/*
 * \brief  Implementation of the Thread API
 * \author Norman Feske
 * \date   2010-01-11
 */

/*
 * Copyright (C) 2010-2017 Genode Labs GmbH
 *
 * This file is part of the Genode OS framework, which is distributed
 * under the terms of the GNU Affero General Public License version 3.
 */

/* Genode includes */
#include <util/construct_at.h>
#include <util/string.h>
#include <util/misc_math.h>
#include <base/thread.h>
#include <base/env.h>
#include <base/sleep.h>
#include <base/snprintf.h>
#include <deprecated/env.h>

/* base-internal includes */
#include <base/internal/stack_allocator.h>
#include <base/internal/globals.h>

using namespace Genode;


void Stack::size(size_t const size)
{
	/* check if the stack needs to be enhanced */
	size_t const stack_size = (addr_t)_stack - _base;
	if (stack_size >= size) { return; }

	/* check if the stack enhancement fits the stack region */
	enum {
		UTCB_SIZE      = sizeof(Native_utcb),
		PAGE_SIZE_LOG2 = 12,
		PAGE_SIZE      = (1UL << PAGE_SIZE_LOG2),
	};
	addr_t const stack_slot_base = Stack_allocator::addr_to_base(this);
	size_t const ds_size = align_addr(size - stack_size, PAGE_SIZE_LOG2);
	if (_base - ds_size < stack_slot_base)
		throw Thread::Stack_too_large();

	/* allocate and attach backing store for the stack enhancement */
	addr_t const ds_addr = _base - ds_size - stack_area_virtual_base();
	try {
		Ram_allocator * const ram = env_stack_area_ram_allocator;
		Ram_dataspace_capability const ds_cap = ram->alloc(ds_size);
		Region_map * const rm = env_stack_area_region_map;
		void * const attach_addr = rm->attach_at(ds_cap, ds_addr, ds_size);

		if (ds_addr != (addr_t)attach_addr)
			throw Thread::Out_of_stack_space();
	}
	catch (Out_of_ram) { throw Thread::Stack_alloc_failed(); }

	/* update stack information */
	_base -= ds_size;
}


Stack *
Thread::_alloc_stack(size_t stack_size, char const *name, bool main_thread)
{
	/* allocate stack */
	Stack *stack = Stack_allocator::stack_allocator().alloc(this, main_thread);
	if (!stack)
		throw Out_of_stack_space();

	/* determine size of dataspace to allocate for the stack */
	enum { PAGE_SIZE_LOG2 = 12 };
	size_t ds_size = align_addr(stack_size, PAGE_SIZE_LOG2);

	if (stack_size >= stack_virtual_size() -
	    sizeof(Native_utcb) - (1UL << PAGE_SIZE_LOG2))
		throw Stack_too_large();

	/*
	 * Calculate base address of the stack
	 *
	 * The stack pointer is always located at the top of the stack header.
	 */
	addr_t ds_addr = Stack_allocator::addr_to_base(stack) +
	                 stack_virtual_size() - ds_size;

	/* add padding for UTCB if defined for the platform */
	if (sizeof(Native_utcb) >= (1 << PAGE_SIZE_LOG2))
		ds_addr -= sizeof(Native_utcb);

	/* allocate and attach backing store for the stack */
	Ram_dataspace_capability ds_cap;
	try {
		ds_cap = env_stack_area_ram_allocator->alloc(ds_size);
		addr_t attach_addr = ds_addr - stack_area_virtual_base();
		if (attach_addr != (addr_t)env_stack_area_region_map->attach_at(ds_cap, attach_addr, ds_size))
			throw Stack_alloc_failed();
	}
	catch (Out_of_ram) { throw Stack_alloc_failed(); }

	/*
	 * Now the stack is backed by memory, so it is safe to access its members.
	 *
	 * We need to initialize the stack object's memory with zeroes, otherwise
	 * the ds_cap isn't invalid. That would cause trouble when the assignment
	 * operator of Native_capability is used.
	 */
	construct_at<Stack>(stack, name, *this, ds_addr, ds_cap);

	Abi::init_stack(stack->top());
	return stack;
}


void Thread::_free_stack(Stack *stack)
{
	addr_t ds_addr = stack->base() - stack_area_virtual_base();
	Ram_dataspace_capability ds_cap = stack->ds_cap();

	/* call de-constructor explicitly before memory gets detached */
	stack->~Stack();

	Genode::env_stack_area_region_map->detach((void *)ds_addr);
	Genode::env_stack_area_ram_allocator->free(ds_cap);

	/* stack ready for reuse */
	Stack_allocator::stack_allocator().free(stack);
}


void Thread::name(char *dst, size_t dst_len)
{
	snprintf(dst, dst_len, "%s", _stack->name().string());
}


Thread::Name Thread::name() const { return _stack->name(); }


void Thread::join() { _join_lock.lock(); }


void *Thread::alloc_secondary_stack(char const *name, size_t stack_size)
{
	Stack *stack = _alloc_stack(stack_size, name, false);
	return (void *)stack->top();
}


void Thread::free_secondary_stack(void* stack_addr)
{
	addr_t base = Stack_allocator::addr_to_base(stack_addr);
	_free_stack(Stack_allocator::base_to_stack(base));
}


Native_thread &Thread::native_thread() {

	return _stack->native_thread(); }


void *Thread::stack_top() const { return (void *)_stack->top(); }


void *Thread::stack_base() const { return (void*)_stack->base(); }


void Thread::stack_size(size_t const size) { _stack->size(size); }


Thread::Stack_info Thread::mystack()
{
	addr_t base = Stack_allocator::addr_to_base(&base);
	Stack *stack = Stack_allocator::base_to_stack(base);
	return { stack->base(), stack->top() };
}


size_t Thread::stack_virtual_size()
{
	return Genode::stack_virtual_size();
}


addr_t Thread::stack_area_virtual_base()
{
	return Genode::stack_area_virtual_base();
}


size_t Thread::stack_area_virtual_size()
{
	return Genode::stack_area_virtual_size();
}


Thread::Thread(size_t weight, const char *name, size_t stack_size,
               Type type, Cpu_session *cpu_session, Affinity::Location affinity)
:
	_cpu_session(cpu_session),
	_affinity(affinity),
	_trace_control(nullptr),
	_stack(type == REINITIALIZED_MAIN ?
	       _stack : _alloc_stack(stack_size, name, type == MAIN)),
	_join_lock(Lock::LOCKED)
{
	_init_platform_thread(weight, type);
}


void Thread::_init_cpu_session_and_trace_control()
{
	/* if no CPU session is given, use it from the environment */
	if (!_cpu_session) {
		_cpu_session = env_deprecated()->cpu_session(); }

	/* initialize trace control now that the CPU session must be valid */
	Dataspace_capability ds = _cpu_session->trace_control();
	if (ds.valid()) {
		_trace_control = env_deprecated()->rm_session()->attach(ds); }
}


Thread::Thread(size_t weight, const char *name, size_t stack_size,
               Type type, Affinity::Location affinity)
: Thread(weight, name, stack_size, type, nullptr, affinity) { }


Thread::Thread(Env &env, Name const &name, size_t stack_size, Location location,
               Weight weight, Cpu_session &cpu)
: Thread(weight.value, name.string(), stack_size, NORMAL,
         &cpu == &env.cpu() ? nullptr : &cpu, location)
{ }


Thread::Thread(Env &env, Name const &name, size_t stack_size)
: Thread(env, name, stack_size, Location(), Weight(), env.cpu()) { }


Thread::~Thread()
{
	if (Thread::myself() == this) {
		error("thread '", _stack->name().string(), "' "
		      "tried to self de-struct - sleeping forever.");
		sleep_forever();
	}

	_deinit_platform_thread();
	_free_stack(_stack);

	cxx_free_tls(this);

	/*
	 * We have to detach the trace control dataspace last because
	 * we cannot invalidate the pointer used by the Trace::Logger
	 * from here and any following RPC call will stumple upon the
	 * detached trace control dataspace.
	 */
	if (_trace_control)
		env_deprecated()->rm_session()->detach(_trace_control);
}
