From 8b2e58b6b12afdd36b05ed2a58a1038f8a954471 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Thomas=20Lov=C3=A9n?= <thomasloven@gmail.com>
Date: Mon, 19 Dec 2016 09:40:08 +0100
Subject: [PATCH] [MEMORY] Copy and write between memory spaces

---
 kernel/boot/kmain.c  |  8 +++-----
 kernel/include/mem.h |  2 ++
 kernel/mem/vmm.c     | 46 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 51 insertions(+), 5 deletions(-)

diff --git a/kernel/boot/kmain.c b/kernel/boot/kmain.c
index de9ef35..640b996 100644
--- a/kernel/boot/kmain.c
+++ b/kernel/boot/kmain.c
@@ -9,11 +9,6 @@
 
 void thread_function()
 {
-  char *str = (char *)0x10000;
-  str[0] = (char)((unsigned int)'0' + get_current_process()->pid);
-  str[1] = (char)((unsigned int)'0' + get_current_thread()->tid);
-  str[3] = '-';
-  str[2] = '\0';
   while(1)
   {
     debug((char *)0x10000);
@@ -49,6 +44,9 @@ int kmain(uint64_t multiboot_magic, void *multiboot_data)
   vmm_set_page(p1->P4, 0x10000, pmm_alloc(), PAGE_PRESENT | PAGE_WRITE);
   vmm_set_page(p2->P4, 0x10000, pmm_alloc(), PAGE_PRESENT | PAGE_WRITE);
 
+  vmm_p4_memcpy(p1->P4, (void *)0x10000, 0, "Hello, 1", 9);
+  vmm_p4_memcpy(p2->P4, (void *)0x10000, 0, "Hello, 2", 9);
+
   scheduler_insert(t1);
   scheduler_insert(t2);
   scheduler_insert(t3);
diff --git a/kernel/include/mem.h b/kernel/include/mem.h
index d14f567..7ca2084 100644
--- a/kernel/include/mem.h
+++ b/kernel/include/mem.h
@@ -57,6 +57,8 @@ void vmm_set_P4(page_table *P4);
 void vmm_free_P4(page_table *P4);
 uintptr_t vmm_get_page(page_table *P4, uintptr_t addr);
 uintptr_t vmm_set_page(page_table *P4, uintptr_t addr, uintptr_t phys, uint32_t flags);
+size_t vmm_p4_memcpy(page_table *dst_P4, void *dst, page_table *src_P4, void *src, size_t n);
+size_t vmm_p4_memset(page_table *P4, void *s, int c, size_t n);
 
 void kfree(void *a);
 void *kmalloc(size_t size);
diff --git a/kernel/mem/vmm.c b/kernel/mem/vmm.c
index ff72a5a..fa4ff56 100644
--- a/kernel/mem/vmm.c
+++ b/kernel/mem/vmm.c
@@ -121,6 +121,52 @@ uintptr_t vmm_set_page(page_table *P4, uintptr_t addr, uintptr_t phys, uint32_t
 }
 
 
+size_t vmm_p4_memcpy(page_table *dst_P4, void *dst, page_table *src_P4, void *src, size_t n)
+{
+  size_t copied = 0;
+  while(n)
+  {
+    size_t d_offset = (uintptr_t)dst % PAGE_SIZE;
+    size_t s_offset = (uintptr_t)src % PAGE_SIZE;
+    size_t d_bytes = PAGE_SIZE - d_offset;
+    size_t s_bytes = PAGE_SIZE - s_offset;
+    size_t bytes = (d_bytes < s_bytes)?d_bytes:s_bytes;
+    bytes = (bytes < n)?bytes:n;
+    void *d_page = STRIP_FLAGS(vmm_get_page(dst_P4, (uintptr_t)dst));
+    void *s_page = STRIP_FLAGS(vmm_get_page(src_P4, (uintptr_t)src));
+    if (!d_page || !s_page)
+      return 0;
+    memcpy(incptr(P2V(d_page), d_offset), incptr(P2V(s_page), s_offset), bytes);
+
+    copied += bytes;
+    n -= bytes;
+    dst = incptr(dst, bytes);
+    src = incptr(src, bytes);
+  }
+  return copied;
+}
+
+size_t vmm_p4_memset(page_table *P4, void *s, int c, size_t n)
+{
+  size_t set = 0;
+  while(n)
+  {
+    size_t offset = (uintptr_t)s % PAGE_SIZE;
+    size_t bytes = PAGE_SIZE - offset;
+    bytes = (bytes < n)?bytes:n;
+    void *page = STRIP_FLAGS(vmm_get_page(P4, (uintptr_t)s));
+    if(!page)
+      return 0;
+    memset(incptr(P2V(page), offset), c, bytes);
+
+    set += bytes;
+    n -= bytes;
+    s = incptr(s, bytes);
+  }
+  return set;
+}
+
+
 registers_t *page_fault_handler(registers_t *r)
 {
   debug("\n ===== PAGE FAULT =====\n");