From 6b0852660258feff9c9da12c5551e4bedf760f7d Mon Sep 17 00:00:00 2001
From: Jeremy Soller <jackpot51@gmail.com>
Date: Wed, 2 Mar 2022 19:21:24 -0700
Subject: [PATCH] Fix mapping framebuffer where pml4 is already created
---
src/arch/x86_64.rs | 26 ++++++++++++++++++--------
1 file changed, 18 insertions(+), 8 deletions(-)
diff --git a/src/arch/x86_64.rs b/src/arch/x86_64.rs
index 8856549..3999a6b 100644
--- a/src/arch/x86_64.rs
+++ b/src/arch/x86_64.rs
@@ -3,17 +3,20 @@ use redoxfs::Disk;
use crate::os::{Os, OsVideoMode};
-pub(crate) const PHYS_OFFSET: u64 = 0xFFFF800000000000;
+pub(crate) const ENTRY_ADDRESS_MASK: u64 = 0x000F_FFFF_FFFF_F000;
+pub(crate) const PAGE_ENTRIES: usize = 512;
+pub(crate) const PAGE_SIZE: usize = 4096;
+pub(crate) const PHYS_OFFSET: u64 = 0xFFFF_8000_0000_0000;
unsafe fn paging_allocate<
D: Disk,
V: Iterator<Item=OsVideoMode>
>(os: &mut dyn Os<D, V>) -> Option<&'static mut [u64]> {
- let ptr = os.alloc_zeroed_page_aligned(4096);
+ let ptr = os.alloc_zeroed_page_aligned(PAGE_SIZE);
if ! ptr.is_null() {
Some(slice::from_raw_parts_mut(
ptr as *mut u64,
- 512 // page size divided by u64 size
+ PAGE_ENTRIES
))
} else {
None
@@ -74,7 +77,7 @@ pub unsafe fn paging_create<
let addr = kernel_phys + kernel_mapped;
pt[pt_i] = addr | 1 << 1 | 1;
pt_i += 1;
- kernel_mapped += 4096;
+ kernel_mapped += PAGE_SIZE as u64;
}
}
}
@@ -100,13 +103,20 @@ pub unsafe fn paging_framebuffer<
let pml4 = slice::from_raw_parts_mut(
page_phys as *mut u64,
- 512
+ PAGE_ENTRIES
);
// Create PDP for framebuffer mapping
- let pdp = paging_allocate(os)?;
- assert_eq!(pml4[pml4_i], 0);
- pml4[pml4_i] = pdp.as_ptr() as u64 | 1 << 1 | 1;
+ let pdp = if pml4[pml4_i] == 0 {
+ let pdp = paging_allocate(os)?;
+ pml4[pml4_i] = pdp.as_ptr() as u64 | 1 << 1 | 1;
+ pdp
+ } else {
+ slice::from_raw_parts_mut(
+ (pml4[pml4_i] & ENTRY_ADDRESS_MASK) as *mut u64,
+ PAGE_ENTRIES
+ )
+ };
// Map framebuffer_size at framebuffer offset
let mut framebuffer_mapped = 0;
--
GitLab