From 3a4136c225b7285e96b55552d62cdf73f747537d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Thomas=20Lov=C3=A9n?= <thomasloven@gmail.com>
Date: Thu, 4 Jan 2018 00:36:59 +0100
Subject: [PATCH] PMM -- calloc function for getting cleared pages

---
 src/kernel/include/memory.h | 1 +
 src/kernel/memory/pmm.c     | 7 +++++++
 src/kernel/memory/vmm.c     | 6 +++---
 src/kernel/memory/vmm.tt    | 4 ++--
 4 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/src/kernel/include/memory.h b/src/kernel/include/memory.h
index e22f554..7ec8b0f 100644
--- a/src/kernel/include/memory.h
+++ b/src/kernel/include/memory.h
@@ -33,6 +33,7 @@ size_t strlen(const char *s);
 
 void pmm_free(uintptr_t page);
 uintptr_t pmm_alloc();
+uintptr_t pmm_calloc();
 
 uintptr_t vmm_get_page(void *P4, uintptr_t addr);
 int vmm_set_page(void *P4, uintptr_t addr, uintptr_t page, uint16_t flags);
diff --git a/src/kernel/memory/pmm.c b/src/kernel/memory/pmm.c
index f979351..78cd3f8 100644
--- a/src/kernel/memory/pmm.c
+++ b/src/kernel/memory/pmm.c
@@ -16,3 +16,10 @@ uintptr_t pmm_alloc()
   page = (uintptr_t)(page?V2P(page):0);
   return page;
 }
+
+uintptr_t pmm_calloc()
+{
+  uintptr_t page = pmm_alloc();
+  memset(P2V(page), 0, 0x1000);
+  return page;
+}
diff --git a/src/kernel/memory/vmm.c b/src/kernel/memory/vmm.c
index 11c03e0..f67c1a6 100644
--- a/src/kernel/memory/vmm.c
+++ b/src/kernel/memory/vmm.c
@@ -77,19 +77,19 @@ int touch_page(void *P4, uintptr_t addr, uint16_t flags)
   flags ^= PAGE_HUGE*huge;
 
   if((!P4e(P4, addr).present)
-      && (!(P4e(P4, addr).value = pmm_alloc())))
+      && (!(P4e(P4, addr).value = pmm_calloc())))
     return -1;
   P4e(P4, addr).value |= flags | PAGE_PRESENT;
 
   if((!P3e(P4, addr).present)
-      && (!(P3e(P4, addr).value = pmm_alloc())))
+      && (!(P3e(P4, addr).value = pmm_calloc())))
     return -1;
   P3e(P4, addr).value |= flags | PAGE_PRESENT;
 
   if(huge) return 0;
 
   if((!P2e(P4, addr).present)
-      && (!(P2e(P4, addr).value = pmm_alloc())))
+      && (!(P2e(P4, addr).value = pmm_calloc())))
     return -1;
   P2e(P4, addr).value |= flags | PAGE_PRESENT;
 
diff --git a/src/kernel/memory/vmm.tt b/src/kernel/memory/vmm.tt
index 0af9e90..3d292e8 100644
--- a/src/kernel/memory/vmm.tt
+++ b/src/kernel/memory/vmm.tt
@@ -119,7 +119,7 @@ TEST(set_page_does_not_overwrite_4kb_pages_with_2mb)
   ASSERT_NEQ_INT(retval, 0);
 }
 
-uintptr_t pmm_alloc()
+uintptr_t pmm_calloc()
 {
   uintptr_t *pages[] = {p3, p2, p1};
   static int counter=0;
@@ -153,7 +153,7 @@ TEST(touch_page_sets_flags)
 }
 TEST(touch_page_fails_if_out_of_pages)
 {
-  pmm_alloc();
+  pmm_calloc();
   int retval = touch_page(p4, 0, 0);
   ASSERT_NEQ_INT(retval, 0);
 }