elf loading and userland

src/arch/x86_64/gdt.c

@@ -35,6 +35,7 @@ static void reloadgdtr(){
 gdtr.offset = &arch_getcls()->gdt;
 gdtr.size   = sizeof(gdt_t) - 1;
 	asm("lgdt (%%rax)" : : "a"(&gdtr) : "memory");
+	asm("ltr %%ax" : : "a"(0x48));
 }
 
 void gdt_init(){

src/arch/x86_64/include/arch/ist.h

@@ -4,20 +4,22 @@
 #include <stdint.h>
 
 typedef struct{
-	uint32_t IOPB;
+	uint32_t reserved;
-	uint64_t reserved3;
-	uint64_t ist7;
-	uint64_t ist6;
-	uint64_t ist5;
-	uint64_t ist4;
-	uint64_t ist3;
-	uint64_t ist2;
-	uint64_t ist1;
-	uint64_t reserved2;
-	uint64_t rsp2;
-	uint64_t rsp1;
 	uint64_t rsp0;
-	uint64_t reserved;
+	uint64_t rsp1;
+	uint64_t rsp2;
+	uint32_t reserved2;
+	uint64_t ist1;
+	uint64_t ist2;
+	uint64_t ist3;
+	uint64_t ist4;
+	uint64_t ist5;
+	uint64_t ist6;
+	uint64_t ist7;
+	uint32_t reserved3;
+	uint32_t reserved4;
+	uint32_t reserved5;
+	uint32_t IOPB;
 } __attribute((packed)) ist_t;
 
 #endif

src/arch/x86_64/include/arch/mmu.h

@@ -24,5 +24,6 @@ void arch_mmu_init();
 void arch_mmu_apinit();
 arch_mmu_tableptr arch_mmu_newcontext();
 void arch_mmu_switchcontext(arch_mmu_tableptr);
+void arch_mmu_changeflags(arch_mmu_tableptr context, void* addr, size_t flags, size_t count);
 
 #endif

src/arch/x86_64/mmu.c

@@ -115,9 +115,11 @@ static uint64_t getmapping(arch_mmu_tableptr context, void* vaddr){
         size_t pt   = (addr >> 21) & 0b111111111;
         size_t page = (addr >> 12) & 0b111111111;
 	
-	if(!context[pdpt]) return 0;
+	uint64_t* table = next(context, pdpt);
 	
-	uint64_t* table = next(context, pd);
+	if(!table) return 0;
+	
+	table = next(table, pd);
 
 	if(!table) return 0;
 
@@ -142,6 +144,20 @@ bool arch_mmu_isaccessed(arch_mmu_tableptr context, void* addr){
 	return (getmapping(context, addr) & ARCH_MMU_MAP_ACCESSED) != 0;
 }
 
+void arch_mmu_changeflags(arch_mmu_tableptr context, void* addr, size_t flags, size_t count){
+	for(size_t i = 0; i < count; ++i){
+		uint64_t mapping = getmapping(context, addr);
+		if(!mapping)
+			continue;
+		mapping &= ~(0xFFF); // get addr
+		mapping &= ~ARCH_MMU_MAP_NOEXEC;
+		mapping |= flags;
+		setpage(context, addr, mapping);
+		addr += PAGE_SIZE;
+	}
+	
+}
+
 int arch_mmu_map(arch_mmu_tableptr context, void* paddr, void* vaddr, size_t flags){
 	uint64_t entry;
 	changeentry(&entry, paddr, flags);

src/arch/x86_64/panic.c

@@ -8,7 +8,6 @@
 #define TRACE_MAXDEPTH 10
 
 static void tracestack(uint64_t** addr){
-	
 	for(size_t depth = 0; depth < TRACE_MAXDEPTH; ++depth){
 
 		uint64_t *calleeaddr = *(addr + 1);
@@ -34,8 +33,11 @@ __attribute((noreturn)) void _panic(char* reason, arch_regs *reg){
 		);
 
 		printf("Panic location: %p\n", reg->rip);
+		
+		if(reg->rbp != 0){
 			printf("Stack trace:\n");
 			tracestack((uint64_t**)reg->rbp);
+		}
 
 	}
 	

src/fs/tmpfs.c

@@ -61,7 +61,7 @@ static int tmpfs_read(int *error, vnode_t* node, void* buff, size_t count, size_
 	if(count > sizemax)
 		count = sizemax;
 	
-	memcpy(buff, node->fsdata, count);
+	memcpy(buff, node->fsdata + offset, count);
 
 	return count;
 	

src/include/kernel/elf.h

@@ -26,6 +26,7 @@
 #define ELF_FLAG_WRITABLE 2
 #define ELF_FLAG_READABLE 4
 
+#define STACK_TOP 0x800000000000
 
 typedef struct{
 	uint32_t magic;

src/include/kernel/vmm.h

@@ -7,7 +7,7 @@
 
 #define KERNEL_SPACE_START 0xFFFF800000000000
 #define KERNEL_SPACE_END   0xFFFFFFFFFFFFFFFF
-#define USER_SPACE_START   0
+#define USER_SPACE_START   0x1000
 #define USER_SPACE_END     0x00007FFFFFFFFFFF
 
 #define VMM_TYPE_FREE 0
@@ -59,5 +59,6 @@ bool		vmm_unmap(void* addr, size_t pagec);
 bool		vmm_map(void* paddr, void* vaddr, size_t pagec, size_t mmuflags);
 void*		vmm_alloc(size_t pagec, size_t mmuflags);
 bool		vmm_setfree(void* addr, size_t pagec);
+bool		vmm_allocnowat(void* addr, size_t mmuflags, size_t size);
 vmm_context*	vmm_newcontext();
 #endif

src/sys/mm/pmm.c

@@ -206,7 +206,7 @@ void pmm_init(){
 
 		if(current->length < bitmapsize || current->base < 0x100000) continue;
 		
-		bitmap = (size_t*)current->base;
+		bitmap = (void*)current->base + (size_t)limine_hhdm_offset;
 		
 		break;
 

src/sys/mm/vmm.c

@@ -351,7 +351,7 @@ static void getcontextinfo(void* addr, int** lock, vmm_mapping*** start){
 	vmm_context *context = arch_getcls()->context;
 	
 	*lock = &context->lock;
-	*start = context->userstart;
+	*start = &context->userstart;
 	
 }
 
@@ -435,6 +435,39 @@ bool vmm_map(void* paddr, void* vaddr, size_t pagec, size_t mmuflags){
 	return result;
 }
 
+bool vmm_allocnowat(void* addr, size_t mmuflags, size_t size){
+	int* lock;
+	vmm_mapping** start;
+	bool result = true;
+	
+	addr = addr - ((uintptr_t)addr % PAGE_SIZE);
+
+	getcontextinfo(addr, &lock, &start);
+	
+	size = size / PAGE_SIZE + (size % PAGE_SIZE ? 1 : 0);
+
+	spinlock_acquire(lock);
+	
+	// XXX allocate 1 page at a time to reduce fragmentation
+
+	void* paddr = pmm_alloc(size);
+	if(!paddr)
+		result = false;
+	else
+		result = setmap(start, addr, size, mmuflags, VMM_TYPE_ANON, 0, 0);
+
+	for(size_t page = 0; page < size && result; ++page)
+		result = arch_mmu_map(arch_getcls()->context->context, paddr + page*PAGE_SIZE, addr + page*PAGE_SIZE, mmuflags);
+	
+	if(!result)
+		pmm_free(paddr, size);
+
+	spinlock_release(lock);
+
+	return result;
+
+}
+
 // called by the page fault handler
 
 bool vmm_dealwithrequest(void* addr){

src/sys/sched/elf.c

@@ -1,6 +1,36 @@
 #include <kernel/elf.h>
 #include <kernel/alloc.h>
+#include <kernel/vmm.h>
 #include <errno.h>
+#include <string.h>
+#include <arch/cls.h>
+
+typedef struct{
+	uint64_t a_type;
+	uint64_t a_val;
+} auxv64_t;
+
+typedef struct {
+	
+	
+} auxv64_list;
+
+static size_t phflagtommuflag(size_t phflags){
+	
+	size_t mmuflags = 0;
+	
+	if(phflags & ELF_FLAG_EXECUTABLE == 0)
+		mmuflags |= ARCH_MMU_MAP_NOEXEC;
+	
+	if(phflags & ELF_FLAG_WRITABLE)
+		mmuflags |= ARCH_MMU_MAP_WRITE;
+	
+	if(phflags & ELF_FLAG_READABLE)
+		mmuflags |= ARCH_MMU_MAP_READ;
+
+	return mmuflags | ARCH_MMU_MAP_USER;
+
+}
 
 static bool check_header64(elf_header64* header){
 	// XXX throw this into arch
@@ -21,6 +51,90 @@ static bool check_header64(elf_header64* header){
 
 }
 
+static void* stacksetup(char* interp, char** argv, char** env){
+	size_t argc = 0;
+	size_t envc = 0;
+	size_t initialsize = 0;
+	size_t argdatasize = 0;
+	size_t envdatasize = 0;
+	size_t auxvsize    = 8;
+
+	while(argv[argc]){
+		argdatasize += strlen(argv[argc]) + 1;
+		initialsize += strlen(argv[argc]) + 1;
+		++argc;
+	}
+
+	while(env[envc]){
+		envdatasize += strlen(env[envc]) + 1;
+		initialsize += strlen(env[envc]) + 1;
+		++envc;
+	}
+	
+	if(interp){
+		argdatasize += strlen(interp) + 1;
+		initialsize += strlen(interp) + 1;
+		initialsize += sizeof(char*); // interpreter ptr
+	}
+	
+	// pointers to args and envs
+
+	initialsize += argc*sizeof(char*); //args
+	initialsize += envc*sizeof(char*); //envs
+	initialsize += 2*sizeof(char**); //argv envp
+	initialsize += sizeof(size_t);   //argc	
+	
+	// allocate memory for the initial section of the stack
+	
+
+	if(!vmm_allocnowat(STACK_TOP - initialsize, ARCH_MMU_MAP_READ | ARCH_MMU_MAP_WRITE | ARCH_MMU_MAP_NOEXEC | ARCH_MMU_MAP_USER, initialsize)) return NULL;
+
+	// get the addresses to copy the data to
+
+	char* argdatastart = STACK_TOP - argdatasize;
+	char* envdatastart = argdatastart - envdatasize;
+	// auxvstart will be aligned
+	void* auxvstart = (void*)(((uintptr_t)envdatastart & (~0xF)) - auxvsize);
+	// count + 1 because of a null entry
+	char** envstart = auxvstart - (envc + 1)*sizeof(char*);
+	char** argstart = (void*)envstart - (argc + 1)*sizeof(char*);
+	if(interp)
+		--argstart;
+	size_t* argcptr = (void*)argstart - sizeof(size_t);
+	
+	// XXX auxv
+
+	// copy the data
+	
+	if(interp){
+		strcpy(argdatastart, interp);
+		*argstart++ = argdatastart;
+		argdatastart += strlen(interp) + 1;
+	}
+
+	for(size_t i = 0; i < argc; ++i){
+		strcpy(argdatastart, argv[i]);
+		*argstart++ = argdatastart;
+		argdatastart += strlen(argv[i]) + 1;
+	}
+
+	*argstart = NULL;
+	
+	for(size_t i = 0; i < envc; ++i){
+		strcpy(envdatastart, env[i]);
+		*envstart++ = envdatastart;
+		envdatastart += strlen(env[i]) + 1;
+	}
+
+	if(interp)
+		argc++;
+	*argcptr = argc;
+	
+
+	return argcptr;
+	
+}
+
 int elf_load(thread_t* thread, vnode_t* node, char** argv, char** env){
 	
 	elf_header64 header;	
@@ -91,6 +205,8 @@ int elf_load(thread_t* thread, vnode_t* node, char** argv, char** env){
 
 	for(size_t currentph = 0; currentph < header.ph_count; ++currentph){
 		
+		// read ph
+
 		readc = vfs_read(&err, node, &ph, header.ph_size, header.ph_pos + currentph*header.ph_size);
 		
 		if(err) goto _fail;
@@ -103,12 +219,46 @@ int elf_load(thread_t* thread, vnode_t* node, char** argv, char** env){
 		if(ph.type != PH_TYPE_LOAD)
 			continue;
 
+		if(!vmm_allocnowat((void*)ph.memaddr, phflagtommuflag(ph.flags), ph.msize)){
+			err = ENOMEM;
+			goto _fail;
+		}
 
+		// set up temporary mmu flags to copy data
+		
+		arch_mmu_changeflags(arch_getcls()->context->context, ph.memaddr, ARCH_MMU_MAP_READ | ARCH_MMU_MAP_WRITE, ph.msize / PAGE_SIZE + (ph.msize % PAGE_SIZE ? 1 : 0));
+
+		// read program data
+		
+		readc = vfs_read(&err, node, (void*)ph.memaddr, ph.fsize, ph.offset);
+		
+		if(err)
+			goto _fail;
+
+		if(readc != ph.fsize){
+			err = EINVAL;
+			goto _fail;
+		}
+
+		// zero if needed
+		
+		size_t zerocount = ph.msize - ph.fsize;
+
+		if(zerocount){
+			void* zeroaddr = ph.memaddr + ph.fsize;
+			memset(zeroaddr, 0, zerocount);
+		}
+		
+		// reset proper mmu flags
+		
+		arch_mmu_changeflags(arch_getcls()->context->context, ph.memaddr, phflagtommuflag(ph.flags), ph.msize / PAGE_SIZE + (ph.msize % PAGE_SIZE ? 1 : 0));
 
 
 	}
 	
+	void* stack = stacksetup(interp, argv, env);
 	
+	arch_regs_setupuser(thread->regs, (void*)header.entry, stack, true);
 
 	return 0;
 

src/sys/sched/scheduler.c

@@ -226,6 +226,7 @@ thread_t* sched_newuthread(void* ip, size_t kstacksize, void* stack, proc_t* pro
 	}
 	
 	thread->priority = prio;
+	thread->proc = proc;
 	arch_regs_setupuser(thread->regs, ip, stack, true);
 
 	if(run)
@@ -268,18 +269,21 @@ void sched_runinit(){
 
 	proc_t* proc = thread->proc;
 
+	vmm_switchcontext(proc->context);
+
 	proc->root = vfs_root();
 	proc->cwd  = vfs_root();
 	proc->pid  = 1;
 
 	vnode_t* node;
 	size_t ret = vfs_open(&node, vfs_root(), "sbin/init");
+
 	if(ret){
 		printf("Open failed: %s\n", strerror(ret));
 		_panic("Could not load init", 0);
 	}
-	char** argv = {"/sbin/init", ""};
+	char* argv[] = {"/sbin/init", NULL};
-	char** env  = {""};
+	char* env[]  = {NULL};
 
 	ret = elf_load(thread, node, argv, env);
 	
@@ -287,6 +291,7 @@ void sched_runinit(){
 		printf("ELF load error: %s\n", strerror(ret));
 		_panic("Could not load init", 0);
 	}
+
 	switch_thread(thread);
 	
 }