cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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try-catch.c (2945B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * An API to allow a function, that may fail, to be executed, and recover in a
      4 * controlled manner.
      5 *
      6 * Copyright (C) 2019, Google LLC.
      7 * Author: Brendan Higgins <brendanhiggins@google.com>
      8 */
      9
     10#include <kunit/test.h>
     11#include <linux/completion.h>
     12#include <linux/kernel.h>
     13#include <linux/kthread.h>
     14
     15#include "try-catch-impl.h"
     16
     17void __noreturn kunit_try_catch_throw(struct kunit_try_catch *try_catch)
     18{
     19	try_catch->try_result = -EFAULT;
     20	kthread_complete_and_exit(try_catch->try_completion, -EFAULT);
     21}
     22EXPORT_SYMBOL_GPL(kunit_try_catch_throw);
     23
     24static int kunit_generic_run_threadfn_adapter(void *data)
     25{
     26	struct kunit_try_catch *try_catch = data;
     27
     28	try_catch->try(try_catch->context);
     29
     30	kthread_complete_and_exit(try_catch->try_completion, 0);
     31}
     32
     33static unsigned long kunit_test_timeout(void)
     34{
     35	/*
     36	 * TODO(brendanhiggins@google.com): We should probably have some type of
     37	 * variable timeout here. The only question is what that timeout value
     38	 * should be.
     39	 *
     40	 * The intention has always been, at some point, to be able to label
     41	 * tests with some type of size bucket (unit/small, integration/medium,
     42	 * large/system/end-to-end, etc), where each size bucket would get a
     43	 * default timeout value kind of like what Bazel does:
     44	 * https://docs.bazel.build/versions/master/be/common-definitions.html#test.size
     45	 * There is still some debate to be had on exactly how we do this. (For
     46	 * one, we probably want to have some sort of test runner level
     47	 * timeout.)
     48	 *
     49	 * For more background on this topic, see:
     50	 * https://mike-bland.com/2011/11/01/small-medium-large.html
     51	 *
     52	 * If tests timeout due to exceeding sysctl_hung_task_timeout_secs,
     53	 * the task will be killed and an oops generated.
     54	 */
     55	return 300 * msecs_to_jiffies(MSEC_PER_SEC); /* 5 min */
     56}
     57
     58void kunit_try_catch_run(struct kunit_try_catch *try_catch, void *context)
     59{
     60	DECLARE_COMPLETION_ONSTACK(try_completion);
     61	struct kunit *test = try_catch->test;
     62	struct task_struct *task_struct;
     63	int exit_code, time_remaining;
     64
     65	try_catch->context = context;
     66	try_catch->try_completion = &try_completion;
     67	try_catch->try_result = 0;
     68	task_struct = kthread_run(kunit_generic_run_threadfn_adapter,
     69				  try_catch,
     70				  "kunit_try_catch_thread");
     71	if (IS_ERR(task_struct)) {
     72		try_catch->catch(try_catch->context);
     73		return;
     74	}
     75
     76	time_remaining = wait_for_completion_timeout(&try_completion,
     77						     kunit_test_timeout());
     78	if (time_remaining == 0) {
     79		kunit_err(test, "try timed out\n");
     80		try_catch->try_result = -ETIMEDOUT;
     81		kthread_stop(task_struct);
     82	}
     83
     84	exit_code = try_catch->try_result;
     85
     86	if (!exit_code)
     87		return;
     88
     89	if (exit_code == -EFAULT)
     90		try_catch->try_result = 0;
     91	else if (exit_code == -EINTR)
     92		kunit_err(test, "wake_up_process() was never called\n");
     93	else if (exit_code)
     94		kunit_err(test, "Unknown error: %d\n", exit_code);
     95
     96	try_catch->catch(try_catch->context);
     97}
     98EXPORT_SYMBOL_GPL(kunit_try_catch_run);