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Keep JIT block entries and replacement hooks out of PSP memory

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The JITs used to find a block by overwriting its first instruction with an "emuhack" holding
the offset into the code space, and replacement functions installed their own emuhack the same
way. Anything that read code (savestates, the debugger, memory dumps, cheats, the function
hasher, games reading their own code) had to translate them back.

Blocks now live in a block shadow: one u32 per guest instruction, indexed by the PC masked with
BLOCK_SHADOW_MASK (1GB on 64-bit, folding the kernel and uncached mirrors; 256MB on 32-bit, iOS
and Switch, where address space is short), with the low bits cleared so a misaligned PC can't
read across two entries. Only the ranges under memory views are committed, so a bad PC still
faults in the dispatcher, and the shadow is reserved before the memory map so it can't land in
a gap of the 4GB window. Entries hold full 32-bit offsets, lifting the 16MB limit. The
dispatchers on every backend, and the IR interpreter's loop, look blocks up there.

A hooked instruction without a compiled block gets the JIT's hook value in its entry: the offset
of the dispatcher's compile path (1 for the interpreters, the IR arena keeping that offset
empty), so dispatching there compiles a block, and the frontends substitute the hook. Compiling
replaces the entry with the block's, and destroying the block puts the hook value back. The hook
value is rewritten when the JIT changes or regenerates its dispatcher.

Hooks live in a map keyed by the masked address, and are dropped when the game overwrites the
hooked instruction, or when an icache invalidation finds the function's hash (immediates masked,
as when matching it) changed. Those checks run when queued invalidations are processed, since
cheats and the debugger queue them before writing. Installing and removing hooks invalidates
deferred, as it happens in HLE calls that can run inside a block. The cache instruction goes
through MIPSState, so it drops changed hooks too.

With clean memory, the save/clear/restore around savestates, memory reads and dumps goes away,
as do the source-range invalidations in the memcpy replacements, sceDmac and the cheats.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
This commit is contained in:
Henrik RydgårdandClaude Opus 5.5 committed 2026-10-11 10:33:30 +02:00
1 parent 0a8ec4d8f1
commit 6d122f416e
57 files changed
+876 -759
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Core/MIPS/JitCommon/JitBlockCache.cpp
+19 -65
View File
@@ -46,7 +46,6 @@ constexpr u32 SENTINEL_VAL = 0xc0ffeefe;
static uint64_t HashJitBlock(const JitBlock &b) {
PROFILE_THIS_SCOPE("jithash");
if (JIT_USE_COMPILEDHASH) {
// Includes the emuhack (or emuhacks) in memory.
if (Memory::IsValidRange(b.originalAddress, b.originalSize * 4)) {
return XXH3_64bits(Memory::GetPointerUnchecked(b.originalAddress), b.originalSize * 4);
} else {
@@ -172,11 +171,8 @@ static void ExpandRange(std::pair<u32, u32> &range, u32 newStart, u32 newEnd) {
void JitBlockCache::FinalizeBlock(int block_num, bool block_link) {
JitBlock &b = blocks_[block_num];
b.originalFirstOpcode = Memory::Read_Opcode_JIT(b.originalAddress);
MIPSOpcode opcode = GetEmuHackOpForBlock(block_num);
Memory::Write_Opcode_JIT(b.originalAddress, opcode);
// Note that this hashes the emuhack too, which is intentional.
b.originalFirstOpcode = Memory::ReadUnchecked_Instruction(b.originalAddress);
Memory::WriteBlockShadow(b.originalAddress, GetShadowValueForBlock(block_num));
b.compiledHash = HashJitBlock(b);
AddBlockMap(block_num);
@@ -207,7 +203,7 @@ void JitBlockCache::FinalizeBlock(int block_num, bool block_link) {
}
}
bool JitBlockCache::RangeMayHaveEmuHacks(u32 start, u32 end) const {
bool JitBlockCache::RangeMayHaveBlocks(u32 start, u32 end) const {
for (int i = 0; i < JITBLOCK_RANGE_COUNT; ++i) {
if (end >= blockMemRanges_[i].first && start <= blockMemRanges_[i].second) {
return true;
@@ -230,16 +226,13 @@ static int binary_search(const JitBlock blocks_[], const u8 *baseoff, int imin,
return -1;
}
int JitBlockCache::GetBlockNumberFromEmuHackOp(MIPSOpcode inst, bool ignoreBad) const {
if (!num_blocks_ || !MIPS_IS_EMUHACK(inst)) // definitely not a JIT block
int JitBlockCache::GetBlockNumberFromShadowValue(u32 value) const {
if (!num_blocks_ || value == 0)
return -1;
int off = (inst & MIPS_EMUHACK_VALUE_MASK);
const u8 *baseoff = codeBlock_->GetBasePtr() + off;
if (baseoff < codeBlock_->GetBasePtr() || baseoff >= codeBlock_->GetCodePtr()) {
if (!ignoreBad) {
ERROR_LOG(Log::JIT, "JitBlockCache: Invalid Emuhack Op %08x", inst.encoding);
}
const u8 *baseoff = codeBlock_->GetBasePtr() + value;
if (baseoff >= codeBlock_->GetCodePtr()) {
ERROR_LOG(Log::JIT, "JitBlockCache: Invalid block shadow value %08x", value);
return -1;
}
@@ -251,17 +244,19 @@ int JitBlockCache::GetBlockNumberFromEmuHackOp(MIPSOpcode inst, bool ignoreBad)
}
}
MIPSOpcode JitBlockCache::GetEmuHackOpForBlock(int blockNum) const {
int off = (int)(blocks_[blockNum].normalEntry - codeBlock_->GetBasePtr());
return MIPSOpcode(MIPS_EMUHACK_OPCODE | off);
u32 JitBlockCache::GetShadowValueForBlock(int blockNum) const {
// Never 0, the dispatcher is at the start of the code space.
const u32 off = (u32)(blocks_[blockNum].normalEntry - codeBlock_->GetBasePtr());
_dbg_assert_(off != 0);
return off;
}
int JitBlockCache::GetBlockNumberFromStartAddress(u32 addr) const {
if (!blocks_ || !Memory::IsValid4AlignedAddress(addr))
return -1;
MIPSOpcode inst = MIPSOpcode(Memory::ReadUnchecked_U32(addr));
int bl = GetBlockNumberFromEmuHackOp(inst);
// A replacement hook's value is the dispatcher's compile path, which isn't any block's entry.
int bl = GetBlockNumberFromShadowValue(Memory::ReadBlockShadow(addr));
if (bl < 0) {
return -1;
}
@@ -365,45 +360,6 @@ void JitBlockCache::UnlinkBlock(int i) {
}
}
std::vector<u32> JitBlockCache::SaveAndClearEmuHackOps() {
std::vector<u32> result;
result.resize(num_blocks_);
for (int block_num = 0; block_num < num_blocks_; ++block_num) {
JitBlock &b = blocks_[block_num];
if (b.invalid)
continue;
const u32 emuhack = GetEmuHackOpForBlock(block_num).encoding;
if (Memory::ReadUnchecked_U32(b.originalAddress) == emuhack)
{
result[block_num] = emuhack;
Memory::Write_Opcode_JIT(b.originalAddress, b.originalFirstOpcode);
}
else
result[block_num] = 0;
}
return result;
}
void JitBlockCache::RestoreSavedEmuHackOps(const std::vector<u32> &saved) {
if (num_blocks_ != (int)saved.size()) {
ERROR_LOG(Log::JIT, "RestoreSavedEmuHackOps: Wrong saved block size.");
return;
}
for (int block_num = 0; block_num < num_blocks_; ++block_num) {
const JitBlock &b = blocks_[block_num];
if (b.invalid || saved[block_num] == 0)
continue;
// Only if we restored it, write it back.
if (Memory::ReadUnchecked_U32(b.originalAddress) == b.originalFirstOpcode.encoding)
Memory::Write_Opcode_JIT(b.originalAddress, MIPSOpcode(saved[block_num]));
}
}
void JitBlockCache::DestroyBlock(int block_num, DestroyType type) {
if (block_num < 0 || block_num >= num_blocks_) {
ERROR_LOG_REPORT(Log::JIT, "DestroyBlock: Invalid block number %d", block_num);
@@ -424,13 +380,12 @@ void JitBlockCache::DestroyBlock(int block_num, DestroyType type) {
b->invalid = true;
// Only restoring the original opcode needs a valid address. The unlinking below has to
// Only clearing the shadow entry needs a valid address. The unlinking below has to
// happen either way - otherwise other blocks go on jumping straight into this one, which
// we've just marked invalid.
if (Memory::IsValid4AlignedAddress(b->originalAddress)) {
if (Memory::ReadUnchecked_U32(b->originalAddress) == GetEmuHackOpForBlock(block_num).encoding) {
Memory::Write_Opcode_JIT(b->originalAddress, b->originalFirstOpcode);
}
// A mirror may have replaced the entry with its own block, leave that alone.
Memory::ClearBlockShadow(b->originalAddress, GetShadowValueForBlock(block_num));
} else {
_dbg_assert_msg_(false, "Destroying block with invalid original address: %08x (block num: %d)", b->originalAddress, block_num);
}
@@ -500,8 +455,7 @@ void JitBlockCache::InvalidateChangedBlocks() {
if (JIT_USE_COMPILEDHASH) {
changed = b.compiledHash != HashJitBlock(b);
} else {
const u32 emuhack = GetEmuHackOpForBlock(block_num).encoding;
changed = Memory::ReadUnchecked_U32(b.originalAddress) != emuhack;
changed = Memory::ReadUnchecked_U32(b.originalAddress) != b.originalFirstOpcode.encoding;
}
if (changed) {