From 3fe5911dbfd6751dbd9bdb936086224b2e45f586 Mon Sep 17 00:00:00 2001
From: Pawel Wieczorkiewicz <wipawel@grsecurity.net>
Date: Fri, 24 Jun 2022 10:04:22 +0200
Subject: [PATCH] tasks: make tasks functions return unsigned long value

Tasks execute functions and now the functions can return a value,
which is stored in task structure's result field.

Signed-off-by: Pawel Wieczorkiewicz <wipawel@grsecurity.net>
---
 common/sched.c            |  2 +-
 drivers/acpi/acpica/osl.c | 18 +++++++++++++++++-
 include/ktf.h             |  2 +-
 include/sched.h           |  2 +-
 tests/test.c              |  3 ++-
 5 files changed, 22 insertions(+), 5 deletions(-)

diff --git a/common/sched.c b/common/sched.c
index 5bbc0bcc..7e6392e8 100644
--- a/common/sched.c
+++ b/common/sched.c
@@ -202,7 +202,7 @@ static void run_task(task_t *task) {
     printk("CPU[%u]: Running task %s[%u]\n", task->cpu, task->name, task->id);
 
     set_task_state(task, TASK_STATE_RUNNING);
-    task->func(task->arg);
+    task->result = task->func(task->arg);
     set_task_state(task, TASK_STATE_DONE);
 }
 
diff --git a/drivers/acpi/acpica/osl.c b/drivers/acpi/acpica/osl.c
index 66a74e25..9d372a00 100644
--- a/drivers/acpi/acpica/osl.c
+++ b/drivers/acpi/acpica/osl.c
@@ -343,16 +343,32 @@ ACPI_THREAD_ID AcpiOsGetThreadId(void) {
     return smp_processor_id() + 1;
 }
 
+struct osd_exec_cb_wrapper {
+    ACPI_OSD_EXEC_CALLBACK Function;
+    void *Context;
+};
+typedef struct osd_exec_cb_wrapper osd_exec_cb_wrapper_t;
+
+unsigned long _osd_exec_cb_wrapper(void *arg) {
+    osd_exec_cb_wrapper_t *cb = arg;
+
+    cb->Function(cb->Context);
+    return 0;
+}
+
 ACPI_STATUS AcpiOsExecute(ACPI_EXECUTE_TYPE Type, ACPI_OSD_EXEC_CALLBACK Function,
                           void *Context) {
     static unsigned counter = 0;
     unsigned cpu = smp_processor_id();
+    osd_exec_cb_wrapper_t cb;
     char name[40];
     task_t *task;
 
     snprintf(name, sizeof(name), "acpi_%u_%u_%u", Type, counter++, cpu);
 
-    task = new_task(name, (task_func_t) Function, Context);
+    cb.Function = Function;
+    cb.Context = Context;
+    task = new_task(name, _osd_exec_cb_wrapper, &cb);
     if (!task)
         return AE_NO_MEMORY;
 
diff --git a/include/ktf.h b/include/ktf.h
index 44f84188..500cc215 100644
--- a/include/ktf.h
+++ b/include/ktf.h
@@ -45,7 +45,7 @@ extern bool opt_debug;
 extern int usermode_call(user_func_t fn, void *fn_arg);
 
 extern void kernel_main(void) __noreturn;
-extern void test_main(void *unused);
+extern unsigned long test_main(void *unused);
 
 #endif /* __ASSEMBLY__ */
 
diff --git a/include/sched.h b/include/sched.h
index be808587..004a5880 100644
--- a/include/sched.h
+++ b/include/sched.h
@@ -30,7 +30,7 @@
 #include <list.h>
 #include <page.h>
 
-typedef void (*task_func_t)(void *arg);
+typedef unsigned long (*task_func_t)(void *arg);
 
 enum task_state {
     TASK_STATE_NEW,
diff --git a/tests/test.c b/tests/test.c
index 0ec088d6..31295511 100644
--- a/tests/test.c
+++ b/tests/test.c
@@ -59,7 +59,7 @@ static get_next_test_result_t get_next_test(test_fn **out_test_fn, char **out_na
     return TESTS_DONE;
 }
 
-void test_main(void *unused) {
+unsigned long test_main(void *unused) {
     char *name;
     test_fn *fn = NULL;
     unsigned n = 0;
@@ -76,4 +76,5 @@ void test_main(void *unused) {
     }
 
     printk("Tests completed: %u\n", n);
+    return 0;
 }