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Kernel: Expose stack base/size and page size in auxv

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Bananymous
2026-07-01 13:04:17 +03:00
parent c5cfa82ffb
commit 59c59c3316
1 changed files with 47 additions and 12 deletions
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59
kernel/kernel/Process.cpp
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@@ -126,6 +126,9 @@ namespace Kernel
TRY(process->m_cmdline.back().append(argument));
}
auto* thread = TRY(Thread::create_userspace(process, process->page_table()));
BAN::ScopeGuard thread_deleter([thread] { delete thread; });
LockGuard _(process->m_process_lock);
auto executable_file = TRY(process->find_file(AT_FDCWD, path.data(), O_EXEC));
@@ -144,7 +147,7 @@ namespace Kernel
process->m_credentials.set_egid(executable_inode->gid());
BAN::Vector<LibELF::AuxiliaryVector> auxiliary_vector;
TRY(auxiliary_vector.reserve(2 + 2 * executable.interp_base.has_value()));
TRY(auxiliary_vector.reserve(5 + 2 * executable.interp_base.has_value()));
if (executable.interp_base.has_value())
{
@@ -159,7 +162,7 @@ namespace Kernel
}));
}
process->m_shared_page_vaddr = process->page_table().reserve_free_page(process->m_mapped_regions.back()->vaddr(), USERSPACE_END);
process->m_shared_page_vaddr = process->page_table().reserve_free_page(executable.interp_base.value_or(0x400000), USERSPACE_END);
if (process->m_shared_page_vaddr == 0)
return BAN::Error::from_errno(ENOMEM);
process->page_table().map_page_at(
@@ -168,11 +171,26 @@ namespace Kernel
PageTable::UserSupervisor | PageTable::Present
);
TRY(auxiliary_vector.push_back({
.a_type = LibELF::AT_PAGESZ,
.a_un = { .a_val = PAGE_SIZE },
}));
TRY(auxiliary_vector.push_back({
.a_type = LibELF::AT_SHARED_PAGE,
.a_un = { .a_ptr = reinterpret_cast<void*>(process->m_shared_page_vaddr) },
}));
TRY(auxiliary_vector.push_back({
.a_type = LibELF::AT_STACK_BASE,
.a_un = { .a_ptr = reinterpret_cast<void*>(thread->userspace_stack().vaddr()) },
}));
TRY(auxiliary_vector.push_back({
.a_type = LibELF::AT_STACK_SIZE,
.a_un = { .a_ptr = reinterpret_cast<void*>(thread->userspace_stack().size()) },
}));
TRY(auxiliary_vector.push_back({
.a_type = LibELF::AT_NULL,
.a_un = { .a_val = 0 },
@@ -186,8 +204,7 @@ namespace Kernel
tls_addr = tls_result.addr;
}
auto* thread = MUST(Thread::create_userspace(process, process->page_table()));
MUST(thread->initialize_userspace(
TRY(thread->initialize_userspace(
executable.entry_point,
process->m_cmdline.span(),
process->m_environ.span(),
@@ -204,6 +221,7 @@ namespace Kernel
#endif
}
thread_deleter.disable();
process->add_thread(thread);
process->register_to_scheduler();
return process;
@@ -824,8 +842,15 @@ namespace Kernel
BAN::String executable_path;
TRY(executable_path.append(executable_file.canonical_path));
// This is ugly but thread insterts userspace stack to process' memory region
BAN::swap(m_mapped_regions, new_mapped_regions);
auto new_thread_or_error = Thread::create_userspace(this, *new_page_table);
BAN::swap(m_mapped_regions, new_mapped_regions);
auto* new_thread = TRY(new_thread_or_error);
BAN::ScopeGuard new_thread_deleter([new_thread] { delete new_thread; });
BAN::Vector<LibELF::AuxiliaryVector> auxiliary_vector;
TRY(auxiliary_vector.reserve(2 + 2 * executable.interp_base.has_value()));
TRY(auxiliary_vector.reserve(5 + 2 * executable.interp_base.has_value()));
BAN::ScopeGuard execfd_guard([this, &auxiliary_vector] {
if (auxiliary_vector.empty())
@@ -848,7 +873,7 @@ namespace Kernel
}));
}
const vaddr_t shared_page_vaddr = new_page_table->reserve_free_page(new_mapped_regions.back()->vaddr(), USERSPACE_END);
const vaddr_t shared_page_vaddr = new_page_table->reserve_free_page(executable.interp_base.value_or(0x400000), USERSPACE_END);
if (shared_page_vaddr == 0)
return BAN::Error::from_errno(ENOMEM);
new_page_table->map_page_at(
@@ -857,22 +882,31 @@ namespace Kernel
PageTable::UserSupervisor | PageTable::Present
);
TRY(auxiliary_vector.push_back({
.a_type = LibELF::AT_PAGESZ,
.a_un = { .a_val = PAGE_SIZE },
}));
TRY(auxiliary_vector.push_back({
.a_type = LibELF::AT_SHARED_PAGE,
.a_un = { .a_ptr = reinterpret_cast<void*>(shared_page_vaddr) },
}));
TRY(auxiliary_vector.push_back({
.a_type = LibELF::AT_STACK_BASE,
.a_un = { .a_ptr = reinterpret_cast<void*>(new_thread->userspace_stack().vaddr()) },
}));
TRY(auxiliary_vector.push_back({
.a_type = LibELF::AT_STACK_SIZE,
.a_un = { .a_ptr = reinterpret_cast<void*>(new_thread->userspace_stack().size()) },
}));
TRY(auxiliary_vector.push_back({
.a_type = LibELF::AT_NULL,
.a_un = { .a_val = 0 },
}));
// This is ugly but thread insterts userspace stack to process' memory region
BAN::swap(m_mapped_regions, new_mapped_regions);
auto new_thread_or_error = Thread::create_userspace(this, *new_page_table);
BAN::swap(m_mapped_regions, new_mapped_regions);
auto* new_thread = TRY(new_thread_or_error);
TRY(new_thread->initialize_userspace(
executable.entry_point,
str_argv.span(),
@@ -926,6 +960,7 @@ namespace Kernel
m_threads.front()->m_process = nullptr;
m_threads.front()->give_keep_alive_page_table(BAN::move(m_page_table));
new_thread_deleter.disable();
MUST(Processor::scheduler().add_thread(new_thread));
m_threads.front() = new_thread;