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jiffies.h: declare jiffies and jiffies_64 with ____cacheline_aligned_in_smp

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jiffies_64 is defined in kernel/time/timer.c with
____cacheline_aligned_in_smp, however this macro is not part of the
declaration of jiffies and jiffies_64 in jiffies.h.

As a result clang generates the following warning:

  kernel/time/timer.c:57:26: error: section does not match previous declaration [-Werror,-Wsection]
  __visible u64 jiffies_64 __cacheline_aligned_in_smp = INITIAL_JIFFIES;
                           ^
  include/linux/cache.h:39:36: note: expanded from macro '__cacheline_aligned_in_smp'
                                     ^
  include/linux/cache.h:34:4: note: expanded from macro '__cacheline_aligned'
                   __section__(".data..cacheline_aligned")))
                   ^
  include/linux/jiffies.h:77:12: note: previous attribute is here
  extern u64 __jiffy_data jiffies_64;
             ^
  include/linux/jiffies.h:70:38: note: expanded from macro '__jiffy_data'

Link: http://lkml.kernel.org/r/20170403190200.70273-1-mka@chromium.org
Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Cc: "Jason A . Donenfeld" <Jason@zx2c4.com>
Cc: Grant Grundler <grundler@chromium.org>
Cc: Michael Davidson <md@google.com>
Cc: Greg Hackmann <ghackmann@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Matthias Kaehlcke 2017-05-08 15:55:05 -07:00 committed by Linus Torvalds
parent 3d88936f35
commit 7c30f352c8
1 changed files with 3 additions and 8 deletions
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11
include/linux/jiffies.h
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@ -1,6 +1,7 @@
#ifndef _LINUX_JIFFIES_H #ifndef _LINUX_JIFFIES_H
#define _LINUX_JIFFIES_H #define _LINUX_JIFFIES_H
#include <linux/cache.h>
#include <linux/math64.h> #include <linux/math64.h>
#include <linux/kernel.h> #include <linux/kernel.h>
#include <linux/types.h> #include <linux/types.h>
@ -63,19 +64,13 @@ extern int register_refined_jiffies(long clock_tick_rate);
/* TICK_USEC is the time between ticks in usec assuming fake USER_HZ */ /* TICK_USEC is the time between ticks in usec assuming fake USER_HZ */
#define TICK_USEC ((1000000UL + USER_HZ/2) / USER_HZ) #define TICK_USEC ((1000000UL + USER_HZ/2) / USER_HZ)
/* some arch's have a small-data section that can be accessed register-relative
* but that can only take up to, say, 4-byte variables. jiffies being part of
* an 8-byte variable may not be correctly accessed unless we force the issue
*/
#define __jiffy_data __attribute__((section(".data")))
/* /*
* The 64-bit value is not atomic - you MUST NOT read it * The 64-bit value is not atomic - you MUST NOT read it
* without sampling the sequence number in jiffies_lock. * without sampling the sequence number in jiffies_lock.
* get_jiffies_64() will do this for you as appropriate. * get_jiffies_64() will do this for you as appropriate.
*/ */
extern u64 __jiffy_data jiffies_64; extern u64 __cacheline_aligned_in_smp jiffies_64;
extern unsigned long volatile __jiffy_data jiffies; extern unsigned long volatile __cacheline_aligned_in_smp jiffies;
#if (BITS_PER_LONG < 64) #if (BITS_PER_LONG < 64)
u64 get_jiffies_64(void); u64 get_jiffies_64(void);