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Improve debug.panic
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@Ratakor
Ratakor committed Oct 29, 2023
1 parent b1e3594 commit 70154a3
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Showing 4 changed files with 199 additions and 112 deletions.
8 changes: 3 additions & 5 deletions kernel/arch/x86_64/apic.zig
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Original file line number Diff line number Diff line change
Expand Up @@ -26,21 +26,19 @@ const IOAPIC = extern struct {
addr: u32 align(1),
base_gsi: u32 align(1),

const Self = @This();

fn read(self: Self, reg: u32) u32 {
fn read(self: IOAPIC, reg: u32) u32 {
const base: [*]volatile u32 = @ptrFromInt(self.addr + vmm.hhdm_offset);
base[0] = reg;
return base[4];
}

fn write(self: Self, reg: u32, value: u32) void {
fn write(self: IOAPIC, reg: u32, value: u32) void {
const base: [*]volatile u32 = @ptrFromInt(self.addr + vmm.hhdm_offset);
base[0] = reg;
base[4] = value;
}

fn gsiCount(self: Self) u32 {
fn gsiCount(self: IOAPIC) u32 {
return (self.read(1) & 0xff0000) >> 16;
}
};
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265 changes: 176 additions & 89 deletions kernel/debug.zig
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Original file line number Diff line number Diff line change
Expand Up @@ -11,7 +11,7 @@ const readIntLittle = std.mem.readIntLittle;
var log_lock: SpinLock = .{};
var panic_lock: SpinLock = .{};

var fba_buffer: [32 * 1024 * 1024]u8 = undefined; // 32MiB
var fba_buffer: [16 * 1024 * 1024]u8 = undefined; // 16MiB
var debug_fba = std.heap.FixedBufferAllocator.init(&fba_buffer);
const debug_allocator = debug_fba.allocator();
var debug_info: ?std.dwarf.DwarfInfo = null;
Expand All @@ -22,35 +22,7 @@ var dmesg = blk: {
};
const dmesg_writer = dmesg.writer();

pub fn init() !void {
errdefer debug_info = null;
const kernel_file = root.kernel_file_request.response.?.kernel_file;

debug_info = .{
.endian = .Little,
.sections = .{
.{ .data = try getSectionSlice(kernel_file.address, ".debug_info"), .owned = true },
.{ .data = try getSectionSlice(kernel_file.address, ".debug_abbrev"), .owned = true },
.{ .data = try getSectionSlice(kernel_file.address, ".debug_str"), .owned = true },
null, // debug_str_offsets
.{ .data = try getSectionSlice(kernel_file.address, ".debug_line"), .owned = true },
null, // debug_line_str
.{ .data = try getSectionSlice(kernel_file.address, ".debug_ranges"), .owned = true },
null, // debug_loclists
null, // debug_rnglists
null, // debug_addr
null, // debug_names
null, // debug_frame
null, // eh_frame
null, // eh_frame_hdr
},
.is_macho = false,
};

try std.dwarf.openDwarfDebugInfo(&debug_info.?, debug_allocator);
}

pub fn panic(msg: []const u8, _: ?*std.builtin.StackTrace, _: ?usize) noreturn {
pub fn panic(msg: []const u8, _: ?*std.builtin.StackTrace, ret_addr: ?usize) noreturn {
@setCold(true);

arch.disableInterrupts();
Expand All @@ -62,7 +34,7 @@ pub fn panic(msg: []const u8, _: ?*std.builtin.StackTrace, _: ?usize) noreturn {
smp.stopAll();

const fmt = "\x1b[m\x1b[31m\nKernel panic:\x1b[m {s}\n";
const stack_iter = StackIterator.init(@returnAddress(), @frameAddress());
const stack_iter = StackIterator.init(ret_addr orelse @returnAddress(), @frameAddress());

dmesg_writer.print(fmt, .{msg}) catch {};
printStackIterator(dmesg_writer, stack_iter);
Expand Down Expand Up @@ -103,83 +75,177 @@ pub fn log(
}

fn printStackIterator(writer: anytype, stack_iter: StackIterator) void {
writer.writeAll("Stack trace: ") catch {};
if (debug_info == null) {
writer.writeAll("Unavailable") catch {};
if (builtin.strip_debug_info) {
writer.writeAll("Unable to dump stack trace: Debug info stripped\n") catch {};
return;
} else {
writer.writeAll("\n") catch {};
}
if (debug_info == null) {
initDebugInfo() catch |err| {
writer.print("Unable to dump stack trace: Unable to init debug info: {s}\n", .{@errorName(err)}) catch {};
return;
};
}

var iter = stack_iter;
while (iter.next()) |addr| {
printSymbol(writer, addr);
while (iter.next()) |return_address| {
const address = if (return_address == 0) continue else return_address - 1;
printSymbolInfo(writer, address) catch |err| {
writer.print("Unable to dump stack trace: {s}\n", .{@errorName(err)}) catch {};
return;
};
}
}

fn printStackTrace(writer: anytype, stack_trace: *std.builtin.StackTrace) void {
writer.writeAll("Stack trace: ") catch {};
if (debug_info == null) {
writer.writeAll("Unavailable") catch {};
return;
fn printSymbolInfo(writer: anytype, address: u64) !void {
const symbol_info: std.debug.SymbolInfo = if (debug_info.?.findCompileUnit(address)) |compile_unit| .{
.symbol_name = debug_info.?.getSymbolName(address) orelse "???",
.compile_unit_name = compile_unit.die.getAttrString(
&debug_info.?,
std.dwarf.AT.name,
debug_info.?.section(.debug_str),
compile_unit.*,
) catch "???",
.line_info = debug_info.?.getLineNumberInfo(debug_allocator, compile_unit.*, address) catch |err| switch (err) {
error.MissingDebugInfo, error.InvalidDebugInfo => null,
else => return err,
},
} else |err| switch (err) {
error.MissingDebugInfo, error.InvalidDebugInfo => .{},
else => return err,
};
defer symbol_info.deinit(debug_allocator);

if (symbol_info.line_info) |li| {
try writer.print("\x1b[1m{s}:{d}:{d}\x1b[m: \x1b[2m0x{x:0>16} in {s} ({s})\x1b[m\n", .{
li.file_name,
li.line,
li.column,
address,
symbol_info.symbol_name,
symbol_info.compile_unit_name,
});

if (printLineFromFile(writer, li)) {
if (li.column > 0) {
try writer.writeByteNTimes(' ', li.column - 1);
try writer.writeAll("\x1b[32m^\x1b[m");
}
try writer.writeAll("\n");
} else |err| switch (err) {
error.EndOfFile, error.FileNotFound => {},
else => return err,
}
} else {
writer.writeAll("\n") catch {};
}

var frame_index: usize = 0;
var frames_left: usize = @min(stack_trace.index, stack_trace.instruction_addresses.len);
while (frames_left != 0) : (frames_left -= 1) {
const return_address = stack_trace.instruction_addresses[frame_index];
printSymbol(writer, return_address);
frame_index = (frame_index + 1) % stack_trace.instruction_addresses.len;
try writer.print("\x1b[1m???:?:?\x1b[m: \x1b[2m0x{x:0>16} in {s} ({s})\x1b[m\n", .{
address,
symbol_info.symbol_name,
symbol_info.compile_unit_name,
});
}
}

fn printSymbol(writer: anytype, address: u64) void {
var symbol_name: []const u8 = "<no symbol info>";
var file_name: []const u8 = "??";
var line: usize = 0;
const source_files = [_][]const u8{
"arch/x86_64/apic.zig",
"arch/x86_64/cpu.zig",
"arch/x86_64/gdt.zig",
"arch/x86_64/idt.zig",
"arch/x86_64/mem.zig",
"arch/x86_64/x86_64.zig",
"arch/x86_64.zig",
"fs/tmpfs.zig",
"acpi.zig",
"arch.zig",
"debug.zig",
"elf.zig",
"event.zig",
"main.zig",
"pmm.zig",
"ps2.zig",
"rand.zig",
"sched.zig",
"serial.zig",
"smp.zig",
"SpinLock.zig",
"STANDARD.F16",
"time.zig",
"TTY.zig",
"vfs.zig",
"vmm.zig",
};

if (debug_info) |*info| blk: {
if (info.getSymbolName(address)) |name| {
symbol_name = name;
}
// TODO: get source files from filesystem instead + zig std lib files
fn printLineFromFile(writer: anytype, line_info: std.debug.LineInfo) !void {
var contents: []const u8 = undefined;

const compile_unit = info.findCompileUnit(address) catch break :blk;
const line_info = info.getLineNumberInfo(debug_allocator, compile_unit.*, address) catch break :blk;
inline for (source_files) |src_path| {
if (std.mem.endsWith(u8, line_info.file_name, src_path)) {
contents = @embedFile(src_path);
break;
}
} else return error.FileNotFound;

file_name = line_info.file_name;
line = line_info.line;
var line: usize = 1;
for (contents) |byte| {
if (line == line_info.line) {
try writer.writeByte(byte);
if (byte == '\n') return;
}
if (byte == '\n') {
line += 1;
}
}

writer.print("0x{x:0>16}: {s} at {s}:{d}\n", .{
address,
symbol_name,
file_name,
line,
}) catch {};
return error.EndOfFile;

// var f = try fs.openFile(line_info.file_name);
// defer f.close();

// var buf: [std.mem.page_size]u8 = undefined;
// var line: usize = 1;
// while (true) {
// const amt_read = try f.read(buf[0..]);
// const slice = buf[0..amt_read];

// for (slice) |byte| {
// if (line == line_info.line) {
// try writer.writeByte(byte);
// if (byte == '\n') return;
// }
// if (byte == '\n') {
// line += 1;
// }
// }

// if (amt_read < buf.len) return error.EndOfFile;
// }
}

fn getSectionData(elf: [*]const u8, shdr: []const u8) []const u8 {
const offset = readIntLittle(u64, shdr[24..][0..8]);
const size = readIntLittle(u64, shdr[32..][0..8]);

return elf[offset .. offset + size];
}

fn getSectionName(names: []const u8, shdr: []const u8) ?[]const u8 {
const offset = readIntLittle(u32, shdr[0..][0..4]);
const len = std.mem.indexOf(u8, names[offset..], "\x00") orelse return null;

return names[offset .. offset + len];
}
fn initDebugInfo() !void {
errdefer debug_info = null;
const kernel_file = root.kernel_file_request.response.?.kernel_file;

fn getShdr(elf: [*]const u8, idx: u16) []const u8 {
const sh_offset = readIntLittle(u64, elf[40 .. 40 + 8]);
const sh_entsize = readIntLittle(u16, elf[58 .. 58 + 2]);
const off = sh_offset + sh_entsize * idx;
debug_info = .{
.endian = .Little,
.sections = .{
.{ .data = try getSectionSlice(kernel_file.address, ".debug_info"), .owned = true },
.{ .data = try getSectionSlice(kernel_file.address, ".debug_abbrev"), .owned = true },
.{ .data = try getSectionSlice(kernel_file.address, ".debug_str"), .owned = true },
null, // debug_str_offsets
.{ .data = try getSectionSlice(kernel_file.address, ".debug_line"), .owned = true },
null, // debug_line_str
.{ .data = try getSectionSlice(kernel_file.address, ".debug_ranges"), .owned = true },
null, // debug_loclists
null, // debug_rnglists
null, // debug_addr
null, // debug_names
null, // debug_frame
null, // eh_frame
null, // eh_frame_hdr
},
.is_macho = false,
};

return elf[off .. off + sh_entsize];
try std.dwarf.openDwarfDebugInfo(&debug_info.?, debug_allocator);
}

fn getSectionSlice(elf: [*]const u8, section_name: []const u8) ![]const u8 {
Expand All @@ -193,7 +259,6 @@ fn getSectionSlice(elf: [*]const u8, section_name: []const u8) ![]const u8 {
const section_names = getSectionData(elf, getShdr(elf, sh_strndx));

var i: u16 = 0;

while (i < sh_num) : (i += 1) {
const header = getShdr(elf, i);

Expand All @@ -204,3 +269,25 @@ fn getSectionSlice(elf: [*]const u8, section_name: []const u8) ![]const u8 {

return error.SectionNotFound;
}

fn getShdr(elf: [*]const u8, idx: u16) []const u8 {
const sh_offset = readIntLittle(u64, elf[40 .. 40 + 8]);
const sh_entsize = readIntLittle(u16, elf[58 .. 58 + 2]);
const off = sh_offset + sh_entsize * idx;

return elf[off .. off + sh_entsize];
}

fn getSectionData(elf: [*]const u8, shdr: []const u8) []const u8 {
const offset = readIntLittle(u64, shdr[24..][0..8]);
const size = readIntLittle(u64, shdr[32..][0..8]);

return elf[offset .. offset + size];
}

fn getSectionName(names: []const u8, shdr: []const u8) ?[]const u8 {
const offset = readIntLittle(u32, shdr[0..][0..4]);
const len = std.mem.indexOf(u8, names[offset..], "\x00") orelse return null;

return names[offset .. offset + len];
}
3 changes: 0 additions & 3 deletions kernel/main.zig
View file
Original file line number Diff line number Diff line change
Expand Up @@ -66,9 +66,6 @@ export fn _start() noreturn {
arch.disableInterrupts();

serial.init();
debug.init() catch |err| {
std.log.warn("Failed to initialize debug info: {}", .{err});
};
arch.init();
pmm.init();
vmm.init();
Expand Down
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