From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sat, 16 Apr 2005 15:20:36 -0700 Subject: Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip! --- arch/um/kernel/tt/process_kern.c | 476 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 476 insertions(+) create mode 100644 arch/um/kernel/tt/process_kern.c (limited to 'arch/um/kernel/tt/process_kern.c') diff --git a/arch/um/kernel/tt/process_kern.c b/arch/um/kernel/tt/process_kern.c new file mode 100644 index 000000000000..f19f7c18febe --- /dev/null +++ b/arch/um/kernel/tt/process_kern.c @@ -0,0 +1,476 @@ +/* + * Copyright (C) 2002 Jeff Dike (jdike@karaya.com) + * Licensed under the GPL + */ + +#include "linux/sched.h" +#include "linux/signal.h" +#include "linux/kernel.h" +#include "linux/interrupt.h" +#include "linux/ptrace.h" +#include "asm/system.h" +#include "asm/pgalloc.h" +#include "asm/ptrace.h" +#include "asm/tlbflush.h" +#include "irq_user.h" +#include "signal_user.h" +#include "kern_util.h" +#include "user_util.h" +#include "os.h" +#include "kern.h" +#include "sigcontext.h" +#include "time_user.h" +#include "mem_user.h" +#include "tlb.h" +#include "mode.h" +#include "init.h" +#include "tt.h" + +void *switch_to_tt(void *prev, void *next, void *last) +{ + struct task_struct *from, *to, *prev_sched; + unsigned long flags; + int err, vtalrm, alrm, prof, cpu; + char c; + /* jailing and SMP are incompatible, so this doesn't need to be + * made per-cpu + */ + static int reading; + + from = prev; + to = next; + + to->thread.prev_sched = from; + + cpu = from->thread_info->cpu; + if(cpu == 0) + forward_interrupts(to->thread.mode.tt.extern_pid); +#ifdef CONFIG_SMP + forward_ipi(cpu_data[cpu].ipi_pipe[0], to->thread.mode.tt.extern_pid); +#endif + local_irq_save(flags); + + vtalrm = change_sig(SIGVTALRM, 0); + alrm = change_sig(SIGALRM, 0); + prof = change_sig(SIGPROF, 0); + + forward_pending_sigio(to->thread.mode.tt.extern_pid); + + c = 0; + set_current(to); + + reading = 0; + err = os_write_file(to->thread.mode.tt.switch_pipe[1], &c, sizeof(c)); + if(err != sizeof(c)) + panic("write of switch_pipe failed, err = %d", -err); + + reading = 1; + if((from->exit_state == EXIT_ZOMBIE) || + (from->exit_state == EXIT_DEAD)) + os_kill_process(os_getpid(), 0); + + err = os_read_file(from->thread.mode.tt.switch_pipe[0], &c, sizeof(c)); + if(err != sizeof(c)) + panic("read of switch_pipe failed, errno = %d", -err); + + /* If the process that we have just scheduled away from has exited, + * then it needs to be killed here. The reason is that, even though + * it will kill itself when it next runs, that may be too late. Its + * stack will be freed, possibly before then, and if that happens, + * we have a use-after-free situation. So, it gets killed here + * in case it has not already killed itself. + */ + prev_sched = current->thread.prev_sched; + if((prev_sched->exit_state == EXIT_ZOMBIE) || + (prev_sched->exit_state == EXIT_DEAD)) + os_kill_process(prev_sched->thread.mode.tt.extern_pid, 1); + + change_sig(SIGVTALRM, vtalrm); + change_sig(SIGALRM, alrm); + change_sig(SIGPROF, prof); + + arch_switch(); + + flush_tlb_all(); + local_irq_restore(flags); + + return(current->thread.prev_sched); +} + +void release_thread_tt(struct task_struct *task) +{ + int pid = task->thread.mode.tt.extern_pid; + + if(os_getpid() != pid) + os_kill_process(pid, 0); +} + +void exit_thread_tt(void) +{ + os_close_file(current->thread.mode.tt.switch_pipe[0]); + os_close_file(current->thread.mode.tt.switch_pipe[1]); +} + +void suspend_new_thread(int fd) +{ + int err; + char c; + + os_stop_process(os_getpid()); + err = os_read_file(fd, &c, sizeof(c)); + if(err != sizeof(c)) + panic("read failed in suspend_new_thread, err = %d", -err); +} + +void schedule_tail(task_t *prev); + +static void new_thread_handler(int sig) +{ + unsigned long disable; + int (*fn)(void *); + void *arg; + + fn = current->thread.request.u.thread.proc; + arg = current->thread.request.u.thread.arg; + + UPT_SC(¤t->thread.regs.regs) = (void *) (&sig + 1); + disable = (1 << (SIGVTALRM - 1)) | (1 << (SIGALRM - 1)) | + (1 << (SIGIO - 1)) | (1 << (SIGPROF - 1)); + SC_SIGMASK(UPT_SC(¤t->thread.regs.regs)) &= ~disable; + + suspend_new_thread(current->thread.mode.tt.switch_pipe[0]); + + force_flush_all(); + if(current->thread.prev_sched != NULL) + schedule_tail(current->thread.prev_sched); + current->thread.prev_sched = NULL; + + init_new_thread_signals(1); + enable_timer(); + free_page(current->thread.temp_stack); + set_cmdline("(kernel thread)"); + + change_sig(SIGUSR1, 1); + change_sig(SIGVTALRM, 1); + change_sig(SIGPROF, 1); + local_irq_enable(); + if(!run_kernel_thread(fn, arg, ¤t->thread.exec_buf)) + do_exit(0); + + /* XXX No set_user_mode here because a newly execed process will + * immediately segfault on its non-existent IP, coming straight back + * to the signal handler, which will call set_user_mode on its way + * out. This should probably change since it's confusing. + */ +} + +static int new_thread_proc(void *stack) +{ + /* local_irq_disable is needed to block out signals until this thread is + * properly scheduled. Otherwise, the tracing thread will get mighty + * upset about any signals that arrive before that. + * This has the complication that it sets the saved signal mask in + * the sigcontext to block signals. This gets restored when this + * thread (or a descendant, since they get a copy of this sigcontext) + * returns to userspace. + * So, this is compensated for elsewhere. + * XXX There is still a small window until local_irq_disable() actually + * finishes where signals are possible - shouldn't be a problem in + * practice since SIGIO hasn't been forwarded here yet, and the + * local_irq_disable should finish before a SIGVTALRM has time to be + * delivered. + */ + + local_irq_disable(); + init_new_thread_stack(stack, new_thread_handler); + os_usr1_process(os_getpid()); + change_sig(SIGUSR1, 1); + return(0); +} + +/* Signal masking - signals are blocked at the start of fork_tramp. They + * are re-enabled when finish_fork_handler is entered by fork_tramp hitting + * itself with a SIGUSR1. set_user_mode has to be run with SIGUSR1 off, + * so it is blocked before it's called. They are re-enabled on sigreturn + * despite the fact that they were blocked when the SIGUSR1 was issued because + * copy_thread copies the parent's sigcontext, including the signal mask + * onto the signal frame. + */ + +void finish_fork_handler(int sig) +{ + UPT_SC(¤t->thread.regs.regs) = (void *) (&sig + 1); + suspend_new_thread(current->thread.mode.tt.switch_pipe[0]); + + force_flush_all(); + if(current->thread.prev_sched != NULL) + schedule_tail(current->thread.prev_sched); + current->thread.prev_sched = NULL; + + enable_timer(); + change_sig(SIGVTALRM, 1); + local_irq_enable(); + if(current->mm != current->parent->mm) + protect_memory(uml_reserved, high_physmem - uml_reserved, 1, + 1, 0, 1); + task_protections((unsigned long) current_thread); + + free_page(current->thread.temp_stack); + local_irq_disable(); + change_sig(SIGUSR1, 0); + set_user_mode(current); +} + +int fork_tramp(void *stack) +{ + local_irq_disable(); + arch_init_thread(); + init_new_thread_stack(stack, finish_fork_handler); + + os_usr1_process(os_getpid()); + change_sig(SIGUSR1, 1); + return(0); +} + +int copy_thread_tt(int nr, unsigned long clone_flags, unsigned long sp, + unsigned long stack_top, struct task_struct * p, + struct pt_regs *regs) +{ + int (*tramp)(void *); + int new_pid, err; + unsigned long stack; + + if(current->thread.forking) + tramp = fork_tramp; + else { + tramp = new_thread_proc; + p->thread.request.u.thread = current->thread.request.u.thread; + } + + err = os_pipe(p->thread.mode.tt.switch_pipe, 1, 1); + if(err < 0){ + printk("copy_thread : pipe failed, err = %d\n", -err); + return(err); + } + + stack = alloc_stack(0, 0); + if(stack == 0){ + printk(KERN_ERR "copy_thread : failed to allocate " + "temporary stack\n"); + return(-ENOMEM); + } + + clone_flags &= CLONE_VM; + p->thread.temp_stack = stack; + new_pid = start_fork_tramp(p->thread_info, stack, clone_flags, tramp); + if(new_pid < 0){ + printk(KERN_ERR "copy_thread : clone failed - errno = %d\n", + -new_pid); + return(new_pid); + } + + if(current->thread.forking){ + sc_to_sc(UPT_SC(&p->thread.regs.regs), + UPT_SC(¤t->thread.regs.regs)); + SC_SET_SYSCALL_RETURN(UPT_SC(&p->thread.regs.regs), 0); + if(sp != 0) SC_SP(UPT_SC(&p->thread.regs.regs)) = sp; + } + p->thread.mode.tt.extern_pid = new_pid; + + current->thread.request.op = OP_FORK; + current->thread.request.u.fork.pid = new_pid; + os_usr1_process(os_getpid()); + + /* Enable the signal and then disable it to ensure that it is handled + * here, and nowhere else. + */ + change_sig(SIGUSR1, 1); + + change_sig(SIGUSR1, 0); + err = 0; + return(err); +} + +void reboot_tt(void) +{ + current->thread.request.op = OP_REBOOT; + os_usr1_process(os_getpid()); + change_sig(SIGUSR1, 1); +} + +void halt_tt(void) +{ + current->thread.request.op = OP_HALT; + os_usr1_process(os_getpid()); + change_sig(SIGUSR1, 1); +} + +void kill_off_processes_tt(void) +{ + struct task_struct *p; + int me; + + me = os_getpid(); + for_each_process(p){ + if(p->thread.mode.tt.extern_pid != me) + os_kill_process(p->thread.mode.tt.extern_pid, 0); + } + if(init_task.thread.mode.tt.extern_pid != me) + os_kill_process(init_task.thread.mode.tt.extern_pid, 0); +} + +void initial_thread_cb_tt(void (*proc)(void *), void *arg) +{ + if(os_getpid() == tracing_pid){ + (*proc)(arg); + } + else { + current->thread.request.op = OP_CB; + current->thread.request.u.cb.proc = proc; + current->thread.request.u.cb.arg = arg; + os_usr1_process(os_getpid()); + change_sig(SIGUSR1, 1); + + change_sig(SIGUSR1, 0); + } +} + +int do_proc_op(void *t, int proc_id) +{ + struct task_struct *task; + struct thread_struct *thread; + int op, pid; + + task = t; + thread = &task->thread; + op = thread->request.op; + switch(op){ + case OP_NONE: + case OP_TRACE_ON: + break; + case OP_EXEC: + pid = thread->request.u.exec.pid; + do_exec(thread->mode.tt.extern_pid, pid); + thread->mode.tt.extern_pid = pid; + cpu_tasks[task->thread_info->cpu].pid = pid; + break; + case OP_FORK: + attach_process(thread->request.u.fork.pid); + break; + case OP_CB: + (*thread->request.u.cb.proc)(thread->request.u.cb.arg); + break; + case OP_REBOOT: + case OP_HALT: + break; + default: + tracer_panic("Bad op in do_proc_op"); + break; + } + thread->request.op = OP_NONE; + return(op); +} + +void init_idle_tt(void) +{ + default_idle(); +} + +extern void start_kernel(void); + +static int start_kernel_proc(void *unused) +{ + int pid; + + block_signals(); + pid = os_getpid(); + + cpu_tasks[0].pid = pid; + cpu_tasks[0].task = current; +#ifdef CONFIG_SMP + cpu_online_map = cpumask_of_cpu(0); +#endif + if(debug) os_stop_process(pid); + start_kernel(); + return(0); +} + +void set_tracing(void *task, int tracing) +{ + ((struct task_struct *) task)->thread.mode.tt.tracing = tracing; +} + +int is_tracing(void *t) +{ + return (((struct task_struct *) t)->thread.mode.tt.tracing); +} + +int set_user_mode(void *t) +{ + struct task_struct *task; + + task = t ? t : current; + if(task->thread.mode.tt.tracing) + return(1); + task->thread.request.op = OP_TRACE_ON; + os_usr1_process(os_getpid()); + return(0); +} + +void set_init_pid(int pid) +{ + int err; + + init_task.thread.mode.tt.extern_pid = pid; + err = os_pipe(init_task.thread.mode.tt.switch_pipe, 1, 1); + if(err) + panic("Can't create switch pipe for init_task, errno = %d", + -err); +} + +int start_uml_tt(void) +{ + void *sp; + int pages; + + pages = (1 << CONFIG_KERNEL_STACK_ORDER); + sp = (void *) ((unsigned long) init_task.thread_info) + + pages * PAGE_SIZE - sizeof(unsigned long); + return(tracer(start_kernel_proc, sp)); +} + +int external_pid_tt(struct task_struct *task) +{ + return(task->thread.mode.tt.extern_pid); +} + +int thread_pid_tt(struct task_struct *task) +{ + return(task->thread.mode.tt.extern_pid); +} + +int is_valid_pid(int pid) +{ + struct task_struct *task; + + read_lock(&tasklist_lock); + for_each_process(task){ + if(task->thread.mode.tt.extern_pid == pid){ + read_unlock(&tasklist_lock); + return(1); + } + } + read_unlock(&tasklist_lock); + return(0); +} + +/* + * Overrides for Emacs so that we follow Linus's tabbing style. + * Emacs will notice this stuff at the end of the file and automatically + * adjust the settings for this buffer only. This must remain at the end + * of the file. + * --------------------------------------------------------------------------- + * Local variables: + * c-file-style: "linux" + * End: + */ -- cgit v1.2.3-59-g8ed1b