[kernel] Implement code address offset for Skyline compatibility (#2858)

- Add debug logging for 32-bit syscall argument tracking.

- Add CodeStartOffset constant (0x500000) applied to only 32-bit code address space
  types in KProcess::LoadFromMetadata.

- Replace CheckMemoryStateContiguous with two-stage CheckMemoryState
  in KPageTableBase::UnmapCodeMemory to discover and verify memory
  state more accurately.

Based on similar fixes in Ryujinx (commit 5e9678c8fe)
Fixes compatibility with:
- Skyline 32-bit modding framework
- CTGP-DX (Mario Kart 8 Deluxe mod)
- Other homebrew using 32bit Skyline

Co-authored-by: JPikachu <jpikachu.eden@gmail.com>
Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/2858
Reviewed-by: Shinmegumi <shinmegumi@eden-emu.dev>
Reviewed-by: Caio Oliveira <caiooliveirafarias0@gmail.com>
Reviewed-by: Lizzie <lizzie@eden-emu.dev>
Co-authored-by: JPikachu <jpikachu@eden-emu.dev>
Co-committed-by: JPikachu <jpikachu@eden-emu.dev>

1 files changed, 5 insertions, 2 deletions

diff --git a/src/core/hle/kernel/k_process.cpp b/src/core/hle/kernel/k_process.cpp
index 51f86b2afd..355a2a5f3b 100644
--- a/src/core/hle/kernel/k_process.cpp
+++ b/src/core/hle/kernel/k_process.cpp
@@ -28,6 +28,9 @@ namespace Kernel {
 
 namespace {
 
+// TODO: Remove this workaround when proper ASLR is implemented for all address spaces.
+constexpr u64 CodeStartOffset = 0x500000UL;
+
 Result TerminateChildren(KernelCore& kernel, KProcess* process,
                          const KThread* thread_to_not_terminate) {
     // Request that all children threads terminate.
@@ -1198,11 +1201,11 @@ Result KProcess::LoadFromMetadata(const FileSys::ProgramMetadata& metadata, std:
         break;
     case FileSys::ProgramAddressSpaceType::Is32Bit:
         flag |= Svc::CreateProcessFlag::AddressSpace32Bit;
-        code_address = 0x20'0000;
+        code_address = 0x20'0000 + CodeStartOffset;
         break;
     case FileSys::ProgramAddressSpaceType::Is32BitNoMap:
         flag |= Svc::CreateProcessFlag::AddressSpace32BitWithoutAlias;
-        code_address = 0x20'0000;
+        code_address = 0x20'0000 + CodeStartOffset;
         break;
     }