From 3be1a565f895d5399a6c1f6d0997dc528537fe86 Mon Sep 17 00:00:00 2001
From: Chloe Marcec <dmarcecguzman@gmail.com>
Date: Sat, 30 Jan 2021 20:40:49 +1100
Subject: kernel: Rewrite resource limit to be more accurate

Matches closer to hardware
---
 src/core/hle/kernel/k_resource_limit.cpp | 155 +++++++++++++++++++++++++++++++
 1 file changed, 155 insertions(+)
 create mode 100644 src/core/hle/kernel/k_resource_limit.cpp

(limited to 'src/core/hle/kernel/k_resource_limit.cpp')

diff --git a/src/core/hle/kernel/k_resource_limit.cpp b/src/core/hle/kernel/k_resource_limit.cpp
new file mode 100644
index 000000000..f943d6562
--- /dev/null
+++ b/src/core/hle/kernel/k_resource_limit.cpp
@@ -0,0 +1,155 @@
+// Copyright 2020 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+// This file references various implementation details from Atmosphere, an open-source firmware for
+// the Nintendo Switch. Copyright 2018-2020 Atmosphere-NX.
+
+#include "common/assert.h"
+#include "core/core.h"
+#include "core/core_timing.h"
+#include "core/core_timing_util.h"
+#include "core/hle/kernel/k_resource_limit.h"
+#include "core/hle/kernel/svc_results.h"
+
+namespace Kernel {
+namespace {
+static const s64 DefaultTimeout =
+    Core::Timing::msToCycles(std::chrono::milliseconds{10000}); // 10 seconds
+}
+
+KResourceLimit::KResourceLimit(KernelCore& kernel, Core::System& system)
+    : Object{kernel}, m_lock{kernel}, cond_var{kernel}, kernel{kernel}, system(system) {}
+KResourceLimit::~KResourceLimit() = default;
+
+s64 KResourceLimit::GetLimitValue(LimitableResource which) const {
+    const auto index = static_cast<std::size_t>(which);
+    s64 value{};
+    {
+        KScopedLightLock lk{m_lock};
+        value = limit_values[index];
+        ASSERT(value >= 0);
+        ASSERT(current_values[index] <= limit_values[index]);
+        ASSERT(current_hints[index] <= current_values[index]);
+    }
+    return value;
+}
+
+s64 KResourceLimit::GetCurrentValue(LimitableResource which) const {
+    const auto index = static_cast<std::size_t>(which);
+    s64 value{};
+    {
+        KScopedLightLock lk{m_lock};
+        value = current_values[index];
+        ASSERT(value >= 0);
+        ASSERT(current_values[index] <= limit_values[index]);
+        ASSERT(current_hints[index] <= current_values[index]);
+    }
+    return value;
+}
+
+s64 KResourceLimit::GetPeakValue(LimitableResource which) const {
+    const auto index = static_cast<std::size_t>(which);
+    s64 value{};
+    {
+        KScopedLightLock lk{m_lock};
+        value = peak_values[index];
+        ASSERT(value >= 0);
+        ASSERT(current_values[index] <= limit_values[index]);
+        ASSERT(current_hints[index] <= current_values[index]);
+    }
+    return value;
+}
+
+s64 KResourceLimit::GetFreeValue(LimitableResource which) const {
+    const auto index = static_cast<std::size_t>(which);
+    s64 value{};
+    {
+        KScopedLightLock lk(m_lock);
+        ASSERT(current_values[index] >= 0);
+        ASSERT(current_values[index] <= limit_values[index]);
+        ASSERT(current_hints[index] <= current_values[index]);
+        value = limit_values[index] - current_values[index];
+    }
+
+    return value;
+}
+
+ResultCode KResourceLimit::SetLimitValue(LimitableResource which, s64 value) {
+    const auto index = static_cast<std::size_t>(which);
+    KScopedLightLock lk(m_lock);
+    R_UNLESS(current_values[index] <= value, Svc::ResultInvalidState);
+
+    limit_values[index] = value;
+
+    return RESULT_SUCCESS;
+}
+
+bool KResourceLimit::Reserve(LimitableResource which, s64 value) {
+    return Reserve(which, value, system.CoreTiming().GetClockTicks() + DefaultTimeout);
+}
+
+bool KResourceLimit::Reserve(LimitableResource which, s64 value, s64 timeout) {
+    ASSERT(value >= 0);
+    const auto index = static_cast<std::size_t>(which);
+    KScopedLightLock lk(m_lock);
+
+    ASSERT(current_hints[index] <= current_values[index]);
+    if (current_hints[index] >= limit_values[index]) {
+        return false;
+    }
+
+    /* Loop until we reserve or run out of time. */
+    while (true) {
+        ASSERT(current_values[index] <= limit_values[index]);
+        ASSERT(current_hints[index] <= current_values[index]);
+
+        /* If we would overflow, don't allow to succeed. */
+        if (current_values[index] + value <= current_values[index]) {
+            break;
+        }
+
+        if (current_values[index] + value <= limit_values[index]) {
+            current_values[index] += value;
+            current_hints[index] += value;
+            peak_values[index] = std::max(peak_values[index], current_values[index]);
+            return true;
+        }
+
+        if (current_hints[index] + value <= limit_values[index] &&
+            (timeout < 0 || system.CoreTiming().GetClockTicks() < static_cast<u64>(timeout))) {
+            waiter_count++;
+            cond_var.Wait(&m_lock, timeout);
+            waiter_count--;
+        } else {
+            break;
+        }
+    }
+
+    return false;
+}
+
+void KResourceLimit::Release(LimitableResource which, s64 value) {
+    Release(which, value, value);
+}
+
+void KResourceLimit::Release(LimitableResource which, s64 value, s64 hint) {
+    ASSERT(value >= 0);
+    ASSERT(hint >= 0);
+
+    const auto index = static_cast<std::size_t>(which);
+    KScopedLightLock lk(m_lock);
+    ASSERT(current_values[index] <= limit_values[index]);
+    ASSERT(current_hints[index] <= current_values[index]);
+    ASSERT(value <= current_values[index]);
+    ASSERT(hint <= current_hints[index]);
+
+    current_values[index] -= value;
+    current_hints[index] -= hint;
+
+    if (waiter_count != 0) {
+        cond_var.Broadcast();
+    }
+}
+
+} // namespace Kernel
-- 
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