[PATCH] s390: fix cmm kernel thread handling

[sfrench/cifs-2.6.git] / arch / i386 / kernel / process.c

diff --git a/arch/i386/kernel/process.c b/arch/i386/kernel/process.c
index 94e2c87edeaa31c76475e48f92e3212ac62119e2..8657c739656a37bbcef81cb36accb486902cf5d1 100644 (file)
--- a/arch/i386/kernel/process.c
+++ b/arch/i386/kernel/process.c
@@ -359,16 +359,16 @@ EXPORT_SYMBOL(kernel_thread);
  */
 void exit_thread(void)
 {
-       struct task_struct *tsk = current;
-       struct thread_struct *t = &tsk->thread;
-
        /* The process may have allocated an io port bitmap... nuke it. */
-       if (unlikely(NULL != t->io_bitmap_ptr)) {
+       if (unlikely(test_thread_flag(TIF_IO_BITMAP))) {
+               struct task_struct *tsk = current;
+               struct thread_struct *t = &tsk->thread;
                int cpu = get_cpu();
                struct tss_struct *tss = &per_cpu(init_tss, cpu);
 
                kfree(t->io_bitmap_ptr);
                t->io_bitmap_ptr = NULL;
+               clear_thread_flag(TIF_IO_BITMAP);
                /*
                 * Careful, clear this in the TSS too:
                 */
@@ -387,6 +387,7 @@ void flush_thread(void)
 
        memset(tsk->thread.debugreg, 0, sizeof(unsigned long)*8);
        memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array));        
+       clear_tsk_thread_flag(tsk, TIF_DEBUG);
        /*
         * Forget coprocessor state..
         */
@@ -431,7 +432,7 @@ int copy_thread(int nr, unsigned long clone_flags, unsigned long esp,
        savesegment(gs,p->thread.gs);
 
        tsk = current;
-       if (unlikely(NULL != tsk->thread.io_bitmap_ptr)) {
+       if (unlikely(test_tsk_thread_flag(tsk, TIF_IO_BITMAP))) {
                p->thread.io_bitmap_ptr = kmalloc(IO_BITMAP_BYTES, GFP_KERNEL);
                if (!p->thread.io_bitmap_ptr) {
                        p->thread.io_bitmap_max = 0;
@@ -439,6 +440,7 @@ int copy_thread(int nr, unsigned long clone_flags, unsigned long esp,
                }
                memcpy(p->thread.io_bitmap_ptr, tsk->thread.io_bitmap_ptr,
                        IO_BITMAP_BYTES);
+               set_tsk_thread_flag(p, TIF_IO_BITMAP);
        }
 
        /*
@@ -533,10 +535,24 @@ int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs)
        return 1;
 }
 
-static inline void
-handle_io_bitmap(struct thread_struct *next, struct tss_struct *tss)
+static noinline void __switch_to_xtra(struct task_struct *next_p,
+                                   struct tss_struct *tss)
 {
-       if (!next->io_bitmap_ptr) {
+       struct thread_struct *next;
+
+       next = &next_p->thread;
+
+       if (test_tsk_thread_flag(next_p, TIF_DEBUG)) {
+               set_debugreg(next->debugreg[0], 0);
+               set_debugreg(next->debugreg[1], 1);
+               set_debugreg(next->debugreg[2], 2);
+               set_debugreg(next->debugreg[3], 3);
+               /* no 4 and 5 */
+               set_debugreg(next->debugreg[6], 6);
+               set_debugreg(next->debugreg[7], 7);
+       }
+
+       if (!test_tsk_thread_flag(next_p, TIF_IO_BITMAP)) {
                /*
                 * Disable the bitmap via an invalid offset. We still cache
                 * the previous bitmap owner and the IO bitmap contents:
@@ -544,6 +560,7 @@ handle_io_bitmap(struct thread_struct *next, struct tss_struct *tss)
                tss->io_bitmap_base = INVALID_IO_BITMAP_OFFSET;
                return;
        }
+
        if (likely(next == tss->io_bitmap_owner)) {
                /*
                 * Previous owner of the bitmap (hence the bitmap content)
@@ -671,20 +688,11 @@ struct task_struct fastcall * __switch_to(struct task_struct *prev_p, struct tas
                set_iopl_mask(next->iopl);
 
        /*
-        * Now maybe reload the debug registers
+        * Now maybe handle debug registers and/or IO bitmaps
         */
-       if (unlikely(next->debugreg[7])) {
-               set_debugreg(next->debugreg[0], 0);
-               set_debugreg(next->debugreg[1], 1);
-               set_debugreg(next->debugreg[2], 2);
-               set_debugreg(next->debugreg[3], 3);
-               /* no 4 and 5 */
-               set_debugreg(next->debugreg[6], 6);
-               set_debugreg(next->debugreg[7], 7);
-       }
-
-       if (unlikely(prev->io_bitmap_ptr || next->io_bitmap_ptr))
-               handle_io_bitmap(next, tss);
+       if (unlikely((task_thread_info(next_p)->flags & _TIF_WORK_CTXSW)
+           || test_tsk_thread_flag(prev_p, TIF_IO_BITMAP)))
+               __switch_to_xtra(next_p, tss);
 
        disable_tsc(prev_p, next_p);