FEX: Removes legacy kernel 32-bit allocator

We only used this so that our Xavier CI system which were running old
kernels could run unit tests. We have now removed the Xaviers from CI
and this is no longer necessary.

Stop pretending that we support kernels older than 5.0 and allowing this
fallback.

The 32-bit allocator is still used for the MAP_32BIT mmap flag, so the
load bearing code can't be fully removed. Just remove the config and the
frontend things using it.

.github/workflows/ccpp.yml

@@ -13,7 +13,6 @@ env:
   BUILD_TYPE: Release
   CC: clang
   CXX: clang++
-  FEX_FORCE32BITALLOCATOR: 1
   FEX_ENABLEAVX: 1
 
 jobs:

.github/workflows/glibc_fault.yml

@@ -20,7 +20,6 @@ env:
   BUILD_TYPE: Release
   CC: clang
   CXX: clang++
-  FEX_FORCE32BITALLOCATOR: 1
   FEX_ENABLEAVX: 1
 
 jobs:

FEXCore/Source/Interface/Config/Config.json.in

@@ -254,16 +254,6 @@
           "Set to false to disable Static Register Allocation"
         ]
       },
-      "Force32BitAllocator": {
-        "Type": "bool",
-        "Default": "false",
-        "Desc": [
-          "Forces use of the 32-bit allocator on 32-bit applications",
-          "Used to work around ulimit problems of CI runner",
-          "Potentially useful for debugging memory problems",
-          "32-bit allocator is always used if your host kernel is older than 4.17"
-        ]
-      },
       "GlobalJITNaming": {
         "Type": "bool",
         "Default": "false",

Source/Tools/FEXLoader/FEXLoader.cpp

@@ -423,26 +423,18 @@ int main(int argc, char **argv, char **const envp) {
     Base48Bit = FEXCore::Allocator::Steal48BitVA();
   } else {
     // Setup our userspace allocator
+    FEXCore::Allocator::SetupHooks();
+    Allocator = FEX::HLE::CreatePassthroughAllocator();
 
-    FEX_CONFIG_OPT(Use32BitAllocator, FORCE32BITALLOCATOR);
-    const bool is_legacy_kernel = (KernelVersion < FEX::HLE::SyscallHandler::KernelVersion(4, 17));
-
-    if (Use32BitAllocator || is_legacy_kernel) {
-      Allocator = FEX::HLE::Create32BitAllocator();
-    } else {
-      FEXCore::Allocator::SetupHooks();
-      Allocator = FEX::HLE::CreatePassthroughAllocator();
-
-      // Now that the upper 32-bit address space is blocked for future allocations,
-      // exhaust all of jemalloc's remaining internal allocations that it reserved before.
-      // TODO: It's unclear how reliably this exhausts those reserves
-      FEXCore::Allocator::YesIKnowImNotSupposedToUseTheGlibcAllocator glibc;
-      void* data;
-      do {
-        data = malloc(0x1);
-      } while (reinterpret_cast<uintptr_t>(data) >> 32 != 0);
-      free(data);
-    }
+    // Now that the upper 32-bit address space is blocked for future allocations,
+    // exhaust all of jemalloc's remaining internal allocations that it reserved before.
+    // TODO: It's unclear how reliably this exhausts those reserves
+    FEXCore::Allocator::YesIKnowImNotSupposedToUseTheGlibcAllocator glibc;
+    void* data;
+    do {
+      data = malloc(0x1);
+    } while (reinterpret_cast<uintptr_t>(data) >> 32 != 0);
+    free(data);
   }
 
   // System allocator is now system allocator or FEX

Source/Tools/TestHarnessRunner/TestHarnessRunner.cpp

@@ -223,17 +223,8 @@ int main(int argc, char **argv, char **const envp) {
 
   if (!Loader.Is64BitMode()) {
     // Setup our userspace allocator
-    uint32_t KernelVersion = FEX::HLE::SyscallHandler::CalculateHostKernelVersion();
-    if (KernelVersion >= FEX::HLE::SyscallHandler::KernelVersion(4, 17)) {
-      FEXCore::Allocator::SetupHooks();
-    }
-
-    if (KernelVersion < FEX::HLE::SyscallHandler::KernelVersion(4, 17)) {
-      Allocator = FEX::HLE::Create32BitAllocator();
-    }
-    else {
-      Allocator = FEX::HLE::CreatePassthroughAllocator();
-    }
+    FEXCore::Allocator::SetupHooks();
+    Allocator = FEX::HLE::CreatePassthroughAllocator();
   }
 #endif