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Commit bcc4a62a authored by Andy Lutomirski's avatar Andy Lutomirski Committed by Ingo Molnar
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x86/vdso: Document vgtod_ts better 



After reading do_hres() and do_course() and scratching my head a
bit, I figured out why the arithmetic is strange.  Document it.

Signed-off-by: default avatarAndy Lutomirski <luto@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/f66f53d81150bbad47d7b282c9207a71a3ce1c16.1538689401.git.luto@kernel.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 89fe0a1f

arch/x86/include/asm/vgtod.h

+9 −0
Original line number Original line Diff line number Diff line
@@ -13,6 +13,15 @@ typedef u64 gtod_long_t; 
typedef unsigned long gtod_long_t;

typedef unsigned long gtod_long_t;

#endif

#endif





/*

 * There is one of these objects in the vvar page for each

 * vDSO-accelerated clockid.  For high-resolution clocks, this encodes

 * the time corresponding to vsyscall_gtod_data.cycle_last.  For coarse

 * clocks, this encodes the actual time.

 *

 * To confuse the reader, for high-resolution clocks, nsec is left-shifted

 * by vsyscall_gtod_data.shift.

 */

struct vgtod_ts {

struct vgtod_ts {

	u64		sec;

	u64		sec;

	u64		nsec;

	u64		nsec;