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authorLinus Torvalds <torvalds@linux-foundation.org>2017-12-15 22:44:59 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2017-12-15 22:44:59 +0300
commit1f76a75561a006fc03559f665c835e0e69c9014d (patch)
tree013179ea7e602ee4a0666142d91e8ad45b505c10 /tools
parenta58653cc1e8b329fe786d103dcd3048115b65a55 (diff)
parent92ccc262e485781ff4c0fb3b7c77a619282df49a (diff)
downloadlinux-1f76a75561a006fc03559f665c835e0e69c9014d.tar.xz
Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking fixes from Ingo Molnar: "Misc fixes: - Fix a S390 boot hang that was caused by the lock-break logic. Remove lock-break to begin with, as review suggested it was unreasonably fragile and our confidence in its continued good health is lower than our confidence in its removal. - Remove the lockdep cross-release checking code for now, because of unresolved false positive warnings. This should make lockdep work well everywhere again. - Get rid of the final (and single) ACCESS_ONCE() straggler and remove the API from v4.15. - Fix a liblockdep build warning" * 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: tools/lib/lockdep: Add missing declaration of 'pr_cont()' checkpatch: Remove ACCESS_ONCE() warning compiler.h: Remove ACCESS_ONCE() tools/include: Remove ACCESS_ONCE() tools/perf: Convert ACCESS_ONCE() to READ_ONCE() locking/lockdep: Remove the cross-release locking checks locking/core: Remove break_lock field when CONFIG_GENERIC_LOCKBREAK=y locking/core: Fix deadlock during boot on systems with GENERIC_LOCKBREAK
Diffstat (limited to 'tools')
-rw-r--r--tools/include/linux/compiler.h21
-rw-r--r--tools/include/linux/lockdep.h1
-rw-r--r--tools/perf/util/mmap.h2
3 files changed, 11 insertions, 13 deletions
diff --git a/tools/include/linux/compiler.h b/tools/include/linux/compiler.h
index 07fd03c74a77..04e32f965ad7 100644
--- a/tools/include/linux/compiler.h
+++ b/tools/include/linux/compiler.h
@@ -84,8 +84,6 @@
#define uninitialized_var(x) x = *(&(x))
-#define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x))
-
#include <linux/types.h>
/*
@@ -135,20 +133,19 @@ static __always_inline void __write_once_size(volatile void *p, void *res, int s
/*
* Prevent the compiler from merging or refetching reads or writes. The
* compiler is also forbidden from reordering successive instances of
- * READ_ONCE, WRITE_ONCE and ACCESS_ONCE (see below), but only when the
- * compiler is aware of some particular ordering. One way to make the
- * compiler aware of ordering is to put the two invocations of READ_ONCE,
- * WRITE_ONCE or ACCESS_ONCE() in different C statements.
+ * READ_ONCE and WRITE_ONCE, but only when the compiler is aware of some
+ * particular ordering. One way to make the compiler aware of ordering is to
+ * put the two invocations of READ_ONCE or WRITE_ONCE in different C
+ * statements.
*
- * In contrast to ACCESS_ONCE these two macros will also work on aggregate
- * data types like structs or unions. If the size of the accessed data
- * type exceeds the word size of the machine (e.g., 32 bits or 64 bits)
- * READ_ONCE() and WRITE_ONCE() will fall back to memcpy and print a
- * compile-time warning.
+ * These two macros will also work on aggregate data types like structs or
+ * unions. If the size of the accessed data type exceeds the word size of
+ * the machine (e.g., 32 bits or 64 bits) READ_ONCE() and WRITE_ONCE() will
+ * fall back to memcpy and print a compile-time warning.
*
* Their two major use cases are: (1) Mediating communication between
* process-level code and irq/NMI handlers, all running on the same CPU,
- * and (2) Ensuring that the compiler does not fold, spindle, or otherwise
+ * and (2) Ensuring that the compiler does not fold, spindle, or otherwise
* mutilate accesses that either do not require ordering or that interact
* with an explicit memory barrier or atomic instruction that provides the
* required ordering.
diff --git a/tools/include/linux/lockdep.h b/tools/include/linux/lockdep.h
index 940c1b075659..6b0c36a58fcb 100644
--- a/tools/include/linux/lockdep.h
+++ b/tools/include/linux/lockdep.h
@@ -48,6 +48,7 @@ static inline int debug_locks_off(void)
#define printk(...) dprintf(STDOUT_FILENO, __VA_ARGS__)
#define pr_err(format, ...) fprintf (stderr, format, ## __VA_ARGS__)
#define pr_warn pr_err
+#define pr_cont pr_err
#define list_del_rcu list_del
diff --git a/tools/perf/util/mmap.h b/tools/perf/util/mmap.h
index efd78b827b05..3a5cb5a6e94a 100644
--- a/tools/perf/util/mmap.h
+++ b/tools/perf/util/mmap.h
@@ -70,7 +70,7 @@ void perf_mmap__read_catchup(struct perf_mmap *md);
static inline u64 perf_mmap__read_head(struct perf_mmap *mm)
{
struct perf_event_mmap_page *pc = mm->base;
- u64 head = ACCESS_ONCE(pc->data_head);
+ u64 head = READ_ONCE(pc->data_head);
rmb();
return head;
}