Kernel: Harvest randomness from various drivers

Random now gets entropy from the following drivers:
- KeyboardDevice
- PATAChannel
- PS2MouseDevice
- E1000NetworkAdapter
- RTL8139NetworkAdapter

Of these devices,  PS2MouseDevice and PATAChannel provide the vast
majority of the entropy.

Kernel/Net/E1000NetworkAdapter.cpp

@@ -204,6 +204,9 @@ void E1000NetworkAdapter::handle_irq(const RegisterState&)
     out32(REG_INTERRUPT_MASK_CLEAR, 0xffffffff);
 
     u32 status = in32(REG_INTERRUPT_CAUSE_READ);
+
+    m_entropy_source.add_random_event(status);
+
     if (status & 4) {
         u32 flags = in32(REG_CTRL);
         out32(REG_CTRL, flags | ECTRL_SLU);

Kernel/Net/E1000NetworkAdapter.h

@@ -28,11 +28,12 @@
 
 #include <AK/NonnullOwnPtrVector.h>
 #include <AK/OwnPtr.h>
+#include <Kernel/IO.h>
 #include <Kernel/Interrupts/IRQHandler.h>
 #include <Kernel/Net/NetworkAdapter.h>
 #include <Kernel/PCI/Access.h>
 #include <Kernel/PCI/Device.h>
-#include <Kernel/IO.h>
+#include <Kernel/Random.h>
 
 namespace Kernel {
 
@@ -103,6 +104,7 @@ private:
     u8 m_interrupt_line { 0 };
     bool m_has_eeprom { false };
     bool m_use_mmio { false };
+    EntropySource m_entropy_source;
 
     static const size_t number_of_rx_descriptors = 32;
     static const size_t number_of_tx_descriptors = 8;

Kernel/Net/RTL8139NetworkAdapter.cpp

@@ -184,6 +184,8 @@ void RTL8139NetworkAdapter::handle_irq(const RegisterState&)
         int status = in16(REG_ISR);
         out16(REG_ISR, status);
 
+        m_entropy_source.add_random_event(status);
+
 #ifdef RTL8139_DEBUG
         klog() << "RTL8139NetworkAdapter::handle_irq status=0x" << String::format("%x", status);
 #endif

Kernel/Net/RTL8139NetworkAdapter.h

@@ -27,10 +27,11 @@
 #pragma once
 
 #include <AK/OwnPtr.h>
+#include <Kernel/IO.h>
 #include <Kernel/Net/NetworkAdapter.h>
 #include <Kernel/PCI/Access.h>
 #include <Kernel/PCI/Device.h>
-#include <Kernel/IO.h>
+#include <Kernel/Random.h>
 
 namespace Kernel {
 
@@ -73,5 +74,6 @@ private:
     u8 m_tx_next_buffer { 0 };
     OwnPtr<Region> m_packet_buffer;
     bool m_link_up { false };
+    EntropySource m_entropy_source;
 };
 }