From ea66641de9eaf3e58be07e7d7f15cd9ec51202fd Mon Sep 17 00:00:00 2001
From: Ratakor <ratakor@disroot.org>
Date: Thu, 28 Sep 2023 20:35:07 +0200
Subject: [PATCH] Add swapgs to idt, start time

---
 kernel/debug.zig | 11 +++++------
 kernel/idt.zig   | 28 +++++++++++-----------------
 kernel/main.zig  |  8 ++++++--
 kernel/time.zig  | 14 ++++++++++++++
 4 files changed, 36 insertions(+), 25 deletions(-)
 create mode 100644 kernel/time.zig

diff --git a/kernel/debug.zig b/kernel/debug.zig
index 266de9c..6d160d5 100644
--- a/kernel/debug.zig
+++ b/kernel/debug.zig
@@ -61,12 +61,10 @@ pub fn printStackTrace(stack_trace: *std.builtin.StackTrace) void {
     }
 }
 
-fn printInfo(address: u64, symbol_name: []const u8, file_name: []const u8, line: usize) void {
-    tty.print("0x{x:0>16}: {s} at {s}:{d}\n", .{ address, symbol_name, file_name, line });
-}
-
 fn printSymbol(address: u64) void {
     var symbol_name: []const u8 = "<no symbol info>";
+    var file_name: []const u8 = "??";
+    var line: usize = 0;
 
     if (debug_info) |*info| brk: {
         if (info.getSymbolName(address)) |name| {
@@ -76,10 +74,11 @@ fn printSymbol(address: u64) void {
         const compile_unit = info.findCompileUnit(address) catch break :brk;
         const line_info = info.getLineNumberInfo(debug_allocator, compile_unit.*, address) catch break :brk;
 
-        return printInfo(address, symbol_name, line_info.file_name, line_info.line);
+        file_name = line_info.file_name;
+        line = line_info.line;
     }
 
-    printInfo(address, symbol_name, "??", 0);
+    tty.print("0x{x:0>16}: {s} at {s}:{d}\n", .{ address, symbol_name, file_name, line });
 }
 
 fn getSectionData(elf: [*]const u8, shdr: []const u8) []const u8 {
diff --git a/kernel/idt.zig b/kernel/idt.zig
index 216e60e..f3b292c 100644
--- a/kernel/idt.zig
+++ b/kernel/idt.zig
@@ -186,25 +186,18 @@ fn makeStubHandler(vector: u8) InterruptStub {
     }.handler;
 }
 
-// TODO swapgs
-
 export fn interruptHandler(ctx: *cpu.Context) callconv(.C) void {
-    // if (ctx.cs != 0x08) {
-    //     asm volatile ("swapgs");
-    // }
     const handler = isr[ctx.isr_vector];
     handler(ctx);
-    // if (ctx.cs != 0x08) {
-    //     asm volatile ("swapgs");
-    // }
 }
 
 export fn commonStub() callconv(.Naked) void {
     asm volatile (
-    // \\cmpq $0x08, 0x8(%%rsp)
-    // \\je 1f
-    // \\swapgs
-    // \\1:
+    // if (cs != gdt.kernel_code) -> swapgs
+        \\cmpq $0x08, 24(%%rsp)
+        \\je 1f
+        \\swapgs
+        \\1:
         \\push %%r15
         \\push %%r14
         \\push %%r13
@@ -247,12 +240,13 @@ export fn commonStub() callconv(.Naked) void {
         \\pop %%r13
         \\pop %%r14
         \\pop %%r15
+        // if (cs != gdt.kernel_code) -> swapgs
+        \\cmpq $0x08, 24(%%rsp)
+        \\je 1f
+        \\swapgs
+        \\1:
+        // restore stack
         \\add $16, %%rsp
-        \\
-        // \\cmpq $0x08, 0x8(%%rsp)
-        // \\je 1f
-        // \\swapgs
-        // \\1:
         \\iretq
     );
 }
diff --git a/kernel/main.zig b/kernel/main.zig
index ee7204e..de13e73 100644
--- a/kernel/main.zig
+++ b/kernel/main.zig
@@ -8,6 +8,7 @@ const idt = @import("idt.zig");
 const pmm = @import("pmm.zig");
 const vmm = @import("vmm.zig");
 const mem = @import("mem.zig");
+const time = @import("time.zig");
 
 pub const std_options = struct {
     pub const logFn = debug.log;
@@ -21,6 +22,7 @@ pub export var kernel_file_request: limine.KernelFileRequest = .{};
 // export var module_request: limine.ModuleRequest = .{};
 // export var rsdp_request: limine.RsdpRequest = .{};
 pub export var kernel_address_request: limine.KernelAddressRequest = .{};
+pub export var boot_time_request: limine.BootTimeRequest = .{};
 
 inline fn halt() noreturn {
     while (true) asm volatile ("hlt");
@@ -76,7 +78,7 @@ fn main() !void {
 
     serial.init();
     debug.init() catch |err| {
-        tty.print("Failed to initialize debug info: {}\n", .{err});
+        tty.print("Failed to initialize debug info: {}\n", .{err}); // TODO warning
     };
     gdt.init();
     idt.init();
@@ -91,7 +93,7 @@ fn main() !void {
     // TODO: apic
     // TODO: acpi
     // TODO: pci
-    // TODO: timers (pit ?)
+    time.init(); // TODO: timers (pit ?)
 
     // TODO: proc
     // TODO: scheduler
@@ -104,6 +106,8 @@ fn main() !void {
     // TODO: start /bin/init <- load elf with std.elf
 
     ///////////////////////////////////////////////////////////////////////////
+    tty.print("{}\n", .{time.realtime});
+
     const buf = try pmm.alloc(1, false);
     defer pmm.free(buf);
     tty.print("{*} {}\n", .{ buf.ptr, buf.len });
diff --git a/kernel/time.zig b/kernel/time.zig
new file mode 100644
index 0000000..dc1aba1
--- /dev/null
+++ b/kernel/time.zig
@@ -0,0 +1,14 @@
+const std = @import("std");
+const root = @import("root");
+
+pub const Timespec = struct {
+    tv_sec: isize = 0,
+    tv_nsec: isize = 0,
+};
+
+pub var realtime: Timespec = .{};
+
+pub fn init() void {
+    const boot_time = root.boot_time_request.response.?;
+    realtime.tv_sec = boot_time.boot_time;
+}