From 5b8a20dbf7aa043088c2302e38f149e7d07fa8ed Mon Sep 17 00:00:00 2001
From: Michael Scire <SciresM@gmail.com>
Date: Mon, 20 Jul 2020 02:11:49 -0700
Subject: [PATCH] kern: fix bug in SvcSetThreadPriority

---
 .../include/mesosphere/kern_k_thread.hpp            |  3 +++
 libraries/libmesosphere/source/kern_k_thread.cpp    | 13 +++++++++++++
 .../libmesosphere/source/svc/kern_svc_thread.cpp    |  2 +-
 3 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/libraries/libmesosphere/include/mesosphere/kern_k_thread.hpp b/libraries/libmesosphere/include/mesosphere/kern_k_thread.hpp
index 90bbacb09..7db14b565 100644
--- a/libraries/libmesosphere/include/mesosphere/kern_k_thread.hpp
+++ b/libraries/libmesosphere/include/mesosphere/kern_k_thread.hpp
@@ -347,8 +347,10 @@ namespace ams::kern {
             constexpr s32 GetIdealCore() const { return this->ideal_core_id; }
             constexpr s32 GetActiveCore() const { return this->core_id; }
             constexpr void SetActiveCore(s32 core) { this->core_id = core; }
+
             constexpr s32 GetPriority() const { return this->priority; }
             constexpr void SetPriority(s32 prio) { this->priority = prio; }
+
             constexpr s32 GetBasePriority() const { return this->base_priority; }
 
             constexpr QueueEntry &GetPriorityQueueEntry(s32 core) { return this->per_core_priority_queue_entry[core]; }
@@ -438,6 +440,7 @@ namespace ams::kern {
 
             void Wakeup();
 
+            void SetBasePriority(s32 priority);
             Result SetPriorityToIdle();
 
             Result Run();
diff --git a/libraries/libmesosphere/source/kern_k_thread.cpp b/libraries/libmesosphere/source/kern_k_thread.cpp
index 3c0681683..16e52b95b 100644
--- a/libraries/libmesosphere/source/kern_k_thread.cpp
+++ b/libraries/libmesosphere/source/kern_k_thread.cpp
@@ -384,6 +384,19 @@ namespace ams::kern {
         }
     }
 
+    void KThread::SetBasePriority(s32 priority) {
+        MESOSPHERE_ASSERT_THIS();
+        MESOSPHERE_ASSERT(ams::svc::HighestThreadPriority <= priority && priority <= ams::svc::LowestThreadPriority);
+
+        KScopedSchedulerLock sl;
+
+        /* Change our base priority. */
+        this->base_priority = priority;
+
+        /* Perform a priority restoration. */
+        RestorePriority(this);
+    }
+
     Result KThread::SetPriorityToIdle() {
         MESOSPHERE_ASSERT_THIS();
 
diff --git a/libraries/libmesosphere/source/svc/kern_svc_thread.cpp b/libraries/libmesosphere/source/svc/kern_svc_thread.cpp
index d1314b6a6..4cf9b3305 100644
--- a/libraries/libmesosphere/source/svc/kern_svc_thread.cpp
+++ b/libraries/libmesosphere/source/svc/kern_svc_thread.cpp
@@ -141,7 +141,7 @@ namespace ams::kern::svc {
             R_UNLESS(thread.IsNotNull(), svc::ResultInvalidHandle());
 
             /* Set the thread priority. */
-            thread->SetPriority(priority);
+            thread->SetBasePriority(priority);
             return ResultSuccess();
         }