From 0b5fcb3f8898dc13cbc376f2120ae3c7182ea088 Mon Sep 17 00:00:00 2001
From: Bananymous <oskari.alaranta@bananymous.com>
Date: Mon, 30 Oct 2023 11:06:13 +0200
Subject: [PATCH] Kernel/LibC: Add crt* files to LibC and remove crt0 from
 kernel

There was no reason for libc get crt0 from kernel.
---
 kernel/CMakeLists.txt               | 15 ++-------------
 libc/CMakeLists.txt                 | 16 +++++++++++++++-
 {kernel => libc}/arch/x86_64/crt0.S | 11 ++++++-----
 libc/arch/x86_64/crti.S             | 16 ++++++++++++++++
 libc/arch/x86_64/crtn.S             | 10 ++++++++++
 5 files changed, 49 insertions(+), 19 deletions(-)
 rename {kernel => libc}/arch/x86_64/crt0.S (63%)
 create mode 100644 libc/arch/x86_64/crti.S
 create mode 100644 libc/arch/x86_64/crtn.S

diff --git a/kernel/CMakeLists.txt b/kernel/CMakeLists.txt
index 2c29fa3695..d7e140a580 100644
--- a/kernel/CMakeLists.txt
+++ b/kernel/CMakeLists.txt
@@ -162,17 +162,6 @@ endif()
 
 target_link_options(kernel PUBLIC -ffreestanding -nostdlib)
 
-add_custom_target(crt0
-	COMMAND ${CMAKE_CXX_COMPILER} -c ${CMAKE_CURRENT_SOURCE_DIR}/arch/${BANAN_ARCH}/crt0.S -o ${CMAKE_CURRENT_BINARY_DIR}/crt0.o
-	DEPENDS headers
-)
-
-add_custom_command(
-	TARGET crt0
-	POST_BUILD
-	COMMAND sudo cp ${CMAKE_CURRENT_BINARY_DIR}/crt0.o ${BANAN_LIB}/
-)
-
 add_custom_target(kernel-headers
 	COMMAND sudo rsync -a ${CMAKE_CURRENT_SOURCE_DIR}/include/ ${BANAN_INCLUDE}/
 	COMMAND sudo rsync -a ${CMAKE_CURRENT_SOURCE_DIR}/lai/include/ ${BANAN_INCLUDE}/
@@ -193,8 +182,8 @@ add_custom_command(
 	TARGET kernel PRE_LINK
 	COMMAND ${CMAKE_CXX_COMPILER} -MD -c ${CMAKE_CURRENT_SOURCE_DIR}/arch/${BANAN_ARCH}/crti.S ${COMPILE_OPTIONS}
 	COMMAND ${CMAKE_CXX_COMPILER} -MD -c ${CMAKE_CURRENT_SOURCE_DIR}/arch/${BANAN_ARCH}/crtn.S ${COMPILE_OPTIONS}
-	COMMAND cp ${CRTBEGIN} .
-	COMMAND cp ${CRTEND} .
+	COMMAND ${CMAKE_COMMAND} -E copy ${CRTBEGIN} .
+	COMMAND ${CMAKE_COMMAND} -E copy ${CRTEND} .
 )
 
 #add_custom_command(
diff --git a/libc/CMakeLists.txt b/libc/CMakeLists.txt
index 76c4f766fd..5432b6f048 100644
--- a/libc/CMakeLists.txt
+++ b/libc/CMakeLists.txt
@@ -31,8 +31,22 @@ add_custom_target(libc-headers
 	USES_TERMINAL
 )
 
+add_custom_target(crtx
+	COMMAND ${CMAKE_C_COMPILER} -c ${CMAKE_CURRENT_SOURCE_DIR}/arch/${BANAN_ARCH}/crt0.S -o crt0.o
+	COMMAND ${CMAKE_C_COMPILER} -c ${CMAKE_CURRENT_SOURCE_DIR}/arch/${BANAN_ARCH}/crti.S -o crti.o
+	COMMAND ${CMAKE_C_COMPILER} -c ${CMAKE_CURRENT_SOURCE_DIR}/arch/${BANAN_ARCH}/crtn.S -o crtn.o
+)
+
+add_custom_target(crtx-install
+	COMMAND sudo cp crt0.o ${BANAN_LIB}/
+	COMMAND sudo cp crti.o ${BANAN_LIB}/
+	COMMAND sudo cp crtn.o ${BANAN_LIB}/
+	DEPENDS crtx
+	USES_TERMINAL
+)
+
 add_library(libc ${LIBC_SOURCES})
-add_dependencies(libc headers crt0)
+add_dependencies(libc headers crtx-install)
 
 target_compile_options(libc PRIVATE -g -Wstack-usage=512)
 
diff --git a/kernel/arch/x86_64/crt0.S b/libc/arch/x86_64/crt0.S
similarity index 63%
rename from kernel/arch/x86_64/crt0.S
rename to libc/arch/x86_64/crt0.S
index dc3fdffc7d..67804f1990 100644
--- a/kernel/arch/x86_64/crt0.S
+++ b/libc/arch/x86_64/crt0.S
@@ -8,19 +8,19 @@ _start:
 	pushq %rbp # rbp=0
 	movq %rsp, %rbp
 
-	# We need those in a moment when we call main.
+	# Save argc, argv, environ
 	pushq %rdx
 	pushq %rsi
 	pushq %rdi
 
-	# Prepare signals, memory allocation, stdio and such.
+	# Prepare malloc, environment
 	movq %rdx, %rdi
 	call _init_libc
 
-	# Run the global constructors.
+	# Call global constructos
 	call _init
 
-	# Restore argc and argv.
+	# Restore argc, argv, environ
 	popq %rdi
 	popq %rsi
 	popq %rdx
@@ -28,7 +28,8 @@ _start:
 	# Run main
 	call main
 
-	# Terminate the process with the exit code.
+	# Cleanly exit the process
 	movl %eax, %edi
 	call exit
+
 .size _start, . - _start
diff --git a/libc/arch/x86_64/crti.S b/libc/arch/x86_64/crti.S
new file mode 100644
index 0000000000..7c9624cc5f
--- /dev/null
+++ b/libc/arch/x86_64/crti.S
@@ -0,0 +1,16 @@
+/* x86-64 crti.s */
+.section .init
+.global _init
+.type _init, @function
+_init:
+	pushq %rbp
+	movq %rsp, %rbp
+	/* gcc will nicely put the contents of crtbegin.o's .init section here. */
+
+.section .fini
+.global _fini
+.type _fini, @function
+_fini:
+	pushq %rbp
+	movq %rsp, %rbp
+	/* gcc will nicely put the contents of crtbegin.o's .fini section here. */
diff --git a/libc/arch/x86_64/crtn.S b/libc/arch/x86_64/crtn.S
new file mode 100644
index 0000000000..5d6f1e9a15
--- /dev/null
+++ b/libc/arch/x86_64/crtn.S
@@ -0,0 +1,10 @@
+/* x86-64 crtn.s */
+.section .init
+	/* gcc will nicely put the contents of crtend.o's .init section here. */
+	popq %rbp
+	ret
+
+.section .fini
+	/* gcc will nicely put the contents of crtend.o's .fini section here. */
+	popq %rbp
+	ret