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[kernel] Move kernel stacks out of the heap

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We were previously allocating kernel stacks as large objects on the
heap. Now keep track of areas of the kernel stack area that are in use,
and allocate them from there. Also required actually implementing
vm_space::commit(). This still needs more work.
This commit is contained in:
Justin C. Miller
2020-08-02 18:15:28 -07:00
parent b98334db28
commit 579eaaf4a0
9 changed files with 123 additions and 33 deletions
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41
src/kernel/objects/thread.cpp
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@@ -3,6 +3,7 @@
#include "objects/thread.h"
#include "objects/process.h"
#include "scheduler.h"
#include "stack_cache.h"
extern "C" void kernel_to_user_trampoline();
static constexpr j6_signal_t thread_default_signals = 0;
@@ -15,9 +16,8 @@ thread::thread(process &parent, uint8_t pri, bool user) :
m_wait_data(0),
m_wait_obj(0)
{
TCB *tcbp = tcb();
tcbp->pml4 = parent.pml4();
tcbp->priority = pri;
m_tcb.pml4 = parent.pml4();
m_tcb.priority = pri;
setup_kernel_stack();
set_state(state::ready);
}
@@ -30,16 +30,15 @@ thread::thread(process &parent, uint8_t pri, uintptr_t rsp0) :
m_wait_data(0),
m_wait_obj(0)
{
TCB *tcbp = tcb();
tcbp->pml4 = parent.pml4();
tcbp->priority = pri;
tcbp->rsp0 = rsp0;
m_tcb.pml4 = parent.pml4();
m_tcb.priority = pri;
m_tcb.rsp0 = rsp0;
set_state(state::ready);
}
thread::~thread()
{
kutil::kfree(reinterpret_cast<void*>(m_tcb.kernel_stack));
stack_cache::get().return_stack(m_tcb.kernel_stack);
}
thread *
@@ -153,27 +152,25 @@ thread::add_thunk_user(uintptr_t rip)
void
thread::setup_kernel_stack()
{
constexpr size_t initial_stack_size = 0x1000;
using memory::frame_size;
using memory::kernel_stack_pages;
static constexpr size_t stack_bytes = kernel_stack_pages * frame_size;
constexpr unsigned null_frame_entries = 2;
constexpr size_t null_frame_size = null_frame_entries * sizeof(uint64_t);
void *stack_bottom = kutil::kalloc(initial_stack_size);
kutil::memset(stack_bottom, 0, initial_stack_size);
uintptr_t stack_addr = stack_cache::get().get_stack();
uintptr_t stack_end = stack_addr + stack_bytes;
log::debug(logs::memory, "Created kernel stack at %016lx size 0x%lx",
stack_bottom, initial_stack_size);
void *stack_top =
kutil::offset_pointer(stack_bottom,
initial_stack_size - null_frame_size);
uint64_t *null_frame = reinterpret_cast<uint64_t*>(stack_top);
uint64_t *null_frame = reinterpret_cast<uint64_t*>(stack_end - null_frame_size);
for (unsigned i = 0; i < null_frame_entries; ++i)
null_frame[i] = 0;
m_tcb.kernel_stack_size = initial_stack_size;
m_tcb.kernel_stack = reinterpret_cast<uintptr_t>(stack_bottom);
m_tcb.rsp0 = reinterpret_cast<uintptr_t>(stack_top);
log::debug(logs::memory, "Created kernel stack at %016lx size 0x%lx",
stack_addr, stack_bytes);
m_tcb.kernel_stack = stack_addr;
m_tcb.rsp0 = reinterpret_cast<uintptr_t>(null_frame);
m_tcb.rsp = m_tcb.rsp0;
}