From bce71331284f028efd1bf99ec9dd9e58fe16cdcd Mon Sep 17 00:00:00 2001
From: Michael Scire <SciresM@gmail.com>
Date: Thu, 23 Jan 2020 19:00:42 -0800
Subject: [PATCH] meso: add script to build mesosphere.bin

---
 .../mesosphere/init/kern_init_layout.hpp      |  2 +-
 .../{ => arch/arm64}/svc/kern_svc_tables.cpp  |  4 +-
 mesosphere/Makefile                           |  3 +-
 mesosphere/build_mesosphere.py                | 45 +++++++++++++++++++
 mesosphere/kernel/source/arch/arm64/start.s   | 25 ++++++++++-
 .../kernel_ldr/source/kern_init_loader.cpp    |  6 ++-
 6 files changed, 79 insertions(+), 6 deletions(-)
 rename libraries/libmesosphere/source/{ => arch/arm64}/svc/kern_svc_tables.cpp (96%)
 create mode 100644 mesosphere/build_mesosphere.py

diff --git a/libraries/libmesosphere/include/mesosphere/init/kern_init_layout.hpp b/libraries/libmesosphere/include/mesosphere/init/kern_init_layout.hpp
index 904defc41..620ef85fe 100644
--- a/libraries/libmesosphere/include/mesosphere/init/kern_init_layout.hpp
+++ b/libraries/libmesosphere/include/mesosphere/init/kern_init_layout.hpp
@@ -27,7 +27,7 @@ namespace ams::kern::init {
         u32 rw_end_offset;
         u32 bss_offset;
         u32 bss_end_offset;
-        u32 ini_end_offset;
+        u32 ini_load_offset;
         u32 dynamic_offset;
         u32 init_array_offset;
         u32 init_array_end_offset;
diff --git a/libraries/libmesosphere/source/svc/kern_svc_tables.cpp b/libraries/libmesosphere/source/arch/arm64/svc/kern_svc_tables.cpp
similarity index 96%
rename from libraries/libmesosphere/source/svc/kern_svc_tables.cpp
rename to libraries/libmesosphere/source/arch/arm64/svc/kern_svc_tables.cpp
index a2fd6a28d..bc5b264fa 100644
--- a/libraries/libmesosphere/source/svc/kern_svc_tables.cpp
+++ b/libraries/libmesosphere/source/arch/arm64/svc/kern_svc_tables.cpp
@@ -16,6 +16,8 @@
 #include <mesosphere.hpp>
 #include <vapours/svc/svc_codegen.hpp>
 
+/* TODO: Enable compilation of this file when the kernel supports supervisor calls. */
+#if 0
 namespace ams::kern::svc {
 
     namespace {
@@ -41,7 +43,6 @@ namespace ams::kern::svc {
 
     }
 
-    /* TODO: 32-bit ABI */
     const std::array<SvcTableEntry, NumSupervisorCalls> SvcTable64From32 = [] {
         std::array<SvcTableEntry, NumSupervisorCalls> table = {};
 
@@ -65,3 +66,4 @@ namespace ams::kern::svc {
     }();
 
 }
+#endif
\ No newline at end of file
diff --git a/mesosphere/Makefile b/mesosphere/Makefile
index 31b597a1c..f511441d1 100644
--- a/mesosphere/Makefile
+++ b/mesosphere/Makefile
@@ -9,7 +9,8 @@ clean: $(CLEAN_TARGETS)
 	@rm -f mesosphere.bin
 
 mesosphere.bin: $(TARGETS)
-	@echo "todo: py script"
+	@python build_mesosphere.py
+	@echo "Built mesosphere.bin..."
 
 $(TARGETS):
 	$(MAKE) -C $@
diff --git a/mesosphere/build_mesosphere.py b/mesosphere/build_mesosphere.py
new file mode 100644
index 000000000..d7e4087da
--- /dev/null
+++ b/mesosphere/build_mesosphere.py
@@ -0,0 +1,45 @@
+#!/usr/bin/env python
+import sys, os
+from struct import pack as pk, unpack as up
+
+def align_up(val, algn):
+    val += algn - 1
+    return val - (val % algn)
+
+
+def main(argc, argv):
+    if argc != 1:
+        print('Usage: %s' % argv[0])
+        return 1
+    with open('kernel_ldr/kernel_ldr.bin', 'rb') as f:
+        kernel_ldr = f.read()
+    with open('kernel/kernel.bin', 'rb') as f:
+        kernel = f.read()
+    kernel_metadata_offset = up('<I', kernel[4:8])[0]
+    assert (kernel_metadata_offset <= len(kernel) - 0x40)
+    assert (kernel[kernel_metadata_offset:kernel_metadata_offset + 4] == b'MSS0')
+    kernel_end = up('<I', kernel[kernel_metadata_offset + 0x30:kernel_metadata_offset + 0x34])[0]
+    assert (kernel_end >= len(kernel))
+
+    embedded_ini = b''
+    embedded_ini_offset = align_up(kernel_end, 0x1000) + 0x1000
+    embedded_ini_end = embedded_ini_offset + 0 # TODO: Create and embed an INI, eventually.
+
+    kernel_ldr_offset = align_up(embedded_ini_end, 0x1000) + 0x1000
+    kernel_ldr_end    = kernel_ldr_offset + len(kernel_ldr)
+
+    with open('mesosphere.bin', 'wb') as f:
+        f.write(kernel[:kernel_metadata_offset + 8])
+        f.write(pk('<II', embedded_ini_offset, kernel_ldr_offset))
+        f.write(kernel[kernel_metadata_offset + 0x10:])
+        f.seek(embedded_ini_offset)
+        f.write(embedded_ini)
+        f.seek(embedded_ini_end)
+        f.seek(kernel_ldr_offset)
+        f.write(kernel_ldr)
+        f.seek(kernel_ldr_end)
+    return 0
+
+
+if __name__ == '__main__':
+    sys.exit(main(len(sys.argv), sys.argv))
diff --git a/mesosphere/kernel/source/arch/arm64/start.s b/mesosphere/kernel/source/arch/arm64/start.s
index c1a234119..bdb838cd0 100644
--- a/mesosphere/kernel/source/arch/arm64/start.s
+++ b/mesosphere/kernel/source/arch/arm64/start.s
@@ -22,4 +22,27 @@
 .global     _start
 _start:
     /* TODO */
-    b _start
\ No newline at end of file
+    b _start
+    .word (__metadata_begin - _start)
+
+__metadata_begin:
+    .ascii "MSS0"                     /* Magic */
+    .word  0                          /* KInitArguments */
+    .word  0                          /* INI1 base address. */
+    .word  0                          /* Kernel Loader base address. */
+__metadata_kernel_layout:
+    .word _start - _start             /* rx_offset */
+    .word __rodata_start     - _start /* rx_end_offset */
+    .word __rodata_start     - _start /* ro_offset */
+    .word __data_start       - _start /* ro_end_offset */
+    .word __data_start       - _start /* rw_offset */
+    .word __bss_start__      - _start /* rw_end_offset */
+    .word __bss_start__      - _start /* bss_offset */
+    .word __bss_end__        - _start /* bss_end_offset */
+    .word __end__            - _start /* ini_load_offset */
+    .word _DYNAMIC           - _start /* dynamic_offset */
+    .word __init_array_start - _start /* init_array_offset */
+    .word __init_array_end   - _start /* init_array_end_offset */
+.if (. - __metadata_begin) != 0x40
+    .error "Incorrect Mesosphere Metadata"
+.endif
\ No newline at end of file
diff --git a/mesosphere/kernel_ldr/source/kern_init_loader.cpp b/mesosphere/kernel_ldr/source/kern_init_loader.cpp
index 134043677..c00477270 100644
--- a/mesosphere/kernel_ldr/source/kern_init_loader.cpp
+++ b/mesosphere/kernel_ldr/source/kern_init_loader.cpp
@@ -269,7 +269,7 @@ namespace ams::kern::init::loader {
         MESOSPHERE_ABORT_UNLESS(util::IsAligned(rw_offset,      0x1000));
         MESOSPHERE_ABORT_UNLESS(util::IsAligned(bss_end_offset, 0x1000));
         const uintptr_t bss_offset            = layout->bss_offset;
-        const uintptr_t ini_end_offset        = layout->ini_end_offset;
+        const uintptr_t ini_load_offset        = layout->ini_load_offset;
         const uintptr_t dynamic_offset        = layout->dynamic_offset;
         const uintptr_t init_array_offset     = layout->init_array_offset;
         const uintptr_t init_array_end_offset = layout->init_array_end_offset;
@@ -277,9 +277,11 @@ namespace ams::kern::init::loader {
         /* Decide if Kernel should have enlarged resource region. */
         const bool use_extra_resources = KSystemControl::Init::ShouldIncreaseThreadResourceLimit();
         const size_t resource_region_size = KernelResourceRegionSize + (use_extra_resources ? ExtraKernelResourceSize : 0);
+        static_assert(KernelResourceRegionSize > InitialProcessBinarySizeMax);
+        static_assert(KernelResourceRegionSize + ExtraKernelResourceSize > InitialProcessBinarySizeMax);
 
         /* Setup the INI1 header in memory for the kernel. */
-        const uintptr_t ini_end_address  = base_address + ini_end_offset + resource_region_size;
+        const uintptr_t ini_end_address  = base_address + ini_load_offset + resource_region_size;
         const uintptr_t ini_load_address = ini_end_address - InitialProcessBinarySizeMax;
         if (ini_base_address != ini_load_address) {
             /* The INI is not at the correct address, so we need to relocate it. */