From 5cad71213b1ef1f6711b04cbfeafebc12ed22db7 Mon Sep 17 00:00:00 2001
From: plutoo <plutoo@universe>
Date: Mon, 1 Jan 2018 22:28:12 +0100
Subject: [PATCH] Cache version values, fix guard paging of threads on 2.0.0+

---
 nx/source/kernel/thread.c  |  6 +++---
 nx/source/kernel/version.c | 30 ++++++++++++++++++++++++------
 nx/source/kernel/virtmem.c | 14 ++++++++------
 3 files changed, 35 insertions(+), 15 deletions(-)

diff --git a/nx/source/kernel/thread.c b/nx/source/kernel/thread.c
index c4f4c01e..cb4edbd6 100644
--- a/nx/source/kernel/thread.c
+++ b/nx/source/kernel/thread.c
@@ -48,8 +48,8 @@ Result threadCreate(
     }
     else {
         // todo: svcMapMemory returns 0xDC01
-        void* stack_mirror = stack;//virtmemReserveMap(stack_sz);
-        //rc = svcMapMemory(stack_mirror, stack, stack_sz);
+        void* stack_mirror = virtmemReserveMap(stack_sz);
+        rc = svcMapMemory(stack_mirror, stack, stack_sz);
 
         if (R_SUCCEEDED(rc))
         {
@@ -82,7 +82,7 @@ Result threadCreate(
                 args->reent->_stderr = cur->_stderr;
 
                 // Set up child thread's TLS segment
-                size_t tls_load_sz = __tdata_lma_end-__tdata_lma;
+                size_t tls_load_sz = __tdata_lma_end - __tdata_lma;
                 size_t tls_bss_sz = tls_sz - tls_load_sz;
                 if (tls_load_sz)
                     memcpy(args->tls, __tdata_lma, tls_load_sz);
diff --git a/nx/source/kernel/version.c b/nx/source/kernel/version.c
index 414164fa..3ce44c00 100644
--- a/nx/source/kernel/version.c
+++ b/nx/source/kernel/version.c
@@ -1,17 +1,35 @@
 // Copyright 2017 plutoo
 #include <switch.h>
 
+static bool g_IsAbove200;
+static bool g_IsAbove300;
+static bool g_IsAbove400;
+static bool g_HasCached = 0;
+
+static void _CacheValues()
+{
+    // This is actually thread safe, might cache twice but that's fine.
+    if (!g_HasCached)
+    {
+        u64 tmp;
+        g_IsAbove200 = (svcGetInfo(&tmp, 12, INVALID_HANDLE, 0) != 0xF001);
+        g_IsAbove300 = (svcGetInfo(&tmp, 18, INVALID_HANDLE, 0) != 0xF001);
+        g_IsAbove400 = (svcGetInfo(&tmp, 19, INVALID_HANDLE, 0) != 0xF001);
+        g_HasCached = true;
+    }
+}
+
 bool kernelAbove200() {
-    u64 tmp;
-    return svcGetInfo(&tmp, 12, INVALID_HANDLE, 0) != 0xF001;
+    _CacheValues();
+    return g_IsAbove200;
 }
 
 bool kernelAbove300() {
-    u64 tmp;
-    return svcGetInfo(&tmp, 18, INVALID_HANDLE, 0) != 0xF001;
+    _CacheValues();
+    return g_IsAbove300;
 }
 
 bool kernelAbove400() {
-    u64 tmp;
-    return svcGetInfo(&tmp, 19, INVALID_HANDLE, 0) != 0xF001;
+    _CacheValues();
+    return g_IsAbove300;
 }
diff --git a/nx/source/kernel/virtmem.c b/nx/source/kernel/virtmem.c
index 8747c3d2..bc244049 100644
--- a/nx/source/kernel/virtmem.c
+++ b/nx/source/kernel/virtmem.c
@@ -6,9 +6,9 @@ typedef struct {
 } VirtualRegion;
 
 enum {
-    REGION_MAP =0,
+    REGION_STACK=0,
     REGION_HEAP=1,
-    REGION_UNK =2,
+    REGION_NEW_STACK=2,
     REGION_MAX
 };
 
@@ -46,7 +46,7 @@ void virtmemSetup() {
         g_AddressSpace.end   = 0x100000000ull;
     }
 
-    if (R_FAILED(_GetRegionFromInfo(&g_Region[REGION_MAP], 2, 3))) {
+    if (R_FAILED(_GetRegionFromInfo(&g_Region[REGION_STACK], 2, 3))) {
         fatalSimple(MAKERESULT(MODULE_LIBNX, LIBNX_BADGETINFO));
     }
 
@@ -56,7 +56,7 @@ void virtmemSetup() {
 
     // Failure is OK, happens on 1.0.0
     // In that case, g_UnkRegion will default to (0, 0).
-    _GetRegionFromInfo(&g_Region[REGION_UNK], 14, 15);
+    _GetRegionFromInfo(&g_Region[REGION_NEW_STACK], 14, 15);
 }
 
 void* virtmemReserve(size_t size) {
@@ -137,6 +137,8 @@ void* virtmemReserveMap(size_t size)
 
     size = (size + 0xFFF) &~ 0xFFF;
 
+    int region_idx = kernelAbove200() ? REGION_NEW_STACK : REGION_STACK;
+
     u64 addr = g_CurrentMapAddr;
     while (1)
     {
@@ -144,8 +146,8 @@ void* virtmemReserveMap(size_t size)
         addr += 0x1000;
 
         // Make sure we stay inside the reserved map region.
-        if (!_InRegion(&g_Region[REGION_MAP], addr)) {
-            addr = g_Region[REGION_MAP].start;
+        if (!_InRegion(&g_Region[region_idx], addr)) {
+            addr = g_Region[region_idx].start;
         }
 
         // Query information about address.