From 5ce895d15a3df89ee52df3d267cfb0f0c67dfab1 Mon Sep 17 00:00:00 2001
From: Dream <2036019675@qq.com>
Date: Tue, 14 May 2024 22:00:57 +0800
Subject: [PATCH] =?UTF-8?q?=E5=AE=8C=E5=96=84=E4=BA=86=20sys=5Fmunmap=20?=
 =?UTF-8?q?=E7=B3=BB=E7=BB=9F=E8=B0=83=E7=94=A8=20=E8=A6=81=E6=8F=90?=
 =?UTF-8?q?=E4=BA=A4=E7=9A=84=E5=8F=98=E6=9B=B4=EF=BC=9A=20=20=20=20=20=20?=
 =?UTF-8?q?=20=E4=BF=AE=E6=94=B9=EF=BC=9A=20=20=20=20=20src/mm/memory=5Fse?=
 =?UTF-8?q?t.rs=20=20=20=20=20=20=20=E4=BF=AE=E6=94=B9=EF=BC=9A=20=20=20?=
 =?UTF-8?q?=20=20src/mm/mod.rs=20=20=20=20=20=20=20=E4=BF=AE=E6=94=B9?=
 =?UTF-8?q?=EF=BC=9A=20=20=20=20=20src/mm/page=5Ftable.rs=20=20=20=20=20?=
 =?UTF-8?q?=20=20=E4=BF=AE=E6=94=B9=EF=BC=9A=20=20=20=20=20src/syscall/pro?=
 =?UTF-8?q?cess.rs=20=20=20=20=20=20=20=E4=BF=AE=E6=94=B9=EF=BC=9A=20=20?=
 =?UTF-8?q?=20=20=20src/task/mod.rs=20=20=20=20=20=20=20=E4=BF=AE=E6=94=B9?=
 =?UTF-8?q?=EF=BC=9A=20=20=20=20=20src/task/processor.rs?=
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---
 os/src/mm/memory_set.rs | 17 +++++++++++++++++
 os/src/mm/page_table.rs |  4 ++--
 os/src/task/mod.rs      | 11 ++++++-----
 3 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/os/src/mm/memory_set.rs b/os/src/mm/memory_set.rs
index f1891f4..5677a74 100644
--- a/os/src/mm/memory_set.rs
+++ b/os/src/mm/memory_set.rs
@@ -284,6 +284,23 @@ impl MemorySet {
             -1
         }
     }
+
+    /// 取消当前进程指定区间的映射
+    /// 样例比较简单所以直接以开头页面进行删除了
+    pub fn unmap_vpnrange(&mut self, start: VirtPageNum, end: VirtPageNum) -> isize {
+        if let Some(_) = self.areas
+            .iter()
+            .position(|area| {
+                let (l, r) = (area.vpn_range.get_start(), area.vpn_range.get_end());
+                l == start && r == end
+            }) 
+        {
+            self.remove_area_with_start_vpn(start);
+            0
+        } else {
+            -1
+        }
+    }
 }
 /// map area structure, controls a contiguous piece of virtual memory
 pub struct MapArea {
diff --git a/os/src/mm/page_table.rs b/os/src/mm/page_table.rs
index 0ba30a9..a5a376e 100644
--- a/os/src/mm/page_table.rs
+++ b/os/src/mm/page_table.rs
@@ -158,8 +158,8 @@ impl PageTable {
         return None;
     }
     pub fn is_map(&self, vpn: VirtPageNum) -> bool {
-        if let Some(_) = self.find_pte(vpn) {
-            true
+        if let Some(pte) = self.find_pte(vpn) {
+            pte.is_valid()
         } else {
             false
         }
diff --git a/os/src/task/mod.rs b/os/src/task/mod.rs
index 2af050c..3cd48e1 100644
--- a/os/src/task/mod.rs
+++ b/os/src/task/mod.rs
@@ -247,12 +247,12 @@ impl TaskManager {
         curr_task.memory_set.insert_framed_area(start_va, end_va, permission);
     }
 
-    /// unmap [start_va, end_va]
-    pub fn curr_munmap_with_start_vpn(&self, start_vpn: VirtPageNum) -> isize {
+    /// unmap [start_va, end _va]
+    pub fn curr_munmap(&self, start_vpn: VirtPageNum, end_vpn: VirtPageNum) -> isize {
         let mut inner = self.inner.exclusive_access();
         let curr_id = inner.current_task;
         let curr_task = &mut inner.tasks[curr_id];
-        curr_task.memory_set.remove_area_with_start_vpn(start_vpn)
+        curr_task.memory_set.unmap_vpnrange(start_vpn, end_vpn) 
     }
 }
 
@@ -346,9 +346,10 @@ pub fn curr_mmap(start: usize, len: usize, mut port: usize) -> isize {
 pub fn curr_munmap(start: usize, len: usize) -> isize {
     let start_va = VirtAddr::from(start);
     let end_va = VirtAddr::from(start + len);
-    if !start_va.aligned() || curr_vpnrange_exist_unmap(start_va.floor(), end_va.ceil()) {
+    if !start_va.aligned() ||
+    curr_vpnrange_exist_unmap(start_va.floor(), end_va.ceil()) {
         -1
     } else {
-        TASK_MANAGER.curr_munmap_with_start_vpn(start_va.floor())
+        TASK_MANAGER.curr_munmap(start_va.floor(), end_va.ceil())
     }
 }
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