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Stack guard implementation

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Alex
2022-11-21 03:20:13 +02:00
parent 1afe255fed
commit eaaf8427dc
7 changed files with 171 additions and 43 deletions
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66
Core/Memory/StackGuard.cpp Normal file
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#include <memory.hpp>
#include <debug.h>
namespace Memory
{
StackGuard::StackGuard(bool User, PageTable *Table)
{
this->UserMode = User;
this->Table = Table;
if (this->UserMode)
{
void *AllocatedStack = KernelAllocator.RequestPages(TO_PAGES(USER_STACK_SIZE));
memset(AllocatedStack, 0, USER_STACK_SIZE);
for (uint64_t i = 0; i < TO_PAGES(USER_STACK_SIZE); i++)
{
Virtual(Table).Map((void *)((uint64_t)AllocatedStack + (i * PAGE_SIZE)),
(void *)(USER_STACK_BASE + (i * PAGE_SIZE)),
PTFlag::RW | PTFlag::US);
}
this->StackBottom = (void *)USER_STACK_BASE;
this->StackTop = (void *)(USER_STACK_BASE + USER_STACK_SIZE);
this->Size = USER_STACK_SIZE;
}
else
{
this->StackBottom = KernelAllocator.RequestPages(TO_PAGES(STACK_SIZE));
memset(this->StackBottom, 0, STACK_SIZE);
this->StackTop = (void *)((uint64_t)this->StackBottom + STACK_SIZE);
this->Size = STACK_SIZE;
}
trace("Allocated stack at %p", this->StackBottom);
}
StackGuard::~StackGuard() { KernelAllocator.FreePages(this->StackBottom, TO_PAGES(this->Size)); }
bool StackGuard::Expand(uint64_t FaultAddress)
{
if (this->UserMode)
{
if (FaultAddress < (uint64_t)this->StackBottom - USER_STACK_SIZE ||
FaultAddress > (uint64_t)this->StackTop)
{
return false; // It's not about the stack.
}
else
{
void *AllocatedStack = KernelAllocator.RequestPages(TO_PAGES(USER_STACK_SIZE));
memset(AllocatedStack, 0, USER_STACK_SIZE);
for (uint64_t i = 0; i < TO_PAGES(USER_STACK_SIZE); i++)
Virtual(this->Table).Map((void *)((uint64_t)AllocatedStack + (i * PAGE_SIZE)), (void *)((uint64_t)this->StackBottom - (i * PAGE_SIZE)), PTFlag::RW | PTFlag::US);
this->StackBottom = (void *)((uint64_t)this->StackBottom - USER_STACK_SIZE);
this->Size += USER_STACK_SIZE;
info("Stack expanded to %p", this->StackBottom);
return true;
}
}
else
{
fixme("Not implemented and probably not needed");
return false;
}
error("Reached end of function! How?");
return false;
}
}