x86/pmap: new pmap_enter function

2 files changed, 72 insertions, 0 deletions

diff --git a/arch/x86/machine/pmap.c b/arch/x86/machine/pmap.c
index 5e572bec..513acc91 100644
--- a/arch/x86/machine/pmap.c
+++ b/arch/x86/machine/pmap.c
@@ -908,6 +908,64 @@ error_pmap:
     return error;
 }
 
+static int
+pmap_enter_ptemap(struct pmap *pmap, unsigned long va, phys_addr_t pa, int prot)
+{
+    const struct pmap_pt_level *pt_level;
+    struct vm_page *page;
+    unsigned int level;
+    pmap_pte_t *pte, pte_bits;
+    phys_addr_t pt_pa;
+
+    pte_bits = PMAP_PTE_RW | PMAP_PTE_P;
+
+    /*
+     * Page tables describing user mappings are protected from user access by
+     * not setting the U/S bit when inserting the root page table into itself.
+     */
+    if (pmap != kernel_pmap)
+        pte_bits |= PMAP_PTE_US;
+
+    for (level = PMAP_NR_LEVELS; level > 1; level--) {
+        pt_level = &pmap_pt_levels[level - 1];
+        pte = &pt_level->ptes[PMAP_PTEMAP_INDEX(va, pt_level->shift)];
+
+        if (*pte & PMAP_PTE_P)
+            continue;
+
+        page = vm_phys_alloc(0);
+
+        /* Note that other pages allocated on the way are not released */
+        if (page == NULL)
+            return ERROR_NOMEM;
+
+        pt_pa = vm_page_to_pa(page);
+        pmap_zero_page(pt_pa);
+        *pte = (pt_pa | pte_bits) & pt_level->mask;
+    }
+
+    pte_bits = pmap_prot_table[prot & VM_PROT_ALL] | PMAP_PTE_P;
+
+    if (pmap == kernel_pmap)
+        pte_bits |= PMAP_PTE_G;
+    else
+        pte_bits |= PMAP_PTE_US;
+
+    pte = PMAP_PTEMAP_BASE + PMAP_PTEMAP_INDEX(va, PMAP_L1_SHIFT);
+    *pte = ((pa & PMAP_PA_MASK) | pte_bits) & pmap_pt_levels[0].mask;
+    return 0;
+}
+
+int
+pmap_enter(struct pmap *pmap, unsigned long va, phys_addr_t pa, int prot)
+{
+    if ((pmap == kernel_pmap) || (pmap == pmap_current()))
+        return pmap_enter_ptemap(pmap, va, pa, prot);
+
+    /* TODO Complete pmap_enter() */
+    panic("pmap: pmap_enter not completely implemented yet");
+}
+
 void
 pmap_load(struct pmap *pmap)
 {
diff --git a/arch/x86/machine/pmap.h b/arch/x86/machine/pmap.h
index 62a9e21f..b67772a9 100644
--- a/arch/x86/machine/pmap.h
+++ b/arch/x86/machine/pmap.h
@@ -180,6 +180,8 @@ void pmap_kgrow(unsigned long end);
  * If protection is VM_PROT_NONE, this function behaves as if it were
  * VM_PROT_READ. Page tables for the new mapping must be preallocated with
  * pmap_kgrow().
+ *
+ * This function is an optimized version of pmap_enter() for the kernel pmap.
  */
 void pmap_kenter(unsigned long va, phys_addr_t pa, int prot);
 
@@ -236,6 +238,18 @@ void pmap_setup(void);
 int pmap_create(struct pmap **pmapp);
 
 /*
+ * Create a mapping on a physical map.
+ *
+ * If protection is VM_PROT_NONE, this function behaves as if it were
+ * VM_PROT_READ.
+ *
+ * This function may be used on the kernel pmap, but not for the purpose of
+ * mapping kernel memory, i.e. data structures used by the kernel memory
+ * allocator should be mapped with pmap_kenter().
+ */
+int pmap_enter(struct pmap *pmap, unsigned long va, phys_addr_t pa, int prot);
+
+/*
  * Load the given pmap on the current processor.
  *
  * This function must be called with interrupts and preemption disabled.