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Set the kernel VMM start address to the virtual address offset #175

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Merged
SamTebbs33 merged 1 commit into from
Jun 24, 2020
Merged

Set the kernel VMM start address to the virtual address offset #175

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10 changes: 7 additions & 3 deletions src/kernel/vmm.zig
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Original file line number Diff line number Diff line change
Expand Up @@ -108,6 +108,10 @@ pub const VmmError = error{
InvalidPhysAddresses,
};

/// The boot-time offset that the virtual addresses are from the physical addresses
/// This is the start of the memory owned by the kernel and so is where the kernel VMM starts
extern var KERNEL_ADDR_OFFSET: *u32;

///
/// Construct a virtual memory manager to keep track of allocated and free virtual memory regions within a certain space
///
Expand Down Expand Up @@ -186,7 +190,7 @@ pub fn VirtualMemoryManager(comptime Payload: type) type {
/// Bitmap(u32).Error.OutOfBounds - The address given is outside of the memory managed
///
pub fn isSet(self: *const Self, virt: usize) bitmap.Bitmap(u32).BitmapError!bool {
return try self.bmp.isSet(virt / BLOCK_SIZE);
return try self.bmp.isSet((virt - self.start) / BLOCK_SIZE);
}

///
Expand Down Expand Up @@ -237,7 +241,7 @@ pub fn VirtualMemoryManager(comptime Payload: type) type {

virt = virtual.start;
while (virt < virtual.end) : (virt += BLOCK_SIZE) {
try self.bmp.setEntry(virt / BLOCK_SIZE);
try self.bmp.setEntry((virt - self.start) / BLOCK_SIZE);
}

if (physical) |p| {
Expand Down Expand Up @@ -348,7 +352,7 @@ pub fn init(mem_profile: *const mem.MemProfile, allocator: *std.mem.Allocator) s
log.logInfo("Init vmm\n", .{});
defer log.logInfo("Done vmm\n", .{});

var vmm = try VirtualMemoryManager(arch.VmmPayload).init(BLOCK_SIZE, 0xFFFFFFFF, allocator, arch.VMM_MAPPER, arch.KERNEL_VMM_PAYLOAD);
var vmm = try VirtualMemoryManager(arch.VmmPayload).init(@ptrToInt(&KERNEL_ADDR_OFFSET), 0xFFFFFFFF, allocator, arch.VMM_MAPPER, arch.KERNEL_VMM_PAYLOAD);

// Map in kernel
// Calculate start and end of mapping
Expand Down