i]->name, field_name)) {
			field = fields[i];
			break;
		}
		/* compute field offset */
		switch (fields[i]->type->type) {
		case lttng_kernel_type_integer:
		case lttng_kernel_type_enum:
			field_offset += sizeof(int64_t);
			break;
		case lttng_kernel_type_array:
			if (!lttng_kernel_type_is_bytewise_integer(lttng_kernel_get_type_array(fields[i]->type)->elem_type))
				return -EINVAL;
			field_offset += sizeof(unsigned long);
			field_offset += sizeof(void *);
			break;
		case lttng_kernel_type_sequence:
			if (!lttng_kernel_type_is_bytewise_integer(lttng_kernel_get_type_sequence(fields[i]->type)->elem_type))
				return -EINVAL;
			field_offset += sizeof(unsigned long);
			field_offset += sizeof(void *);
			break;
		case lttng_kernel_type_string:
			field_offset += sizeof(void *);
			break;
		case lttng_kernel_type_struct:	/* Unsupported. */
		case lttng_kernel_type_variant:	/* Unsupported. */
		default:
			return -EINVAL;
		}
	}
	if (!field)
		return -EINVAL;

	/* Check if field offset is too large for 16-bit offset */
	if (field_offset > LTTNG_KERNEL_ABI_FILTER_BYTECODE_MAX_LEN - 1)
		return -EINVAL;

	/* set type */
	op = (struct load_op *) &runtime->code[reloc_offset];

	switch (bytecode_op) {
	case BYTECODE_OP_LOAD_FIELD_REF:
	{
		struct field_ref *field_ref;

		field_ref = (struct field_ref *) op->data;
		switch (field->type->type) {
		case lttng_kernel_type_integer:
		case lttng_kernel_type_enum:
			op->op = BYTECODE_OP_LOAD_FIELD_REF_S64;
			break;
		case lttng_kernel_type_array:
		{
			const struct lttng_kernel_type_array *array_type = lttng_kernel_get_type_array(field->type);
			const struct lttng_kernel_type_common *elem_type = array_type->elem_type;
			const struct lttng_kernel_type_integer *elem_integer_type;

			if (!lttng_kernel_type_is_bytewise_integer(elem_type) || array_type->encoding == lttng_kernel_string_encoding_none)
				return -EINVAL;
			elem_integer_type = container_of(elem_type, const struct lttng_kernel_type_integer, parent);
			if (elem_integer_type->user)
				op->op = BYTECODE_OP_LOAD_FIELD_REF_USER_SEQUENCE;
			else
				op->op = BYTECODE_OP_LOAD_FIELD_REF_SEQUENCE;
			break;
		}
		case lttng_kernel_type_sequence:
		{
			const struct lttng_kernel_type_sequence *sequence_type = lttng_kernel_get_type_sequence(field->type);
			const struct lttng_kernel_type_common *elem_type = sequence_type->elem_type;
			const struct lttng_kernel_type_integer *elem_integer_type;

			if (!lttng_kernel_type_is_bytewise_integer(elem_type) || sequence_type->encoding == lttng_kernel_string_encoding_none)
				return -EINVAL;
			elem_integer_type = container_of(elem_type, const struct lttng_kernel_type_integer, parent);
			if (elem_integer_type->user)
				op->op = BYTECODE_OP_LOAD_FIELD_REF_USER_SEQUENCE;
			else
				op->op = BYTECODE_OP_LOAD_FIELD_REF_SEQUENCE;
			break;
		}
		case lttng_kernel_type_string:
		{
			const struct lttng_kernel_type_string *string_type = lttng_kernel_get_type_string(field->type);

			if (string_type->user)
				op->op = BYTECODE_OP_LOAD_FIELD_REF_USER_STRING;
			else
				op->op = BYTECODE_OP_LOAD_FIELD_REF_STRING;
			break;
		}
		case lttng_kernel_type_struct:	/* Unsupported. */
		case lttng_kernel_type_variant:	/* Unsupported. */
		default:
			return -EINVAL;
		}
		/* set offset */
		field_ref->offset = (uint16_t) field_offset;
		break;
	}
	default:
		return -EINVAL;
	}
	return 0;
}

static
int apply_context_reloc(struct bytecode_runtime *runtime,
		uint32_t runtime_len,
		uint32_t reloc_offset,
		const char *context_name,
		enum bytecode_op bytecode_op)
{
	struct load_op *op;
	struct lttng_kernel_ctx_field *ctx_field;
	int idx;

	dbg_printk("Apply context reloc: %u %s\n", reloc_offset, context_name);

	/* Get context index */
	idx = lttng_kernel_get_context_index(lttng_static_ctx, context_name);
	if (idx < 0)
		return -ENOENT;

	/* Check if idx is too large for 16-bit offset */
	if (idx > LTTNG_KERNEL_ABI_FILTER_BYTECODE_MAX_LEN - 1)
		return -EINVAL;

	/* Get context return type */
	ctx_field = &lttng_static_ctx->fields[idx];
	op = (struct load_op *) &runtime->code[reloc_offset];

	switch (bytecode_op) {
	case BYTECODE_OP_GET_CONTEXT_REF:
	{
		struct field_ref *field_ref;

		field_ref = (struct field_ref *) op->data;
		switch (ctx_field->event_field->type->type) {
		case lttng_kernel_type_integer:
		case lttng_kernel_type_enum:
			op->op = BYTECODE_OP_GET_CONTEXT_REF_S64;
			break;
			/* Sequence and array supported as string */
		case lttng_kernel_type_string:
		{
			const struct lttng_kernel_type_string *string_type = lttng_kernel_get_type_string(ctx_field->event_field->type);

			BUG_ON(string_type->user);
			op->op = BYTECODE_OP_GET_CONTEXT_REF_STRING;
			break;
		}
		case lttng_kernel_type_array:
		{
			const struct lttng_kernel_type_array *array_type = lttng_kernel_get_type_array(ctx_field->event_field->type);
			const struct lttng_kernel_type_common *elem_type = array_type->elem_type;
			const struct lttng_kernel_type_integer *elem_integer_type;

			if (!lttng_kernel_type_is_bytewise_integer(elem_type) || array_type->encoding == lttng_kernel_string_encoding_none)
				return -EINVAL;
			elem_integer_type = container_of(elem_type, const struct lttng_kernel_type_integer, parent);
			BUG_ON(elem_integer_type->user);
			op->op = BYTECODE_OP_GET_CONTEXT_REF_STRING;
			break;
		}
		case lttng_kernel_type_sequence:
		{
			const struct lttng_kernel_type_sequence *sequence_type = lttng_kernel_get_type_sequence(ctx_field->event_field->type);
			const struct lttng_kernel_type_common *elem_type = sequence_type->elem_type;
			const struct lttng_kernel_type_integer *elem_integer_type;

			if (!lttng_kernel_type_is_bytewise_integer(elem_type) || sequence_type->encoding == lttng_kernel_string_encoding_none)
				return -EINVAL;
			elem_integer_type = container_of(elem_type, const struct lttng_kernel_type_integer, parent);
			BUG_ON(elem_integer_type->user);
			op->op = BYTECODE_OP_GET_CONTEXT_REF_STRING;
			break;
		}
		case lttng_kernel_type_struct:	/* Unsupported. */
		case lttng_kernel_type_variant:	/* Unsupported. */
		default:
			return -EINVAL;
		}
		/* set offset to context index within channel contexts */
		field_ref->offset = (uint16_t) idx;
		break;
	}
	default:
		return -EINVAL;
	}
	return 0;
}

static
int apply_reloc(const struct lttng_kernel_event_desc *event_desc,
		struct bytecode_runtime *runtime,
		uint32_t runtime_len,
		uint32_t reloc_offset,
		const char *name)
{
	struct load_op *op;

	dbg_printk("Apply reloc: %u %s\n", reloc_offset, name);

	/* Ensure that the reloc is within the code */
	if (runtime_len - reloc_offset < sizeof(uint16_t))
		return -EINVAL;

	op = (struct load_op *) &runtime->code[reloc_offset];
	switch (op->op) {
	case BYTECODE_OP_LOAD_FIELD_REF:
		return apply_field_reloc(event_desc, runtime, runtime_len,
			reloc_offset, name, op->op);
	case BYTECODE_OP_GET_CONTEXT_REF:
		return apply_context_reloc(runtime, runtime_len,
			reloc_offset, name, op->op);
	case BYTECODE_OP_GET_SYMBOL:
	case BYTECODE_OP_GET_SYMBOL_FIELD:
		/*
		 * Will be handled by load specialize phase or
		 * dynamically by interpreter.
		 */
		return 0;
	default:
		printk(KERN_WARNING "LTTng: filter: Unknown reloc op type %u\n", op->op);
		return -EINVAL;
	}
	return 0;
}

static
int bytecode_is_linked(struct lttng_kernel_bytecode_node *bytecode,
		struct list_head *bytecode_runtime_head)
{
	struct lttng_kernel_bytecode_runtime *bc_runtime;

	list_for_each_entry(bc_runtime, bytecode_runtime_head, node) {
		if (bc_runtime->bc == bytecode)
			return 1;
	}
	return 0;
}

/*
 * Take a bytecode with reloc table and link it to an event to create a
 * bytecode runtime.
 */
static
int link_bytecode(const struct lttng_kernel_event_desc *event_desc,
		struct lttng_kernel_ctx *ctx,
		struct lttng_kernel_bytecode_node *bytecode,
		struct list_head *bytecode_runtime_head,
		struct list_head *insert_loc)
{
	int ret, offset, next_offset;
	struct bytecode_runtime *runtime = NULL;
	size_t runtime_alloc_len;

	if (!bytecode)
		return 0;
	/* Bytecode already linked */
	if (bytecode_is_linked(bytecode, bytecode_runtime_head))
		return 0;

	dbg_printk("Linking...\n");

	/* We don't need the reloc table in the runtime */
	runtime_alloc_len = sizeof(*runtime) + bytecode->bc.reloc_offset;
	runtime = kzalloc(runtime_alloc_len, GFP_KERNEL);
	if (!runtime) {
		ret = -ENOMEM;
		goto alloc_error;
	}
	runtime->p.type = bytecode->type;
	runtime->p.bc = bytecode;
	runtime->p.ctx = ctx;
	runtime->len = bytecode->bc.reloc_offset;
	/* copy original bytecode */
	memcpy(runtime->code, bytecode->bc.data, runtime->len);
	/* Validate bytecode load instructions before relocs. */
	ret = lttng_bytecode_validate_load(runtime);
	if (ret) {
		goto link_error;
	}
	/*
	 * apply relocs. Those are a uint16_t (offset in bytecode)
	 * followed by a string (field name).
	 */
	for (offset = bytecode->bc.reloc_offset;
			offset < bytecode->bc.len;
			offset = next_offset) {
		uint16_t reloc_offset =
			*(uint16_t *) &bytecode->bc.data[offset];
		const char *name =
			(const char *) &bytecode->bc.data[offset + sizeof(uint16_t)];

		ret = apply_reloc(event_desc, runtime, runtime->len, reloc_offset, name);
		if (ret) {
			goto link_error;
		}
		next_offset = offset + sizeof(uint16_t) + strlen(name) + 1;
	}
	/* Validate bytecode */
	ret = lttng_bytecode_validate(runtime);
	if (ret) {
		goto link_error;
	}
	/* Specialize bytecode */
	ret = lttng_bytecode_specialize(event_desc, runtime);
	if (ret) {
		goto link_error;
	}
	runtime->p.interpreter_func = lttng_bytecode_interpret;
	runtime->p.link_failed = 0;
	list_add_rcu(&runtime->p.node, insert_loc);
	dbg_printk("Linking successful.\n");
	return 0;

link_error:

	runtime->p.interpreter_func = lttng_bytecode_interpret_error;
	runtime->p.link_failed = 1;
	list_add_rcu(&runtime->p.node, insert_loc);
alloc_error:
	dbg_printk("Linking failed.\n");
	return ret;
}

void lttng_bytecode_sync_state(struct lttng_kernel_bytecode_runtime *runtime)
{
	struct lttng_kernel_bytecode_node *bc = runtime->bc;

	if (!bc->enabler->enabled || runtime->link_failed)
		runtime->interpreter_func = lttng_bytecode_interpret_error;
	else
		runtime->interpreter_func = lttng_bytecode_interpret;
}

/*
 * Given the lists of bytecode programs of an instance (event or event
 * notifier) and of a matching enabler, try to link all the enabler's bytecode
 * programs with the instance.
 *
 * This function is called after we confirmed that name enabler and the
 * instance are matching names (or glob pattern matching).
 */
void lttng_enabler_link_bytecode(const struct lttng_kernel_event_desc *event_desc,
		struct lttng_kernel_ctx *ctx,
		struct list_head *instance_bytecode_head,
		struct list_head *enabler_bytecode_head)
{
	struct lttng_kernel_bytecode_node *enabler_bc;
	struct lttng_kernel_bytecode_runtime *runtime;

	WARN_ON_ONCE(!event_desc);

	/* Go over all the bytecode programs of the enabler.  */
	list_for_each_entry(enabler_bc, enabler_bytecode_head, node) {
		int found = 0, ret;
		struct list_head *insert_loc;

		/*
		 * Check if the current enabler bytecode program is already
		 * linked with the instance.
		 */
		list_for_each_entry(runtime, instance_bytecode_head, node) {
			if (runtime->bc == enabler_bc) {
				found = 1;
				break;
			}
		}

		/*
		 * Skip bytecode already linked, go to the next enabler
		 * bytecode program.
		 */
		if (found)
			continue;

		/*
		 * Insert at specified priority (seqnum) in increasing
		 * order. If there already is a bytecode of the same priority,
		 * insert the new bytecode right after it.
		 */
		list_for_each_entry_reverse(runtime,
				instance_bytecode_head, node) {
			if (runtime->bc->bc.seqnum <= enabler_bc->bc.seqnum) {
				/* insert here */
				insert_loc = &runtime->node;
				goto add_within;
			}
		}
		/* Add to head to list */
		insert_loc = instance_bytecode_head;
	add_within:
		dbg_printk("linking bytecode\n");
		ret = link_bytecode(event_desc, ctx, enabler_bc, instance_bytecode_head, insert_loc);
		if (ret) {
			dbg_printk("[lttng filter] warning: cannot link event bytecode\n");
		}
	}
}

void lttng_free_event_filter_runtime(struct lttng_kernel_event_common *event)
{
	struct bytecode_runtime *runtime, *tmp;

	list_for_each_entry_safe(runtime, tmp,
			&event->priv->filter_bytecode_runtime_head, p.node) {
		kfree(runtime->data);
		kfree(runtime);
	}
}
Commit	Line	Data
	1	/* SPDX-License-Identifier: MIT
	2	*
	3	* lttng-bytecode.c
	4	*
	5	* LTTng modules bytecode code.
	6	*
	7	* Copyright (C) 2010-2016 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	8	*/
	9
	10	#include <linux/list.h>
	11	#include <linux/slab.h>
	12
	13	#include <lttng/lttng-bytecode.h>
	14	#include <lttng/events-internal.h>
	15
	16	static const char *opnames[] = {
	17	[ BYTECODE_OP_UNKNOWN ] = "UNKNOWN",
	18
	19	[ BYTECODE_OP_RETURN ] = "RETURN",
	20
	21	/* binary */
	22	[ BYTECODE_OP_MUL ] = "MUL",
	23	[ BYTECODE_OP_DIV ] = "DIV",
	24	[ BYTECODE_OP_MOD ] = "MOD",
	25	[ BYTECODE_OP_PLUS ] = "PLUS",
	26	[ BYTECODE_OP_MINUS ] = "MINUS",
	27	[ BYTECODE_OP_BIT_RSHIFT ] = "BIT_RSHIFT",
	28	[ BYTECODE_OP_BIT_LSHIFT ] = "BIT_LSHIFT",
	29	[ BYTECODE_OP_BIT_AND ] = "BIT_AND",
	30	[ BYTECODE_OP_BIT_OR ] = "BIT_OR",
	31	[ BYTECODE_OP_BIT_XOR ] = "BIT_XOR",
	32
	33	/* binary comparators */
	34	[ BYTECODE_OP_EQ ] = "EQ",
	35	[ BYTECODE_OP_NE ] = "NE",
	36	[ BYTECODE_OP_GT ] = "GT",
	37	[ BYTECODE_OP_LT ] = "LT",
	38	[ BYTECODE_OP_GE ] = "GE",
	39	[ BYTECODE_OP_LE ] = "LE",
	40
	41	/* string binary comparators */
	42	[ BYTECODE_OP_EQ_STRING ] = "EQ_STRING",
	43	[ BYTECODE_OP_NE_STRING ] = "NE_STRING",
	44	[ BYTECODE_OP_GT_STRING ] = "GT_STRING",
	45	[ BYTECODE_OP_LT_STRING ] = "LT_STRING",
	46	[ BYTECODE_OP_GE_STRING ] = "GE_STRING",
	47	[ BYTECODE_OP_LE_STRING ] = "LE_STRING",
	48
	49	/* s64 binary comparators */
	50	[ BYTECODE_OP_EQ_S64 ] = "EQ_S64",
	51	[ BYTECODE_OP_NE_S64 ] = "NE_S64",
	52	[ BYTECODE_OP_GT_S64 ] = "GT_S64",
	53	[ BYTECODE_OP_LT_S64 ] = "LT_S64",
	54	[ BYTECODE_OP_GE_S64 ] = "GE_S64",
	55	[ BYTECODE_OP_LE_S64 ] = "LE_S64",
	56
	57	/* double binary comparators */
	58	[ BYTECODE_OP_EQ_DOUBLE ] = "EQ_DOUBLE",
	59	[ BYTECODE_OP_NE_DOUBLE ] = "NE_DOUBLE",
	60	[ BYTECODE_OP_GT_DOUBLE ] = "GT_DOUBLE",
	61	[ BYTECODE_OP_LT_DOUBLE ] = "LT_DOUBLE",
	62	[ BYTECODE_OP_GE_DOUBLE ] = "GE_DOUBLE",
	63	[ BYTECODE_OP_LE_DOUBLE ] = "LE_DOUBLE",
	64
	65	/* Mixed S64-double binary comparators */
	66	[ BYTECODE_OP_EQ_DOUBLE_S64 ] = "EQ_DOUBLE_S64",
	67	[ BYTECODE_OP_NE_DOUBLE_S64 ] = "NE_DOUBLE_S64",
	68	[ BYTECODE_OP_GT_DOUBLE_S64 ] = "GT_DOUBLE_S64",
	69	[ BYTECODE_OP_LT_DOUBLE_S64 ] = "LT_DOUBLE_S64",
	70	[ BYTECODE_OP_GE_DOUBLE_S64 ] = "GE_DOUBLE_S64",
	71	[ BYTECODE_OP_LE_DOUBLE_S64 ] = "LE_DOUBLE_S64",
	72
	73	[ BYTECODE_OP_EQ_S64_DOUBLE ] = "EQ_S64_DOUBLE",
	74	[ BYTECODE_OP_NE_S64_DOUBLE ] = "NE_S64_DOUBLE",
	75	[ BYTECODE_OP_GT_S64_DOUBLE ] = "GT_S64_DOUBLE",
	76	[ BYTECODE_OP_LT_S64_DOUBLE ] = "LT_S64_DOUBLE",
	77	[ BYTECODE_OP_GE_S64_DOUBLE ] = "GE_S64_DOUBLE",
	78	[ BYTECODE_OP_LE_S64_DOUBLE ] = "LE_S64_DOUBLE",
	79
	80	/* unary */
	81	[ BYTECODE_OP_UNARY_PLUS ] = "UNARY_PLUS",
	82	[ BYTECODE_OP_UNARY_MINUS ] = "UNARY_MINUS",
	83	[ BYTECODE_OP_UNARY_NOT ] = "UNARY_NOT",
	84	[ BYTECODE_OP_UNARY_PLUS_S64 ] = "UNARY_PLUS_S64",
	85	[ BYTECODE_OP_UNARY_MINUS_S64 ] = "UNARY_MINUS_S64",
	86	[ BYTECODE_OP_UNARY_NOT_S64 ] = "UNARY_NOT_S64",
	87	[ BYTECODE_OP_UNARY_PLUS_DOUBLE ] = "UNARY_PLUS_DOUBLE",
	88	[ BYTECODE_OP_UNARY_MINUS_DOUBLE ] = "UNARY_MINUS_DOUBLE",
	89	[ BYTECODE_OP_UNARY_NOT_DOUBLE ] = "UNARY_NOT_DOUBLE",
	90
	91	/* logical */
	92	[ BYTECODE_OP_AND ] = "AND",
	93	[ BYTECODE_OP_OR ] = "OR",
	94
	95	/* load field ref */
	96	[ BYTECODE_OP_LOAD_FIELD_REF ] = "LOAD_FIELD_REF",
	97	[ BYTECODE_OP_LOAD_FIELD_REF_STRING ] = "LOAD_FIELD_REF_STRING",
	98	[ BYTECODE_OP_LOAD_FIELD_REF_SEQUENCE ] = "LOAD_FIELD_REF_SEQUENCE",
	99	[ BYTECODE_OP_LOAD_FIELD_REF_S64 ] = "LOAD_FIELD_REF_S64",
	100	[ BYTECODE_OP_LOAD_FIELD_REF_DOUBLE ] = "LOAD_FIELD_REF_DOUBLE",
	101
	102	/* load from immediate operand */
	103	[ BYTECODE_OP_LOAD_STRING ] = "LOAD_STRING",
	104	[ BYTECODE_OP_LOAD_S64 ] = "LOAD_S64",
	105	[ BYTECODE_OP_LOAD_DOUBLE ] = "LOAD_DOUBLE",
	106
	107	/* cast */
	108	[ BYTECODE_OP_CAST_TO_S64 ] = "CAST_TO_S64",
	109	[ BYTECODE_OP_CAST_DOUBLE_TO_S64 ] = "CAST_DOUBLE_TO_S64",
	110	[ BYTECODE_OP_CAST_NOP ] = "CAST_NOP",
	111
	112	/* get context ref */
	113	[ BYTECODE_OP_GET_CONTEXT_REF ] = "GET_CONTEXT_REF",
	114	[ BYTECODE_OP_GET_CONTEXT_REF_STRING ] = "GET_CONTEXT_REF_STRING",
	115	[ BYTECODE_OP_GET_CONTEXT_REF_S64 ] = "GET_CONTEXT_REF_S64",
	116	[ BYTECODE_OP_GET_CONTEXT_REF_DOUBLE ] = "GET_CONTEXT_REF_DOUBLE",
	117
	118	/* load userspace field ref */
	119	[ BYTECODE_OP_LOAD_FIELD_REF_USER_STRING ] = "LOAD_FIELD_REF_USER_STRING",
	120	[ BYTECODE_OP_LOAD_FIELD_REF_USER_SEQUENCE ] = "LOAD_FIELD_REF_USER_SEQUENCE",
	121
	122	/*
	123	* load immediate star globbing pattern (literal string)
	124	* from immediate.
	125	*/
	126	[ BYTECODE_OP_LOAD_STAR_GLOB_STRING ] = "LOAD_STAR_GLOB_STRING",
	127
	128	/* globbing pattern binary operator: apply to */
	129	[ BYTECODE_OP_EQ_STAR_GLOB_STRING ] = "EQ_STAR_GLOB_STRING",
	130	[ BYTECODE_OP_NE_STAR_GLOB_STRING ] = "NE_STAR_GLOB_STRING",
	131
	132	/*
	133	* Instructions for recursive traversal through composed types.
	134	*/
	135	[ BYTECODE_OP_GET_CONTEXT_ROOT ] = "GET_CONTEXT_ROOT",
	136	[ BYTECODE_OP_GET_APP_CONTEXT_ROOT ] = "GET_APP_CONTEXT_ROOT",
	137	[ BYTECODE_OP_GET_PAYLOAD_ROOT ] = "GET_PAYLOAD_ROOT",
	138
	139	[ BYTECODE_OP_GET_SYMBOL ] = "GET_SYMBOL",
	140	[ BYTECODE_OP_GET_SYMBOL_FIELD ] = "GET_SYMBOL_FIELD",
	141	[ BYTECODE_OP_GET_INDEX_U16 ] = "GET_INDEX_U16",
	142	[ BYTECODE_OP_GET_INDEX_U64 ] = "GET_INDEX_U64",
	143
	144	[ BYTECODE_OP_LOAD_FIELD ] = "LOAD_FIELD",
	145	[ BYTECODE_OP_LOAD_FIELD_S8 ] = "LOAD_FIELD_S8",
	146	[ BYTECODE_OP_LOAD_FIELD_S16 ] = "LOAD_FIELD_S16",
	147	[ BYTECODE_OP_LOAD_FIELD_S32 ] = "LOAD_FIELD_S32",
	148	[ BYTECODE_OP_LOAD_FIELD_S64 ] = "LOAD_FIELD_S64",
	149	[ BYTECODE_OP_LOAD_FIELD_U8 ] = "LOAD_FIELD_U8",
	150	[ BYTECODE_OP_LOAD_FIELD_U16 ] = "LOAD_FIELD_U16",
	151	[ BYTECODE_OP_LOAD_FIELD_U32 ] = "LOAD_FIELD_U32",
	152	[ BYTECODE_OP_LOAD_FIELD_U64 ] = "LOAD_FIELD_U64",
	153	[ BYTECODE_OP_LOAD_FIELD_STRING ] = "LOAD_FIELD_STRING",
	154	[ BYTECODE_OP_LOAD_FIELD_SEQUENCE ] = "LOAD_FIELD_SEQUENCE",
	155	[ BYTECODE_OP_LOAD_FIELD_DOUBLE ] = "LOAD_FIELD_DOUBLE",
	156
	157	[ BYTECODE_OP_UNARY_BIT_NOT ] = "UNARY_BIT_NOT",
	158
	159	[ BYTECODE_OP_RETURN_S64 ] = "RETURN_S64",
	160	};
	161
	162	const char *lttng_bytecode_print_op(enum bytecode_op op)
	163	{
	164	if (op >= NR_BYTECODE_OPS)
	165	return "UNKNOWN";
	166	else
	167	return opnames[op];
	168	}
	169
	170	static
	171	int apply_field_reloc(const struct lttng_kernel_event_desc *event_desc,
	172	struct bytecode_runtime *runtime,
	173	uint32_t runtime_len,
	174	uint32_t reloc_offset,
	175	const char *field_name,
	176	enum bytecode_op bytecode_op)
	177	{
	178	const struct lttng_kernel_event_field * const fields, field = NULL;
	179	unsigned int nr_fields, i;
	180	struct load_op *op;
	181	uint32_t field_offset = 0;
	182
	183	dbg_printk("Apply field reloc: %u %s\n", reloc_offset, field_name);
	184
	185	/* Lookup event by name */
	186	if (!event_desc)
	187	return -EINVAL;
	188	fields = event_desc->tp_class->fields;
	189	if (!fields)
	190	return -EINVAL;
	191	nr_fields = event_desc->tp_class->nr_fields;
	192	for (i = 0; i < nr_fields; i++) {
	193	if (fields[i]->nofilter)
	194	continue;
	195	if (!strcmp(fields[i]->name, field_name)) {
	196	field = fields[i];
	197	break;
	198	}
	199	/* compute field offset */
	200	switch (fields[i]->type->type) {
	201	case lttng_kernel_type_integer:
	202	case lttng_kernel_type_enum:
	203	field_offset += sizeof(int64_t);
	204	break;
	205	case lttng_kernel_type_array:
	206	if (!lttng_kernel_type_is_bytewise_integer(lttng_kernel_get_type_array(fields[i]->type)->elem_type))
	207	return -EINVAL;
	208	field_offset += sizeof(unsigned long);
	209	field_offset += sizeof(void *);
	210	break;
	211	case lttng_kernel_type_sequence:
	212	if (!lttng_kernel_type_is_bytewise_integer(lttng_kernel_get_type_sequence(fields[i]->type)->elem_type))
	213	return -EINVAL;
	214	field_offset += sizeof(unsigned long);
	215	field_offset += sizeof(void *);
	216	break;
	217	case lttng_kernel_type_string:
	218	field_offset += sizeof(void *);
	219	break;
	220	case lttng_kernel_type_struct: /* Unsupported. */
	221	case lttng_kernel_type_variant: /* Unsupported. */
	222	default:
	223	return -EINVAL;
	224	}
	225	}
	226	if (!field)
	227	return -EINVAL;
	228
	229	/* Check if field offset is too large for 16-bit offset */
	230	if (field_offset > LTTNG_KERNEL_ABI_FILTER_BYTECODE_MAX_LEN - 1)
	231	return -EINVAL;
	232
	233	/* set type */
	234	op = (struct load_op *) &runtime->code[reloc_offset];
	235
	236	switch (bytecode_op) {
	237	case BYTECODE_OP_LOAD_FIELD_REF:
	238	{
	239	struct field_ref *field_ref;
	240
	241	field_ref = (struct field_ref *) op->data;
	242	switch (field->type->type) {
	243	case lttng_kernel_type_integer:
	244	case lttng_kernel_type_enum:
	245	op->op = BYTECODE_OP_LOAD_FIELD_REF_S64;
	246	break;
	247	case lttng_kernel_type_array:
	248	{
	249	const struct lttng_kernel_type_array *array_type = lttng_kernel_get_type_array(field->type);
	250	const struct lttng_kernel_type_common *elem_type = array_type->elem_type;
	251	const struct lttng_kernel_type_integer *elem_integer_type;
	252
	253	if (!lttng_kernel_type_is_bytewise_integer(elem_type) \|\| array_type->encoding == lttng_kernel_string_encoding_none)
	254	return -EINVAL;
	255	elem_integer_type = container_of(elem_type, const struct lttng_kernel_type_integer, parent);
	256	if (elem_integer_type->user)
	257	op->op = BYTECODE_OP_LOAD_FIELD_REF_USER_SEQUENCE;
	258	else
	259	op->op = BYTECODE_OP_LOAD_FIELD_REF_SEQUENCE;
	260	break;
	261	}
	262	case lttng_kernel_type_sequence:
	263	{
	264	const struct lttng_kernel_type_sequence *sequence_type = lttng_kernel_get_type_sequence(field->type);
	265	const struct lttng_kernel_type_common *elem_type = sequence_type->elem_type;
	266	const struct lttng_kernel_type_integer *elem_integer_type;
	267
	268	if (!lttng_kernel_type_is_bytewise_integer(elem_type) \|\| sequence_type->encoding == lttng_kernel_string_encoding_none)
	269	return -EINVAL;
	270	elem_integer_type = container_of(elem_type, const struct lttng_kernel_type_integer, parent);
	271	if (elem_integer_type->user)
	272	op->op = BYTECODE_OP_LOAD_FIELD_REF_USER_SEQUENCE;
	273	else
	274	op->op = BYTECODE_OP_LOAD_FIELD_REF_SEQUENCE;
	275	break;
	276	}
	277	case lttng_kernel_type_string:
	278	{
	279	const struct lttng_kernel_type_string *string_type = lttng_kernel_get_type_string(field->type);
	280
	281	if (string_type->user)
	282	op->op = BYTECODE_OP_LOAD_FIELD_REF_USER_STRING;
	283	else
	284	op->op = BYTECODE_OP_LOAD_FIELD_REF_STRING;
	285	break;
	286	}
	287	case lttng_kernel_type_struct: /* Unsupported. */
	288	case lttng_kernel_type_variant: /* Unsupported. */
	289	default:
	290	return -EINVAL;
	291	}
	292	/* set offset */
	293	field_ref->offset = (uint16_t) field_offset;
	294	break;
	295	}
	296	default:
	297	return -EINVAL;
	298	}
	299	return 0;
	300	}
	301
	302	static
	303	int apply_context_reloc(struct bytecode_runtime *runtime,
	304	uint32_t runtime_len,
	305	uint32_t reloc_offset,
	306	const char *context_name,
	307	enum bytecode_op bytecode_op)
	308	{
	309	struct load_op *op;
	310	struct lttng_kernel_ctx_field *ctx_field;
	311	int idx;
	312
	313	dbg_printk("Apply context reloc: %u %s\n", reloc_offset, context_name);
	314
	315	/* Get context index */
	316	idx = lttng_kernel_get_context_index(lttng_static_ctx, context_name);
	317	if (idx < 0)
	318	return -ENOENT;
	319
	320	/* Check if idx is too large for 16-bit offset */
	321	if (idx > LTTNG_KERNEL_ABI_FILTER_BYTECODE_MAX_LEN - 1)
	322	return -EINVAL;
	323
	324	/* Get context return type */
	325	ctx_field = &lttng_static_ctx->fields[idx];
	326	op = (struct load_op *) &runtime->code[reloc_offset];
	327
	328	switch (bytecode_op) {
	329	case BYTECODE_OP_GET_CONTEXT_REF:
	330	{
	331	struct field_ref *field_ref;
	332
	333	field_ref = (struct field_ref *) op->data;
	334	switch (ctx_field->event_field->type->type) {
	335	case lttng_kernel_type_integer:
	336	case lttng_kernel_type_enum:
	337	op->op = BYTECODE_OP_GET_CONTEXT_REF_S64;
	338	break;
	339	/* Sequence and array supported as string */
	340	case lttng_kernel_type_string:
	341	{
	342	const struct lttng_kernel_type_string *string_type = lttng_kernel_get_type_string(ctx_field->event_field->type);
	343
	344	BUG_ON(string_type->user);
	345	op->op = BYTECODE_OP_GET_CONTEXT_REF_STRING;
	346	break;
	347	}
	348	case lttng_kernel_type_array:
	349	{
	350	const struct lttng_kernel_type_array *array_type = lttng_kernel_get_type_array(ctx_field->event_field->type);
	351	const struct lttng_kernel_type_common *elem_type = array_type->elem_type;
	352	const struct lttng_kernel_type_integer *elem_integer_type;
	353
	354	if (!lttng_kernel_type_is_bytewise_integer(elem_type) \|\| array_type->encoding == lttng_kernel_string_encoding_none)
	355	return -EINVAL;
	356	elem_integer_type = container_of(elem_type, const struct lttng_kernel_type_integer, parent);
	357	BUG_ON(elem_integer_type->user);
	358	op->op = BYTECODE_OP_GET_CONTEXT_REF_STRING;
	359	break;
	360	}
	361	case lttng_kernel_type_sequence:
	362	{
	363	const struct lttng_kernel_type_sequence *sequence_type = lttng_kernel_get_type_sequence(ctx_field->event_field->type);
	364	const struct lttng_kernel_type_common *elem_type = sequence_type->elem_type;
	365	const struct lttng_kernel_type_integer *elem_integer_type;
	366
	367	if (!lttng_kernel_type_is_bytewise_integer(elem_type) \|\| sequence_type->encoding == lttng_kernel_string_encoding_none)
	368	return -EINVAL;
	369	elem_integer_type = container_of(elem_type, const struct lttng_kernel_type_integer, parent);
	370	BUG_ON(elem_integer_type->user);
	371	op->op = BYTECODE_OP_GET_CONTEXT_REF_STRING;
	372	break;
	373	}
	374	case lttng_kernel_type_struct: /* Unsupported. */
	375	case lttng_kernel_type_variant: /* Unsupported. */
	376	default:
	377	return -EINVAL;
	378	}
	379	/* set offset to context index within channel contexts */
	380	field_ref->offset = (uint16_t) idx;
	381	break;
	382	}
	383	default:
	384	return -EINVAL;
	385	}
	386	return 0;
	387	}
	388
	389	static
	390	int apply_reloc(const struct lttng_kernel_event_desc *event_desc,
	391	struct bytecode_runtime *runtime,
	392	uint32_t runtime_len,
	393	uint32_t reloc_offset,
	394	const char *name)
	395	{
	396	struct load_op *op;
	397
	398	dbg_printk("Apply reloc: %u %s\n", reloc_offset, name);
	399
	400	/* Ensure that the reloc is within the code */
	401	if (runtime_len - reloc_offset < sizeof(uint16_t))
	402	return -EINVAL;
	403
	404	op = (struct load_op *) &runtime->code[reloc_offset];
	405	switch (op->op) {
	406	case BYTECODE_OP_LOAD_FIELD_REF:
	407	return apply_field_reloc(event_desc, runtime, runtime_len,
	408	reloc_offset, name, op->op);
	409	case BYTECODE_OP_GET_CONTEXT_REF:
	410	return apply_context_reloc(runtime, runtime_len,
	411	reloc_offset, name, op->op);
	412	case BYTECODE_OP_GET_SYMBOL:
	413	case BYTECODE_OP_GET_SYMBOL_FIELD:
	414	/*
	415	* Will be handled by load specialize phase or
	416	* dynamically by interpreter.
	417	*/
	418	return 0;
	419	default:
	420	printk(KERN_WARNING "LTTng: filter: Unknown reloc op type %u\n", op->op);
	421	return -EINVAL;
	422	}
	423	return 0;
	424	}
	425
	426	static
	427	int bytecode_is_linked(struct lttng_kernel_bytecode_node *bytecode,
	428	struct list_head *bytecode_runtime_head)
	429	{
	430	struct lttng_kernel_bytecode_runtime *bc_runtime;
	431
	432	list_for_each_entry(bc_runtime, bytecode_runtime_head, node) {
	433	if (bc_runtime->bc == bytecode)
	434	return 1;
	435	}
	436	return 0;
	437	}
	438
	439	/*
	440	* Take a bytecode with reloc table and link it to an event to create a
	441	* bytecode runtime.
	442	*/
	443	static
	444	int link_bytecode(const struct lttng_kernel_event_desc *event_desc,
	445	struct lttng_kernel_ctx *ctx,
	446	struct lttng_kernel_bytecode_node *bytecode,
	447	struct list_head *bytecode_runtime_head,
	448	struct list_head *insert_loc)
	449	{
	450	int ret, offset, next_offset;
	451	struct bytecode_runtime *runtime = NULL;
	452	size_t runtime_alloc_len;
	453
	454	if (!bytecode)
	455	return 0;
	456	/* Bytecode already linked */
	457	if (bytecode_is_linked(bytecode, bytecode_runtime_head))
	458	return 0;
	459
	460	dbg_printk("Linking...\n");
	461
	462	/* We don't need the reloc table in the runtime */
	463	runtime_alloc_len = sizeof(*runtime) + bytecode->bc.reloc_offset;
	464	runtime = kzalloc(runtime_alloc_len, GFP_KERNEL);
	465	if (!runtime) {
	466	ret = -ENOMEM;
	467	goto alloc_error;
	468	}
	469	runtime->p.type = bytecode->type;
	470	runtime->p.bc = bytecode;
	471	runtime->p.ctx = ctx;
	472	runtime->len = bytecode->bc.reloc_offset;
	473	/* copy original bytecode */
	474	memcpy(runtime->code, bytecode->bc.data, runtime->len);
	475	/* Validate bytecode load instructions before relocs. */
	476	ret = lttng_bytecode_validate_load(runtime);
	477	if (ret) {
	478	goto link_error;
	479	}
	480	/*
	481	* apply relocs. Those are a uint16_t (offset in bytecode)
	482	* followed by a string (field name).
	483	*/
	484	for (offset = bytecode->bc.reloc_offset;
	485	offset < bytecode->bc.len;
	486	offset = next_offset) {
	487	uint16_t reloc_offset =
	488	(uint16_t ) &bytecode->bc.data[offset];
	489	const char *name =
	490	(const char *) &bytecode->bc.data[offset + sizeof(uint16_t)];
	491
	492	ret = apply_reloc(event_desc, runtime, runtime->len, reloc_offset, name);
	493	if (ret) {
	494	goto link_error;
	495	}
	496	next_offset = offset + sizeof(uint16_t) + strlen(name) + 1;
	497	}
	498	/* Validate bytecode */
	499	ret = lttng_bytecode_validate(runtime);
	500	if (ret) {
	501	goto link_error;
	502	}
	503	/* Specialize bytecode */
	504	ret = lttng_bytecode_specialize(event_desc, runtime);
	505	if (ret) {
	506	goto link_error;
	507	}
	508	runtime->p.interpreter_func = lttng_bytecode_interpret;
	509	runtime->p.link_failed = 0;
	510	list_add_rcu(&runtime->p.node, insert_loc);
	511	dbg_printk("Linking successful.\n");
	512	return 0;
	513
	514	link_error:
	515
	516	runtime->p.interpreter_func = lttng_bytecode_interpret_error;
	517	runtime->p.link_failed = 1;
	518	list_add_rcu(&runtime->p.node, insert_loc);
	519	alloc_error:
	520	dbg_printk("Linking failed.\n");
	521	return ret;
	522	}
	523
	524	void lttng_bytecode_sync_state(struct lttng_kernel_bytecode_runtime *runtime)
	525	{
	526	struct lttng_kernel_bytecode_node *bc = runtime->bc;
	527
	528	if (!bc->enabler->enabled \|\| runtime->link_failed)
	529	runtime->interpreter_func = lttng_bytecode_interpret_error;
	530	else
	531	runtime->interpreter_func = lttng_bytecode_interpret;
	532	}
	533
	534	/*
	535	* Given the lists of bytecode programs of an instance (event or event
	536	* notifier) and of a matching enabler, try to link all the enabler's bytecode
	537	* programs with the instance.
	538	*
	539	* This function is called after we confirmed that name enabler and the
	540	* instance are matching names (or glob pattern matching).
	541	*/
	542	void lttng_enabler_link_bytecode(const struct lttng_kernel_event_desc *event_desc,
	543	struct lttng_kernel_ctx *ctx,
	544	struct list_head *instance_bytecode_head,
	545	struct list_head *enabler_bytecode_head)
	546	{
	547	struct lttng_kernel_bytecode_node *enabler_bc;
	548	struct lttng_kernel_bytecode_runtime *runtime;
	549
	550	WARN_ON_ONCE(!event_desc);
	551
	552	/* Go over all the bytecode programs of the enabler. */
	553	list_for_each_entry(enabler_bc, enabler_bytecode_head, node) {
	554	int found = 0, ret;
	555	struct list_head *insert_loc;
	556
	557	/*
	558	* Check if the current enabler bytecode program is already
	559	* linked with the instance.
	560	*/
	561	list_for_each_entry(runtime, instance_bytecode_head, node) {
	562	if (runtime->bc == enabler_bc) {
	563	found = 1;
	564	break;
	565	}
	566	}
	567
	568	/*
	569	* Skip bytecode already linked, go to the next enabler
	570	* bytecode program.
	571	*/
	572	if (found)
	573	continue;
	574
	575	/*
	576	* Insert at specified priority (seqnum) in increasing
	577	* order. If there already is a bytecode of the same priority,
	578	* insert the new bytecode right after it.
	579	*/
	580	list_for_each_entry_reverse(runtime,
	581	instance_bytecode_head, node) {
	582	if (runtime->bc->bc.seqnum <= enabler_bc->bc.seqnum) {
	583	/* insert here */
	584	insert_loc = &runtime->node;
	585	goto add_within;
	586	}
	587	}
	588	/* Add to head to list */
	589	insert_loc = instance_bytecode_head;
	590	add_within:
	591	dbg_printk("linking bytecode\n");
	592	ret = link_bytecode(event_desc, ctx, enabler_bc, instance_bytecode_head, insert_loc);
	593	if (ret) {
	594	dbg_printk("[lttng filter] warning: cannot link event bytecode\n");
	595	}
	596	}
	597	}
	598
	599	void lttng_free_event_filter_runtime(struct lttng_kernel_event_common *event)
	600	{
	601	struct bytecode_runtime runtime, tmp;
	602
	603	list_for_each_entry_safe(runtime, tmp,
	604	&event->priv->filter_bytecode_runtime_head, p.node) {
	605	kfree(runtime->data);
	606	kfree(runtime);
	607	}
	608	}