From 4db13cabae241c4c93614c9e2e966d6e19adf87d Mon Sep 17 00:00:00 2001
From: notaz <notasas@gmail.com>
Date: Tue, 1 Oct 2024 19:43:13 +0300
Subject: [PATCH] add dedicated mmap functions for libnx

the previous code would call svcUnmapPhysicalMemory() on mem possibly
allocated by aligned_alloc() which didn't look right
---
 frontend/libretro.c        | 33 ++++++++++++++++++++++++++++++---
 frontend/switch/sys/mman.h |  2 ++
 2 files changed, 32 insertions(+), 3 deletions(-)

diff --git a/frontend/libretro.c b/frontend/libretro.c
index bcd3c615..52c2c1c9 100644
--- a/frontend/libretro.c
+++ b/frontend/libretro.c
@@ -498,6 +498,31 @@ static void pl_3ds_munmap(void *ptr, size_t size, enum psxMapTag tag)
 }
 #endif
 
+#ifdef HAVE_LIBNX
+static void *pl_switch_mmap(unsigned long addr, size_t size,
+    enum psxMapTag tag, int *can_retry_addr)
+{
+   void *ret = MAP_FAILED;
+   *can_retry_addr = 0;
+   (void)addr;
+
+   // there's svcMapPhysicalMemory() but user logs show it doesn't hand out
+   // any desired addresses, so don't even bother
+   ret = aligned_alloc(0x1000, size);
+   if (!ret)
+      return MAP_FAILED;
+   memset(ret, 0, size);
+   return ret;
+}
+
+static void pl_switch_munmap(void *ptr, size_t size, enum psxMapTag tag)
+{
+   (void)size;
+   (void)tag;
+   free(ptr);
+}
+#endif
+
 #ifdef VITA
 typedef struct
 {
@@ -3792,11 +3817,13 @@ void retro_init(void)
    syscall(SYS_ptrace, 0 /*PTRACE_TRACEME*/, 0, 0, 0);
 #endif
 
-#ifdef _3DS
+#if defined(_3DS)
    psxMapHook = pl_3ds_mmap;
    psxUnmapHook = pl_3ds_munmap;
-#endif
-#ifdef VITA
+#elif defined(HAVE_LIBNX)
+   psxMapHook = pl_switch_mmap;
+   psxUnmapHook = pl_switch_munmap;
+#elif defined(VITA)
    if (init_vita_mmap() < 0)
       abort();
    psxMapHook = pl_vita_mmap;
diff --git a/frontend/switch/sys/mman.h b/frontend/switch/sys/mman.h
index 2e084a64..1d31e252 100644
--- a/frontend/switch/sys/mman.h
+++ b/frontend/switch/sys/mman.h
@@ -20,6 +20,7 @@ extern "C" {
 
 #define ALIGNMENT       0x1000
 
+#if 0 // not used
 static inline void *mmap(void *addr, size_t len, int prot, int flags, int fd, off_t offset)
 {
     (void)fd;
@@ -51,6 +52,7 @@ static inline int munmap(void *addr, size_t len)
     }
     return 0;
 }
+#endif
 
 #ifdef __cplusplus
 };
-- 
2.39.2