libretro, add libmappedmemory option for drc

this platform requires *freeing* of the drc memory, so add a hook for that, inside an ifdef so we don't have to touch every platform

Makefile.libretro

@@ -290,6 +290,8 @@ else ifeq ($(platform), wiiu)
 	CFLAGS += -DGEKKO -DWIIU -DHW_RVL -DHW_WUP -D__wiiu__ -ffunction-sections -fdata-sections -mcpu=750 -meabi -mhard-float
 	STATIC_LINKING = 1
 	STATIC_LINKING_LINK = 1
+	OBJS += platform/libretro/wiiu/libmemorymapping.o
+	CFLAGS += -isystem $(DEVKITPRO)/wut/include
 
 # Nintendo Switch (libtransistor)
 else ifeq ($(platform), switch)

cpu/drc/cmn.c

@@ -57,6 +57,9 @@ void drc_cmn_init(void)
 
 void drc_cmn_cleanup(void)
 {
+#ifdef HW_WUP
+  plat_mem_free_for_drc(tcache);
+#endif
 }
 
 // vim:shiftwidth=2:expandtab

pico/pico.h

@@ -38,6 +38,7 @@ extern void  plat_munmap(void *ptr, size_t size);
 
 // memory for the dynarec; plat_mem_get_for_drc() can just return NULL
 extern void *plat_mem_get_for_drc(size_t size);
+extern void  plat_mem_free_for_drc(void *mem);
 extern int   plat_mem_set_exec(void *ptr, size_t size);
 
 // this one should handle display mode changes

platform/libretro/libretro.c

@@ -60,6 +60,9 @@ void linearFree(void* mem);
 
 static int ctr_svchack_successful = 0;
 
+#elif defined(HW_WUP)
+#include "wiiu/libmemorymapping.h"
+
 #elif defined(VITA)
 #define TARGET_SIZE_2 24 // 2^24 = 16 megabytes
 
@@ -486,16 +489,28 @@ void *plat_mem_get_for_drc(size_t size)
 #if defined VITA
    sceKernelGetMemBlockBase(sceBlock, &mem);
 #elif defined HW_WUP
-   // For WiiU, a slice of RWX memory left from the exploit is used, see:
-   // https://github.com/embercold/pcsx_rearmed/commit/af0453223
-   mem = (void *)(0x01000000 - size);
+   // First try Aroma libmappedmemory...
+   mem = wiiu_alloc_mappedmemory(size, 4096);
+   if (!mem)
+     // Then fall back to RWX memory left from the exploit.
+     // https://github.com/embercold/pcsx_rearmed/commit/af0453223
+     // May want to remove this once Aroma libretro is common.
+     mem = (void *)(0x01000000 - size);
 #elif defined __PS3__
    ps3mapi_process_page_allocate(sysProcessGetPid(), size, PAGE_SIZE_AUTO, 0x2F, 1, page_table);
    mem = (void *)page_table[0];
 #endif
    return mem;
 }
 
+#ifdef HW_WUP
+void plat_mem_free_for_drc(void *mem)
+{
+  wiiu_free_mappedmemory(mem);
+  wiiu_deinit_mappedmemory();
+}
+#endif
+
 int plat_mem_set_exec(void *ptr, size_t size)
 {
    int ret = -1;

platform/libretro/wiiu/libmemorymapping.c

@@ -0,0 +1,50 @@
+#include "libmemorymapping.h"
+
+#include <coreinit/dynload.h>
+#include <stdbool.h>
+#include <stdint.h>
+
+// Aroma libmappedmemory - Maschell promises he won't break ABI here
+static void* (**MEMAllocFromMappedMemoryEx)(uint32_t size, int32_t alignment);
+static void* (**MEMFreeToMappedMemory)(void *ptr);
+static OSDynLoad_Module libmappedmemory;
+
+static bool wiiu_init_libmappedmemory() {
+  OSDynLoad_Error err;
+
+  // already ran?
+  if (MEMAllocFromMappedMemoryEx)
+    return true;
+
+  err = OSDynLoad_Acquire("homebrew_memorymapping", &libmappedmemory);
+  if (err != OS_DYNLOAD_OK)
+    return false;
+
+  err = OSDynLoad_FindExport(libmappedmemory, OS_DYNLOAD_EXPORT_DATA, "MEMAllocFromMappedMemoryEx", (void**)&MEMAllocFromMappedMemoryEx);
+  if (err != OS_DYNLOAD_OK)
+    return false;
+
+  err = OSDynLoad_FindExport(libmappedmemory, OS_DYNLOAD_EXPORT_DATA, "MEMFreeToMappedMemory", (void**)&MEMFreeToMappedMemory);
+  if (err != OS_DYNLOAD_OK)
+    return false;
+
+  return true;
+}
+
+void *wiiu_alloc_mappedmemory(uint32_t size, int32_t alignment) {
+  if (!wiiu_init_libmappedmemory()) return NULL;
+
+  return (*MEMAllocFromMappedMemoryEx)(size, alignment);
+}
+
+void wiiu_free_mappedmemory(void *mem) {
+  if (!wiiu_init_libmappedmemory()) return;
+
+  (*MEMFreeToMappedMemory)(mem);
+}
+
+void wiiu_deinit_mappedmemory(void) {
+  OSDynLoad_Release(libmappedmemory);
+  MEMAllocFromMappedMemoryEx = NULL;
+  MEMFreeToMappedMemory = NULL;
+}

platform/libretro/wiiu/libmemorymapping.h

@@ -0,0 +1,10 @@
+#ifndef LIBMEMORYMAPPING_H
+#define LIBMEMORYMAPPING_H
+
+#include <stdint.h>
+
+void *wiiu_alloc_mappedmemory(uint32_t size, int32_t alignment);
+void wiiu_free_mappedmemory(void *mem);
+void wiiu_deinit_mappedmemory(void);
+
+#endif // LIBMEMORYMAPPING_H