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LibELF: Extract TLS offset calculation logic to separate function

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Itamar 2021-04-24 11:24:02 +03:00 • committed by Andreas Kling
parent 373e8bcbc7
commit 1c24388d74
2 changed files with 11 additions and 3 deletions
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11
Userland/Libraries/LibELF/DynamicLoader.cpp
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@ -460,10 +460,9 @@ DynamicLoader::RelocationResult DynamicLoader::do_relocation(size_t total_tls_si
auto res = lookup_symbol(symbol);
if (!res.has_value())
break;
u32 symbol_value = res.value().value;
auto* dynamic_object_of_symbol = res.value().dynamic_object;
VERIFY(dynamic_object_of_symbol);
*patch_ptr = dynamic_object_of_symbol->tls_offset().value() + symbol_value - total_tls_size;
*patch_ptr = negative_offset_from_tls_block_end(res.value().value, dynamic_object_of_symbol->tls_offset().value(), total_tls_size);
break;
}
case R_386_JMP_SLOT: {
@ -488,6 +487,14 @@ DynamicLoader::RelocationResult DynamicLoader::do_relocation(size_t total_tls_si
return RelocationResult::Success;
}
ssize_t DynamicLoader::negative_offset_from_tls_block_end(size_t value_of_symbol, size_t tls_offset, size_t total_tls_size) const
{
auto negative_offset = static_cast<ssize_t>(tls_offset + value_of_symbol - total_tls_size);
// Offset has to be strictly negative. Otherwise we'd collide with the thread's ThreadSpecificData structure.
VERIFY(negative_offset < 0);
return negative_offset;
}
// Defined in <arch>/plt_trampoline.S
extern "C" void _plt_trampoline(void) __attribute__((visibility("hidden")));

3
Userland/Libraries/LibELF/DynamicLoader.h
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@ -130,6 +130,7 @@ private:
};
RelocationResult do_relocation(size_t total_tls_size, const DynamicObject::Relocation&, ShouldInitializeWeak should_initialize_weak);
size_t calculate_tls_size() const;
ssize_t negative_offset_from_tls_block_end(size_t value_of_symbol, size_t tls_offset, size_t total_tls_size) const;
String m_filename;
String m_program_interpreter;
@ -150,7 +151,7 @@ private:
VirtualAddress m_dynamic_section_address;
size_t m_tls_offset { 0 };
size_t m_tls_size { 0 };
size_t m_tls_size { 0 }; // TLS size of the current object
Vector<DynamicObject::Relocation> m_unresolved_relocations;