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Map user pages in the proper mode. 

This causes the user code to execute succesfully.
However now we don't differentiate between syscalls so we pass right
over the exit syscall and continue executing until we fault.
This commit is contained in:
Drew Galbraith 2023-05-29 13:02:13 -07:00
parent 7184f527a0
commit 6f5b65de30
1 changed files with 11 additions and 4 deletions
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15
zion/memory/paging_util.cpp
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@ -6,6 +6,7 @@
#define PRESENT_BIT 0x1
#define READ_WRITE_BIT 0x2
#define USER_MODE_BIT 0x4;
#define SIGN_EXT 0xFFFF0000'00000000
#define RECURSIVE ((uint64_t)0x1FE)
#define PML_OFFSET 39
@ -79,23 +80,29 @@ void MapPage(uint64_t virt, uint64_t phys) {
panic("Allocating Over Existing Page: %m", virt);
}
uint64_t access_bits = PRESENT_BIT | READ_WRITE_BIT;
uint64_t higher_half = 0xffff8000'00000000;
if ((virt & higher_half) != higher_half) {
access_bits |= USER_MODE_BIT;
}
if (!PageDirectoryPointerLoaded(virt)) {
uint64_t page = phys_mem::AllocatePage();
*Pml4Entry(virt) = page | PRESENT_BIT | READ_WRITE_BIT;
*Pml4Entry(virt) = page | access_bits;
ZeroOutPage(PageDirectoryPointerEntry(virt));
}
if (!PageDirectoryLoaded(virt)) {
uint64_t page = phys_mem::AllocatePage();
*PageDirectoryPointerEntry(virt) = page | PRESENT_BIT | READ_WRITE_BIT;
*PageDirectoryPointerEntry(virt) = page | access_bits;
ZeroOutPage(PageDirectoryEntry(virt));
}
if (!PageTableLoaded(virt)) {
uint64_t page = phys_mem::AllocatePage();
*PageDirectoryEntry(virt) = page | PRESENT_BIT | READ_WRITE_BIT;
*PageDirectoryEntry(virt) = page | access_bits;
ZeroOutPage(PageTableEntry(virt));
}
*PageTableEntry(virt) = PageAlign(phys) | PRESENT_BIT | READ_WRITE_BIT;
*PageTableEntry(virt) = PageAlign(phys) | access_bits;
ZeroOutPage(reinterpret_cast<uint64_t*>(virt));
}