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1// SPDX-License-Identifier: GPL-2.02/*3 * KUnit function redirection (static stubbing) API.4 *5 * Copyright (C) 2022, Google LLC.6 * Author: David Gow <davidgow@google.com>7 */8 9#include <kunit/test.h>10#include <kunit/static_stub.h>11#include "hooks-impl.h"12 13 14/* Context for a static stub. This is stored in the resource data. */15struct kunit_static_stub_ctx {16 void *real_fn_addr;17 void *replacement_addr;18};19 20static void __kunit_static_stub_resource_free(struct kunit_resource *res)21{22 kfree(res->data);23}24 25/* Matching function for kunit_find_resource(). match_data is real_fn_addr. */26static bool __kunit_static_stub_resource_match(struct kunit *test,27 struct kunit_resource *res,28 void *match_real_fn_addr)29{30 /* This pointer is only valid if res is a static stub resource. */31 struct kunit_static_stub_ctx *ctx = res->data;32 33 /* Make sure the resource is a static stub resource. */34 if (res->free != &__kunit_static_stub_resource_free)35 return false;36 37 return ctx->real_fn_addr == match_real_fn_addr;38}39 40/* Hook to return the address of the replacement function. */41void *__kunit_get_static_stub_address_impl(struct kunit *test, void *real_fn_addr)42{43 struct kunit_resource *res;44 struct kunit_static_stub_ctx *ctx;45 void *replacement_addr;46 47 res = kunit_find_resource(test,48 __kunit_static_stub_resource_match,49 real_fn_addr);50 51 if (!res)52 return NULL;53 54 ctx = res->data;55 replacement_addr = ctx->replacement_addr;56 kunit_put_resource(res);57 return replacement_addr;58}59 60void kunit_deactivate_static_stub(struct kunit *test, void *real_fn_addr)61{62 struct kunit_resource *res;63 64 KUNIT_ASSERT_PTR_NE_MSG(test, real_fn_addr, NULL,65 "Tried to deactivate a NULL stub.");66 67 /* Look up the existing stub for this function. */68 res = kunit_find_resource(test,69 __kunit_static_stub_resource_match,70 real_fn_addr);71 72 /* Error out if the stub doesn't exist. */73 KUNIT_ASSERT_PTR_NE_MSG(test, res, NULL,74 "Tried to deactivate a nonexistent stub.");75 76 /* Free the stub. We 'put' twice, as we got a reference77 * from kunit_find_resource()78 */79 kunit_remove_resource(test, res);80 kunit_put_resource(res);81}82EXPORT_SYMBOL_GPL(kunit_deactivate_static_stub);83 84/* Helper function for kunit_activate_static_stub(). The macro does85 * typechecking, so use it instead.86 */87void __kunit_activate_static_stub(struct kunit *test,88 void *real_fn_addr,89 void *replacement_addr)90{91 struct kunit_static_stub_ctx *ctx;92 struct kunit_resource *res;93 94 KUNIT_ASSERT_PTR_NE_MSG(test, real_fn_addr, NULL,95 "Tried to activate a stub for function NULL");96 97 /* If the replacement address is NULL, deactivate the stub. */98 if (!replacement_addr) {99 kunit_deactivate_static_stub(test, replacement_addr);100 return;101 }102 103 /* Look up any existing stubs for this function, and replace them. */104 res = kunit_find_resource(test,105 __kunit_static_stub_resource_match,106 real_fn_addr);107 if (res) {108 ctx = res->data;109 ctx->replacement_addr = replacement_addr;110 111 /* We got an extra reference from find_resource(), so put it. */112 kunit_put_resource(res);113 } else {114 ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);115 KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ctx);116 ctx->real_fn_addr = real_fn_addr;117 ctx->replacement_addr = replacement_addr;118 res = kunit_alloc_resource(test, NULL,119 &__kunit_static_stub_resource_free,120 GFP_KERNEL, ctx);121 }122}123EXPORT_SYMBOL_GPL(__kunit_activate_static_stub);124