arch/x86/mmuContext.c

@@ -20,6 +20,10 @@ struct mmu_context {
 static struct mmu_context *listContext    = NULL;
 static struct mmu_context *currentContext = NULL;
 
+struct mmu_context * mmuContextGetCurrent(){
+    return currentContext;
+}
+
 int mmuContextSetup()
 {
     struct mmu_context *initialCtx;
@@ -84,6 +88,63 @@ struct mmu_context *mmuContextCreate()
     return ctx;
 }
 
+int mmuContextRef(struct mmu_context *ctx)
+{
+    uint32_t flags;
+
+    disable_IRQs(flags);
+
+    // ref == 0 => suppression
+    assert(ctx->ref > 0);
+    ctx->ref++;
+
+    restore_IRQs(flags);
+
+    return 0;
+}
+
+int mmuContextUnref(struct mmu_context *ctx)
+{
+    uint32_t flags;
+
+    disable_IRQs(flags);
+
+    assert(ctx->ref > 0);
+    ctx->ref--;
+
+    if (ctx->ref == 0) {
+        list_delete(listContext, ctx);
+        pagingClearUserContext(ctx->vaddr_PD);
+        areaFree(ctx->vaddr_PD);
+        free(ctx);
+    }
+
+    restore_IRQs(flags);
+
+    return 0;
+}
+
+int mmuContextSwitch(struct mmu_context *ctx)
+{
+    uint32_t flags;
+
+    disable_IRQs(flags);
+    assert(ctx->ref > 0);
+    assert(currentContext->ref > 0);
+
+    if (ctx != currentContext) {
+        struct mmu_context *prev = currentContext;
+
+        ctx->ref++;
+        currentContext = ctx;
+        pagingSetCurrentPDPaddr(ctx->paddr_PD);
+        mmuContextUnref(prev);
+    }
+
+    restore_IRQs(flags);
+    return 0;
+}
+
 int mmuContextSyncKernelPDE(int pdEntry, void *pde, size_t pdeSize)
 {
     uint32_t flags;

arch/x86/paging.c

@@ -1,3 +1,4 @@
+#include "allocArea.h"
 #include "paging.h"
 #include "errno.h"
 #include "kernel.h"
@@ -269,6 +270,45 @@ int pagingSetCurrentPDPaddr(paddr_t paddrPD)
     return 0;
 }
 
+// unmap page inside this MMU context
+int pagingClearUserContext(vaddr_t vaddr_PD)
+{
+    struct pde *pd = (struct pde *)vaddr_PD;
+    //Tmp pt to unref page they reference
+    struct pte *pt = (struct pte *)areaAlloc(1, 0);
+
+    if(pt == NULL)
+        return -ENOMEM;
+
+    for (int pdIdx = PAGING_BASE_USER_ADDRESS >> PD_SHIFT; pdIdx < 1024; pdIdx++) {
+
+        if(!pd[pdIdx].present){
+            memset(&pd[pdIdx], 0, sizeof(struct pde));
+
+            continue;
+        }
+        paddr_t ptAddr = pd[pdIdx].pt_addr << PT_SHIFT;
+        assert(!pageMap(ptAddr, (vaddr_t)pt, PAGING_MEM_USER | PAGING_MEM_WRITE));
+        for(int ptIdx = 0; ptIdx < 1024; ptIdx ++){
+            if(!pt[ptIdx].present){
+                memset(&pt[ptIdx], 0, sizeof(struct pte));
+
+                continue;
+            }
+            unrefPhyPage(pt[ptIdx].paddr);
+            memset(&pt[ptIdx], 0, sizeof(struct pte));
+        }
+        assert(!pageUnmap((vaddr_t)pt));
+        memset(&pd[pdIdx], 0, sizeof(struct pde));
+
+        unrefPhyPage(ptAddr);
+    }
+
+    areaFree((vaddr_t)pt);
+
+    return 0;
+}
+
 int pagingCopyKernelSpace(vaddr_t destVaddrPD, paddr_t destPaddrPD, vaddr_t srcVaddrPD)
 {
     struct pde *src_pd  = (struct pde *)srcVaddrPD;

arch/x86/paging.h

@@ -28,3 +28,4 @@ int pagingSetCurrentPDPaddr(paddr_t paddrPD);
 paddr_t pagingGetPaddr(vaddr_t vaddr);
 paddr_t pagingGetCurrentPDPaddr();
 int pagingCopyKernelSpace(vaddr_t destVaddrPD, paddr_t destPaddrPD, vaddr_t srcVaddrPD);
+int pagingClearUserContext(vaddr_t vaddr_PD);

core/main.c

@@ -11,6 +11,7 @@
 #include "klibc.h"
 #include "kthread.h"
 #include "mem.h"
+#include "mmuContext.h"
 #include "multiboot.h"
 #include "paging.h"
 #include "pit.h"
@@ -163,6 +164,7 @@ void kmain(unsigned long magic, unsigned long addr)
     printf("[Setup] allocation system\n");
     areaInit(firstUsedByMem, lastUsedByMem, _stack_bottom, _stack_top);
 
+    mmuContextSetup();
     cpu_context_subsystem_setup();
 
     printf("[Setup] thread system\n");

core/mmuContext.h

@@ -6,3 +6,7 @@ struct mmu_context;
 int mmuContextSetup();
 struct mmu_context *mmuContextCreate();
 int mmuContextSyncKernelPDE(int pdEntry, void *pde, size_t pdeSize);
+int mmuContextSwitch(struct mmu_context *ctx);
+struct mmu_context *mmuContextGetCurrent();
+int mmuContextRef(struct mmu_context *ctx);
+int mmuContextUnref(struct mmu_context *ctx);

tests/test.c

@@ -7,6 +7,7 @@
 #include "kthread.h"
 #include "list.h"
 #include "mem.h"
+#include "mmuContext.h"
 #include "paging.h"
 #include "serial.h"
 #include "stack.h"
@@ -363,11 +364,23 @@ void testATAThread(){
     }
 }
 
-void testATA(){
+static void testATA(){
     kthreadCreate("ATA_TEST", testATAThread, NULL);
     //testATAThread();
 }
 
+static void testMMUContext()
+{
+    printf("Testing mmu\n");
+    struct mmu_context *current = mmuContextGetCurrent();
+    assert(current != NULL);
+    struct mmu_context *new = mmuContextCreate();
+    assert(new != NULL);
+    mmuContextSwitch(new);
+    mmuContextSwitch(current);
+    mmuContextUnref(new);
+}
+
 void run_test(void)
 {
     testATA();
@@ -402,4 +415,5 @@ void run_test(void)
     test_backtrace();
     testCoroutine();
     testKthread();
+    testMMUContext();
 }