// SPDX-License-Identifier: GPL-2.0/* * KUnit function redirection (static stubbing) API. * * Copyright (C) 2022, Google LLC. * Author: David Gow <davidgow@google.com> */ #include <kunit/test.h>#include <kunit/static_stub.h>#include "hooks-impl.h"  /* Context for a static stub. This is stored in the resource data. */struct kunit_static_stub_ctx {	void *real_fn_addr;	void *replacement_addr;}; static void __kunit_static_stub_resource_free(struct kunit_resource *res){	kfree(res->data);} /* Matching function for kunit_find_resource(). match_data is real_fn_addr. */static bool __kunit_static_stub_resource_match(struct kunit *test,						struct kunit_resource *res,						void *match_real_fn_addr){	/* This pointer is only valid if res is a static stub resource. */	struct kunit_static_stub_ctx *ctx = res->data; 	/* Make sure the resource is a static stub resource. */	if (res->free != &__kunit_static_stub_resource_free)		return false; 	return ctx->real_fn_addr == match_real_fn_addr;} /* Hook to return the address of the replacement function. */void *__kunit_get_static_stub_address_impl(struct kunit *test, void *real_fn_addr){	struct kunit_resource *res;	struct kunit_static_stub_ctx *ctx;	void *replacement_addr; 	res = kunit_find_resource(test,				  __kunit_static_stub_resource_match,				  real_fn_addr); 	if (!res)		return NULL; 	ctx = res->data;	replacement_addr = ctx->replacement_addr;	kunit_put_resource(res);	return replacement_addr;} void kunit_deactivate_static_stub(struct kunit *test, void *real_fn_addr){	struct kunit_resource *res; 	KUNIT_ASSERT_PTR_NE_MSG(test, real_fn_addr, NULL,				"Tried to deactivate a NULL stub."); 	/* Look up the existing stub for this function. */	res = kunit_find_resource(test,				  __kunit_static_stub_resource_match,				  real_fn_addr); 	/* Error out if the stub doesn't exist. */	KUNIT_ASSERT_PTR_NE_MSG(test, res, NULL,				"Tried to deactivate a nonexistent stub."); 	/* Free the stub. We 'put' twice, as we got a reference	 * from kunit_find_resource()	 */	kunit_remove_resource(test, res);	kunit_put_resource(res);}EXPORT_SYMBOL_GPL(kunit_deactivate_static_stub); /* Helper function for kunit_activate_static_stub(). The macro does * typechecking, so use it instead. */void __kunit_activate_static_stub(struct kunit *test,				  void *real_fn_addr,				  void *replacement_addr){	struct kunit_static_stub_ctx *ctx;	struct kunit_resource *res; 	KUNIT_ASSERT_PTR_NE_MSG(test, real_fn_addr, NULL,				"Tried to activate a stub for function NULL"); 	/* If the replacement address is NULL, deactivate the stub. */	if (!replacement_addr) {		kunit_deactivate_static_stub(test, real_fn_addr);		return;	} 	/* Look up any existing stubs for this function, and replace them. */	res = kunit_find_resource(test,				  __kunit_static_stub_resource_match,				  real_fn_addr);	if (res) {		ctx = res->data;		ctx->replacement_addr = replacement_addr; 		/* We got an extra reference from find_resource(), so put it. */		kunit_put_resource(res);	} else {		ctx = kmalloc_obj(*ctx);		KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ctx);		ctx->real_fn_addr = real_fn_addr;		ctx->replacement_addr = replacement_addr;		res = kunit_alloc_resource(test, NULL,				     &__kunit_static_stub_resource_free,				     GFP_KERNEL, ctx);	}}EXPORT_SYMBOL_GPL(__kunit_activate_static_stub);