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

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JitArm64: Make HandleFastmemFault less unsafe
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Mai M 2021-08-24 08:33:58 -04:00 committed by GitHub
commit 922f53e16e
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GPG key ID: 4AEE18F83AFDEB23
2 changed files with 12 additions and 13 deletions
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2
Source/Core/Core/PowerPC/JitArm64/Jit.h
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@ -195,7 +195,7 @@ protected:
struct FastmemArea
{
u32 length;
const u8* fastmem_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.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);
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();
const u8* handler_loc = GetCodePtr();
m_handler_to_loc[handler] = handler_loc;
fastmem_area->fastmem_code = fastmem_start;
fastmem_area->slowmem_code = handler_loc;
fastmem_area->length = fastmem_end - fastmem_start;
}
else
{
const u8* handler_loc = handler_loc_iter->second;
fastmem_area->fastmem_code = fastmem_start;
fastmem_area->slowmem_code = handler_loc;
fastmem_area->length = fastmem_end - fastmem_start;
return;
}
}
@ -253,33 +253,32 @@ bool JitArm64::HandleFastmemFault(uintptr_t access_address, SContext* ctx)
return false;
}
auto slow_handler_iter = m_fault_to_handler.upper_bound((const u8*)ctx->CTX_PC);
slow_handler_iter--;
const u8* pc = reinterpret_cast<const u8*>(ctx->CTX_PC);
auto slow_handler_iter = m_fault_to_handler.upper_bound(pc);
// no fastmem area found
if (slow_handler_iter == m_fault_to_handler.end())
return false;
const u8* fault_location = slow_handler_iter->first;
const u32 fastmem_area_length = slow_handler_iter->second.length;
const u8* fastmem_area_start = slow_handler_iter->second.fastmem_code;
const u8* fastmem_area_end = slow_handler_iter->first;
// no overlapping fastmem area found
if ((const u8*)ctx->CTX_PC - fault_location > fastmem_area_length)
if (pc < fastmem_area_start)
return false;
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);
const u32 num_insts_max = fastmem_area_length / 4 - 1;
for (u32 i = 0; i < num_insts_max; ++i)
while (emitter.GetCodePtr() < fastmem_area_end)
emitter.NOP();
m_fault_to_handler.erase(slow_handler_iter);
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;
}