From 28c8afe3c5fc43d7417811347911ebd9e3ab80da Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Thomas=20Lov=C3=A9n?= <thomasloven@gmail.com>
Date: Wed, 27 Dec 2017 22:40:41 +0100
Subject: [PATCH] VMM - set_page with tests

---
 src/kernel/memory/vmm.c  | 13 +++++++++++++
 src/kernel/memory/vmm.tt | 39 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 52 insertions(+)

diff --git a/src/kernel/memory/vmm.c b/src/kernel/memory/vmm.c
index 7167a2c..15447d6 100644
--- a/src/kernel/memory/vmm.c
+++ b/src/kernel/memory/vmm.c
@@ -36,3 +36,16 @@ uintptr_t vmm_get_page(void *P4, uintptr_t addr)
   else
     return -1;
 }
+
+int vmm_set_page(void *P4, uintptr_t addr, uintptr_t page, uint16_t flags)
+{
+  if(!(P4
+      && P4e(P4, addr).present
+      && P3e(P4, addr).present
+      && P2e(P4, addr).present
+    ))
+    return -1;
+
+  P1e(P4, addr).value = page | flags;
+  return 0;
+}
diff --git a/src/kernel/memory/vmm.tt b/src/kernel/memory/vmm.tt
index a5553d9..3388f8a 100644
--- a/src/kernel/memory/vmm.tt
+++ b/src/kernel/memory/vmm.tt
@@ -75,3 +75,42 @@ TEST(get_page_fails_if_PTE_not_present)
 
   ASSERT_EQ_PTR(ret, -1);
 }
+
+TEST(set_page_sets_page)
+{
+  p4[0] = (uintptr_t)p3;
+  p4[0] |= PAGE_PRESENT;
+  p3[0] = (uintptr_t)p2;
+  p3[0] |= PAGE_PRESENT;
+  p2[0] = (uintptr_t)p1;
+  p2[0] |= PAGE_PRESENT;
+
+  vmm_set_page(p4, 0, 0x1234567890ABC000, PAGE_PRESENT);
+
+  ASSERT_EQ_PTR(p1[0], 0x1234567890ABC000 | PAGE_PRESENT);
+}
+TEST(set_page_returns_success_if_working)
+{
+  p4[0] = (uintptr_t)p3;
+  p4[0] |= PAGE_PRESENT;
+  p3[0] = (uintptr_t)p2;
+  p3[0] |= PAGE_PRESENT;
+  p2[0] = (uintptr_t)p1;
+  p2[0] |= PAGE_PRESENT;
+
+  int retval = vmm_set_page(p4, 0, 0x1234567890ABC000, PAGE_PRESENT);
+
+  ASSERT_EQ_INT(retval, 0);
+}
+TEST(set_page_fails_if_PT_missing)
+{
+  p4[0] = (uintptr_t)p3;
+  p4[0] |= PAGE_PRESENT;
+  p3[0] = (uintptr_t)p2;
+  p2[0] = (uintptr_t)p1;
+  p2[0] |= PAGE_PRESENT;
+
+  int retval = vmm_set_page(p4, 0, 0x1234567890ABC000, PAGE_PRESENT);
+
+  ASSERT_NEQ_INT(retval, 0);
+}