Pull novell-bugzilla-156426 into release branch

[pandora-kernel.git] / 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
index a189a2b..a9c1443 100644 (file)
--- a/arch/um/kernel/tt/process_kern.c
+++ b/arch/um/kernel/tt/process_kern.c
@@ -13,20 +13,19 @@
 #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 "mode_kern.h"
 #include "init.h"
 #include "tt.h"
 
-void *switch_to_tt(void *prev, void *next, void *last)
+void switch_to_tt(void *prev, void *next)
 {
        struct task_struct *from, *to, *prev_sched;
        unsigned long flags;
@@ -36,9 +35,7 @@ void *switch_to_tt(void *prev, void *next, void *last)
        from = prev;
        to = next;
 
-       to->thread.prev_sched = from;
-
-       cpu = from->thread_info->cpu;
+       cpu = task_thread_info(from)->cpu;
        if(cpu == 0)
                forward_interrupts(to->thread.mode.tt.extern_pid);
 #ifdef CONFIG_SMP
@@ -53,7 +50,13 @@ void *switch_to_tt(void *prev, void *next, void *last)
        forward_pending_sigio(to->thread.mode.tt.extern_pid);
 
        c = 0;
-       set_current(to);
+
+       /* Notice that here we "up" the semaphore on which "to" is waiting, and
+        * below (the read) we wait on this semaphore (which is implemented by
+        * switch_pipe) and go sleeping. Thus, after that, we have resumed in
+        * "to", and can't use any more the value of "from" (which is outdated),
+        * nor the value in "to" (since it was the task which stole us the CPU,
+        * which we don't care about). */
 
        err = os_write_file(to->thread.mode.tt.switch_pipe[1], &c, sizeof(c));
        if(err != sizeof(c))
@@ -81,12 +84,10 @@ void *switch_to_tt(void *prev, void *next, void *last)
        change_sig(SIGALRM, alrm);
        change_sig(SIGPROF, prof);
 
-       arch_switch();
+       arch_switch_to_tt(prev_sched, current);
 
        flush_tlb_all();
        local_irq_restore(flags);
-
-       return(current->thread.prev_sched);
 }
 
 void release_thread_tt(struct task_struct *task)
@@ -147,7 +148,6 @@ static void new_thread_handler(int sig)
        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))
@@ -258,7 +258,7 @@ int copy_thread_tt(int nr, unsigned long clone_flags, unsigned long sp,
 
        clone_flags &= CLONE_VM;
        p->thread.temp_stack = stack;
-       new_pid = start_fork_tramp(p->thread_info, stack, clone_flags, tramp);
+       new_pid = start_fork_tramp(task_stack_page(p), stack, clone_flags, tramp);
        if(new_pid < 0){
                printk(KERN_ERR "copy_thread : clone failed - errno = %d\n", 
                       -new_pid);
@@ -348,7 +348,7 @@ int do_proc_op(void *t, int proc_id)
                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;
+               cpu_tasks[task_thread_info(task)->cpu].pid = pid;
                break;
        case OP_FORK:
                attach_process(thread->request.u.fork.pid);
@@ -430,7 +430,7 @@ int start_uml_tt(void)
        int pages;
 
        pages = (1 << CONFIG_KERNEL_STACK_ORDER);
-       sp = (void *) ((unsigned long) init_task.thread_info) +
+       sp = task_stack_page(&init_task) +
                pages * PAGE_SIZE - sizeof(unsigned long);
        return(tracer(start_kernel_proc, sp));
 }