Cleanup loader and unify init and spawn paths.
This commit is contained in:
Ali Mashtizadeh
parent
1676ae4056
commit
1df34b2d2e
@ -56,6 +56,7 @@ typedef struct Process {
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uint64_t pid;
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AS *space;
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Spinlock lock;
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uintptr_t entrypoint;
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uint64_t nextThreadID;
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uintptr_t ustackNext; // Next user stack
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TAILQ_ENTRY(Process) processList;
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@ -19,6 +19,13 @@
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#include <sys/vfs.h>
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extern Handle *Console_OpenHandle();
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/*
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* Loader_CheckHeader --
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*
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* Check that the program has a valid ELF header.
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*/
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bool
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Loader_CheckHeader(const Elf64_Ehdr *ehdr)
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{
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@ -39,125 +46,15 @@ Loader_CheckHeader(const Elf64_Ehdr *ehdr)
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return true;
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}
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bool
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Loader_LoadFirst(Thread *thr, VNode *vn, void *buf, uint64_t len)
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{
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int i;
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const Elf64_Ehdr *ehdr;
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const Elf64_Phdr *phdr;
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AS *as = thr->space;
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ehdr = (const Elf64_Ehdr *)(buf);
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phdr = (const Elf64_Phdr *)(buf + ehdr->e_phoff);
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if (!Loader_CheckHeader(ehdr)) {
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Log(loader, "Not a valid executable!\n");
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return false;
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}
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Log(loader, "%8s %16s %8s %8s\n", "Offset", "VAddr", "FileSize", "MemSize");
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for (i = 0; i < ehdr->e_phnum; i++)
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{
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ASSERT(phdr[i].p_type != PT_DYNAMIC);
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if (phdr[i].p_type == PT_LOAD) {
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uint64_t va = phdr[i].p_vaddr;
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uint64_t memsz = phdr[i].p_memsz;
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Log(loader, "%08llx %016llx %08llx %08llx\n", phdr[i].p_offset,
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phdr[i].p_vaddr, phdr[i].p_filesz, phdr[i].p_memsz);
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// Make sure it is page aligned
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va = va & ~(uint64_t)PGMASK;
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memsz += phdr[i].p_vaddr - va;
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Log(loader, "AllocMap %016llx %08llx\n", va, memsz);
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if (!PMap_AllocMap(as, va, memsz, PTE_W)) {
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// XXX: Cleanup!
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ASSERT(false);
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return false;
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}
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}
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}
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PMap_AllocMap(as, MEM_USERSPACE_STKBASE, MEM_USERSPACE_STKLEN, PTE_W);
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PMap_LoadAS(as); // Reload CR3
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for (i = 0; i < ehdr->e_phnum; i++)
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{
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ASSERT(phdr[i].p_type != PT_DYNAMIC);
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if (phdr[i].p_type == PT_LOAD) {
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if (phdr[i].p_filesz != 0) {
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Log(loader, "Read %lx %lx %lx\n", phdr[i].p_vaddr, phdr[i].p_offset, phdr[i].p_filesz);
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VFS_Read(vn, (void *)phdr[i].p_vaddr,
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phdr[i].p_offset, phdr[i].p_filesz);
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}
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memset((void *)(phdr[i].p_vaddr + phdr[i].p_filesz),
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0,
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(uintptr_t)(phdr[i].p_memsz - phdr[i].p_filesz));
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}
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}
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Log(loader, "Jumping to userspace\n");
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uintptr_t ap[3];
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ap[0] = 0;
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ap[1] = 0;
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ap[2] = 0xDEADBEEF;
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uintptr_t rsp = MEM_USERSPACE_STKTOP - PGSIZE;
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Copy_Out(&ap[0], rsp, sizeof(uintptr_t)*3);
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TrapFrame tf;
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memset(&tf, 0, sizeof(tf));
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tf.ds = SEL_UDS | 3;
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tf.rip = ehdr->e_entry;
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tf.cs = SEL_UCS | 3;
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tf.rsp = rsp;
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tf.ss = SEL_UDS | 3;
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tf.rflags = RFLAGS_IF;
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tf.rdi = rsp;
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Trap_Pop(&tf);
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return true;
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}
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Handle *Console_OpenHandle();
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void
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Loader_LoadInit()
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{
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int status;
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void *pg;
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VNode *init;
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pg = PAlloc_AllocPage();
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if (!pg)
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Panic("Not enough memory!");
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init = VFS_Lookup("/sbin/init");
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status = VFS_Open(init);
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if (status < 0)
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Panic("Loading init process failed!");
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status = VFS_Read(init, pg, 0, 1024);
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if (status < 0)
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Panic("Reading init process failed!");
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Thread *thr = Sched_Current();
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// Open stdin/out/err
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Handle *handle = Console_OpenHandle();
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Handle_Add(thr->proc, handle);
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handle = Console_OpenHandle();
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Handle_Add(thr->proc, handle);
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handle = Console_OpenHandle();
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Handle_Add(thr->proc, handle);
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Loader_LoadFirst(thr, init, pg, 1024);
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VFS_Close(init);
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}
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void
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LoaderFileHelper(AS *as, VNode *vn, uintptr_t vaddr,
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/*
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* LoaderLoadSegment --
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*
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* Loads a single segment into the target address space. This function
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* loads a single page at a time because it has to lookup the address
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* mappings through the page tables.
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*/
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static void
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LoaderLoadSegment(AS *as, VNode *vn, uintptr_t vaddr,
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uintptr_t offset, uintptr_t len)
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{
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void *raddr;
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@ -187,8 +84,14 @@ LoaderFileHelper(AS *as, VNode *vn, uintptr_t vaddr,
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}
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}
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void
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LoaderZeroHelper(AS *as, uintptr_t vaddr, uintptr_t len)
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/*
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* LoaderZeroSegment --
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*
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* Zeroes a segment of memory in the target address space. This is done
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* one page a time while translating the virtual address to physical.
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*/
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static void
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LoaderZeroSegment(AS *as, uintptr_t vaddr, uintptr_t len)
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{
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void *raddr;
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@ -215,6 +118,11 @@ LoaderZeroHelper(AS *as, uintptr_t vaddr, uintptr_t len)
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}
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}
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/*
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* Loader_Load --
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*
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* Load the ELF binary into the process belonging to the thread.
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*/
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bool
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Loader_Load(Thread *thr, VNode *vn, void *buf, uint64_t len)
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{
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@ -261,17 +169,101 @@ Loader_Load(Thread *thr, VNode *vn, void *buf, uint64_t len)
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ASSERT(phdr[i].p_type != PT_DYNAMIC);
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if (phdr[i].p_type == PT_LOAD) {
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if (phdr[i].p_filesz != 0) {
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LoaderFileHelper(as, vn, phdr[i].p_vaddr,
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phdr[i].p_offset, phdr[i].p_filesz);
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LoaderLoadSegment(as, vn, phdr[i].p_vaddr,
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phdr[i].p_offset, phdr[i].p_filesz);
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}
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LoaderZeroHelper(as,
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phdr[i].p_vaddr + phdr[i].p_filesz,
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phdr[i].p_memsz - phdr[i].p_filesz);
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LoaderZeroSegment(as,
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phdr[i].p_vaddr + phdr[i].p_filesz,
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phdr[i].p_memsz - phdr[i].p_filesz);
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}
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}
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Thread_SetupUThread(thr, ehdr->e_entry, MEM_USERSPACE_STKTOP - PGSIZE);
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/* Save the process entry point (i.e., _start) */
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thr->proc->entrypoint = ehdr->e_entry;
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return true;
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}
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/*
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* Loader_LoadInit --
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*
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* The init process is created from the execution kernel thread that
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* initializes the system. This function initializes the thread and
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* process state then loads the init binary.
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*/
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void
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Loader_LoadInit()
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{
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int status;
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void *pg;
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VNode *initvn;
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pg = PAlloc_AllocPage();
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if (!pg)
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Panic("Not enough memory!");
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initvn = VFS_Lookup("/sbin/init");
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status = VFS_Open(initvn);
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if (status < 0)
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Panic("Loading init process failed!");
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status = VFS_Read(initvn, pg, 0, 1024);
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if (status < 0)
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Panic("Reading init process failed!");
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Thread *thr = Sched_Current();
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// Open stdin/out/err
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Handle *handle = Console_OpenHandle();
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Handle_Add(thr->proc, handle);
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handle = Console_OpenHandle();
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Handle_Add(thr->proc, handle);
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handle = Console_OpenHandle();
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Handle_Add(thr->proc, handle);
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/*
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* Load init binary
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*/
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Loader_Load(thr, initvn, pg, 1024);
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VFS_Close(initvn);
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Log(loader, "Jumping to userspace\n");
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/*
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* Reload the page tables for the current process
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*/
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PMap_LoadAS(thr->space); // Reload CR3
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/*
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* Pass in zero arguments with null pointers to init
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*/
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uintptr_t ap[3];
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ap[0] = 0;
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ap[1] = 0;
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ap[2] = 0xDEADBEEF;
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uintptr_t rsp = MEM_USERSPACE_STKTOP - PGSIZE;
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Copy_Out(&ap[0], rsp, sizeof(uintptr_t)*3);
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/*
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* The last step is to return into userspace handing control to init. We
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* create a valid trap frame and return into userspace using Trap_Pop().
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*/
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TrapFrame tf;
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memset(&tf, 0, sizeof(tf));
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tf.ds = SEL_UDS | 3;
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tf.rip = thr->proc->entrypoint;
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tf.cs = SEL_UCS | 3;
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tf.rsp = rsp;
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tf.ss = SEL_UDS | 3;
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tf.rflags = RFLAGS_IF;
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tf.rdi = rsp;
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Trap_Pop(&tf);
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/*
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* We should never reach this point!
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*/
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Panic("Unreachable: Trap_Pop() returned!\n");
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}
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@ -168,6 +168,9 @@ Syscall_Spawn(uint64_t user_path, uint64_t user_argv)
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Loader_Load(thr, file, pg, 1024);
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/* Initialize the trap frame for entering into the process. */
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Thread_SetupUThread(thr, proc->entrypoint, MEM_USERSPACE_STKTOP - PGSIZE);
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/* Translate mapping for stack page */
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argstart = (char *)DMPA2VA(PMap_Translate(thr->space, MEM_USERSPACE_STKTOP - PGSIZE));
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argstart += sizeof(uintptr_t)*8;
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