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Profiler: Load the actual kernel binary for disassembly

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/boot/Kernel.debug only contains the symbol table and DWARF debug
information, and has its `.text` and other PT_LOAD segments stripped
out. When we try to parse its data as instructions, we get a crash from
within LibX86.

We now load the actual /boot/Kernel binary when we want to disassemble
kernel functions.
This commit is contained in:
Daniel Bertalan 2021-10-26 18:17:49 +02:00 • committed by Andreas Kling
parent 80b660132c
commit 8e1f882ac9
1 changed files with 27 additions and 7 deletions
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34
Userland/DevTools/Profiler/DisassemblyModel.cpp
View file

@ -34,17 +34,36 @@ static Color color_for_percent(int percent)
return heat_gradient().get_pixel(percent, 0); return heat_gradient().get_pixel(percent, 0);
} }
static Optional<MappedObject> s_kernel_binary;
static ELF::Image* try_load_kernel_binary()
{
if (s_kernel_binary.has_value())
return &s_kernel_binary->elf;
auto kernel_binary_or_error = MappedFile::map("/boot/Kernel");
if (!kernel_binary_or_error.is_error()) {
auto kernel_binary = kernel_binary_or_error.release_value();
s_kernel_binary = { { kernel_binary, ELF::Image(kernel_binary->bytes()) } };
return &s_kernel_binary->elf;
}
return nullptr;
}
DisassemblyModel::DisassemblyModel(Profile& profile, ProfileNode& node) DisassemblyModel::DisassemblyModel(Profile& profile, ProfileNode& node)
: m_profile(profile) : m_profile(profile)
, m_node(node) , m_node(node)
{ {
const ELF::Image* elf;
FlatPtr base_address = 0; FlatPtr base_address = 0;
OwnPtr<Debug::DebugInfo> debug_info;
const ELF::Image* elf;
if (auto maybe_kernel_base = Symbolication::kernel_base(); maybe_kernel_base.has_value() && m_node.address() >= *maybe_kernel_base) { if (auto maybe_kernel_base = Symbolication::kernel_base(); maybe_kernel_base.has_value() && m_node.address() >= *maybe_kernel_base) {
if (!g_kernel_debuginfo_object.has_value()) if (!g_kernel_debuginfo_object.has_value())
return; return;
elf = &g_kernel_debuginfo_object->elf; base_address = maybe_kernel_base.release_value();
base_address = maybe_kernel_base.value(); elf = try_load_kernel_binary();
if (elf == nullptr)
return;
debug_info = make<Debug::DebugInfo>(g_kernel_debuginfo_object->elf, String::empty(), base_address);
} else { } else {
auto& process = node.process(); auto& process = node.process();
auto library_data = process.library_metadata.library_containing(node.address()); auto library_data = process.library_metadata.library_containing(node.address());
@ -52,16 +71,17 @@ DisassemblyModel::DisassemblyModel(Profile& profile, ProfileNode& node)
dbgln("no library data for address {:p}", node.address()); dbgln("no library data for address {:p}", node.address());
return; return;
} }
elf = &library_data->object->elf;
base_address = library_data->base; base_address = library_data->base;
elf = &library_data->object->elf;
debug_info = make<Debug::DebugInfo>(library_data->object->elf, String::empty(), base_address);
} }
VERIFY(elf != nullptr); VERIFY(elf != nullptr);
VERIFY(debug_info != nullptr);
FlatPtr function_address = node.address() - base_address; FlatPtr function_address = node.address() - base_address;
auto is_function_address = false; auto is_function_address = false;
Debug::DebugInfo debug_info { *elf, {}, base_address }; auto function = debug_info->get_containing_function(function_address);
auto function = debug_info.get_containing_function(function_address);
if (function.has_value()) { if (function.has_value()) {
if (function_address == function->address_low) if (function_address == function->address_low)
is_function_address = true; is_function_address = true;
@ -107,7 +127,7 @@ DisassemblyModel::DisassemblyModel(Profile& profile, ProfileNode& node)
u32 samples_at_this_instruction = m_node.events_per_address().get(address_in_profiled_program).value_or(0); u32 samples_at_this_instruction = m_node.events_per_address().get(address_in_profiled_program).value_or(0);
float percent = ((float)samples_at_this_instruction / (float)m_node.event_count()) * 100.0f; float percent = ((float)samples_at_this_instruction / (float)m_node.event_count()) * 100.0f;
m_instructions.append({ insn.value(), disassembly, instruction_bytes, address_in_profiled_program, samples_at_this_instruction, percent, debug_info.get_source_position_with_inlines(address_in_profiled_program - base_address) }); m_instructions.append({ insn.value(), disassembly, instruction_bytes, address_in_profiled_program, samples_at_this_instruction, percent, debug_info->get_source_position_with_inlines(address_in_profiled_program - base_address) });
offset_into_symbol += insn.value().length(); offset_into_symbol += insn.value().length();
} }