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Add the ability to copy memory to non resident process.

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Use/Test this by loading the user space elf from the kernel process
before it starts rather than as a part of the first thread.

This simplifies thread start a fair bit.
This commit is contained in:
Drew Galbraith 2023-05-30 01:27:47 -07:00
parent f6609983d2
commit b9b45c5e45
9 changed files with 55 additions and 38 deletions
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35
zion/memory/paging_util.cpp
View file

@ -69,7 +69,7 @@ uint64_t* PageTableEntry(uint64_t pt_phys, uint64_t addr) {
ShiftForEntryIndexing(addr, PT_OFFSET));
}
bool IsPageResident(uint64_t cr3, uint64_t virt) {
uint64_t PagePhysIfResident(uint64_t cr3, uint64_t virt) {
uint64_t* pml4_entry = Pml4Entry(cr3, virt);
if (!(*pml4_entry & PRESENT_BIT)) {
return false;
@ -86,10 +86,10 @@ bool IsPageResident(uint64_t cr3, uint64_t virt) {
if (!(*pt_entry & PRESENT_BIT)) {
return false;
}
return true;
return *pt_entry & ~0xFFF;
}
void MapPage(uint64_t cr3, uint64_t virt) {
uint64_t MapPage(uint64_t cr3, uint64_t virt) {
uint64_t access_bits = PRESENT_BIT | READ_WRITE_BIT;
uint64_t higher_half = 0xffff8000'00000000;
if ((virt & higher_half) != higher_half) {
@ -121,8 +121,10 @@ void MapPage(uint64_t cr3, uint64_t virt) {
*pt_entry = PageAlign(phys) | access_bits;
ZeroOutPage(reinterpret_cast<uint64_t*>(boot::GetHigherHalfDirectMap() +
PageAlign(phys)));
return phys;
} else {
panic("Page already allocated.");
return 0;
}
}
@ -152,14 +154,15 @@ void InitializePml4(uint64_t pml4_physical_addr) {
pml4_virtual[Pml4Index(hhdm)] = *Pml4Entry(curr_cr3, hhdm);
}
void AllocatePageIfNecessary(uint64_t addr, uint64_t cr3) {
uint64_t AllocatePageIfNecessary(uint64_t addr, uint64_t cr3) {
if (cr3 == 0) {
cr3 = CurrCr3();
}
if (IsPageResident(cr3, addr)) {
return;
uint64_t phys = PagePhysIfResident(cr3, addr);
if (phys) {
return phys;
}
MapPage(cr3, addr);
return MapPage(cr3, addr);
}
void EnsureResident(uint64_t addr, uint64_t size) {
@ -170,3 +173,21 @@ void EnsureResident(uint64_t addr, uint64_t size) {
addr += 0x1000;
}
}
void CopyIntoNonResidentProcess(uint64_t base, uint64_t size, uint64_t dest_cr3,
uint64_t dest_virt) {
if (size > 0x1000) {
panic("Unimplemented NR copy > 1 page");
}
if (dest_virt & 0xFFF) {
panic("Unimplemented NR copy to non page aligned");
}
uint64_t phys = AllocatePageIfNecessary(dest_virt, dest_cr3);
uint8_t* src = reinterpret_cast<uint8_t*>(base);
uint8_t* dest =
reinterpret_cast<uint8_t*>(phys + boot::GetHigherHalfDirectMap());
for (uint64_t i = 0; i < size; i++) {
dest[i] = src[i];
}
}