From 23f49414bd007c2aba6ed7b7b9a08f6019641ed7 Mon Sep 17 00:00:00 2001
From: 4lDO2 <4lDO2@protonmail.com>
Date: Fri, 10 Jun 2022 11:43:50 +0200
Subject: [PATCH] Fix phys offset, lock grants correctly.

---
 src/acpi/mod.rs        | 12 ++++++------
 src/context/memory.rs  |  3 ++-
 src/syscall/process.rs |  6 +++---
 3 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/src/acpi/mod.rs b/src/acpi/mod.rs
index 45c384d..d65696e 100644
--- a/src/acpi/mod.rs
+++ b/src/acpi/mod.rs
@@ -30,7 +30,7 @@ mod rsdp;
 
 pub fn get_sdt(sdt_address: usize, active_table: &mut ActivePageTable) -> &'static Sdt {
     {
-        let page = Page::containing_address(VirtualAddress::new(sdt_address + crate::KERNEL_OFFSET));
+        let page = Page::containing_address(VirtualAddress::new(sdt_address + crate::PHYS_OFFSET));
         if active_table.translate_page(page).is_none() {
             let frame = Frame::containing_address(PhysicalAddress::new(sdt_address));
             let result = active_table.map_to(page, frame, PageFlags::new());
@@ -38,15 +38,15 @@ pub fn get_sdt(sdt_address: usize, active_table: &mut ActivePageTable) -> &'stat
         }
     }
 
-    let sdt = unsafe { &*((sdt_address + crate::KERNEL_OFFSET) as *const Sdt) };
+    let sdt = unsafe { &*((sdt_address + crate::PHYS_OFFSET) as *const Sdt) };
 
     // Map extra SDT frames if required
     {
-        let start_page = Page::containing_address(VirtualAddress::new(sdt_address + 4096 + crate::KERNEL_OFFSET));
-        let end_page = Page::containing_address(VirtualAddress::new(sdt_address + sdt.length as usize + crate::KERNEL_OFFSET));
+        let start_page = Page::containing_address(VirtualAddress::new(sdt_address + 4096 + crate::PHYS_OFFSET));
+        let end_page = Page::containing_address(VirtualAddress::new(sdt_address + sdt.length as usize + crate::PHYS_OFFSET));
         for page in Page::range_inclusive(start_page, end_page) {
             if active_table.translate_page(page).is_none() {
-                let frame = Frame::containing_address(PhysicalAddress::new(page.start_address().data() - crate::KERNEL_OFFSET));
+                let frame = Frame::containing_address(PhysicalAddress::new(page.start_address().data() - crate::PHYS_OFFSET));
                 let result = active_table.map_to(page, frame, PageFlags::new());
                 result.flush();
             }
@@ -125,7 +125,7 @@ pub unsafe fn init(active_table: &mut ActivePageTable, already_supplied_rsdps: O
         rxsdt.map_all(active_table);
 
         for sdt_address in rxsdt.iter() {
-            let sdt = &*((sdt_address + crate::KERNEL_OFFSET) as *const Sdt);
+            let sdt = &*((sdt_address + crate::PHYS_OFFSET) as *const Sdt);
 
             let signature = get_sdt_signature(sdt);
             if let Some(ref mut ptrs) = *(SDT_POINTERS.write()) {
diff --git a/src/context/memory.rs b/src/context/memory.rs
index 802c49b..244d51e 100644
--- a/src/context/memory.rs
+++ b/src/context/memory.rs
@@ -94,9 +94,10 @@ impl UserGrants {
     // TODO: Alignment (x86_64: 4 KiB, 2 MiB, or 1 GiB).
     pub fn find_free(&self, size: usize) -> Option<Region> {
         // Get first available hole, but do reserve the page starting from zero as most compiled
-        // language cannot handle null pointers safely even if they do point to valid memory. If an
+        // languages cannot handle null pointers safely even if they point to valid memory. If an
         // application absolutely needs to map the 0th page, they will have to do so explicitly via
         // MAP_FIXED/MAP_FIXED_NOREPLACE.
+        // TODO: Allow explicitly allocating guard pages?
 
         let (hole_start, hole_size) = self.holes.iter().find(|(hole_offset, hole_size)| size <= if hole_offset.data() == 0 { hole_size.saturating_sub(PAGE_SIZE) } else { **hole_size })?;
         // Create new region
diff --git a/src/syscall/process.rs b/src/syscall/process.rs
index 3df8164..243ca48 100644
--- a/src/syscall/process.rs
+++ b/src/syscall/process.rs
@@ -191,8 +191,8 @@ pub fn clone(flags: CloneFlags, stack_base: usize, info: Option<&CloneInfo>) ->
 
         // If not cloning virtual memory, use fmap to re-obtain every grant where possible
         if !flags.contains(CLONE_VM) {
-            let grants = Arc::get_mut(&mut grants).ok_or(Error::new(EBUSY))?.get_mut();
-            let old_grants = mem::take(grants);
+            let mut grants = grants.write();
+            let old_grants = mem::take(&mut *grants);
 
             // TODO: Find some way to do this without having to allocate.
 
@@ -1018,7 +1018,7 @@ pub fn usermode_bootstrap(mut data: Box<[u8]>) -> ! {
     for (index, page) in grant.pages().enumerate() {
         let len = if data.len() - index * PAGE_SIZE < PAGE_SIZE { data.len() % PAGE_SIZE } else { PAGE_SIZE };
         let frame = active_table.translate_page(page).expect("expected mapped init memory to have a corresponding frame");
-        unsafe { ((frame.start_address().data() + crate::KERNEL_OFFSET) as *mut u8).copy_from_nonoverlapping(data.as_ptr().add(index * PAGE_SIZE), len); }
+        unsafe { ((frame.start_address().data() + crate::PHYS_OFFSET) as *mut u8).copy_from_nonoverlapping(data.as_ptr().add(index * PAGE_SIZE), len); }
     }
 
     context::contexts().current().expect("expected a context to exist when executing init").read().grants.write().insert(grant);