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PowerPC: Check page crossing for non-translated reads 

This fixes a problem where Dolphin could crash if a non-translated
read crossed the end of a physical memory region.

The same change was applied to WriteToHardware in ecbce0a.
This commit is contained in:
JosJuice 2022-05-07 14:21:30 +02:00
parent 8335ec70e5
commit 3b3c60dc4c
1 changed files with 14 additions and 26 deletions
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40
Source/Core/Core/PowerPC/MMU.cpp
View File

@ -173,6 +173,20 @@ static void GenerateDSIException(u32 effective_address, bool write);
template <XCheckTLBFlag flag, typename T, bool never_translate = false>
static T ReadFromHardware(u32 em_address)
{
const u32 em_address_start_page = em_address & ~(HW_PAGE_SIZE - 1);
const u32 em_address_end_page = (em_address + sizeof(T) - 1) & ~(HW_PAGE_SIZE - 1);
if (em_address_start_page != em_address_end_page)
{
// This could be unaligned down to the byte level... hopefully this is rare, so doing it this
// way isn't too terrible.
// TODO: floats on non-word-aligned boundaries should technically cause alignment exceptions.
// Note that "word" means 32-bit, so paired singles or doubles might still be 32-bit aligned!
u64 var = 0;
for (u32 i = 0; i < sizeof(T); ++i)
var = (var << 8) | ReadFromHardware<flag, u8, never_translate>(em_address + i);
return static_cast<T>(var);
}
if (!never_translate && MSR.DR)
{
auto translated_addr = TranslateAddress<flag>(em_address);
@ -182,35 +196,9 @@ static T ReadFromHardware(u32 em_address)
GenerateDSIException(em_address, false);
return 0;
}
if ((em_address & (HW_PAGE_SIZE - 1)) > HW_PAGE_SIZE - sizeof(T))
{
// This could be unaligned down to the byte level... hopefully this is rare, so doing it this
// way isn't too terrible.
// TODO: floats on non-word-aligned boundaries should technically cause alignment exceptions.
// Note that "word" means 32-bit, so paired singles or doubles might still be 32-bit aligned!
u32 em_address_next_page = (em_address + sizeof(T) - 1) & ~(HW_PAGE_SIZE - 1);
auto addr_next_page = TranslateAddress<flag>(em_address_next_page);
if (!addr_next_page.Success())
{
if (flag == XCheckTLBFlag::Read)
GenerateDSIException(em_address_next_page, false);
return 0;
}
T var = 0;
u32 addr_translated = translated_addr.address;
for (u32 addr = em_address; addr < em_address + sizeof(T); addr++, addr_translated++)
{
if (addr == em_address_next_page)
addr_translated = addr_next_page.address;
var = (var << 8) | ReadFromHardware<flag, u8, true>(addr_translated);
}
return var;
}
em_address = translated_addr.address;
}
// TODO: Make sure these are safe for unaligned addresses.
if (Memory::m_pRAM && (em_address & 0xF8000000) == 0x00000000)
{
// Handle RAM; the masking intentionally discards bits (essentially creating