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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/um/kernel/tt/process_kern.c
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!
Diffstat (limited to 'arch/um/kernel/tt/process_kern.c')
-rw-r--r--arch/um/kernel/tt/process_kern.c476
1 files changed, 476 insertions, 0 deletions
diff --git a/arch/um/kernel/tt/process_kern.c b/arch/um/kernel/tt/process_kern.c
new file mode 100644
index 00000000000..f19f7c18feb
--- /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(&current->thread.regs.regs) = (void *) (&sig + 1);
+ disable = (1 << (SIGVTALRM - 1)) | (1 << (SIGALRM - 1)) |
+ (1 << (SIGIO - 1)) | (1 << (SIGPROF - 1));
+ SC_SIGMASK(UPT_SC(&current->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, &current->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(&current->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(&current->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:
+ */