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x86/ioperm: Save an indentation level in tss_update_io_bitmap()

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... for better readability.

No functional changes.

[ Minor edit. ]

Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Borislav Petkov 2019-11-30 16:00:53 +01:00 committed by Ingo Molnar
parent 59c4bd853a
commit 7b0b8cfd26
1 changed files with 27 additions and 27 deletions
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54
arch/x86/kernel/process.c
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@ -377,37 +377,37 @@ static void tss_copy_io_bitmap(struct tss_struct *tss, struct io_bitmap *iobm)
void tss_update_io_bitmap(void)
{
struct tss_struct *tss = this_cpu_ptr(&cpu_tss_rw);
struct thread_struct *t = &current->thread;
u16 *base = &tss->x86_tss.io_bitmap_base;
if (test_thread_flag(TIF_IO_BITMAP)) {
struct thread_struct *t = &current->thread;
if (IS_ENABLED(CONFIG_X86_IOPL_IOPERM) && t->iopl_emul == 3) {
*base = IO_BITMAP_OFFSET_VALID_ALL;
} else {
struct io_bitmap *iobm = t->io_bitmap;
/*
* Only copy bitmap data when the sequence number
* differs. The update time is accounted to the
* incoming task.
*/
if (tss->io_bitmap.prev_sequence != iobm->sequence)
tss_copy_io_bitmap(tss, iobm);
/* Enable the bitmap */
*base = IO_BITMAP_OFFSET_VALID_MAP;
}
/*
* Make sure that the TSS limit is covering the io bitmap.
* It might have been cut down by a VMEXIT to 0x67 which
* would cause a subsequent I/O access from user space to
* trigger a #GP because tbe bitmap is outside the TSS
* limit.
*/
refresh_tss_limit();
} else {
if (!test_thread_flag(TIF_IO_BITMAP)) {
tss_invalidate_io_bitmap(tss);
return;
}
if (IS_ENABLED(CONFIG_X86_IOPL_IOPERM) && t->iopl_emul == 3) {
*base = IO_BITMAP_OFFSET_VALID_ALL;
} else {
struct io_bitmap *iobm = t->io_bitmap;
/*
* Only copy bitmap data when the sequence number differs. The
* update time is accounted to the incoming task.
*/
if (tss->io_bitmap.prev_sequence != iobm->sequence)
tss_copy_io_bitmap(tss, iobm);
/* Enable the bitmap */
*base = IO_BITMAP_OFFSET_VALID_MAP;
}
/*
* Make sure that the TSS limit is covering the IO bitmap. It might have
* been cut down by a VMEXIT to 0x67 which would cause a subsequent I/O
* access from user space to trigger a #GP because tbe bitmap is outside
* the TSS limit.
*/
refresh_tss_limit();
}
#else /* CONFIG_X86_IOPL_IOPERM */
static inline void switch_to_bitmap(unsigned long tifp) { }