feat: debug kernel stack (#1176)

* feat: debug kernel stack

Signed-off-by: Godones <chenlinfeng25@outlook.com>

* fix: Create guard pages for the kstack through remap

Signed-off-by: Godones <chenlinfeng25@outlook.com>

* feat(arch/x86_64): 启用内核态写保护功能

添加enable_kernel_wp函数来设置CR0的WP位，防止内核错误写入只读页面

Signed-off-by: longjin <longjin@DragonOS.org>

* fix(x86_64/mm): 在内核地址错误处理中添加RIP寄存器信息

Signed-off-by: longjin <longjin@DragonOS.org>

* fix: Fixed the error introduced by enabling WP flag on x86

Restore accidentally deleted functions.

Signed-off-by: Godones <chenlinfeng25@outlook.com>

* refactor: 移除kstack_protect默认特性并优化内存管理

- 从default特性中移除kstack_protect
- 为X86_64MMBootstrapInfo添加kernel_rodata_start字段
- 调整内核页标志对rodata区域的判断逻辑

Signed-off-by: longjin <longjin@DragonOS.org>

* fix(mm): 解决加载二进制文件到用户空间的时候,忘记关闭wp的问题

Signed-off-by: longjin <longjin@DragonOS.org>

* fix

Signed-off-by: longjin <longjin@DragonOS.org>

---------

Signed-off-by: Godones <chenlinfeng25@outlook.com>
Signed-off-by: longjin <longjin@DragonOS.org>
Co-authored-by: longjin <longjin@DragonOS.org>

kernel/src/arch/loongarch64/mm/mod.rs

@@ -137,6 +137,10 @@ impl MemoryManagementArch for LoongArch64MMArch {
     fn make_entry(paddr: crate::mm::PhysAddr, page_flags: usize) -> usize {
         todo!()
     }
+
+    fn enable_kernel_wp() {}
+
+    fn disable_kernel_wp() {}
 }
 
 /// 获取内核地址默认的页面标志

kernel/src/arch/riscv64/mm/mod.rs

@@ -284,6 +284,10 @@ impl MemoryManagementArch for RiscV64MMArch {
     const PAGE_READONLY_EXEC: usize = 0;
 
     const PROTECTION_MAP: [EntryFlags<MMArch>; 16] = protection_map();
+
+    fn enable_kernel_wp() {}
+
+    fn disable_kernel_wp() {}
 }
 
 const fn protection_map() -> [EntryFlags<MMArch>; 16] {

kernel/src/arch/x86_64/mm/fault.rs

@@ -149,18 +149,37 @@ impl X86_64MMArch {
     /// - `error_code`: 错误标志
     /// - `address`: 发生缺页异常的虚拟地址
     pub fn do_kern_addr_fault(
-        _regs: &'static TrapFrame,
+        regs: &'static TrapFrame,
         error_code: X86PfErrorCode,
         address: VirtAddr,
     ) {
+        unsafe { crate::debug::traceback::lookup_kallsyms(regs.rip, 0xff) };
+        let pcb = crate::process::ProcessManager::current_pcb();
+        let kstack_guard_addr = pcb.kernel_stack().guard_page_address();
+        if let Some(guard_page) = kstack_guard_addr {
+            let guard_page_size = pcb.kernel_stack().guard_page_size().unwrap();
+            if address.data() >= guard_page.data()
+                && address.data() < guard_page.data() + guard_page_size
+            {
+                // 发生在内核栈保护页上
+                error!(
+                    "kernel stack guard page fault at {:#x}, guard page range: {:#x} - {:#x}",
+                    address.data(),
+                    guard_page.data(),
+                    guard_page.data() + guard_page_size
+                );
+            }
+        }
         panic!(
             "do_kern_addr_fault has not yet been implemented, 
-        fault address: {:#x}, 
+        fault address: {:#x},
+        rip: {:#x},
         error_code: {:#b}, 
         pid: {}\n",
             address.data(),
+            regs.rip,
             error_code,
-            crate::process::ProcessManager::current_pid().data()
+            pcb.pid().data()
         );
         //TODO https://code.dragonos.org.cn/xref/linux-6.6.21/arch/x86/mm/fault.c#do_kern_addr_fault
     }

kernel/src/arch/x86_64/mm/mod.rs

@@ -42,12 +42,14 @@ static mut INITIAL_CR3_VALUE: PhysAddr = PhysAddr::new(0);
 
 static INNER_ALLOCATOR: SpinLock<Option<BuddyAllocator<MMArch>>> = SpinLock::new(None);
 
+#[allow(dead_code)]
 #[derive(Clone, Copy, Debug)]
 pub struct X86_64MMBootstrapInfo {
     kernel_load_base_paddr: usize,
     kernel_code_start: usize,
     kernel_code_end: usize,
     kernel_data_end: usize,
+    kernel_rodata_start: usize,
     kernel_rodata_end: usize,
     start_brk: usize,
 }
@@ -134,6 +136,7 @@ impl MemoryManagementArch for X86_64MMArch {
             fn _text();
             fn _etext();
             fn _edata();
+            fn _rodata();
             fn _erodata();
             fn _end();
             fn _default_kernel_load_base();
@@ -146,6 +149,7 @@ impl MemoryManagementArch for X86_64MMArch {
             kernel_code_start: _text as usize,
             kernel_code_end: _etext as usize,
             kernel_data_end: _edata as usize,
+            kernel_rodata_start: _rodata as usize,
             kernel_rodata_end: _erodata as usize,
             start_brk: _end as usize,
         };
@@ -158,15 +162,14 @@ impl MemoryManagementArch for X86_64MMArch {
         boot_callbacks()
             .early_init_memory_blocks()
             .expect("init memory area failed");
-
-        debug!("bootstrap info: {:?}", unsafe { BOOTSTRAP_MM_INFO });
+        debug!("bootstrap info: {:#x?}", unsafe { BOOTSTRAP_MM_INFO });
         debug!("phys[0]=virt[0x{:x}]", unsafe {
             MMArch::phys_2_virt(PhysAddr::new(0)).unwrap().data()
         });
 
         // 初始化内存管理器
         unsafe { allocator_init() };
-
+        Self::enable_kernel_wp();
         send_to_default_serial8250_port("x86 64 mm init done\n\0".as_bytes());
     }
 
@@ -366,10 +369,35 @@ impl MemoryManagementArch for X86_64MMArch {
     const PAGE_WRITE: usize = 0;
     const PAGE_WRITE_EXEC: usize = 0;
     const PAGE_EXEC: usize = 0;
+
+    /// 启用 内核态的 Write Protect
+    /// 这样即使在内核态，CPU也会检查页面的写保护位
+    /// 防止内核错误地写入只读页面
+    fn enable_kernel_wp() {
+        unsafe {
+            use x86::controlregs::{cr0, cr0_write, Cr0};
+            let mut cr0_val = cr0();
+            cr0_val.insert(Cr0::CR0_WRITE_PROTECT);
+            cr0_write(cr0_val);
+            // log::debug!("CR0.WP bit enabled for kernel write protection");
+        }
+    }
+
+    /// 禁用 内核态的 Write Protect
+    fn disable_kernel_wp() {
+        unsafe {
+            use x86::controlregs::{cr0, cr0_write, Cr0};
+            let mut cr0_val = cr0();
+            cr0_val.remove(Cr0::CR0_WRITE_PROTECT);
+            cr0_write(cr0_val);
+            // log::debug!("CR0.WP bit disabled for kernel write protection");
+        }
+    }
 }
 
 /// 获取保护标志的映射表
 ///
+/// 参考: https://code.dragonos.org.cn/xref/linux-6.6.21/arch/x86/mm/pgprot.c#8
 ///
 /// ## 返回值
 /// - `[usize; 16]`: 长度为16的映射表
@@ -681,7 +709,7 @@ pub unsafe fn kernel_page_flags<A: MemoryManagementArch>(virt: VirtAddr) -> Entr
     if virt.data() >= info.kernel_code_start && virt.data() < info.kernel_code_end {
         // Remap kernel code  execute
         return EntryFlags::new().set_execute(true).set_write(true);
-    } else if virt.data() >= info.kernel_data_end && virt.data() < info.kernel_rodata_end {
+    } else if virt.data() >= info.kernel_rodata_start && virt.data() < info.kernel_rodata_end {
         // Remap kernel rodata read only
         return EntryFlags::new().set_execute(true);
     } else {