ShuriZma
/
dolphin
mirror of https://github.com/dolphin-emu/dolphin.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Merge pull request #10049 from JosJuice/jitarm64-fault-to-handler 

JitArm64: Make HandleFastmemFault less unsafe
This commit is contained in:
Mai M 2021-08-24 08:33:58 -04:00 committed by GitHub
parent 19f8e39929 0cf8405126
commit 922f53e16e
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 12 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
Source/Core/Core/PowerPC/JitArm64/Jit.h
View File

@ -195,7 +195,7 @@ protected:
struct FastmemArea struct FastmemArea
{ {
u32 length; const u8* fastmem_code;
const u8* slowmem_code; const u8* slowmem_code;
}; };

23
Source/Core/Core/PowerPC/JitArm64/JitArm64_BackPatch.cpp
View File

@ -134,7 +134,7 @@ void JitArm64::EmitBackpatchRoutine(u32 flags, bool fastmem, bool do_farcode, AR
handler.fprs = fprs_to_push; handler.fprs = fprs_to_push;
handler.flags = flags; handler.flags = flags;
FastmemArea* fastmem_area = &m_fault_to_handler[fastmem_start]; FastmemArea* fastmem_area = &m_fault_to_handler[fastmem_end];
auto handler_loc_iter = m_handler_to_loc.find(handler); auto handler_loc_iter = m_handler_to_loc.find(handler);
if (handler_loc_iter == m_handler_to_loc.end()) if (handler_loc_iter == m_handler_to_loc.end())
@ -143,14 +143,14 @@ void JitArm64::EmitBackpatchRoutine(u32 flags, bool fastmem, bool do_farcode, AR
SwitchToFarCode(); SwitchToFarCode();
const u8* handler_loc = GetCodePtr(); const u8* handler_loc = GetCodePtr();
m_handler_to_loc[handler] = handler_loc; m_handler_to_loc[handler] = handler_loc;
fastmem_area->fastmem_code = fastmem_start;
fastmem_area->slowmem_code = handler_loc; fastmem_area->slowmem_code = handler_loc;
fastmem_area->length = fastmem_end - fastmem_start;
} }
else else
{ {
const u8* handler_loc = handler_loc_iter->second; const u8* handler_loc = handler_loc_iter->second;
fastmem_area->fastmem_code = fastmem_start;
fastmem_area->slowmem_code = handler_loc; fastmem_area->slowmem_code = handler_loc;
fastmem_area->length = fastmem_end - fastmem_start;
return; return;
} }
} }
@ -253,33 +253,32 @@ bool JitArm64::HandleFastmemFault(uintptr_t access_address, SContext* ctx)
return false; return false;
} }
auto slow_handler_iter = m_fault_to_handler.upper_bound((const u8*)ctx->CTX_PC); const u8* pc = reinterpret_cast<const u8*>(ctx->CTX_PC);
slow_handler_iter--; auto slow_handler_iter = m_fault_to_handler.upper_bound(pc);
// no fastmem area found // no fastmem area found
if (slow_handler_iter == m_fault_to_handler.end()) if (slow_handler_iter == m_fault_to_handler.end())
return false; return false;
const u8* fault_location = slow_handler_iter->first; const u8* fastmem_area_start = slow_handler_iter->second.fastmem_code;
const u32 fastmem_area_length = slow_handler_iter->second.length; const u8* fastmem_area_end = slow_handler_iter->first;
// no overlapping fastmem area found // no overlapping fastmem area found
if ((const u8*)ctx->CTX_PC - fault_location > fastmem_area_length) if (pc < fastmem_area_start)
return false; return false;
const Common::ScopedJITPageWriteAndNoExecute enable_jit_page_writes; const Common::ScopedJITPageWriteAndNoExecute enable_jit_page_writes;
ARM64XEmitter emitter((u8*)fault_location); ARM64XEmitter emitter(const_cast<u8*>(fastmem_area_start));
emitter.BL(slow_handler_iter->second.slowmem_code); emitter.BL(slow_handler_iter->second.slowmem_code);
const u32 num_insts_max = fastmem_area_length / 4 - 1; while (emitter.GetCodePtr() < fastmem_area_end)
for (u32 i = 0; i < num_insts_max; ++i)
emitter.NOP(); emitter.NOP();
m_fault_to_handler.erase(slow_handler_iter); m_fault_to_handler.erase(slow_handler_iter);
emitter.FlushIcache(); emitter.FlushIcache();
ctx->CTX_PC = reinterpret_cast<std::uintptr_t>(fault_location); ctx->CTX_PC = reinterpret_cast<std::uintptr_t>(fastmem_area_start);
return true; return true;
} }