diff options
Diffstat (limited to 'arch/x86/kernel/ioport.c')
-rw-r--r-- | arch/x86/kernel/ioport.c | 25 |
1 files changed, 4 insertions, 21 deletions
diff --git a/arch/x86/kernel/ioport.c b/arch/x86/kernel/ioport.c index 7c1ab5c2b395..198beadb3732 100644 --- a/arch/x86/kernel/ioport.c +++ b/arch/x86/kernel/ioport.c @@ -21,9 +21,8 @@ static atomic64_t io_bitmap_sequence; */ long ksys_ioperm(unsigned long from, unsigned long num, int turn_on) { - unsigned int i, max_long, bytes, bytes_updated; struct thread_struct *t = ¤t->thread; - struct tss_struct *tss; + unsigned int i, max_long; struct io_bitmap *iobm; if ((from + num <= from) || (from + num > IO_BITMAP_BITS)) @@ -50,10 +49,9 @@ long ksys_ioperm(unsigned long from, unsigned long num, int turn_on) } /* - * Update the bitmap and the TSS copy with preemption disabled to - * prevent a race against context switch. + * Update the tasks bitmap. The update of the TSS bitmap happens on + * exit to user mode. So this needs no protection. */ - preempt_disable(); if (turn_on) bitmap_clear(iobm->bitmap, from, num); else @@ -69,11 +67,8 @@ long ksys_ioperm(unsigned long from, unsigned long num, int turn_on) max_long = i; } - bytes = (max_long + 1) * sizeof(unsigned long); - bytes_updated = max(bytes, t->io_bitmap->max); + iobm->max = (max_long + 1) * sizeof(unsigned long); - /* Update the thread data */ - iobm->max = bytes; /* Update the sequence number to force an update in switch_to() */ iobm->sequence = atomic64_add_return(1, &io_bitmap_sequence); @@ -85,18 +80,6 @@ long ksys_ioperm(unsigned long from, unsigned long num, int turn_on) t->io_bitmap = iobm; set_thread_flag(TIF_IO_BITMAP); - /* Update the TSS */ - tss = this_cpu_ptr(&cpu_tss_rw); - memcpy(tss->io_bitmap.bitmap, iobm->bitmap, bytes_updated); - /* Store the new end of the zero bits */ - tss->io_bitmap.prev_max = bytes; - /* Make the bitmap base in the TSS valid */ - tss->x86_tss.io_bitmap_base = IO_BITMAP_OFFSET_VALID; - /* Make sure the TSS limit covers the I/O bitmap. */ - refresh_tss_limit(); - - preempt_enable(); - return 0; } |