diff options
Diffstat (limited to 'arch/i386/kernel/process.c')
| -rw-r--r-- | arch/i386/kernel/process.c | 50 |
1 files changed, 29 insertions, 21 deletions
diff --git a/arch/i386/kernel/process.c b/arch/i386/kernel/process.c index 94e2c87edea..8657c739656 100644 --- 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); |