Feature uart

.gitignore

@@ -58,6 +58,8 @@ tmp/
 !/third_party/rust_crates/vendor/**/tmp/
 json_generator_tests_*.txt
 tables_generator_tests_*.txt
+zig-cache/
+zig-out/
 
 ### fx configuration and cache files.
 # NOTE: For any new files, please write files under the top-level .fx/ directory
@@ -92,7 +94,6 @@ tables_generator_tests_*.txt
 /out/
 /prebuilt/
 /test_data/
-/zig-out/
 
 # Third party repos.
 /third_party/*

sdk/lib/zbi-format/build.zig

@@ -0,0 +1,25 @@
+//! Copyright 2025 The Drift Authors. All rights reserved.
+//! Use of this source code is governed by a BSD-style license that can be
+//! found in the LICENSE file.
+
+const std = @import("std");
+
+pub fn build(b: *std.Build) void {
+    const target = b.standardTargetOptions(.{});
+    const optimize = b.standardOptimizeOption(.{});
+
+    const mod = b.addModule("zbi_format", .{
+        .root_source_file = b.path("src/root.zig"),
+        .target = target,
+        .optimize = optimize,
+    });
+
+    const test_step = b.step("test", "Run unit tests");
+    const unit_tests = b.addTest(.{
+        .root_module = mod,
+        .target = b.graph.host,
+    });
+
+    const run_unit_tests = b.addRunArtifact(unit_tests);
+    test_step.dependOn(&run_unit_tests.step);
+}

sdk/lib/zbi-format/build.zig.zon

@@ -0,0 +1,6 @@
+.{
+    .name = .zbi_format,
+    .fingerprint = 0x53525b7b9572617,
+    .version = "0.0.1",
+    .paths = .{""},
+}

sdk/lib/zbi-format/src/driver_config.zig

@@ -0,0 +1,118 @@
+//! Copyright 2025 The Drift Authors. All rights reserved.
+//! Use of this source code is governed by a BSD-style license that can be
+//! found in the LICENSE file.
+
+const std = @import("std");
+
+/// ZBI_TYPE_KERNEL_DRIVER item types (for zbi_header_t.extra)
+pub const KernelDriverType = u32;
+
+// 'PSCI'
+pub const ZBI_KERNEL_DRIVER_ARM_PSCI: KernelDriverType = 0x49435350;
+
+// 'GIC2'
+pub const ZBI_KERNEL_DRIVER_ARM_GIC_V2: KernelDriverType = 0x32434947;
+
+// 'GIC3'
+pub const ZBI_KERNEL_DRIVER_ARM_GIC_V3: KernelDriverType = 0x33434947;
+
+// 'ATIM'
+pub const ZBI_KERNEL_DRIVER_ARM_GENERIC_TIMER: KernelDriverType = 0x4d495441;
+
+// 'ATMM'
+pub const ZBI_KERNEL_DRIVER_ARM_GENERIC_TIMER_MMIO: KernelDriverType = 0x4d4d5441;
+
+// 'PL0U'
+pub const ZBI_KERNEL_DRIVER_PL011_UART: KernelDriverType = 0x55304c50;
+
+// 'AMLU'
+pub const ZBI_KERNEL_DRIVER_AMLOGIC_UART: KernelDriverType = 0x554c4d41;
+
+// 'AMLH'
+pub const ZBI_KERNEL_DRIVER_AMLOGIC_HDCP: KernelDriverType = 0x484c4d41;
+
+// 'DW8U'
+pub const ZBI_KERNEL_DRIVER_DW8250_UART: KernelDriverType = 0x44573855;
+
+// 'RMLH' (typoed, originally intended to by 'AMLR')
+pub const ZBI_KERNEL_DRIVER_AMLOGIC_RNG_V1: KernelDriverType = 0x484c4d52;
+
+// 'AMLR'
+pub const ZBI_KERNEL_DRIVER_AMLOGIC_RNG_V2: KernelDriverType = 0x524c4d41;
+
+// 'WD32'
+pub const ZBI_KERNEL_DRIVER_GENERIC32_WATCHDOG: KernelDriverType = 0x32334457;
+
+// 'GENI'
+pub const ZBI_KERNEL_DRIVER_GENI_UART: KernelDriverType = 0x494e4547;
+
+// '8250'
+pub const ZBI_KERNEL_DRIVER_I8250_PIO_UART: KernelDriverType = 0x30353238;
+
+// '825M'
+pub const ZBI_KERNEL_DRIVER_I8250_MMIO32_UART: KernelDriverType = 0x4d353238;
+
+// '825B'
+pub const ZBI_KERNEL_DRIVER_I8250_MMIO8_UART: KernelDriverType = 0x42353238;
+
+// 'MMTP'
+pub const ZBI_KERNEL_DRIVER_MOTMOT_POWER: KernelDriverType = 0x4d4d5450;
+
+// '370P'
+pub const ZBI_KERNEL_DRIVER_AS370_POWER: KernelDriverType = 0x50303733;
+
+// 'MNFP'
+pub const ZBI_KERNEL_DRIVER_MOONFLOWER_POWER: KernelDriverType = 0x4d4e4650;
+
+// 'IMXU'
+pub const ZBI_KERNEL_DRIVER_IMX_UART: KernelDriverType = 0x55584d49;
+
+// 'PLIC'
+pub const ZBI_KERNEL_DRIVER_RISCV_PLIC: KernelDriverType = 0x43494c50;
+
+// 'RTIM'
+pub const ZBI_KERNEL_DRIVER_RISCV_GENERIC_TIMER: KernelDriverType = 0x4d495452;
+
+// 'PXAU'
+pub const ZBI_KERNEL_DRIVER_PXA_UART: KernelDriverType = 0x50584155;
+
+// 'EXYU'
+pub const ZBI_KERNEL_DRIVER_EXYNOS_USI_UART: KernelDriverType = 0x45585955;
+
+/// Kernel driver struct that can be used for simple drivers.
+/// Used by ZBI_KERNEL_DRIVER_PL011_UART, ZBI_KERNEL_DRIVER_AMLOGIC_UART, and
+/// ZBI_KERNEL_DRIVER_GENI_UART, ZBI_KERNEL_DRIVER_I8250_MMIO_UART.
+pub const SimpleDriverConfig = packed struct {
+    mmio_phys: u64,
+    irq: u32,
+    flags: u32,
+};
+
+/// IRQ flags for kernel drivers
+pub const IrqFlags = packed struct(u32) {
+    /// When no flag is set, implies no information was obtained, and the
+    /// kernel will apply default configuration as it sees fit.
+    edge_triggered: bool = false,
+    level_triggered: bool = false,
+    polarity_low: bool = false,
+    polarity_high: bool = false,
+
+    _padding: u28 = 0,
+
+    comptime {
+        std.debug.assert(@sizeOf(@This()) == @sizeOf(u32));
+        std.debug.assert(@bitSizeOf(@This()) == @bitSizeOf(u32));
+    }
+
+    pub fn toInt(self: @This()) u32 {
+        return @bitCast(self);
+    }
+};
+
+/// Simple PIO driver configuration
+/// Used by ZBI_KERNEL_DRIVER_I8250_PIO_UART.
+pub const SimplePioConfig = packed struct {
+    base: u16,
+    reserved: u16,
+    irq: u32,
+};

sdk/lib/zbi-format/src/root.zig

@@ -0,0 +1,9 @@
+//! Copyright 2025 The Drift Authors. All rights reserved.
+//! Use of this source code is governed by a BSD-style license that can be
+//! found in the LICENSE file.
+
+pub const driver_config = @import("driver_config.zig");
+
+comptime {
+    _ = driver_config;
+}

slipstream/kernel/arch/x86/.build.zig

@@ -3,10 +3,10 @@
 //! found in the LICENSE file.
 
 const std = @import("std");
+const cfg = @import("drift/build_config");
+
 const Target = std.Target;
 const Module = std.Build.Module;
-
-const cfg = @import("drift/build_config");
 const BuildConfig = cfg.BuildConfig;
 
 // These set the ABI contract between C++ and assembly code.

slipstream/kernel/arch/x86/IdleStates.zig

@@ -2,9 +2,10 @@
 //! Use of this source code is governed by a BSD-style license that can be
 //! found in the LICENSE file.
 
-const std = @import("std");
 const IdleState = @This();
 
+const std = @import("std");
+
 pub const X86_MAX_CSTATES = 12;
 
 // A human-readable name for the state

slipstream/kernel/arch/x86/faults.zig

@@ -3,6 +3,7 @@
 //! found in the LICENSE file.
 
 const std = @import("std");
+
 const regs = @import("regs.zig");
 const x86 = @import("x86.zig");
 

slipstream/kernel/arch/x86/mp.zig

@@ -3,6 +3,7 @@
 //! found in the LICENSE file.
 
 const std = @import("std");
+
 const cpu = @import("../../kernel/cpu.zig");
 const Thread = @import("../../kernel/Thread.zig");
 const PerCpu = @import("../../kernel/PerCpu.zig");
@@ -181,12 +182,12 @@ inline fn percpuFor(cpu_num: CpuNum) *X86PerCpu {
 /// Called from assembly.
 export fn initPercpu(cpu_num: CpuNum) callconv(.C) void {
     const percpu = percpuFor(cpu_num);
-    assert.debug_assert(@src(), percpu.cpu_num == cpu_num);
-    assert.debug_assert(@src(), percpu.direct == percpu);
+    assert.debugAssert(@src(), percpu.cpu_num == cpu_num, "percpu.cpu_num == cpu_num");
+    assert.debugAssert(@src(), percpu.direct == percpu, "percpu.direct == percpu");
 
     // Assembly code has already set up %gs.base so that this function's own code can use it
     // implicitly for stack-protector or safe-stack.
-    assert.debug_assert(@src(), x86.readMsr(registers.X86_MSR_IA32_GS_BASE) == @intFromPtr(percpu));
+    assert.debugAssert(@src(), x86.readMsr(registers.X86_MSR_IA32_GS_BASE) == @intFromPtr(percpu), "x86.readMsr(registers.X86_MSR_IA32_GS_BASE) == @intFromPtr(percpu)");
 
     // Set the KERNEL_GS_BASE MSR to 0
     // When we enter user space, this will be populated via a swapgs
@@ -273,9 +274,9 @@ pub fn forceHaltAllButLocalAndBsp() void {
 
 pub fn setupPercpu(cpu_num: CpuNum, percpu: *PerCpu) void {
     const arch_percpu = percpuFor(cpu_num);
-    //assert.debug_assert(@src(), arch_percpu != null);
-    assert.debug_assert(@src(), arch_percpu.high_level_percpu == null or
-        arch_percpu.high_level_percpu == percpu);
+    //assert.debugAssert(@src(), arch_percpu != null, "arch_percpu != null");
+    assert.debugAssert(@src(), arch_percpu.high_level_percpu == null or
+        arch_percpu.high_level_percpu == percpu, "arch_percpu.high_level_percpu == null or arch_percpu.high_level_percpu == percpu");
     arch_percpu.high_level_percpu = percpu;
 }
 

slipstream/kernel/arch/x86/spin_lock.zig

@@ -3,9 +3,10 @@
 //! found in the LICENSE file.
 
 const std = @import("std");
+const arch = @import("lib/arch").intrin;
+
 const assert = @import("../../kernel/assert.zig");
 const mp = @import("mp.zig");
-const arch = @import("../../lib/arch/x86/intrin.zig");
 const ArchSpinLock = @import("../../kernel/arch/SpinLock.zig");
 
 inline fn archSpinLockCore(lock: *ArchSpinLock, val: u32) void {

slipstream/kernel/arch/x86/start.S

@@ -12,6 +12,7 @@
 #include <arch/x86/descriptor.h>
 #include <arch/x86/mmu.h>
 #include <arch/x86/registers.h>
+#include <slipstream/tls.h>
 #include "multiboot.h"
 
 #define MSR_EFER 0xc0000080
@@ -21,6 +22,14 @@
 #define PHYS_ADDR_DELTA (KERNEL_BASE + KERNEL_LOAD_OFFSET - PHYS_LOAD_ADDRESS)
 #define PHYS(x) ((x) - PHYS_ADDR_DELTA)
 
+// Clobbers %rax, %rdx.
+.macro sample_ticks out
+  rdtsc
+  shl $32, %rdx
+  or %rdx, %rax
+  mov %rax, \out
+.endm
+
 .section ".text.boot"
 .code32
 .global _start
@@ -197,9 +206,14 @@ farjump64:
     jmp  *%rax
 
 highaddr:
+    // As early as possible collect the time stamp.
+    sample_ticks %r15
+
     /* load the high kernel stack */
     mov  $(_kstack + 4096), %rsp
 
+    mov %r15, kernel_entry_ticks(%rip)
+
     /* reload the gdtr */
     lgdt _gdtr
 
@@ -232,7 +246,15 @@ highaddr:
     // call would make it eligible for stack-guard checking itself.  But
     // %gs is not set up yet in the prologue of the function, so it would
     // crash if it tried to use the stack-guard.
-    call choose_stack_guard
+    call chooseStackGuard
+
+    // Move it into place.
+    mov %rax, %gs:SX_TLS_STACK_GUARD_OFFSET
+    // Don't leak that value to other code.
+    xor %eax, %eax
+
+    // Collect the time stamp of entering "normal" Zig code in virtual space.
+    sample_ticks kernel_virtual_entry_ticks(%rip)
 
     /* call the main module */
     call lk_main

slipstream/kernel/arch/x86/x86.zig

@@ -3,6 +3,7 @@
 //! found in the LICENSE file.
 
 const std = @import("std");
+
 const regs = @import("regs.zig");
 
 pub const registers = @cImport({

slipstream/kernel/build.zig

@@ -3,20 +3,20 @@
 //! found in the LICENSE file.
 
 const std = @import("std");
+const cfg = @import("drift/build_config");
+
 const Build = std.Build;
 const Target = std.Target;
 const Module = std.Build.Module;
 
-const cfg = @import("drift/build_config");
-
 pub fn build(b: *Build) !void {
     const build_config: *cfg.BuildConfig = try cfg.BuildConfig.init(b);
 
     const options = b.addOptions();
     options.addOption(u32, "SMP_MAX_CPUS", 1);
     options.addOption(bool, "DEBUG_ASSERT_IMPLEMENTED", true);
 
-    const kernel = b.createModule(.{
+    const kernel = b.addModule("kernel", .{
         .root_source_file = b.path("root.zig"),
         .optimize = .Debug,
     });
@@ -41,9 +41,10 @@ pub fn build(b: *Build) !void {
     standalone(build_config, kernel);
 
     const deps = [_]struct { name: []const u8, dep_name: []const u8, module_name: []const u8 }{
-        .{ .name = "dbl", .dep_name = "dbl", .module_name = "dbl" },
-        .{ .name = "lazy_init", .dep_name = "lazy_init", .module_name = "lazy_init" },
-        .{ .name = "lockdep", .dep_name = "lockdep", .module_name = "lockdep" },
+        .{ .name = "lib/arch", .dep_name = "lib/arch", .module_name = "arch" },
+        .{ .name = "ulib/dbl", .dep_name = "ulib/dbl", .module_name = "dbl" },
+        .{ .name = "ulib/lazy_init", .dep_name = "ulib/lazy_init", .module_name = "lazy_init" },
+        .{ .name = "ulib/lockdep", .dep_name = "ulib/lockdep", .module_name = "lockdep" },
     };
 
     for (deps) |dep| {

slipstream/kernel/build.zig.zon

@@ -7,14 +7,17 @@
         .@"drift/build_config" = .{
             .path = "../../build",
         },
-        .lazy_init = .{
-            .path = "../system/ulib/lazy_init",
+        .@"lib/arch" = .{
+            .path = "../../slipstream/kernel/lib/arch",
         },
-        .dbl = .{
-            .path = "../system/ulib/dbl",
+        .@"ulib/dbl" = .{
+            .path = "../../slipstream/system/ulib/dbl",
         },
-        .lockdep = .{
-            .path = "../system/ulib/lockdep",
+        .@"ulib/lazy_init" = .{
+            .path = "../../slipstream/system/ulib/lazy_init",
+        },
+        .@"ulib/lockdep" = .{
+            .path = "../../slipstream/system/ulib/lockdep",
         },
     },
 }