From d7933002795dcfd702e231c88141ada8501901ae Mon Sep 17 00:00:00 2001
From: Achilleas Anagnostopoulos <achilleas.imap.mbox@gmail.com>
Date: Wed, 21 Jun 2017 07:57:05 +0100
Subject: [PATCH] Move TLB-handling code to the cpu pkg

---
 kernel/cpu/cpu_amd64.go                         | 11 +++++++++++
 kernel/{mem/vmm/tlb_amd64.s => cpu/cpu_amd64.s} | 11 ++++++-----
 kernel/mem/vmm/map.go                           |  3 ++-
 kernel/mem/vmm/pdt.go                           |  5 +++--
 kernel/mem/vmm/tlb.go                           | 11 -----------
 5 files changed, 22 insertions(+), 19 deletions(-)
 create mode 100644 kernel/cpu/cpu_amd64.go
 rename kernel/{mem/vmm/tlb_amd64.s => cpu/cpu_amd64.s} (53%)
 delete mode 100644 kernel/mem/vmm/tlb.go

diff --git a/kernel/cpu/cpu_amd64.go b/kernel/cpu/cpu_amd64.go
new file mode 100644
index 0000000..4943fa2
--- /dev/null
+++ b/kernel/cpu/cpu_amd64.go
@@ -0,0 +1,11 @@
+package cpu
+
+// FlushTLBEntry flushes a TLB entry for a particular virtual address.
+func FlushTLBEntry(virtAddr uintptr)
+
+// SwitchPDT sets the root page table directory to point to the specified
+// physical address and flushes the TLB.
+func SwitchPDT(pdtPhysAddr uintptr)
+
+// ActivePDT returns the physical address of the currently active page table.
+func ActivePDT() uintptr
diff --git a/kernel/mem/vmm/tlb_amd64.s b/kernel/cpu/cpu_amd64.s
similarity index 53%
rename from kernel/mem/vmm/tlb_amd64.s
rename to kernel/cpu/cpu_amd64.s
index 0f12a43..002c8cb 100644
--- a/kernel/mem/vmm/tlb_amd64.s
+++ b/kernel/cpu/cpu_amd64.s
@@ -1,15 +1,16 @@
- #include "textflag.h"
- 
-TEXT ·flushTLBEntry(SB),NOSPLIT,$0
+#include "textflag.h"
+
+TEXT ·FlushTLBEntry(SB),NOSPLIT,$0
 	INVLPG virtAddr+0(FP)
 	RET
 
-TEXT ·switchPDT(SB),NOSPLIT,$0
+TEXT ·SwitchPDT(SB),NOSPLIT,$0
 	// loading CR3 also triggers a TLB flush
 	MOVQ pdtPhysAddr+0(FP), CR3
 	RET
 
-TEXT ·activePDT(SB),NOSPLIT,$0
+TEXT ·ActivePDT(SB),NOSPLIT,$0
 	MOVQ CR3, AX
 	MOVQ AX, ret+0(FP)
 	RET
+
diff --git a/kernel/mem/vmm/map.go b/kernel/mem/vmm/map.go
index 4dfe64d..fc472da 100644
--- a/kernel/mem/vmm/map.go
+++ b/kernel/mem/vmm/map.go
@@ -4,6 +4,7 @@ import (
 	"unsafe"
 
 	"github.com/achilleasa/gopher-os/kernel"
+	"github.com/achilleasa/gopher-os/kernel/cpu"
 	"github.com/achilleasa/gopher-os/kernel/mem"
 	"github.com/achilleasa/gopher-os/kernel/mem/pmm"
 )
@@ -18,7 +19,7 @@ var (
 
 	// flushTLBEntryFn is used by tests to override calls to flushTLBEntry
 	// which will cause a fault if called in user-mode.
-	flushTLBEntryFn = flushTLBEntry
+	flushTLBEntryFn = cpu.FlushTLBEntry
 
 	errNoHugePageSupport = &kernel.Error{Module: "vmm", Message: "huge pages are not supported"}
 )
diff --git a/kernel/mem/vmm/pdt.go b/kernel/mem/vmm/pdt.go
index e60b336..68505cd 100644
--- a/kernel/mem/vmm/pdt.go
+++ b/kernel/mem/vmm/pdt.go
@@ -4,6 +4,7 @@ import (
 	"unsafe"
 
 	"github.com/achilleasa/gopher-os/kernel"
+	"github.com/achilleasa/gopher-os/kernel/cpu"
 	"github.com/achilleasa/gopher-os/kernel/mem"
 	"github.com/achilleasa/gopher-os/kernel/mem/pmm"
 )
@@ -11,11 +12,11 @@ import (
 var (
 	// activePDTFn is used by tests to override calls to activePDT which
 	// will cause a fault if called in user-mode.
-	activePDTFn = activePDT
+	activePDTFn = cpu.ActivePDT
 
 	// switchPDTFn is used by tests to override calls to switchPDT which
 	// will cause a fault if called in user-mode.
-	switchPDTFn = switchPDT
+	switchPDTFn = cpu.SwitchPDT
 
 	// mapFn is used by tests and is automatically inlined by the compiler.
 	mapFn = Map
diff --git a/kernel/mem/vmm/tlb.go b/kernel/mem/vmm/tlb.go
deleted file mode 100644
index 703e597..0000000
--- a/kernel/mem/vmm/tlb.go
+++ /dev/null
@@ -1,11 +0,0 @@
-package vmm
-
-// flushTLBEntry flushes a TLB entry for a particular virtual address.
-func flushTLBEntry(virtAddr uintptr)
-
-// switchPDT sets the root page table directory to point to the specified
-// physical address and flushes the TLB.
-func switchPDT(pdtPhysAddr uintptr)
-
-// activePDT returns the physical address of the currently active page table.
-func activePDT() uintptr