start with allocation

Makefile

@@ -8,7 +8,7 @@ LD = $(CROSS)ld
 OBJCOPY = $(CROSS)objcopy
 OBJDUMP = $(CROSS)objdump
 
-kernel_sources = interrupts.cc panic.cc data.cc test.cc
+kernel_sources = interrupts.cc panic.cc data.cc test.cc alloc.cc
 boot_sources = init.cc
 BUILT_SOURCES = $(kernel_sources) $(boot_sources)
 
@@ -22,7 +22,10 @@ PYPP = /usr/bin/pypp
 uimage: all.raw Makefile
 	mkimage -A MIPS -O Linux -C none -a $(load) -e 0x$(shell /bin/sh -c '$(OBJDUMP) -t all | grep __start$$ | cut -b-8') -n "Shevek's kernel" -d $< $@ | sed -e 's/:/;/g'
 
-%.o:%.cc Makefile kernel.hh
+arch.hh: mips.hh
+	ln -s $< $@
+
+%.o:%.cc Makefile kernel.hh arch.hh
 	$(CC) $(CPPFLAGS) $(CXXFLAGS) -c $< -o $@
 
 %.o:%.S Makefile
@@ -40,6 +43,6 @@ junk = mdebug.abi32 reginfo comment pdr
 	gzip < $< > $@
 
 clean:
-	rm -f all uimage *.o all.raw.gz
+	rm -f all uimage *.o all.raw.gz arch.hh
 
 .PHONY: clean

alloc.ccp

@@ -0,0 +1,142 @@
+#include "kernel.hh"
+
+void *Memory::palloc ():
+	if use >= limit:
+		return NULL
+	FreePage *ret = junk_pages
+	if !ret:
+		ret = zero_pages
+		zero_pages = ret->next
+	else:
+		junk_pages = ret->next
+	return ret
+	
+void *Memory::zalloc ():
+	if use >= limit:
+		return NULL
+	FreePage *ret = zero_pages
+	if !ret:
+		ret = junk_pages
+		for unsigned i = 1; i < PAGE_SIZE; ++i:
+			((unsigned *)ret)[i] = 0
+		junk_pages = ret->next
+	else:
+		zero_pages = ret->next
+	ret->next = NULL
+	return ret
+
+void Memory::pfree (void *page):
+	FreePage *p = (FreePage *)page
+	p->next = junk_pages
+	junk_pages = p
+
+void Memory::zfree (void *page):
+	FreePage *p = (FreePage *)page
+	p->next = zero_pages
+	zero_pages = p
+
+void *Memory::search_free (unsigned size, void *&first):
+	Free *f
+	unsigned s = 0
+	for f = frees; f; f = f->next:
+		if f->next_obj:
+			s = f->next_obj - f
+		else:
+			s = PAGE_SIZE - ((unsigned)f & ~PAGE_MASK)
+		if s >= size:
+			break
+	if !f:
+		f = (Free *)palloc ()
+		if !f:
+			return NULL
+		f->marker = ~0
+		f->next = frees
+		f->prev = NULL
+		frees = f
+		if f->next:
+			f->next->prev = f
+		f->next_obj = NULL
+		f->prev_obj = NULL
+		s = PAGE_SIZE
+	// We have a free block, possibly too large.
+	if s >= size + sizeof (Free):
+		// Create the new object at the end and keep the Free.
+		Free *obj = (Free *)((unsigned)f + s - size)
+		obj->next_obj = f->next_obj
+		if (obj->next_obj)
+			obj->next_obj->prev_obj = obj
+		obj->prev_obj = f
+		f->next_obj = obj
+		f = obj
+	else:
+		if f->prev:
+			f->prev->next = f->next
+		else:
+			frees = f->next
+		if f->next:
+			f->next->prev = f->prev
+	f->next = first
+	f->prev = NULL
+	if f->next:
+		f->next->prev = f
+	first = f
+	return f
+
+void Object_base::free_obj (Memory *parent):
+	Free *self
+	// Merge with previous, if it exists and is a Free.
+	if prev_obj && prev_obj->is_free ():
+		self = (Free *)prev_obj
+		self->next_obj = next_obj
+		if next_obj:
+			next_obj->prev_obj = self
+	else:
+		self = (Free *)this
+		self->next = parent->frees
+		self->prev = NULL
+		if self->next:
+			self->next->prev = self
+		parent->frees = self
+		self->marker = ~0
+	// Merge with next, if it exists and is a Free.
+	if self->next_obj && self->next_obj->is_free ():
+		self->next_obj = self->next_obj->next_obj
+		if self->next_obj:
+			self->next_obj->prev_obj = self
+	// Free page if the resulting object is the only thing in it.
+	if !self->prev_obj && !self->next_obj:
+		if self->next:
+			self->next->prev = self->prev
+		if self->prev:
+			self->prev->next = self->next
+		else:
+			parent->frees = self->next
+		parent->pfree (self)
+
+Page *Memory::alloc_page ():
+	Page *ret = (Page *)search_free (sizeof (Page), pages)
+	ret->physical = zalloc ()
+	if !ret->physical:
+		ret->free (this, pages)
+	return ret
+
+Thread *Memory::alloc_thread ():
+	Thread *ret = (Thread *)search_free (sizeof (Thread), threads)
+	ret->address_space = this
+	ret->pc = 0
+	ret->sp = 0
+	Thread_arch_init (ret)
+	ret->schedule_prev = NULL
+	ret->schedule_next = NULL
+	return ret
+
+Memory *Memory::alloc_memory ():
+	Memory *ret = (Memory *)search_free (sizeof (Memory), memories)
+	ret->frees = NULL
+	ret->pages = NULL
+	ret->threads = NULL
+	ret->memories = NULL
+	ret->limit = ~0
+	ret->used = 0
+	Memory_arch_init (ret)
+	return ret

init.ccp

@@ -1,6 +1,26 @@
 #pypp 0
+// Also declare things which only work during kernel init.
+#define INIT
 #include "kernel.hh"
 
+#define cp0_get(reg, sel, target) do { __asm__ volatile ("mfc0 %0, $" #reg ", " #sel : "=r (target)); } while (0)
+#define cp0_set(reg, value) do { __asm__ volatile ("mtc0 %0, $" #reg :: "r (value)); } while (0)
+#define cp0_set0(reg) do { __asm__ volatile ("mtc0 $zero, $" #reg); } while (0)
+
+// cp0 registers.
+#define INDEX 0
+#define ENTRY_LO0 2
+#define ENTRY_LO1 3
+#define PAGE_MASK 5
+#define WIRED 6
+#define COUNT 9
+#define ENTRY_HI 10
+#define COMPARE 11
+#define STATUS 12
+#define CAUSE 13
+#define EPC 14
+#define CONFIG 16
+
 static void init_idle ():
 	// initialize idle task as if it is currently running.
 	idle.size = sizeof (Thread)
@@ -34,58 +54,57 @@ static void init_idle ():
 	idle_page.physical = 0
 
 static void init_cp0 ():
-	// Set timer to a defined value (11 is Compare)
+	// Set timer to a defined value
-	__asm__ volatile ("mtc0 %0, $11, 0" :: "r"(1000000))
+	cp0_set (COMPARE, 1000000)
-	// Reset timer (9 is Count)
+	// Reset timer
-	__asm__ volatile ("mtc0 $zero, $9, 0")
+	cp0_set0 (COUNT)
-	// Use the interrupt vector for interrupts (13 is Cause)
+	// Use the interrupt vector for interrupts
-	__asm__ volatile ("mtc0 %0, $13" :: "r"(1 << 23))
+	cp0_set (CAUSE, 1 << 23)
 
 	// clear the tlb, hardwire page 0 to 0xffffffff
 	// and soft-wire it to (0x294 << 20) + (0x290 << 10)
 	// (for the idle task).
 
-	// 6 is Wired.
+	cp0_set (WIRED, 1)
-	__asm__ volatile ("mtc0 %0, $6" :: "r"(1))
+	cp0_set0 (PAGE_MASK)
-	// 5 is PageMask.
+	cp0_set0 (ENTRY_LO0)
-	__asm__ volatile ("mtc0 $zero, $5")
+	cp0_set0 (ENTRY_LO1)
-	// 2 is EntryLo0.
-	__asm__ volatile ("mtc0 $zero, $2")
-	// 3 is EntryLo1.
-	__asm__ volatile ("mtc0 $zero, $3")
 	// Get number of tlb entries (is 31).
 	unsigned num;
-	__asm__ volatile ("mfc0 %0, $16, 1" : "=r"(num))
+	cp0_get (CONFIG, 1, num)
 	num >>= 25
 	num &= 0x3f
 	// Clear the tlb.
 	#if 0
 	for unsigned i = 1; i < num; ++i:
 		// this address doesn't reach the tlb, so it can't trigger exceptions.
-		// 10 is EntryHi
+		cp0_set (ENTRY_HI, 0x70000000 + 0x1000 * i)
-		__asm__ volatile ("mtc0 %0, $10" :: "r"(0x70000000 + 0x1000 * i))
+		cp0_set (INDEX, i)
-		// 0 is Index.
-		__asm__ volatile ("mtc0 %0, $0" :: "r"(i))
 		// write the data.
 		__asm__ volatile ("tlbwi")
 	#endif
 	// Fill the upper page in kseg3.
-	__asm__ volatile ("mtc0 %0, $10" :: "r"(0xfffff000))
+	cp0_set (ENTRY_HI, 0xfffff000)
-	__asm__ volatile ("mtc0 %0, $2" :: "r"(0x0000001d))
+	cp0_set (ENTRY_LO0, 0x1d)
-	__asm__ volatile ("mtc0 %0, $3" :: "r"(0x0000001f))
+	cp0_set (ENTRY_LO1, 0x1f)
-	__asm__ volatile ("mtc0 %0, $0" :: "r"(0))
+	cp0_set0 (INDEX)
 	__asm__ volatile ("tlbwi")
 	// Fill the idle task's page in useg.  Set it to non-cachable.
-	__asm__ volatile ("mtc0 %0, $10" :: "r"(0x284a0000))
+	cp0_set (ENTRY_HI, 0x284a0000)
-	__asm__ volatile ("mtc0 %0, $2" :: "r"(0x00000016))
+	cp0_set (ENTRY_LO0, 0x16)
-	__asm__ volatile ("mtc0 %0, $3" :: "r"(0x00000014))
+	cp0_set (ENTRY_LO1, 0x14)
 	__asm__ volatile ("tlbwr")
 	// Allow eret to be used to jump to the idle task.
-	// 14 is EPC.
+	cp0_set (EPC, 0x284a0288)
-	__asm__ volatile ("mtc0 %0, $14" :: "r"(0x284a0288))
 	// Enable all interrupts and say we're handling an exception.
-	// 12 is Status.
+	// Since we're going to enter the idle task, allow access to cp0.
-	__asm__ volatile ("mtc0 %0, $12" :: "r"(0x1000ff13))
+	cp0_set (STATUS, 0x1000ff13)
+
+static void init_threads ():
+	for unsigned i = 0; i < NUM_THREADS; ++i:
+		Memory *mem = top_memory.alloc_memory ()
+		Thread *thread = mem->alloc_thread ()
+		// TODO
 
 /// Initialize the kernel, finish by falling into the idle task.
 extern unsigned _end
@@ -119,7 +138,8 @@ void init ():
 	top_memory.used = 0
 	top_memory.cpu.directory = NULL
 	top_memory.cpu.asid = 0
-	// TOOO: set up initial threads.
+	
+	init_threads ()
 
 	// Done; return to user space (the idle task).
 	__asm__ volatile ("eret")

kernel.hhp

@@ -2,66 +2,75 @@
 #ifndef _KERNEL_HH
 #define _KERNEL_HH
 
+#ifndef EXTERN
+#define EXTERN extern
+#endif
+
 #define NULL 0
 
-class Object
+struct Object_base
-class Page
+struct Object
-class Thread
+struct Page
-class Memory
+struct Thread
+struct Memory
 
-struct Object:
+#include "arch.hh"
-	unsigned size
-	Object *prev, *next
 
-struct Page : public Object:
+struct Object_base:
-	Page *page_prev, *page_next
+	// Next and previous object of any type in the same page.
-	unsigned physical
+	Object *prev_obj, *next_obj
+	void free_obj (Memory *parent)
+	inline bool is_free ()
 
-struct Thread : public Object:
+template <typename _T> struct Object : public Object_base:
-	struct Cpu:
+	// Next and previous object of the same type in any page.
-		unsigned at, v0, v1, a0, a1, a2, a3
+	_T *prev, *next
-		unsigned t0, t1, t2, t3, t4, t5, t6, t7, t8, t9
+	void free (Memory *parent, _T *&first)
-		unsigned gp, sp, fp, ra, hi, lo, k0, k1, pc
+
-	Cpu cpu
+struct Free : public Object <Free>
-	Thread *thread_prev, *thread_next
+	// This marker is ~0.  No other kernel structure may allow this value
-	Thread *schedule_prev, *schedule_next
+	// at this point.  It is used to recognize free chunks.
+	unsigned marker
+
+bool Object_base::is_free ():
+	return ((Free *)this)->marker == ~0
+
+struct Page : public Object <Page>:
+	void *physical
+
+struct Thread : public Object <Thread>:
 	Memory *address_space
+	unsigned pc, sp
+	Thread_arch arch
+	Thread *schedule_prev, *schedule_next
 
-struct Memory : public Object:
+struct Memory : public Object <Memory>:
-	Memory *memory_prev, *memory_next
+	Free *frees
 	Page *pages
 	Thread *threads
 	Memory *memories
 	unsigned limit, used
-	struct Cpu:
+	Memory_arch arch
-		unsigned asid
+
-		Page ***directory
+	// Allocation of pages.
-	Cpu cpu
+	void *palloc ()
+	void *zalloc ()
+	void pfree (void *page)
+	void zfree (void *page)
+
+	// Allocation routines for kernel structures
+	void *search_free (unsigned size, void *&first)
+	Page *alloc_page ()
+	Thread *alloc_thread ()
+	Memory *alloc_memory ()
 
 // Functions which can be called from assembly must not be mangled.
 extern "C":
-	// Kernel entry points, called from entry.S.
-	void init ()
-	Thread *interrupt (Thread *current)
-	Thread *cache_error (Thread *current)
-	Thread *exception (Thread *current)
-
-	// tlb stuff.  tlb_refill is also an entry point.
-	void tlb_setup ()
-	Thread *tlb_refill (Thread *current, unsigned EntryHi)
-
-	// Start running the idle task for the first time.
-	void run_idle (Thread *self)
-
 	// Panic.  n is sent over caps led.  message is currently ignored.
 	void panic (unsigned n, char const *message)
 	// Debug: switch caps led
 	void led (bool on, bool tick)
 
-#ifndef EXTERN
-#define EXTERN extern
-#endif
-
 struct FreePage:
 	FreePage *next
 
@@ -72,4 +81,13 @@ EXTERN Thread idle
 EXTERN Memory idle_memory
 EXTERN Page idle_page
 
+template <typename _T> void Object <_T>::free (Memory *parent, _T *&first):
+	if prev:
+		prev->next = next
+	else:
+		first = next
+	if next:
+		next->prev = prev
+	free_obj (parent)
+
 #endif

mips.hhp

@@ -0,0 +1,35 @@
+#pypp 0
+#ifndef _ARCH_HH
+#define _ARCH_HH
+
+struct Thread_arch:
+	unsigned at, v0, v1, a0, a1, a2, a3
+	unsigned t0, t1, t2, t3, t4, t5, t6, t7, t8, t9
+	unsigned gp, fp, ra, hi, lo, k0, k1
+
+#define Thread_arch_init(thread) do { thread->at = 0; thread->v0 = 0; thread->v1 = 0; thread->a0 = 0; thread->a1 = 0; thread->a2 = 0; thread->a3 = 0; thread->t0 = 0; thread->t1 = 0; thread->t2 = 0; thread->t3 = 0; thread->t4 = 0; thread->t5 = 0; thread->t6 = 0; thread->t7 = 0; thread->t8 = 0; thread->t9 = 0; thread->gp = 0; thread->fp = 0; thread->ra = 0; thread->hi = 0; thread->lo = 0; thread->k0 = 0; thread->k1 = 0; } while (0)
+
+struct Memory_arch:
+	unsigned asid
+	Page ***directory
+
+EXTERN unsigned g_asid
+
+#define Memory_arch_init(mem) do { mem->asid = g_asid++; g_asid &= 0x3f; mem->directory = NULL; } while (0)
+
+// Functions which can be called from assembly must not be mangled.
+extern "C":
+	// Kernel entry points, called from entry.S.
+	Thread *interrupt (Thread *current)
+	Thread *cache_error (Thread *current)
+	Thread *exception (Thread *current)
+	Thread *tlb_refill (Thread *current, unsigned EntryHi)
+
+	#ifdef INIT
+	// Initialize most things (the rest is done in boot.S)
+	void init ()
+	// Start running the idle task for the first time.
+	void run_idle (Thread *self)
+	#endif
+
+#endif