add mmu context

arch/x86/mmuContext.c

@@ -0,0 +1,79 @@
+#include "mmuContext.h"
+#include "alloc.h"
+#include "allocArea.h"
+#include "errno.h"
+#include "klibc.h"
+#include "irq.h"
+#include "list.h"
+#include "paging.h"
+#include "stdarg.h"
+#include "types.h"
+
+struct mmu_context {
+    paddr_t paddr_PD;
+    vaddr_t vaddr_PD;
+    uint32_t ref;
+
+    struct mmu_context *next, *prev;
+};
+
+static struct mmu_context *listContext    = NULL;
+static struct mmu_context *currentContext = NULL;
+
+int mmuContextSetup()
+{
+    struct mmu_context *initialCtx;
+    int ret = 0;
+
+    initialCtx = malloc(sizeof(struct mmu_context));
+
+    if (initialCtx == NULL)
+        return -ENOMEM;
+
+    initialCtx->paddr_PD = pagingGetCurrentPDPaddr();
+    initialCtx->vaddr_PD = areaAlloc(1, 0);
+
+    ret = pageMap(initialCtx->vaddr_PD, initialCtx->paddr_PD,
+                  PAGING_MEM_WRITE | PAGING_MEM_READ);
+
+    if (ret)
+        return ret;
+
+    list_singleton(listContext, initialCtx);
+    currentContext = initialCtx;
+
+    // We create the context and we are using it
+    initialCtx->ref = 2;
+    return 0;
+}
+
+struct mmu_context *mmuContextCreate()
+{
+    struct mmu_context *ctx;
+    uint32_t flags;
+
+    ctx = malloc(sizeof(struct mmu_context));
+
+    if (ctx == NULL)
+        return NULL;
+
+    ctx->vaddr_PD = areaAlloc(1, AREA_PHY_MAP);
+
+    if (ctx->vaddr_PD == (vaddr_t)NULL) {
+        pr_info("Fail to allocate MMU Context\n");
+        free(ctx);
+
+        return NULL;
+    }
+
+    ctx->paddr_PD = pagingGetPaddr(ctx->vaddr_PD);
+
+    ctx->ref = 1;
+
+    //TODO copy kernel space
+    disable_IRQs(flags);
+    list_add_tail(listContext, ctx);
+    restore_IRQs(flags);
+
+    return ctx;
+}

arch/x86/paging.c

@@ -198,7 +198,38 @@ int pageUnmap(vaddr_t vaddr)
     return 0;
 }
 
+paddr_t pagingGetPaddr(vaddr_t vaddr)
+{
+    /* Get the page directory entry and table entry index for this
+       address */
+    unsigned pdEntry    = vaddr >> PD_SHIFT;
+    unsigned ptEntry    = vaddr >> PT_SHIFT;
+    unsigned pageOffset = vaddr & PAGE_MASK;
+
+    /* Get the PD of the current context */
+    struct pde *pd =
+        (struct pde *)((PD_MIRROR_PAGE_IDX << PD_SHIFT) + (PD_MIRROR_PAGE_IDX << PT_SHIFT));
+
+    /* Address of the PT in the mirroring */
+    struct pte *pt = (struct pte *)((PD_MIRROR_PAGE_IDX << PD_SHIFT) + (pdEntry << PT_SHIFT));
+
+    /* No page mapped at this address ? */
+    if (!pd[pdEntry].present)
+        return (paddr_t)NULL;
+    if (!pt[ptEntry].present)
+        return (paddr_t)NULL;
+
+    return (pt[ptEntry].paddr << PT_SHIFT) + pageOffset;
+}
+
 unsigned long getNbMappedPage(void)
 {
     return mappedPage;
 }
+
+paddr_t pagingGetCurrentPDPaddr()
+{
+  struct pdbr pdbr;
+  asm volatile("movl %%cr3, %0\n": "=r"(pdbr));
+  return (pdbr.pd_paddr << 12);
+}

arch/x86/paging.h

@@ -10,3 +10,6 @@ int pagingSetup(paddr_t lowerKernelAddr, paddr_t upperKernelAddr);
 int pageMap(vaddr_t vaddr, paddr_t paddr, int flags);
 int pageUnmap(vaddr_t vaddr);
 unsigned long getNbMappedPage(void);
+
+paddr_t pagingGetPaddr(vaddr_t vaddr);
+paddr_t pagingGetCurrentPDPaddr();

core/mmuContext.h

@@ -0,0 +1,5 @@
+#pragma once
+
+struct mmu_context;
+int mmuContextSetup();
+struct mmu_context *mmuContextCreate();