context: add copy kernel context

fix also some indentation

arch/x86/mmuContext.c

@@ -2,8 +2,8 @@
 #include "alloc.h"
 #include "allocArea.h"
 #include "errno.h"
-#include "klibc.h"
 #include "irq.h"
+#include "klibc.h"
 #include "list.h"
 #include "paging.h"
 #include "stdarg.h"
@@ -70,7 +70,13 @@ struct mmu_context *mmuContextCreate()
 
     ctx->ref = 1;
 
-    //TODO copy kernel space
+    if (pagingCopyKernelSpace(ctx->vaddr_PD, ctx->paddr_PD, currentContext->vaddr_PD)) {
+        pr_err("Fail to copy Kernel space\n");
+        free(ctx);
+
+        return NULL;
+    }
+
     disable_IRQs(flags);
     list_add_tail(listContext, ctx);
     restore_IRQs(flags);
@@ -78,7 +84,7 @@ struct mmu_context *mmuContextCreate()
     return ctx;
 }
 
-int mmuContextSyncKernelPDE(int pdEntry, void * pde, size_t pdeSize)
+int mmuContextSyncKernelPDE(int pdEntry, void *pde, size_t pdeSize)
 {
     uint32_t flags;
     struct mmu_context *destContext;
@@ -92,7 +98,7 @@ int mmuContextSyncKernelPDE(int pdEntry, void * pde, size_t pdeSize)
         assert(destContext->ref > 0);
 
         dest_pd = (void *)destContext->vaddr_PD;
-        memcpy(dest_pd + pdEntry *pdeSize, pde, pdeSize);
+        memcpy(dest_pd + pdEntry * pdeSize, pde, pdeSize);
     }
     restore_IRQs(flags);
 

arch/x86/paging.c

@@ -133,17 +133,15 @@ int pageMap(vaddr_t vaddr, paddr_t paddr, int flags)
     uint pdEntry = vaddr >> (PD_SHIFT);
     uint ptEntry = (vaddr >> PT_SHIFT) & PTE_MASK;
 
-    if ((vaddr >= PAGING_MIRROR_VADDR) &&
+    if ((vaddr >= PAGING_MIRROR_VADDR) && (vaddr < PAGING_MIRROR_VADDR + PAGING_MIRROR_SIZE))
-        (vaddr < PAGING_MIRROR_VADDR + PAGING_MIRROR_SIZE))
         return -EINVAL;
 
     // Thank to mirroring, we can access the PD
     struct pde *pd =
-        (struct pde *)(PAGING_MIRROR_VADDR + PAGE_SIZE*(PAGING_MIRROR_VADDR>>PD_SHIFT));
+        (struct pde *)(PAGING_MIRROR_VADDR + PAGE_SIZE * (PAGING_MIRROR_VADDR >> PD_SHIFT));
 
     struct pte *pt = (struct pte *)((PAGING_MIRROR_VADDR) + (pdEntry * PAGE_SIZE));
 
-
     if (!pd[pdEntry].present) {
         paddr_t ptPhy = allocPhyPage(1);
         if (ptPhy == (vaddr_t)NULL)
@@ -153,10 +151,10 @@ int pageMap(vaddr_t vaddr, paddr_t paddr, int flags)
         pd[pdEntry].write   = 1;
         pd[pdEntry].pt_addr = (ptPhy >> PT_SHIFT);
 
-        if(vaddr < PAGING_BASE_USER_ADDRESS){
+        if (vaddr < PAGING_BASE_USER_ADDRESS) {
             pd[pdEntry].user = 0;
             mmuContextSyncKernelPDE(pdEntry, &pd[pdEntry], sizeof(struct pde));
-        }else{
+        } else {
             assert(flags & PAGING_MEM_USER);
             pd[pdEntry].user = 1;
         }
@@ -190,13 +188,12 @@ int pageUnmap(vaddr_t vaddr)
     uint pdEntry = vaddr >> (PD_SHIFT);
     uint ptEntry = (vaddr >> PT_SHIFT) & PTE_MASK;
 
-    if ((vaddr >= PAGING_MIRROR_VADDR) &&
+    if ((vaddr >= PAGING_MIRROR_VADDR) && (vaddr < PAGING_MIRROR_VADDR + PAGING_MIRROR_SIZE))
-        (vaddr < PAGING_MIRROR_VADDR + PAGING_MIRROR_SIZE))
         return -EINVAL;
 
     // Thank to mirroring, we can access the PD
     struct pde *pd =
-        (struct pde *)(PAGING_MIRROR_VADDR + PAGE_SIZE*(PAGING_MIRROR_VADDR>>PD_SHIFT));
+        (struct pde *)(PAGING_MIRROR_VADDR + PAGE_SIZE * (PAGING_MIRROR_VADDR >> PD_SHIFT));
 
     struct pte *pt = (struct pte *)((PAGING_MIRROR_VADDR) + (pdEntry * PAGE_SIZE));
     if (!pd[pdEntry].present)
@@ -230,7 +227,7 @@ paddr_t pagingGetPaddr(vaddr_t vaddr)
 
     // Thank to mirroring, we can access the PD
     struct pde *pd =
-        (struct pde *)(PAGING_MIRROR_VADDR + PAGE_SIZE*(PAGING_MIRROR_VADDR>>PD_SHIFT));
+        (struct pde *)(PAGING_MIRROR_VADDR + PAGE_SIZE * (PAGING_MIRROR_VADDR >> PD_SHIFT));
 
     struct pte *pt = (struct pte *)((PAGING_MIRROR_VADDR) + (pdEntry * PAGE_SIZE));
 
@@ -251,7 +248,7 @@ unsigned long getNbMappedPage(void)
 paddr_t pagingGetCurrentPDPaddr()
 {
     struct pdbr pdbr;
-  asm volatile("movl %%cr3, %0\n": "=r"(pdbr));
+    asm volatile("movl %%cr3, %0\n" : "=r"(pdbr));
     return (pdbr.pd_paddr << 12);
 }
 
@@ -263,11 +260,50 @@ int pagingSetCurrentPDPaddr(paddr_t paddrPD)
     assert(IS_ALIGNED(paddrPD, PAGE_SIZE));
 
     /* Setup the value of the PDBR */
-  memset(& pdbr, 0x0, sizeof(struct pdbr)); /* Reset the PDBR */
+    memset(&pdbr, 0x0, sizeof(struct pdbr)); /* Reset the PDBR */
     pdbr.pd_paddr = (paddrPD >> 12);
 
     /* Configure the MMU according to the PDBR */
-  asm volatile ("movl %0,%%cr3\n" ::"r"(pdbr));
+    asm volatile("movl %0,%%cr3\n" ::"r"(pdbr));
+
+    return 0;
+}
+
+int pagingCopyKernelSpace(vaddr_t destVaddrPD, paddr_t destPaddrPD, vaddr_t srcVaddrPD)
+{
+    struct pde *src_pd  = (struct pde *)srcVaddrPD;
+    struct pde *dest_pd = (struct pde *)destVaddrPD;
+    struct pde mirror_pde;
+    uint index_in_pd;
+
+    /* Fill destination PD with zeros */
+    memset((void *)destVaddrPD, 0x0, PAGE_SIZE);
+
+    /* Synchronize it with the master Kernel MMU context. Stop just
+       before the mirroring ! */
+    for (index_in_pd = 0; index_in_pd < (PAGING_MIRROR_VADDR >> 22); /* 1 PDE = 1 PT
+                                                = 1024 Pages
+                                                = 4MB */
+         index_in_pd++) {
+        /* Copy the master's configuration */
+        dest_pd[index_in_pd] = src_pd[index_in_pd];
+
+        /* We DON'T mark the underlying PT and pages as referenced
+       because all the PD are equivalent in the kernel space: as
+       soon as a page is mapped in the kernel, it is mapped by X
+       address spaces, and as soon as it is unmapped by 1 address
+       space, it is unmapped in all the others. So that for X
+       address spaces, the reference counter will be either 0 or X,
+       and not something else: using the reference counter correctly
+       won't be of any use and would consume some time in updating it. */
+    }
+
+    /* Setup the mirroring for the new address space */
+    mirror_pde.present                 = TRUE;
+    mirror_pde.write                   = 1;
+    mirror_pde.user                    = 0; /* This is a KERNEL PDE */
+    mirror_pde.pt_addr                 = (destPaddrPD >> 12);
+    dest_pd[PAGING_MIRROR_VADDR >> 22] = mirror_pde;
 
     return 0;
 }

arch/x86/paging.h

@@ -27,3 +27,4 @@ unsigned long getNbMappedPage(void);
 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);