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feat: implement software breakpoints

This commit is contained in:
Rekai Nyangadzayi Musuka 2023-01-29 07:17:12 -06:00
parent 81ff227ea7
commit d7b8d7acb1
3 changed files with 153 additions and 57 deletions
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83
src/Packet.zig
View File

@ -49,10 +49,7 @@ const String = union(enum) {
pub fn parse(self: *Self, allocator: Allocator, emu: *Emulator) !String {
switch (self.contents[0]) {
// Required
'?' => {
const ret = try std.fmt.allocPrint(allocator, "S{x:0>2}", .{@enumToInt(Signal.Int)});
return .{ .alloc = ret };
},
'?' => return .{ .static = "T05" }, // FIXME: which errno?
'g' => {
const r = emu.registers();
const cpsr = emu.cpsr();
@ -140,45 +137,55 @@ pub fn parse(self: *Self, allocator: Allocator, emu: *Emulator) !String {
},
// Breakpoints
'z' => switch (self.contents[1]) {
'0' => return .{ .static = "" }, //TODO: Remove Software Breakpoint
'1' => {
var tokens = std.mem.tokenize(u8, self.contents[2..], ",");
'z' => {
var tokens = std.mem.tokenize(u8, self.contents[2..], ",");
const addr_str = tokens.next() orelse return error.InvalidPacket;
const addr = try std.fmt.parseInt(u32, addr_str, 16);
const addr_str = tokens.next() orelse return error.InvalidPacket;
const addr = try std.fmt.parseInt(u32, addr_str, 16);
emu.state.hw_bkpt.remove(addr);
return .{ .static = "OK" };
},
'2' => return .{ .static = "" }, // TODO: Remove Write Watchpoint
'3' => return .{ .static = "" }, // TODO: Remove Read Watchpoint
'4' => return .{ .static = "" }, // TODO: Remove Access Watchpoint
else => return .{ .static = "" },
switch (self.contents[1]) {
'0' => {
emu.removeBkpt(.Software, addr);
return .{ .static = "OK" };
},
'1' => {
emu.removeBkpt(.Hardware, addr);
return .{ .static = "OK" };
},
'2' => return .{ .static = "" }, // TODO: Remove Write Watchpoint
'3' => return .{ .static = "" }, // TODO: Remove Read Watchpoint
'4' => return .{ .static = "" }, // TODO: Remove Access Watchpoint
else => return .{ .static = "" },
}
},
'Z' => switch (self.contents[1]) {
'0' => return .{ .static = "" }, //TODO: Insert Software Breakpoint
'1' => {
var tokens = std.mem.tokenize(u8, self.contents[2..], ",");
const addr_str = tokens.next() orelse return error.InvalidPacket;
const kind_str = tokens.next() orelse return error.InvalidPacket;
'Z' => {
var tokens = std.mem.tokenize(u8, self.contents[2..], ",");
const addr_str = tokens.next() orelse return error.InvalidPacket;
const kind_str = tokens.next() orelse return error.InvalidPacket;
const addr = try std.fmt.parseInt(u32, addr_str, 16);
const kind = try std.fmt.parseInt(u32, kind_str, 16);
const addr = try std.fmt.parseInt(u32, addr_str, 16);
const kind = try std.fmt.parseInt(u32, kind_str, 16);
emu.state.hw_bkpt.add(addr, kind) catch |e| {
switch (e) {
error.OutOfSpace => return .{ .static = "E22" }, // FIXME: Which errno?
else => return e,
}
};
switch (self.contents[1]) {
'0' => {
try emu.addBkpt(.Software, addr, kind);
return .{ .static = "OK" };
},
'1' => {
emu.addBkpt(.Hardware, addr, kind) catch |e| {
switch (e) {
error.OutOfSpace => return .{ .static = "E22" }, // FIXME: which errno?
else => return e,
}
};
return .{ .static = "OK" };
},
'2' => return .{ .static = "" }, // TODO: Insert Write Watchpoint
'3' => return .{ .static = "" }, // TODO: Insert Read Watchpoint
'4' => return .{ .static = "" }, // TODO: Insert Access Watchpoint
else => return .{ .static = "" },
return .{ .static = "OK" };
},
'2' => return .{ .static = "" }, // TODO: Insert Write Watchpoint
'3' => return .{ .static = "" }, // TODO: Insert Read Watchpoint
'4' => return .{ .static = "" }, // TODO: Insert Access Watchpoint
else => return .{ .static = "" },
}
},
// TODO: Figure out the difference between 'M' and 'X'
@ -202,7 +209,7 @@ pub fn parse(self: *Self, allocator: Allocator, emu: *Emulator) !String {
if (substr(self.contents[1..], "Attached")) return .{ .static = "1" }; // Tell GDB we're attached to a process
if (substr(self.contents[1..], "Supported")) {
const format = "PacketSize={x:};qXfer:features:read+;qXfer:memory-map:read+";
const format = "PacketSize={x:};swbreak+;hwbreak+;qXfer:features:read+;qXfer:memory-map:read+";
// TODO: Anything else?
const ret = try std.fmt.allocPrint(allocator, format, .{Self.max_len});

86
src/State.zig
View File

@ -1,6 +1,62 @@
const std = @import("std");
const Allocator = std.mem.Allocator;
const ArrayList = std.ArrayList;
hw_bkpt: HwBkpt = .{},
sw_bkpt: SwBkpt,
pub fn init(allocator: Allocator) @This() {
return .{ .sw_bkpt = SwBkpt.init(allocator) };
}
pub fn deinit(self: *@This()) void {
self.sw_bkpt.deinit();
self.* = undefined;
}
const SwBkpt = struct {
const log = std.log.scoped(.SwBkpt);
list: std.ArrayList(Bkpt),
pub fn init(allocator: Allocator) @This() {
return .{ .list = ArrayList(Bkpt).init(allocator) };
}
pub fn deinit(self: *@This()) void {
self.deinit();
self.* = undefined;
}
pub fn isHit(self: *const @This(), addr: u32) bool {
for (self.list.items) |bkpt| {
if (bkpt.addr == addr) return true;
}
return false;
}
pub fn add(self: *@This(), addr: u32, kind: u32) !void {
for (self.list.items) |bkpt| {
if (bkpt.addr == addr) return; // indempotent
}
try self.list.append(.{ .addr = addr, .kind = try Bkpt.Kind.from(u32, kind) });
log.warn("Added Breakpoint at 0x{X:0>8}", .{addr});
}
pub fn remove(self: *@This(), addr: u32) void {
for (self.list.items) |bkpt, i| {
if (bkpt.addr == addr) {
_ = self.list.orderedRemove(i);
log.debug("Removed Breakpoint at 0x{X:0>8}", .{addr});
return;
}
}
}
};
const HwBkpt = struct {
const log = std.log.scoped(.HwBkpt);
@ -9,9 +65,7 @@ const HwBkpt = struct {
pub fn isHit(self: *const @This(), addr: u32) bool {
for (self.list) |bkpt_opt| {
if (bkpt_opt == null) continue;
const bkpt = bkpt_opt.?;
const bkpt = bkpt_opt orelse continue;
if (bkpt.addr == addr) return true;
}
@ -20,17 +74,14 @@ const HwBkpt = struct {
pub fn add(self: *@This(), addr: u32, kind: u32) !void {
for (self.list) |*bkpt_opt| {
if (bkpt_opt.* != null) {
const bkpt = bkpt_opt.*.?;
if (bkpt.addr == addr) return; // makes this fn indempotent
if (bkpt_opt.*) |bkpt| {
if (bkpt.addr == addr) return; // idempotent
} else {
bkpt_opt.* = .{ .addr = addr, .kind = try Bkpt.Kind.from(u32, kind) };
log.debug("Added Breakpoint at 0x{X:0>8}", .{addr});
continue;
return;
}
bkpt_opt.* = .{ .addr = addr, .kind = try Bkpt.Kind.from(u32, kind) };
log.debug("Added Breakpoint at 0x{X:0>8}", .{addr});
return;
}
return error.OutOfSpace;
@ -38,11 +89,14 @@ const HwBkpt = struct {
pub fn remove(self: *@This(), addr: u32) void {
for (self.list) |*bkpt_opt| {
if (bkpt_opt.* == null) continue;
const bkpt = bkpt_opt.*.?; // FIXME: bkpt_opt.?.addr works though?
const bkpt = bkpt_opt.* orelse continue;
log.debug("Removed Breakpoint at 0x{X:0>8}", .{addr});
if (bkpt.addr == addr) bkpt_opt.* = null;
if (bkpt.addr == addr) {
bkpt_opt.* = null;
log.debug("Removed Breakpoint at 0x{X:0>8}", .{addr});
break;
}
}
}
};

41
src/lib.zig
View File

@ -1,3 +1,6 @@
const std = @import("std");
const Allocator = std.mem.Allocator;
/// Re-export of the server interface
pub const Server = @import("Server.zig");
const State = @import("State.zig");
@ -13,7 +16,7 @@ pub const Emulator = struct {
SingleStep: void,
};
state: State = .{},
state: State,
ptr: *anyopaque,
@ -25,7 +28,7 @@ pub const Emulator = struct {
stepFn: *const fn (*anyopaque) void,
pub fn init(ptr: anytype) Self {
pub fn init(allocator: Allocator, ptr: anytype) Self {
const Ptr = @TypeOf(ptr);
const ptr_info = @typeInfo(Ptr);
@ -66,7 +69,21 @@ pub const Emulator = struct {
}
};
return .{ .ptr = ptr, .readFn = gen.readImpl, .writeFn = gen.writeImpl, .registersFn = gen.registersImpl, .cpsrFn = gen.cpsrImpl, .stepFn = gen.stepImpl };
return .{
.ptr = ptr,
.readFn = gen.readImpl,
.writeFn = gen.writeImpl,
.registersFn = gen.registersImpl,
.cpsrFn = gen.cpsrImpl,
.stepFn = gen.stepImpl,
.state = State.init(allocator),
};
}
pub fn deinit(self: *Self) void {
self.state.deinit();
self.* = undefined;
}
pub inline fn read(self: Self, addr: u32) u8 {
@ -104,8 +121,26 @@ pub const Emulator = struct {
const r15 = r[15] -| if (is_thumb) @as(u32, 4) else 8;
if (self.state.sw_bkpt.isHit(r15)) return .{ .Trap = .SwBkpt };
if (self.state.hw_bkpt.isHit(r15)) return .{ .Trap = .HwBkpt };
return .SingleStep;
}
const BkptType = enum { Hardware, Software };
// TODO: Consider properly implementing Software interrupts?
pub fn addBkpt(self: *Self, comptime @"type": BkptType, addr: u32, kind: u32) !void {
switch (@"type") {
.Hardware => try self.state.hw_bkpt.add(addr, kind),
.Software => try self.state.sw_bkpt.add(addr, kind),
}
}
pub fn removeBkpt(self: *Self, comptime @"type": BkptType, addr: u32) void {
switch (@"type") {
.Hardware => self.state.hw_bkpt.remove(addr),
.Software => self.state.sw_bkpt.remove(addr),
}
}
};