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Kernel: Allocate kernel stacks for threads using the region allocator.

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This patch moves away from using kmalloc memory for thread kernel stacks.
This reduces pressure on kmalloc (16 KB per thread adds up fast) and
prevents kernel stack overflow from scribbling all over random unrelated
kernel memory.
This commit is contained in:
Andreas Kling 2019-05-14 11:51:00 +02:00
parent 8c3ad802d8
commit c8a216b107
6 changed files with 65 additions and 24 deletions
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17
Kernel/Thread.cpp
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@ -45,12 +45,14 @@ Thread::Thread(Process& process)
// FIXME: This memory is leaked.
// But uh, there's also no kernel process termination, so I guess it's not technically leaked...
dword stack_bottom = (dword)kmalloc_eternal(default_kernel_stack_size);
m_tss.esp = (stack_bottom + default_kernel_stack_size) & 0xffffff8;
m_tss.esp = (stack_bottom + default_kernel_stack_size) & 0xfffffff8u;
} else {
// Ring3 processes need a separate stack for Ring0.
m_kernel_stack = kmalloc(default_kernel_stack_size);
m_kernel_stack_region = MM.allocate_kernel_region(default_kernel_stack_size, String::format("Kernel Stack (Thread %d)", m_tid));
m_kernel_stack_region->commit();
m_tss.ss0 = 0x10;
m_tss.esp0 = ((dword)m_kernel_stack + default_kernel_stack_size) & 0xffffff8;
m_tss.esp0 = m_kernel_stack_region->laddr().offset(default_kernel_stack_size).get() & 0xfffffff8u;
}
// HACK: Ring2 SS in the TSS is the current PID.
@ -78,11 +80,6 @@ Thread::~Thread()
if (selector())
gdt_free_entry(selector());
if (m_kernel_stack) {
kfree(m_kernel_stack);
m_kernel_stack = nullptr;
}
if (m_kernel_stack_for_signal_handler) {
kfree(m_kernel_stack_for_signal_handler);
m_kernel_stack_for_signal_handler = nullptr;
@ -438,7 +435,7 @@ void Thread::push_value_on_stack(dword value)
void Thread::make_userspace_stack_for_main_thread(Vector<String> arguments, Vector<String> environment)
{
auto* region = m_process.allocate_region(LinearAddress(), default_userspace_stack_size, "stack");
auto* region = m_process.allocate_region(LinearAddress(), default_userspace_stack_size, "Stack (Main thread)");
ASSERT(region);
m_tss.esp = region->laddr().offset(default_userspace_stack_size).get();
@ -484,7 +481,7 @@ void Thread::make_userspace_stack_for_main_thread(Vector<String> arguments, Vect
void Thread::make_userspace_stack_for_secondary_thread(void *argument)
{
auto* region = m_process.allocate_region(LinearAddress(), default_userspace_stack_size, String::format("Thread %u Stack", tid()));
auto* region = m_process.allocate_region(LinearAddress(), default_userspace_stack_size, String::format("Stack (Thread %d)", tid()));
ASSERT(region);
m_tss.esp = region->laddr().offset(default_userspace_stack_size).get();