Kernel: Add argc and argv to process entry

kernel/arch/x86_64/Thread.S

@@ -25,13 +25,14 @@ continue_thread:
 	movq $0, %rax
 	jmp *%rsi
 
-# void thread_jump_userspace(uint64_t rsp, uint64_t rip)
+# void thread_userspace_trampoline(uint64_t rsp, uint64_t rip, int argc, char** argv)
-.global thread_jump_userspace
+.global thread_userspace_trampoline
-thread_jump_userspace:
+thread_userspace_trampoline:
 	pushq $0x23
 	pushq %rdi
 	pushfq
 	pushq $0x1B
 	pushq %rsi
-	movq $0, %rdi
+	movq %rdx, %rdi
+	movq %rcx, %rsi
 	iretq

kernel/include/kernel/Thread.h

@@ -2,6 +2,7 @@
 
 #include <BAN/NoCopyMove.h>
 #include <BAN/RefPtr.h>
+#include <kernel/Memory/Heap.h>
 
 #include <sys/types.h>
 
@@ -27,11 +28,9 @@ namespace Kernel
 
 	public:
 		static BAN::ErrorOr<Thread*> create(entry_t, void*, Process*);
-		static BAN::ErrorOr<Thread*> create_userspace(uintptr_t, Process*);
+		static BAN::ErrorOr<Thread*> create_userspace(uintptr_t, Process*, int, char**);
 		~Thread();
 
-		void jump_userspace(uintptr_t rip);
-
 		pid_t tid() const { return m_tid; }
 
 		void set_rsp(uintptr_t rsp) { m_rsp = rsp; validate_stack(); }
@@ -44,7 +43,7 @@ namespace Kernel
 		void terminate() { m_state = State::Terminating; }
 
 		uintptr_t stack_base() const { return (uintptr_t)m_stack_base; }
-		size_t stack_size() const { return m_stack_size; }
+		size_t stack_size() const { return m_is_userspace ? m_userspace_stack_size : m_kernel_stack_size; }
 
 		uintptr_t interrupt_stack_base() const { return (uintptr_t)m_interrupt_stack; }
 		uintptr_t interrupt_stack_size() const { return m_interrupt_stack_size; }
@@ -57,23 +56,33 @@ namespace Kernel
 
 	private:
 		Thread(pid_t tid, Process*);
+		void on_exit();
 		
 		void validate_stack() const;
 
-		BAN::ErrorOr<void> initialize(entry_t, void*);
+	private:
-		void on_exit();
+		struct userspace_entry_t
+		{
+			uintptr_t entry;
+			int argc  { 0 };
+			char** argv  { 0 };
+		};
 
 	private:
-		static constexpr size_t m_stack_size			= 4096 * 1;
+		static constexpr size_t m_kernel_stack_size		= PAGE_SIZE * 1;
-		static constexpr size_t m_interrupt_stack_size	= 4096;
+		static constexpr size_t m_userspace_stack_size	= PAGE_SIZE * 1;
-		void*		m_interrupt_stack	{ nullptr };
+		static constexpr size_t m_interrupt_stack_size	= PAGE_SIZE;
-		void*		m_stack_base		{ nullptr };
+		vaddr_t		m_interrupt_stack	{ 0 };
+		vaddr_t		m_stack_base		{ 0 };
 		uintptr_t	m_rip				{ 0 };
 		uintptr_t	m_rsp				{ 0 };
 		const pid_t	m_tid				{ 0 };
 		State		m_state				{ State::NotStarted };
 		Process*	m_process			{ nullptr };
 		bool		m_in_syscall		{ false };
+		bool		m_is_userspace		{ false };
+
+		userspace_entry_t m_userspace_entry;
 
 		friend class Scheduler;
 	};

kernel/kernel/Memory/FixedWidthAllocator.cpp

@@ -1,6 +1,7 @@
 #include <kernel/CriticalScope.h>
 #include <kernel/Memory/FixedWidthAllocator.h>
 #include <kernel/Memory/MMU.h>
+#include <kernel/Memory/MMUScope.h>
 #include <kernel/Process.h>
 
 namespace Kernel
@@ -20,9 +21,7 @@ namespace Kernel
 		m_allocated_pages = m_mmu.get_free_page();
 		m_mmu.map_page_at(allocated_pages_paddr, m_allocated_pages, MMU::Flags::ReadWrite | MMU::Flags::Present);
 
-		CriticalScope _;
+		MMUScope _(m_mmu);
-
-		m_mmu.load();
 
 		memset((void*)m_nodes_page, 0, PAGE_SIZE);
 		memset((void*)m_allocated_pages, 0, PAGE_SIZE);
@@ -38,8 +37,6 @@ namespace Kernel
 
 		m_free_list = node_table;
 		m_used_list = nullptr;
-
-		Process::current().mmu().load();
 	}
 
 	FixedWidthAllocator::~FixedWidthAllocator()

kernel/kernel/Process.cpp

@@ -3,6 +3,7 @@
 #include <kernel/FS/VirtualFileSystem.h>
 #include <kernel/LockGuard.h>
 #include <kernel/Memory/Heap.h>
+#include <kernel/Memory/MMUScope.h>
 #include <kernel/Process.h>
 #include <kernel/Scheduler.h>
 #include <LibELF/ELF.h>
@@ -87,11 +88,9 @@ namespace Kernel
 				}
 
 				{
-					CriticalScope _;
+					MMUScope _(process->mmu());
-					process->mmu().load();
 					memcpy((void*)elf_program_header.p_vaddr, elf->data() + elf_program_header.p_offset, elf_program_header.p_filesz);
 					memset((void*)(elf_program_header.p_vaddr + elf_program_header.p_filesz), 0, elf_program_header.p_memsz - elf_program_header.p_filesz);
-					Process::current().mmu().load();
 				}
 				break;
 			}
@@ -100,7 +99,16 @@ namespace Kernel
 			}
 		}
 
-		auto* thread = MUST(Thread::create_userspace(elf_file_header.e_entry, process));
+		char** argv = nullptr;
+		{
+			MMUScope _(process->mmu());
+			argv = (char**)MUST(process->allocate(sizeof(char**) * 1));
+			argv[0] = (char*)MUST(process->allocate(path.size() + 1));
+			memcpy(argv[0], path.data(), path.size());
+			argv[0][path.size()] = '\0';
+		}
+
+		auto* thread = MUST(Thread::create_userspace(elf_file_header.e_entry, process, 1, argv));
 		process->add_thread(thread);
 
 		delete elf;

kernel/kernel/Thread.cpp

@@ -1,16 +1,15 @@
 #include <BAN/Errors.h>
+#include <kernel/CriticalScope.h>
 #include <kernel/InterruptController.h>
 #include <kernel/Memory/kmalloc.h>
 #include <kernel/Process.h>
 #include <kernel/Scheduler.h>
 #include <kernel/Thread.h>
 
-#define PAGE_SIZE 4096
-
 namespace Kernel
 {
 
-	extern "C" void thread_jump_userspace(uintptr_t rsp, uintptr_t rip);
+	extern "C" void thread_userspace_trampoline(uint64_t rsp, uint64_t rip, int argc, char** argv);
 
 	template<size_t size, typename T>
 	static void write_to_stack(uintptr_t& rsp, const T& value)
@@ -19,32 +18,66 @@ namespace Kernel
 		memcpy((void*)rsp, (void*)&value, size);
 	}
 
+	static pid_t s_next_tid = 1;
+
 	BAN::ErrorOr<Thread*> Thread::create(entry_t entry, void* data, Process* process)
 	{
-		static pid_t next_tid = 1;
+		// Create the thread object
-		auto* thread = new Thread(next_tid++, process);
+		Thread* thread = new Thread(s_next_tid++, process);
 		if (thread == nullptr)
 			return BAN::Error::from_errno(ENOMEM);
-		TRY(thread->initialize(entry, data));
+
+		// Initialize stack and registers
+		thread->m_stack_base = (vaddr_t)kmalloc(m_kernel_stack_size, PAGE_SIZE);
+		if (thread->m_stack_base == 0)
+			return BAN::Error::from_errno(ENOMEM);
+		thread->m_rsp = (uintptr_t)thread->m_stack_base + m_kernel_stack_size;
+		thread->m_rip = (uintptr_t)entry;		
+
+		// Initialize stack for returning
+		write_to_stack<sizeof(void*)>(thread->m_rsp, thread);
+		write_to_stack<sizeof(void*)>(thread->m_rsp, &Thread::on_exit);
+		write_to_stack<sizeof(void*)>(thread->m_rsp, data);
+
 		return thread;
 	}
 
-	BAN::ErrorOr<Thread*> Thread::create_userspace(uintptr_t entry, Process* process)
+	BAN::ErrorOr<Thread*> Thread::create_userspace(uintptr_t entry, Process* process, int argc, char** argv)
 	{
-		Thread* thread = TRY(Thread::create(
+		// Create the thread object
-			[](void* entry)
+		Thread* thread = new Thread(s_next_tid++, process);
-			{
+		if (thread == nullptr)
-				Thread::current().jump_userspace((uintptr_t)entry);
-				ASSERT_NOT_REACHED();
-			}, (void*)entry, process
-		));
-		thread->m_interrupt_stack = kmalloc(m_interrupt_stack_size, PAGE_SIZE);
-		if (thread->m_interrupt_stack == nullptr)
-		{
-			delete thread;
 			return BAN::Error::from_errno(ENOMEM);
+		thread->m_is_userspace = true;
+
+		// Allocate stack
+		thread->m_stack_base = (uintptr_t)kmalloc(m_userspace_stack_size, PAGE_SIZE);
+		ASSERT(thread->m_stack_base);
+		process->mmu().identity_map_range(thread->m_stack_base, m_userspace_stack_size, MMU::Flags::UserSupervisor | MMU::Flags::ReadWrite | MMU::Flags::Present);
+
+		// Allocate interrupt stack
+		thread->m_interrupt_stack = (vaddr_t)kmalloc(m_interrupt_stack_size, PAGE_SIZE);
+		ASSERT(thread->m_interrupt_stack);
+
+		thread->m_userspace_entry = { .entry = entry, .argc = argc, .argv = argv };
+
+		// Setup registers and entry
+		static entry_t entry_trampoline(
+			[](void*)
+			{
+				userspace_entry_t& entry = Thread::current().m_userspace_entry;
+				thread_userspace_trampoline(Thread::current().rsp(), entry.entry, entry.argc, entry.argv);
+				ASSERT_NOT_REACHED();
 			}
-		process->mmu().identity_map_range(thread->stack_base(), thread->stack_size(), MMU::Flags::UserSupervisor | MMU::Flags::ReadWrite | MMU::Flags::Present);
+		);
+		thread->m_rsp = thread->m_stack_base + m_userspace_stack_size;
+		thread->m_rip = (uintptr_t)entry_trampoline;
+
+		// Setup stack for returning
+		write_to_stack<sizeof(void*)>(thread->m_rsp, thread);
+		write_to_stack<sizeof(void*)>(thread->m_rsp, &Thread::on_exit);
+		write_to_stack<sizeof(void*)>(thread->m_rsp, nullptr);
+
 		return thread;
 	}
 
@@ -63,32 +96,13 @@ namespace Kernel
 		return *m_process;
 	}
 
-	BAN::ErrorOr<void> Thread::initialize(entry_t entry, void* data)
-	{
-		m_stack_base = kmalloc(m_stack_size, PAGE_SIZE);
-		if (m_stack_base == nullptr)
-			return BAN::Error::from_errno(ENOMEM);
-		m_rsp = (uintptr_t)m_stack_base + m_stack_size;
-		m_rip = (uintptr_t)entry;
-
-		write_to_stack<sizeof(void*)>(m_rsp, this);
-		write_to_stack<sizeof(void*)>(m_rsp, &Thread::on_exit);
-		write_to_stack<sizeof(void*)>(m_rsp, data);
-
-		return {};
-	}
-
 	Thread::~Thread()
 	{
 		dprintln("thread {} ({}) exit", tid(), m_process->pid());
-		if (m_interrupt_stack)
-			kfree(m_interrupt_stack);
-		kfree(m_stack_base);
-	}
 
-	void Thread::jump_userspace(uintptr_t rip)
+		if (m_interrupt_stack)
-	{
+			kfree((void*)m_interrupt_stack);
-		thread_jump_userspace(rsp(), rip);
+		kfree((void*)m_stack_base);
 	}
 
 	void Thread::validate_stack() const

kernel/kernel/kernel.cpp

@@ -180,7 +180,7 @@ static void init2(void* tty1)
 
 	((TTY*)tty1)->initialize_device();
 
-	MUST(Process::create_userspace("/usr/bin/test"sv));
+	MUST(Process::create_userspace("/usr/bin/cat"sv));
 	return;
 
 	Process::create_kernel(

userspace/CMakeLists.txt

@@ -3,6 +3,7 @@ cmake_minimum_required(VERSION 3.26)
 project(userspace CXX)
 
 set(USERSPACE_PROJECTS
+	cat
 	test
 	yes
 )

userspace/cat/CMakeLists.txt

@@ -0,0 +1,17 @@
+cmake_minimum_required(VERSION 3.26)
+
+project(cat CXX)
+
+set(SOURCES
+	main.cpp
+)
+
+add_executable(cat ${SOURCES})
+target_compile_options(cat PUBLIC -O2 -g)
+add_dependencies(cat libc-install)
+target_link_options(cat PUBLIC -nodefaultlibs -lc)
+
+add_custom_target(cat-install
+	COMMAND cp ${CMAKE_CURRENT_BINARY_DIR}/cat ${BANAN_BIN}/
+	DEPENDS cat
+)

userspace/cat/main.cpp

@@ -0,0 +1,50 @@
+#include <stdio.h>
+
+bool cat_file(FILE* fp)
+{
+	char buffer[1024];
+	size_t n_read;
+	while ((n_read = fread(buffer, 1, sizeof(buffer) - 1, fp)) > 0)
+	{
+		buffer[n_read] = '\0';
+		fputs(buffer, stdout);
+	}
+	if (ferror(fp))
+	{
+		perror("fread");
+		return false;
+	}
+	return true;
+}
+
+int main(int argc, char** argv)
+{
+	int ret = 0;
+
+	printf("argc %d, argv %p\n", argc, argv);
+	for (int i = 0; i < argc; i++)
+		printf("%s\n", argv[i]);
+
+	if (argc > 1)
+	{
+		for (int i = 1; i < argc; i++)
+		{
+			FILE* fp = fopen(argv[i], "r");
+			if (fp == nullptr)
+			{
+				perror(argv[i]);
+				ret = 1;
+				continue;
+			}
+			if (cat_file(fp))
+				ret = 1;
+			fclose(fp);
+		}
+	}
+	else
+	{
+		ret = cat_file(stdin);
+	}
+
+	return ret;
+}

userspace/test/test.cpp

@@ -1,36 +1,12 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <math.h>
 
 #define ERROR(msg) { perror(msg); return 1; }
 #define BUF_SIZE 1024
 
 int main()
 {
-	printf("%.2e\n", 1230.0);
-	printf("%.2e\n", 123.0);
-	printf("%.2e\n", 12.3);
-	printf("%.2e\n", 1.23);
-	printf("%.2e\n", 0.123);
-	printf("%.2e\n", 0.0123);
-	printf("%.2e\n", 0.00123);
-
-	printf("%e\n", 123.456);
-	printf("%.2e\n", 123.456);
-	printf("%.0e\n", 123.456);
-	printf("%#.0e\n", 123.456);
-
-	printf("%e\n", -123.456);
-	printf("%.2e\n", -123.456);
-	printf("%.0e\n", -123.456);
-	printf("%#.0e\n", -123.456);
-
-	printf("%e\n", 0.0);
-	printf("%e\n", -0.0);
-
-	return 0;
-
 	FILE* fp = fopen("/usr/include/stdio.h", "r");
 	if (fp == NULL)
 		ERROR("fopen");