Allocated space for CPU-local data

We don't yet have support for CPU-local data, but when we do, we
will need space to store each CPU's copy of the data.

Signed-off-by: SlyMarbo <[email protected]>

Author: SlyMarbo

kernel/src/memory/README.md

@@ -13,6 +13,7 @@ Firefly uses the following layout of virtual memory:
 | Kernel stack 0       | `0xffff_8000_5555_0000` | `0xffff_8000_555c_ffff` |       128x 4 KiB page |   512 KiB |
 | Kernel stacks 1+     | `0xffff_8000_555d_0000` | `0xffff_8000_5d5c_ffff` |    32,768x 4 KiB page |   128 MiB |
 | MMIO address space   | `0xffff_8000_6666_0000` | `0xffff_8000_6675_ffff` |       256x 4 KiB page |     1 MiB |
+| CPU-local storage    | `0xffff_8000_7777_0000` | `0xffff_8000_7f76_ffff` |    32,768x 4 KiB page |   128 MiB |
 | Physical memory map  | `0xffff_8000_8000_0000` | `0xffff_ffff_ffff_ffff` |        rest of memory | < 128 TiB |
 
 ## Paging

kernel/src/memory/constants.rs

@@ -25,6 +25,7 @@ use x86_64::{PhysAddr, VirtAddr};
 // | Kernel stack 0       | 0xffff_8000_5555_0000 | 0xffff_8000_555c_ffff |
 // | Kernel stacks 1+     | 0xffff_8000_555d_0000 | 0xffff_8000_5d5c_ffff |
 // | MMIO address space   | 0xffff_8000_6666_0000 | 0xffff_8000_6675_ffff |
+// | CPU-local storage    | 0xffff_8000_7777_0000 | 0xffff_8000_7f76_ffff |
 // | Physical memory map  | 0xffff_8000_8000_0000 | 0xffff_ffff_ffff_ffff |
 
 /// NULL_PAGE is reserved and always unmapped to ensure that null pointer
@@ -91,6 +92,15 @@ pub const MMIO_SPACE: VirtAddrRange = VirtAddrRange::new(MMIO_SPACE_START, MMIO_
 const MMIO_SPACE_START: VirtAddr = const_virt_addr(0xffff_8000_6666_0000 as u64);
 const MMIO_SPACE_END: VirtAddr = const_virt_addr(0xffff_8000_6675_ffff as u64);
 
+/// CPU_LOCAL is the virtual address space used for storing
+/// CPU-local data. Successive CPU cores use successive chunks of
+/// the address space, with each chunk containing a copy of the
+/// .tdata and .tbss segments from the TLS template.
+///
+pub const CPU_LOCAL: VirtAddrRange = VirtAddrRange::new(CPU_LOCAL_START, CPU_LOCAL_END);
+const CPU_LOCAL_START: VirtAddr = const_virt_addr(0xffff_8000_7777_0000 as u64);
+const CPU_LOCAL_END: VirtAddr = const_virt_addr(0xffff_8000_7f76_ffff as u64);
+
 /// PHYSICAL_MEMORY_OFFSET is the virtual address at which the mapping of
 /// all physical memory begins. That is, for any valid physical address,
 /// that address can be reached at the same virtual address, plus

kernel/src/memory/mod.rs

@@ -31,8 +31,8 @@ pub mod pmm;
 pub mod vmm;
 
 pub use crate::memory::constants::{
-    phys_to_virt_addr, VirtAddrRange, BOOT_INFO, KERNEL_BINARY, KERNEL_HEAP, KERNEL_STACK,
-    KERNEL_STACK_0, KERNEL_STACK_GUARD, MMIO_SPACE, NULL_PAGE, PHYSICAL_MEMORY,
+    phys_to_virt_addr, VirtAddrRange, BOOT_INFO, CPU_LOCAL, KERNEL_BINARY, KERNEL_HEAP,
+    KERNEL_STACK, KERNEL_STACK_0, KERNEL_STACK_GUARD, MMIO_SPACE, NULL_PAGE, PHYSICAL_MEMORY,
     PHYSICAL_MEMORY_OFFSET, USERSPACE,
 };