kern: improve resource region size definitions/calculations

libmesosphere/include/mesosphere/arch/arm64/init/kern_k_init_page_table.hpp

@@ -74,6 +74,10 @@ namespace ams::kern::arch::arm64::init {
             static ALWAYS_INLINE void ClearNewPageTable(KPhysicalAddress address) {
                 ClearPhysicalMemory(address, PageSize);
             }
+        public:
+            static consteval size_t GetMaximumOverheadSize(size_t size) {
+                return (util::DivideUp(size, L1BlockSize) + util::DivideUp(size, L2BlockSize)) * PageSize;
+            }
         private:
             size_t NOINLINE GetBlockCount(KVirtualAddress virt_addr, size_t size, size_t block_size) {
                 const KVirtualAddress end_virt_addr = virt_addr + size;

libmesosphere/include/mesosphere/kern_initial_process.hpp

@@ -20,7 +20,7 @@
 namespace ams::kern {
 
     constexpr u32 InitialProcessBinaryMagic      = util::FourCC<'I','N','I','1'>::Code;
-    constexpr size_t InitialProcessBinarySizeMax = 0xC00000;
+    constexpr size_t InitialProcessBinarySizeMax = 12_MB;
 
     struct InitialProcessBinaryHeader {
         u32 magic;

libmesosphere/include/mesosphere/kern_k_memory_layout.hpp

@@ -39,6 +39,19 @@ namespace ams::kern {
     constexpr size_t KernelPhysicalAddressSpaceLast = KernelPhysicalAddressSpaceEnd - 1ul;
     constexpr size_t KernelPhysicalAddressSpaceSize = KernelPhysicalAddressSpaceEnd - KernelPhysicalAddressSpaceBase;
 
+    constexpr size_t KernelPageTableHeapSize    = init::KInitialPageTable::GetMaximumOverheadSize(8_GB);
+    constexpr size_t KernelInitialPageHeapSize  = 128_KB;
+
+    constexpr size_t KernelSlabHeapDataSize           = 5_MB;
+    constexpr size_t KernelSlabHeapGapsSize           = 2_MB - 64_KB;
+    constexpr size_t KernelSlabHeapGapsSizeDeprecated = 2_MB;
+    constexpr size_t KernelSlabHeapSize               = KernelSlabHeapDataSize + KernelSlabHeapGapsSize;
+
+    /* NOTE: This is calculated from KThread slab counts, assuming KThread size <= 0x860. */
+    constexpr size_t KernelSlabHeapAdditionalSize     = 0x68000;
+
+    constexpr size_t KernelResourceSize               = KernelPageTableHeapSize + KernelInitialPageHeapSize + KernelSlabHeapSize;
+
     enum KMemoryRegionType : u32 {
         KMemoryRegionAttr_CarveoutProtected = 0x04000000,
         KMemoryRegionAttr_DidKernelMap      = 0x08000000,
@@ -544,6 +557,7 @@ namespace ams::kern {
             }
 
             static void InitializeLinearMemoryRegionTrees(KPhysicalAddress aligned_linear_phys_start, KVirtualAddress linear_virtual_start);
+            static size_t GetResourceRegionSizeForInit();
 
             static NOINLINE auto GetKernelRegionExtents()      { return GetVirtualMemoryRegionTree().GetDerivedRegionExtents(KMemoryRegionType_Kernel); }
             static NOINLINE auto GetKernelCodeRegionExtents()  { return GetVirtualMemoryRegionTree().GetDerivedRegionExtents(KMemoryRegionType_KernelCode); }

libmesosphere/source/init/kern_init_slab_setup.cpp

@@ -71,8 +71,12 @@ namespace ams::kern::init {
 
         constexpr size_t SlabCountExtraKThread          = 160;
 
-        /* This is used for gaps between the slab allocators. */
+        namespace test {
-        constexpr size_t SlabRegionReservedSize         = 2_MB - 64_KB;
+
+            constexpr size_t RequiredSizeForExtraThreadCount = SlabCountExtraKThread * (sizeof(KThread) + (sizeof(KLinkedListNode) * 17) + (sizeof(KThreadLocalPage) / 8) + sizeof(KEventInfo));
+            static_assert(RequiredSizeForExtraThreadCount <= KernelSlabHeapAdditionalSize);
+
+        }
 
         /* Global to hold our resource counts. */
         KSlabResourceCounts g_slab_resource_counts = {
@@ -121,6 +125,10 @@ namespace ams::kern::init {
         }
     }
 
+    size_t CalculateSlabHeapGapSize() {
+        return (kern::GetTargetFirmware() >= TargetFirmware_10_0_0) ? KernelSlabHeapGapsSize : KernelSlabHeapGapsSizeDeprecated;
+    }
+
     size_t CalculateTotalSlabHeapSize() {
         size_t size = 0;
 
@@ -135,7 +143,7 @@ namespace ams::kern::init {
         #undef ADD_SLAB_SIZE
 
         /* Add the reserved size. */
-        size += SlabRegionReservedSize;
+        size += CalculateSlabHeapGapSize();
 
         return size;
     }
@@ -175,11 +183,12 @@ namespace ams::kern::init {
         }
 
         /* Create an array to represent the gaps between the slabs. */
+        const size_t total_gap_size = CalculateSlabHeapGapSize();
         size_t slab_gaps[util::size(slab_types)];
         for (size_t i = 0; i < util::size(slab_gaps); i++) {
             /* Note: This is an off-by-one error from Nintendo's intention, because GenerateRandomRange is inclusive. */
             /* However, Nintendo also has the off-by-one error, and it's "harmless", so we will include it ourselves. */
-            slab_gaps[i] = KSystemControl::GenerateRandomRange(0, SlabRegionReservedSize);
+            slab_gaps[i] = KSystemControl::GenerateRandomRange(0, total_gap_size);
         }
 
         /* Sort the array, so that we can treat differences between values as offsets to the starts of slabs. */

libmesosphere/source/kern_k_memory_layout.cpp

@@ -168,6 +168,19 @@ namespace ams::kern {
         }
     }
 
+    size_t KMemoryLayout::GetResourceRegionSizeForInit() {
+        /* Calculate resource region size based on whether we allow extra threads. */
+        const bool use_extra_resources = KSystemControl::Init::ShouldIncreaseThreadResourceLimit();
+        size_t resource_region_size = KernelResourceSize + (use_extra_resources ? KernelSlabHeapAdditionalSize : 0);
+
+        /* 10.0.0 reduced the slab heap gaps by 64K. */
+        if (kern::GetTargetFirmware() < ams::TargetFirmware_10_0_0) {
+            resource_region_size += (KernelSlabHeapGapsSizeDeprecated - KernelSlabHeapGapsSize);
+        }
+
+        return resource_region_size;
+    }
+
     namespace init {
 
         namespace {