From 03ed3ce9a0758bf0d14a13144892c731216e25c6 Mon Sep 17 00:00:00 2001
From: Philipp Oppermann <dev@phil-opp.com>
Date: Sun, 6 Mar 2016 12:39:15 +0100
Subject: [PATCH] Replace buggy range.step_by with a Frame::range_inclusive
 function

---
 src/lib.rs               |  1 -
 src/memory/mod.rs        | 26 ++++++++++++++++++++++++++
 src/memory/paging/mod.rs | 23 +++++++++--------------
 3 files changed, 35 insertions(+), 15 deletions(-)

diff --git a/src/lib.rs b/src/lib.rs
index 24dd630a..55987839 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -9,7 +9,6 @@
 
 #![feature(lang_items)]
 #![feature(const_fn, unique)]
-#![feature(step_by)]
 #![no_std]
 
 extern crate rlibc;
diff --git a/src/memory/mod.rs b/src/memory/mod.rs
index dc80ec73..139b69fb 100644
--- a/src/memory/mod.rs
+++ b/src/memory/mod.rs
@@ -33,6 +33,32 @@ impl Frame {
     fn clone(&self) -> Frame {
         Frame { number: self.number }
     }
+
+    fn range_inclusive(start: Frame, end: Frame) -> FrameIter {
+        FrameIter {
+            start: start,
+            end: end,
+        }
+    }
+}
+
+struct FrameIter {
+    start: Frame,
+    end: Frame,
+}
+
+impl Iterator for FrameIter {
+    type Item = Frame;
+
+    fn next(&mut self) -> Option<Frame> {
+        if self.start <= self.end {
+            let frame = self.start.clone();
+            self.start.number += 1;
+            Some(frame)
+        } else {
+            None
+        }
+    }
 }
 
 pub trait FrameAllocator {
diff --git a/src/memory/paging/mod.rs b/src/memory/paging/mod.rs
index b0a15bd7..1e12de6e 100644
--- a/src/memory/paging/mod.rs
+++ b/src/memory/paging/mod.rs
@@ -165,19 +165,17 @@ pub fn remap_the_kernel<A>(allocator: &mut A, boot_info: &BootInformation)
                 continue;
             }
 
+            assert!(section.addr as usize % PAGE_SIZE == 0,
+                    "sections need to be page aligned");
             println!("mapping section at addr: {:#x}, size: {:#x}",
                      section.addr,
                      section.size);
 
             let flags = EntryFlags::from_elf_section_flags(section);
 
-            let range = Range {
-                start: section.addr as usize,
-                end: (section.addr + section.size) as usize,
-            };
-            for address in range.step_by(PAGE_SIZE) {
-                assert!(address % PAGE_SIZE == 0, "sections need to be page aligned");
-                let frame = Frame::containing_address(address);
+            let start_frame = Frame::containing_address(section.start_address());
+            let end_frame = Frame::containing_address(section.end_address() - 1);
+            for frame in Frame::range_inclusive(start_frame, end_frame) {
                 mapper.identity_map(frame, flags, allocator);
             }
         }
@@ -187,13 +185,10 @@ pub fn remap_the_kernel<A>(allocator: &mut A, boot_info: &BootInformation)
         mapper.identity_map(vga_buffer_frame, WRITABLE, allocator);
 
         // identity map the multiboot info structure
-        let multiboot_start = boot_info as *const _ as usize;
-        let range = Range {
-            start: multiboot_start,
-            end: multiboot_start + (boot_info.total_size as usize),
-        };
-        for address in range.step_by(PAGE_SIZE) {
-            mapper.identity_map(Frame::containing_address(address), PRESENT, allocator);
+        let multiboot_start = Frame::containing_address(boot_info.start_address());
+        let multiboot_end = Frame::containing_address(boot_info.end_address() - 1);
+        for frame in Frame::range_inclusive(multiboot_start, multiboot_end) {
+            mapper.identity_map(frame, PRESENT, allocator);
         }
     });