From 54dff232142e255ff644d73de1c8d80122f5ad7b Mon Sep 17 00:00:00 2001
From: Mark Rutland <mark.rutland@arm.com>
Date: Tue, 4 Jan 2022 09:50:18 +0000
Subject: [PATCH 01/14] MAINTAINERS: add myself as reviewer for atomics
As I've fiddled about with the atomic infrastructure a fair bit now,
Peter suggested I should add myself as a reviewer or maintainer to make
sure I'm Cc'd on anything I might have an opinion on.
For now, add myself as a reviewer.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Boqun Feng <boqun.feng@gmail.com>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20220104095018.1990058-1-mark.rutland@arm.com
---
MAINTAINERS | 1 +
1 file changed, 1 insertion(+)
diff --git a/MAINTAINERS b/MAINTAINERS
index ea3e6c914384..bccca3e5e2cd 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3193,6 +3193,7 @@ ATOMIC INFRASTRUCTURE
M: Will Deacon <will@kernel.org>
M: Peter Zijlstra <peterz@infradead.org>
R: Boqun Feng <boqun.feng@gmail.com>
+R: Mark Rutland <mark.rutland@arm.com>
L: linux-kernel@vger.kernel.org
S: Maintained
F: arch/*/include/asm/atomic*.h
From e204193b138af347fbbbe026e68cb3385112f387 Mon Sep 17 00:00:00 2001
From: Xiu Jianfeng <xiujianfeng@huawei.com>
Date: Mon, 13 Dec 2021 21:26:18 +0800
Subject: [PATCH 02/14] lockdep: Use memset_startat() helper in reinit_class()
use memset_startat() helper to simplify the code, there is no functional
change in this patch.
Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20211213132618.105737-1-xiujianfeng@huawei.com
---
kernel/locking/lockdep.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 4a882f83aeb9..89b3df51fd98 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -6011,13 +6011,10 @@ static void zap_class(struct pending_free *pf, struct lock_class *class)
static void reinit_class(struct lock_class *class)
{
- void *const p = class;
- const unsigned int offset = offsetof(struct lock_class, key);
-
WARN_ON_ONCE(!class->lock_entry.next);
WARN_ON_ONCE(!list_empty(&class->locks_after));
WARN_ON_ONCE(!list_empty(&class->locks_before));
- memset(p + offset, 0, sizeof(*class) - offset);
+ memset_startat(class, 0, key);
WARN_ON_ONCE(!class->lock_entry.next);
WARN_ON_ONCE(!list_empty(&class->locks_after));
WARN_ON_ONCE(!list_empty(&class->locks_before));
From 61cc4534b6550997c97a03759ab46b29d44c0017 Mon Sep 17 00:00:00 2001
From: Waiman Long <longman@redhat.com>
Date: Sun, 2 Jan 2022 21:35:58 -0500
Subject: [PATCH 03/14] locking/lockdep: Avoid potential access of invalid
memory in lock_class
It was found that reading /proc/lockdep after a lockdep splat may
potentially cause an access to freed memory if lockdep_unregister_key()
is called after the splat but before access to /proc/lockdep [1]. This
is due to the fact that graph_lock() call in lockdep_unregister_key()
fails after the clearing of debug_locks by the splat process.
After lockdep_unregister_key() is called, the lock_name may be freed
but the corresponding lock_class structure still have a reference to
it. That invalid memory pointer will then be accessed when /proc/lockdep
is read by a user and a use-after-free (UAF) error will be reported if
KASAN is enabled.
To fix this problem, lockdep_unregister_key() is now modified to always
search for a matching key irrespective of the debug_locks state and
zap the corresponding lock class if a matching one is found.
[1] https://lore.kernel.org/lkml/77f05c15-81b6-bddd-9650-80d5f23fe330@i-love.sakura.ne.jp/
Fixes: 8b39adbee805 ("locking/lockdep: Make lockdep_unregister_key() honor 'debug_locks' again")
Reported-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lkml.kernel.org/r/20220103023558.1377055-1-longman@redhat.com
---
kernel/locking/lockdep.c | 24 +++++++++++++++---------
1 file changed, 15 insertions(+), 9 deletions(-)
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 89b3df51fd98..2e6892ec3756 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -6287,7 +6287,13 @@ void lockdep_reset_lock(struct lockdep_map *lock)
lockdep_reset_lock_reg(lock);
}
-/* Unregister a dynamically allocated key. */
+/*
+ * Unregister a dynamically allocated key.
+ *
+ * Unlike lockdep_register_key(), a search is always done to find a matching
+ * key irrespective of debug_locks to avoid potential invalid access to freed
+ * memory in lock_class entry.
+ */
void lockdep_unregister_key(struct lock_class_key *key)
{
struct hlist_head *hash_head = keyhashentry(key);
@@ -6302,10 +6308,8 @@ void lockdep_unregister_key(struct lock_class_key *key)
return;
raw_local_irq_save(flags);
- if (!graph_lock())
- goto out_irq;
+ lockdep_lock();
- pf = get_pending_free();
hlist_for_each_entry_rcu(k, hash_head, hash_entry) {
if (k == key) {
hlist_del_rcu(&k->hash_entry);
@@ -6313,11 +6317,13 @@ void lockdep_unregister_key(struct lock_class_key *key)
break;
}
}
- WARN_ON_ONCE(!found);
- __lockdep_free_key_range(pf, key, 1);
- call_rcu_zapped(pf);
- graph_unlock();
-out_irq:
+ WARN_ON_ONCE(!found && debug_locks);
+ if (found) {
+ pf = get_pending_free();
+ __lockdep_free_key_range(pf, key, 1);
+ call_rcu_zapped(pf);
+ }
+ lockdep_unlock();
raw_local_irq_restore(flags);
/* Wait until is_dynamic_key() has finished accessing k->hash_entry. */
From acb13ea0baf8db8d05a3910c06e997c90825faad Mon Sep 17 00:00:00 2001
From: Borislav Petkov <bp@suse.de>
Date: Thu, 13 Jan 2022 16:53:56 +0100
Subject: [PATCH 04/14] asm-generic/bitops: Always inline all bit manipulation
helpers
Make it consistent with the atomic/atomic-instrumented.h helpers.
And defconfig size is actually going down!
text data bss dec hex filename
22352096 8213152 1917164 32482412 1efa46c vmlinux.x86-64.defconfig.before
22350551 8213184 1917164 32480899 1ef9e83 vmlinux.x86-64.defconfig.after
Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Marco Elver <elver@google.com>
Link: https://lore.kernel.org/r/20220113155357.4706-2-bp@alien8.de
---
include/asm-generic/bitops/instrumented-atomic.h | 12 ++++++------
.../asm-generic/bitops/instrumented-non-atomic.h | 16 ++++++++--------
2 files changed, 14 insertions(+), 14 deletions(-)
diff --git a/include/asm-generic/bitops/instrumented-atomic.h b/include/asm-generic/bitops/instrumented-atomic.h
index c90192b1c755..4225a8ca9c1a 100644
--- a/include/asm-generic/bitops/instrumented-atomic.h
+++ b/include/asm-generic/bitops/instrumented-atomic.h
@@ -23,7 +23,7 @@
* Note that @nr may be almost arbitrarily large; this function is not
* restricted to acting on a single-word quantity.
*/
-static inline void set_bit(long nr, volatile unsigned long *addr)
+static __always_inline void set_bit(long nr, volatile unsigned long *addr)
{
instrument_atomic_write(addr + BIT_WORD(nr), sizeof(long));
arch_set_bit(nr, addr);
@@ -36,7 +36,7 @@ static inline void set_bit(long nr, volatile unsigned long *addr)
*
* This is a relaxed atomic operation (no implied memory barriers).
*/
-static inline void clear_bit(long nr, volatile unsigned long *addr)
+static __always_inline void clear_bit(long nr, volatile unsigned long *addr)
{
instrument_atomic_write(addr + BIT_WORD(nr), sizeof(long));
arch_clear_bit(nr, addr);
@@ -52,7 +52,7 @@ static inline void clear_bit(long nr, volatile unsigned long *addr)
* Note that @nr may be almost arbitrarily large; this function is not
* restricted to acting on a single-word quantity.
*/
-static inline void change_bit(long nr, volatile unsigned long *addr)
+static __always_inline void change_bit(long nr, volatile unsigned long *addr)
{
instrument_atomic_write(addr + BIT_WORD(nr), sizeof(long));
arch_change_bit(nr, addr);
@@ -65,7 +65,7 @@ static inline void change_bit(long nr, volatile unsigned long *addr)
*
* This is an atomic fully-ordered operation (implied full memory barrier).
*/
-static inline bool test_and_set_bit(long nr, volatile unsigned long *addr)
+static __always_inline bool test_and_set_bit(long nr, volatile unsigned long *addr)
{
kcsan_mb();
instrument_atomic_read_write(addr + BIT_WORD(nr), sizeof(long));
@@ -79,7 +79,7 @@ static inline bool test_and_set_bit(long nr, volatile unsigned long *addr)
*
* This is an atomic fully-ordered operation (implied full memory barrier).
*/
-static inline bool test_and_clear_bit(long nr, volatile unsigned long *addr)
+static __always_inline bool test_and_clear_bit(long nr, volatile unsigned long *addr)
{
kcsan_mb();
instrument_atomic_read_write(addr + BIT_WORD(nr), sizeof(long));
@@ -93,7 +93,7 @@ static inline bool test_and_clear_bit(long nr, volatile unsigned long *addr)
*
* This is an atomic fully-ordered operation (implied full memory barrier).
*/
-static inline bool test_and_change_bit(long nr, volatile unsigned long *addr)
+static __always_inline bool test_and_change_bit(long nr, volatile unsigned long *addr)
{
kcsan_mb();
instrument_atomic_read_write(addr + BIT_WORD(nr), sizeof(long));
diff --git a/include/asm-generic/bitops/instrumented-non-atomic.h b/include/asm-generic/bitops/instrumented-non-atomic.h
index 37363d570b9b..7ab1ecc37782 100644
--- a/include/asm-generic/bitops/instrumented-non-atomic.h
+++ b/include/asm-generic/bitops/instrumented-non-atomic.h
@@ -22,7 +22,7 @@
* region of memory concurrently, the effect may be that only one operation
* succeeds.
*/
-static inline void __set_bit(long nr, volatile unsigned long *addr)
+static __always_inline void __set_bit(long nr, volatile unsigned long *addr)
{
instrument_write(addr + BIT_WORD(nr), sizeof(long));
arch___set_bit(nr, addr);
@@ -37,7 +37,7 @@ static inline void __set_bit(long nr, volatile unsigned long *addr)
* region of memory concurrently, the effect may be that only one operation
* succeeds.
*/
-static inline void __clear_bit(long nr, volatile unsigned long *addr)
+static __always_inline void __clear_bit(long nr, volatile unsigned long *addr)
{
instrument_write(addr + BIT_WORD(nr), sizeof(long));
arch___clear_bit(nr, addr);
@@ -52,13 +52,13 @@ static inline void __clear_bit(long nr, volatile unsigned long *addr)
* region of memory concurrently, the effect may be that only one operation
* succeeds.
*/
-static inline void __change_bit(long nr, volatile unsigned long *addr)
+static __always_inline void __change_bit(long nr, volatile unsigned long *addr)
{
instrument_write(addr + BIT_WORD(nr), sizeof(long));
arch___change_bit(nr, addr);
}
-static inline void __instrument_read_write_bitop(long nr, volatile unsigned long *addr)
+static __always_inline void __instrument_read_write_bitop(long nr, volatile unsigned long *addr)
{
if (IS_ENABLED(CONFIG_KCSAN_ASSUME_PLAIN_WRITES_ATOMIC)) {
/*
@@ -90,7 +90,7 @@ static inline void __instrument_read_write_bitop(long nr, volatile unsigned long
* This operation is non-atomic. If two instances of this operation race, one
* can appear to succeed but actually fail.
*/
-static inline bool __test_and_set_bit(long nr, volatile unsigned long *addr)
+static __always_inline bool __test_and_set_bit(long nr, volatile unsigned long *addr)
{
__instrument_read_write_bitop(nr, addr);
return arch___test_and_set_bit(nr, addr);
@@ -104,7 +104,7 @@ static inline bool __test_and_set_bit(long nr, volatile unsigned long *addr)
* This operation is non-atomic. If two instances of this operation race, one
* can appear to succeed but actually fail.
*/
-static inline bool __test_and_clear_bit(long nr, volatile unsigned long *addr)
+static __always_inline bool __test_and_clear_bit(long nr, volatile unsigned long *addr)
{
__instrument_read_write_bitop(nr, addr);
return arch___test_and_clear_bit(nr, addr);
@@ -118,7 +118,7 @@ static inline bool __test_and_clear_bit(long nr, volatile unsigned long *addr)
* This operation is non-atomic. If two instances of this operation race, one
* can appear to succeed but actually fail.
*/
-static inline bool __test_and_change_bit(long nr, volatile unsigned long *addr)
+static __always_inline bool __test_and_change_bit(long nr, volatile unsigned long *addr)
{
__instrument_read_write_bitop(nr, addr);
return arch___test_and_change_bit(nr, addr);
@@ -129,7 +129,7 @@ static inline bool __test_and_change_bit(long nr, volatile unsigned long *addr)
* @nr: bit number to test
* @addr: Address to start counting from
*/
-static inline bool test_bit(long nr, const volatile unsigned long *addr)
+static __always_inline bool test_bit(long nr, const volatile unsigned long *addr)
{
instrument_atomic_read(addr + BIT_WORD(nr), sizeof(long));
return arch_test_bit(nr, addr);
From 1dc01abad6544cb9d884071b626b706e37aa9601 Mon Sep 17 00:00:00 2001
From: Borislav Petkov <bp@suse.de>
Date: Thu, 13 Jan 2022 16:53:57 +0100
Subject: [PATCH 05/14] cpumask: Always inline helpers which use bit
manipulation functions
Former are always inlined so do that for the latter too, for
consistency.
Size impact is a whopping 5 bytes increase! :-)
text data bss dec hex filename
22350551 8213184 1917164 32480899 1ef9e83 vmlinux.x86-64.defconfig.before
22350556 8213152 1917164 32480872 1ef9e68 vmlinux.x86-64.defconfig.after
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Marco Elver <elver@google.com>
Link: https://lore.kernel.org/r/20220113155357.4706-3-bp@alien8.de
---
include/linux/cpumask.h | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
index 64dae70d31f5..6b06c698cd2a 100644
--- a/include/linux/cpumask.h
+++ b/include/linux/cpumask.h
@@ -341,12 +341,12 @@ extern int cpumask_next_wrap(int n, const struct cpumask *mask, int start, bool
* @cpu: cpu number (< nr_cpu_ids)
* @dstp: the cpumask pointer
*/
-static inline void cpumask_set_cpu(unsigned int cpu, struct cpumask *dstp)
+static __always_inline void cpumask_set_cpu(unsigned int cpu, struct cpumask *dstp)
{
set_bit(cpumask_check(cpu), cpumask_bits(dstp));
}
-static inline void __cpumask_set_cpu(unsigned int cpu, struct cpumask *dstp)
+static __always_inline void __cpumask_set_cpu(unsigned int cpu, struct cpumask *dstp)
{
__set_bit(cpumask_check(cpu), cpumask_bits(dstp));
}
@@ -357,12 +357,12 @@ static inline void __cpumask_set_cpu(unsigned int cpu, struct cpumask *dstp)
* @cpu: cpu number (< nr_cpu_ids)
* @dstp: the cpumask pointer
*/
-static inline void cpumask_clear_cpu(int cpu, struct cpumask *dstp)
+static __always_inline void cpumask_clear_cpu(int cpu, struct cpumask *dstp)
{
clear_bit(cpumask_check(cpu), cpumask_bits(dstp));
}
-static inline void __cpumask_clear_cpu(int cpu, struct cpumask *dstp)
+static __always_inline void __cpumask_clear_cpu(int cpu, struct cpumask *dstp)
{
__clear_bit(cpumask_check(cpu), cpumask_bits(dstp));
}
@@ -374,7 +374,7 @@ static inline void __cpumask_clear_cpu(int cpu, struct cpumask *dstp)
*
* Returns 1 if @cpu is set in @cpumask, else returns 0
*/
-static inline int cpumask_test_cpu(int cpu, const struct cpumask *cpumask)
+static __always_inline int cpumask_test_cpu(int cpu, const struct cpumask *cpumask)
{
return test_bit(cpumask_check(cpu), cpumask_bits((cpumask)));
}
@@ -388,7 +388,7 @@ static inline int cpumask_test_cpu(int cpu, const struct cpumask *cpumask)
*
* test_and_set_bit wrapper for cpumasks.
*/
-static inline int cpumask_test_and_set_cpu(int cpu, struct cpumask *cpumask)
+static __always_inline int cpumask_test_and_set_cpu(int cpu, struct cpumask *cpumask)
{
return test_and_set_bit(cpumask_check(cpu), cpumask_bits(cpumask));
}
@@ -402,7 +402,7 @@ static inline int cpumask_test_and_set_cpu(int cpu, struct cpumask *cpumask)
*
* test_and_clear_bit wrapper for cpumasks.
*/
-static inline int cpumask_test_and_clear_cpu(int cpu, struct cpumask *cpumask)
+static __always_inline int cpumask_test_and_clear_cpu(int cpu, struct cpumask *cpumask)
{
return test_and_clear_bit(cpumask_check(cpu), cpumask_bits(cpumask));
}
From c441e934b604a3b5f350a9104124cf6a3ba07a34 Mon Sep 17 00:00:00 2001
From: Minchan Kim <minchan@kernel.org>
Date: Sat, 15 Jan 2022 15:16:57 -0800
Subject: [PATCH 06/14] locking: Add missing __sched attributes
This patch adds __sched attributes to a few missing places
to show blocked function rather than locking function
in get_wchan.
Signed-off-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220115231657.84828-1-minchan@kernel.org
---
kernel/locking/percpu-rwsem.c | 5 +++--
kernel/locking/rwsem.c | 2 +-
2 files changed, 4 insertions(+), 3 deletions(-)
diff --git a/kernel/locking/percpu-rwsem.c b/kernel/locking/percpu-rwsem.c
index 70a32a576f3f..c9fdae94e098 100644
--- a/kernel/locking/percpu-rwsem.c
+++ b/kernel/locking/percpu-rwsem.c
@@ -7,6 +7,7 @@
#include <linux/rcupdate.h>
#include <linux/sched.h>
#include <linux/sched/task.h>
+#include <linux/sched/debug.h>
#include <linux/errno.h>
int __percpu_init_rwsem(struct percpu_rw_semaphore *sem,
@@ -162,7 +163,7 @@ static void percpu_rwsem_wait(struct percpu_rw_semaphore *sem, bool reader)
__set_current_state(TASK_RUNNING);
}
-bool __percpu_down_read(struct percpu_rw_semaphore *sem, bool try)
+bool __sched __percpu_down_read(struct percpu_rw_semaphore *sem, bool try)
{
if (__percpu_down_read_trylock(sem))
return true;
@@ -211,7 +212,7 @@ static bool readers_active_check(struct percpu_rw_semaphore *sem)
return true;
}
-void percpu_down_write(struct percpu_rw_semaphore *sem)
+void __sched percpu_down_write(struct percpu_rw_semaphore *sem)
{
might_sleep();
rwsem_acquire(&sem->dep_map, 0, 0, _RET_IP_);
diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c
index 69aba4abe104..acde5d6f1254 100644
--- a/kernel/locking/rwsem.c
+++ b/kernel/locking/rwsem.c
@@ -1048,7 +1048,7 @@ out_nolock:
/*
* Wait until we successfully acquire the write lock
*/
-static struct rw_semaphore *
+static struct rw_semaphore __sched *
rwsem_down_write_slowpath(struct rw_semaphore *sem, int state)
{
long count;
From dc1b4df09acdca7a89806b28f235cd6d8dcd3d24 Mon Sep 17 00:00:00 2001
From: Mark Rutland <mark.rutland@arm.com>
Date: Mon, 7 Feb 2022 10:19:43 +0000
Subject: [PATCH 07/14] atomics: Fix atomic64_{read_acquire,set_release}
fallbacks
Arnd reports that on 32-bit architectures, the fallbacks for
atomic64_read_acquire() and atomic64_set_release() are broken as they
use smp_load_acquire() and smp_store_release() respectively, which do
not work on types larger than the native word size.
Since those contain compiletime_assert_atomic_type(), any attempt to use
those fallbacks will result in a build-time error. e.g. with the
following added to arch/arm/kernel/setup.c:
| void test_atomic64(atomic64_t *v)
| {
| atomic64_set_release(v, 5);
| atomic64_read_acquire(v);
| }
The compiler will complain as follows:
| In file included from <command-line>:
| In function 'arch_atomic64_set_release',
| inlined from 'test_atomic64' at ./include/linux/atomic/atomic-instrumented.h:669:2:
| ././include/linux/compiler_types.h:346:38: error: call to '__compiletime_assert_9' declared with attribute error: Need native word sized stores/loads for atomicity.
| 346 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
| | ^
| ././include/linux/compiler_types.h:327:4: note: in definition of macro '__compiletime_assert'
| 327 | prefix ## suffix(); \
| | ^~~~~~
| ././include/linux/compiler_types.h:346:2: note: in expansion of macro '_compiletime_assert'
| 346 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
| | ^~~~~~~~~~~~~~~~~~~
| ././include/linux/compiler_types.h:349:2: note: in expansion of macro 'compiletime_assert'
| 349 | compiletime_assert(__native_word(t), \
| | ^~~~~~~~~~~~~~~~~~
| ./include/asm-generic/barrier.h:133:2: note: in expansion of macro 'compiletime_assert_atomic_type'
| 133 | compiletime_assert_atomic_type(*p); \
| | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| ./include/asm-generic/barrier.h:164:55: note: in expansion of macro '__smp_store_release'
| 164 | #define smp_store_release(p, v) do { kcsan_release(); __smp_store_release(p, v); } while (0)
| | ^~~~~~~~~~~~~~~~~~~
| ./include/linux/atomic/atomic-arch-fallback.h:1270:2: note: in expansion of macro 'smp_store_release'
| 1270 | smp_store_release(&(v)->counter, i);
| | ^~~~~~~~~~~~~~~~~
| make[2]: *** [scripts/Makefile.build:288: arch/arm/kernel/setup.o] Error 1
| make[1]: *** [scripts/Makefile.build:550: arch/arm/kernel] Error 2
| make: *** [Makefile:1831: arch/arm] Error 2
Fix this by only using smp_load_acquire() and smp_store_release() for
native atomic types, and otherwise falling back to the regular barriers
necessary for acquire/release semantics, as we do in the more generic
acquire and release fallbacks.
Since the fallback templates are used to generate the atomic64_*() and
atomic_*() operations, the __native_word() check is added to both. For
the atomic_*() operations, which are always 32-bit, the __native_word()
check is redundant but not harmful, as it is always true.
For the example above this works as expected on 32-bit, e.g. for arm
multi_v7_defconfig:
| <test_atomic64>:
| push {r4, r5}
| dmb ish
| pldw [r0]
| mov r2, #5
| mov r3, #0
| ldrexd r4, [r0]
| strexd r4, r2, [r0]
| teq r4, #0
| bne 484 <test_atomic64+0x14>
| ldrexd r2, [r0]
| dmb ish
| pop {r4, r5}
| bx lr
... and also on 64-bit, e.g. for arm64 defconfig:
| <test_atomic64>:
| bti c
| paciasp
| mov x1, #0x5
| stlr x1, [x0]
| ldar x0, [x0]
| autiasp
| ret
Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20220207101943.439825-1-mark.rutland@arm.com
---
include/linux/atomic/atomic-arch-fallback.h | 38 ++++++++++++++++++---
scripts/atomic/fallbacks/read_acquire | 11 +++++-
scripts/atomic/fallbacks/set_release | 7 +++-
3 files changed, 49 insertions(+), 7 deletions(-)
diff --git a/include/linux/atomic/atomic-arch-fallback.h b/include/linux/atomic/atomic-arch-fallback.h
index a3dba31df01e..6db58d180866 100644
--- a/include/linux/atomic/atomic-arch-fallback.h
+++ b/include/linux/atomic/atomic-arch-fallback.h
@@ -151,7 +151,16 @@
static __always_inline int
arch_atomic_read_acquire(const atomic_t *v)
{
- return smp_load_acquire(&(v)->counter);
+ int ret;
+
+ if (__native_word(atomic_t)) {
+ ret = smp_load_acquire(&(v)->counter);
+ } else {
+ ret = arch_atomic_read(v);
+ __atomic_acquire_fence();
+ }
+
+ return ret;
}
#define arch_atomic_read_acquire arch_atomic_read_acquire
#endif
@@ -160,7 +169,12 @@ arch_atomic_read_acquire(const atomic_t *v)
static __always_inline void
arch_atomic_set_release(atomic_t *v, int i)
{
- smp_store_release(&(v)->counter, i);
+ if (__native_word(atomic_t)) {
+ smp_store_release(&(v)->counter, i);
+ } else {
+ __atomic_release_fence();
+ arch_atomic_set(v, i);
+ }
}
#define arch_atomic_set_release arch_atomic_set_release
#endif
@@ -1258,7 +1272,16 @@ arch_atomic_dec_if_positive(atomic_t *v)
static __always_inline s64
arch_atomic64_read_acquire(const atomic64_t *v)
{
- return smp_load_acquire(&(v)->counter);
+ s64 ret;
+
+ if (__native_word(atomic64_t)) {
+ ret = smp_load_acquire(&(v)->counter);
+ } else {
+ ret = arch_atomic64_read(v);
+ __atomic_acquire_fence();
+ }
+
+ return ret;
}
#define arch_atomic64_read_acquire arch_atomic64_read_acquire
#endif
@@ -1267,7 +1290,12 @@ arch_atomic64_read_acquire(const atomic64_t *v)
static __always_inline void
arch_atomic64_set_release(atomic64_t *v, s64 i)
{
- smp_store_release(&(v)->counter, i);
+ if (__native_word(atomic64_t)) {
+ smp_store_release(&(v)->counter, i);
+ } else {
+ __atomic_release_fence();
+ arch_atomic64_set(v, i);
+ }
}
#define arch_atomic64_set_release arch_atomic64_set_release
#endif
@@ -2358,4 +2386,4 @@ arch_atomic64_dec_if_positive(atomic64_t *v)
#endif
#endif /* _LINUX_ATOMIC_FALLBACK_H */
-// cca554917d7ea73d5e3e7397dd70c484cad9b2c4
+// 8e2cc06bc0d2c0967d2f8424762bd48555ee40ae
diff --git a/scripts/atomic/fallbacks/read_acquire b/scripts/atomic/fallbacks/read_acquire
index 803ba7561076..a0ea1d26e6b2 100755
--- a/scripts/atomic/fallbacks/read_acquire
+++ b/scripts/atomic/fallbacks/read_acquire
@@ -2,6 +2,15 @@ cat <<EOF
static __always_inline ${ret}
arch_${atomic}_read_acquire(const ${atomic}_t *v)
{
- return smp_load_acquire(&(v)->counter);
+ ${int} ret;
+
+ if (__native_word(${atomic}_t)) {
+ ret = smp_load_acquire(&(v)->counter);
+ } else {
+ ret = arch_${atomic}_read(v);
+ __atomic_acquire_fence();
+ }
+
+ return ret;
}
EOF
diff --git a/scripts/atomic/fallbacks/set_release b/scripts/atomic/fallbacks/set_release
index 86ede759f24e..05cdb7f42477 100755
--- a/scripts/atomic/fallbacks/set_release
+++ b/scripts/atomic/fallbacks/set_release
@@ -2,6 +2,11 @@ cat <<EOF
static __always_inline void
arch_${atomic}_set_release(${atomic}_t *v, ${int} i)
{
- smp_store_release(&(v)->counter, i);
+ if (__native_word(${atomic}_t)) {
+ smp_store_release(&(v)->counter, i);
+ } else {
+ __atomic_release_fence();
+ arch_${atomic}_set(v, i);
+ }
}
EOF
From 9983a9d577db415c41099a20a5637ab25dd3c240 Mon Sep 17 00:00:00 2001
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Tue, 8 Feb 2022 18:08:02 +0100
Subject: [PATCH 08/14] locking/local_lock: Make the empty local_lock_*()
function a macro.
It has been said that local_lock() does not add any overhead compared to
preempt_disable() in a !LOCKDEP configuration. A micro benchmark showed
an unexpected result which can be reduced to the fact that local_lock()
was not entirely optimized away.
In the !LOCKDEP configuration local_lock_acquire() is an empty static
inline function. On x86 the this_cpu_ptr() argument of that function is
fully evaluated leading to an additional mov+add instructions which are
not needed and not used.
Replace the static inline function with a macro. The typecheck() macro
ensures that the argument is of proper type while the resulting
disassembly shows no traces of this_cpu_ptr().
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Waiman Long <longman@redhat.com>
Link: https://lkml.kernel.org/r/YgKjciR60fZft2l4@linutronix.de
---
include/linux/local_lock_internal.h | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/include/linux/local_lock_internal.h b/include/linux/local_lock_internal.h
index 975e33b793a7..6d635e8306d6 100644
--- a/include/linux/local_lock_internal.h
+++ b/include/linux/local_lock_internal.h
@@ -44,9 +44,9 @@ static inline void local_lock_debug_init(local_lock_t *l)
}
#else /* CONFIG_DEBUG_LOCK_ALLOC */
# define LOCAL_LOCK_DEBUG_INIT(lockname)
-static inline void local_lock_acquire(local_lock_t *l) { }
-static inline void local_lock_release(local_lock_t *l) { }
-static inline void local_lock_debug_init(local_lock_t *l) { }
+# define local_lock_acquire(__ll) do { typecheck(local_lock_t *, __ll); } while (0)
+# define local_lock_release(__ll) do { typecheck(local_lock_t *, __ll); } while (0)
+# define local_lock_debug_init(__ll) do { typecheck(local_lock_t *, __ll); } while (0)
#endif /* !CONFIG_DEBUG_LOCK_ALLOC */
#define INIT_LOCAL_LOCK(lockname) { LOCAL_LOCK_DEBUG_INIT(lockname) }
From 1c6f9ec0095459b5120a1cb059d442f56d3cb6e7 Mon Sep 17 00:00:00 2001
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Tue, 8 Feb 2022 18:21:10 +0100
Subject: [PATCH 09/14] locking: Enable RT_MUTEXES by default on PREEMPT_RT.
The CONFIG_RT_MUTEXES option is enabled by CONFIG_FUTEX and CONFIG_I2C.
If both are disabled then a CONFIG_PREEMPT_RT build fails to compile.
It is not possible to have a PREEMPT_RT kernel without RT_MUTEX support
because RT_MUTEX based locking is always used.
Enable CONFIG_RT_MUTEXES by default on PREEMPT_RT builds.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/YgKmhjkcuqWXdUjQ@linutronix.de
---
init/Kconfig | 1 +
1 file changed, 1 insertion(+)
diff --git a/init/Kconfig b/init/Kconfig
index e9119bf54b1f..beb5b866c318 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -2054,6 +2054,7 @@ source "arch/Kconfig"
config RT_MUTEXES
bool
+ default y if PREEMPT_RT
config BASE_SMALL
int
From f5c54f77b07b278cfde4a654e111c39996ac8b5b Mon Sep 17 00:00:00 2001
From: Borislav Petkov <bp@suse.de>
Date: Fri, 4 Feb 2022 09:30:13 +0100
Subject: [PATCH 10/14] cpumask: Add a x86-specific cpumask_clear_cpu() helper
Add a x86-specific cpumask_clear_cpu() helper which will be used in
places where the explicit KASAN-instrumentation in the *_bit() helpers
is unwanted.
Also, always inline two more cpumask generic helpers.
allyesconfig:
text data bss dec hex filename
190553143 159425889 32076404 382055436 16c5b40c vmlinux.before
190551812 159424945 32076404 382053161 16c5ab29 vmlinux.after
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Marco Elver <elver@google.com>
Link: https://lore.kernel.org/r/20220204083015.17317-2-bp@alien8.de
---
arch/x86/include/asm/cpumask.h | 10 ++++++++++
include/linux/cpumask.h | 4 ++--
2 files changed, 12 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/cpumask.h b/arch/x86/include/asm/cpumask.h
index 3afa990d756b..c5aed9e9226c 100644
--- a/arch/x86/include/asm/cpumask.h
+++ b/arch/x86/include/asm/cpumask.h
@@ -20,11 +20,21 @@ static __always_inline bool arch_cpu_online(int cpu)
{
return arch_test_bit(cpu, cpumask_bits(cpu_online_mask));
}
+
+static __always_inline void arch_cpumask_clear_cpu(int cpu, struct cpumask *dstp)
+{
+ arch_clear_bit(cpumask_check(cpu), cpumask_bits(dstp));
+}
#else
static __always_inline bool arch_cpu_online(int cpu)
{
return cpu == 0;
}
+
+static __always_inline void arch_cpumask_clear_cpu(int cpu, struct cpumask *dstp)
+{
+ return;
+}
#endif
#define arch_cpu_is_offline(cpu) unlikely(!arch_cpu_online(cpu))
diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
index 6b06c698cd2a..fe29ac7cc469 100644
--- a/include/linux/cpumask.h
+++ b/include/linux/cpumask.h
@@ -102,7 +102,7 @@ extern atomic_t __num_online_cpus;
extern cpumask_t cpus_booted_once_mask;
-static inline void cpu_max_bits_warn(unsigned int cpu, unsigned int bits)
+static __always_inline void cpu_max_bits_warn(unsigned int cpu, unsigned int bits)
{
#ifdef CONFIG_DEBUG_PER_CPU_MAPS
WARN_ON_ONCE(cpu >= bits);
@@ -110,7 +110,7 @@ static inline void cpu_max_bits_warn(unsigned int cpu, unsigned int bits)
}
/* verify cpu argument to cpumask_* operators */
-static inline unsigned int cpumask_check(unsigned int cpu)
+static __always_inline unsigned int cpumask_check(unsigned int cpu)
{
cpu_max_bits_warn(cpu, nr_cpumask_bits);
return cpu;
From b008893b08dcc8c30d756db05c229a1491bcb992 Mon Sep 17 00:00:00 2001
From: Borislav Petkov <bp@suse.de>
Date: Fri, 4 Feb 2022 09:30:14 +0100
Subject: [PATCH 11/14] x86/ptrace: Always inline v8086_mode() for
instrumentation
Instrumentation glue like KASAN causes the following warning:
vmlinux.o: warning: objtool: mce_gather_info()+0x5f: call to v8086_mode.constprop.0() leaves .noinstr.text section
due to gcc creating a function call for that oneliner. Force-inline it
and even save some vmlinux bytes (.config is close to an allmodconfig):
text data bss dec hex filename
209431677 208257651 34411048 452100376 1af28118 vmlinux.before
209431519 208257615 34411048 452100182 1af28056 vmlinux.after
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Marco Elver <elver@google.com>
Link: https://lore.kernel.org/r/20220204083015.17317-3-bp@alien8.de
---
arch/x86/include/asm/ptrace.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h
index 703663175a5a..4357e0f2cd5f 100644
--- a/arch/x86/include/asm/ptrace.h
+++ b/arch/x86/include/asm/ptrace.h
@@ -137,7 +137,7 @@ static __always_inline int user_mode(struct pt_regs *regs)
#endif
}
-static inline int v8086_mode(struct pt_regs *regs)
+static __always_inline int v8086_mode(struct pt_regs *regs)
{
#ifdef CONFIG_X86_32
return (regs->flags & X86_VM_MASK);
From fb7275acd6fb988313dddd8d3d19efa70d9015ad Mon Sep 17 00:00:00 2001
From: Waiman Long <longman@redhat.com>
Date: Thu, 10 Feb 2022 22:55:26 -0500
Subject: [PATCH 12/14] locking/lockdep: Iterate lock_classes directly when
reading lockdep files
When dumping lock_classes information via /proc/lockdep, we can't take
the lockdep lock as the lock hold time is indeterminate. Iterating
over all_lock_classes without holding lock can be dangerous as there
is a slight chance that it may branch off to other lists leading to
infinite loop or even access invalid memory if changes are made to
all_lock_classes list in parallel.
To avoid this problem, iteration of lock classes is now done directly
on the lock_classes array itself. The lock_classes_in_use bitmap is
checked to see if the lock class is being used. To avoid iterating
the full array all the times, a new max_lock_class_idx value is added
to track the maximum lock_class index that is currently being used.
We can theoretically take the lockdep lock for iterating all_lock_classes
when other lockdep files (lockdep_stats and lock_stat) are accessed as
the lock hold time will be shorter for them. For consistency, they are
also modified to iterate the lock_classes array directly.
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220211035526.1329503-2-longman@redhat.com
---
kernel/locking/lockdep.c | 14 +++++---
kernel/locking/lockdep_internals.h | 6 ++--
kernel/locking/lockdep_proc.c | 51 +++++++++++++++++++++++++-----
3 files changed, 56 insertions(+), 15 deletions(-)
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 2e6892ec3756..50036c10b518 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -183,11 +183,9 @@ static DECLARE_BITMAP(list_entries_in_use, MAX_LOCKDEP_ENTRIES);
static struct hlist_head lock_keys_hash[KEYHASH_SIZE];
unsigned long nr_lock_classes;
unsigned long nr_zapped_classes;
-#ifndef CONFIG_DEBUG_LOCKDEP
-static
-#endif
+unsigned long max_lock_class_idx;
struct lock_class lock_classes[MAX_LOCKDEP_KEYS];
-static DECLARE_BITMAP(lock_classes_in_use, MAX_LOCKDEP_KEYS);
+DECLARE_BITMAP(lock_classes_in_use, MAX_LOCKDEP_KEYS);
static inline struct lock_class *hlock_class(struct held_lock *hlock)
{
@@ -338,7 +336,7 @@ static inline void lock_release_holdtime(struct held_lock *hlock)
* elements. These elements are linked together by the lock_entry member in
* struct lock_class.
*/
-LIST_HEAD(all_lock_classes);
+static LIST_HEAD(all_lock_classes);
static LIST_HEAD(free_lock_classes);
/**
@@ -1252,6 +1250,7 @@ register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
struct lockdep_subclass_key *key;
struct hlist_head *hash_head;
struct lock_class *class;
+ int idx;
DEBUG_LOCKS_WARN_ON(!irqs_disabled());
@@ -1317,6 +1316,9 @@ register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
* of classes.
*/
list_move_tail(&class->lock_entry, &all_lock_classes);
+ idx = class - lock_classes;
+ if (idx > max_lock_class_idx)
+ max_lock_class_idx = idx;
if (verbose(class)) {
graph_unlock();
@@ -6000,6 +6002,8 @@ static void zap_class(struct pending_free *pf, struct lock_class *class)
WRITE_ONCE(class->name, NULL);
nr_lock_classes--;
__clear_bit(class - lock_classes, lock_classes_in_use);
+ if (class - lock_classes == max_lock_class_idx)
+ max_lock_class_idx--;
} else {
WARN_ONCE(true, "%s() failed for class %s\n", __func__,
class->name);
diff --git a/kernel/locking/lockdep_internals.h b/kernel/locking/lockdep_internals.h
index ecb8662e7a4e..bbe9000260d0 100644
--- a/kernel/locking/lockdep_internals.h
+++ b/kernel/locking/lockdep_internals.h
@@ -121,7 +121,6 @@ static const unsigned long LOCKF_USED_IN_IRQ_READ =
#define MAX_LOCKDEP_CHAIN_HLOCKS (MAX_LOCKDEP_CHAINS*5)
-extern struct list_head all_lock_classes;
extern struct lock_chain lock_chains[];
#define LOCK_USAGE_CHARS (2*XXX_LOCK_USAGE_STATES + 1)
@@ -151,6 +150,10 @@ extern unsigned int nr_large_chain_blocks;
extern unsigned int max_lockdep_depth;
extern unsigned int max_bfs_queue_depth;
+extern unsigned long max_lock_class_idx;
+
+extern struct lock_class lock_classes[MAX_LOCKDEP_KEYS];
+extern unsigned long lock_classes_in_use[];
#ifdef CONFIG_PROVE_LOCKING
extern unsigned long lockdep_count_forward_deps(struct lock_class *);
@@ -205,7 +208,6 @@ struct lockdep_stats {
};
DECLARE_PER_CPU(struct lockdep_stats, lockdep_stats);
-extern struct lock_class lock_classes[MAX_LOCKDEP_KEYS];
#define __debug_atomic_inc(ptr) \
this_cpu_inc(lockdep_stats.ptr);
diff --git a/kernel/locking/lockdep_proc.c b/kernel/locking/lockdep_proc.c
index b8d9a050c337..15fdc7fa5c68 100644
--- a/kernel/locking/lockdep_proc.c
+++ b/kernel/locking/lockdep_proc.c
@@ -24,14 +24,33 @@
#include "lockdep_internals.h"
+/*
+ * Since iteration of lock_classes is done without holding the lockdep lock,
+ * it is not safe to iterate all_lock_classes list directly as the iteration
+ * may branch off to free_lock_classes or the zapped list. Iteration is done
+ * directly on the lock_classes array by checking the lock_classes_in_use
+ * bitmap and max_lock_class_idx.
+ */
+#define iterate_lock_classes(idx, class) \
+ for (idx = 0, class = lock_classes; idx <= max_lock_class_idx; \
+ idx++, class++)
+
static void *l_next(struct seq_file *m, void *v, loff_t *pos)
{
- return seq_list_next(v, &all_lock_classes, pos);
+ struct lock_class *class = v;
+
+ ++class;
+ *pos = class - lock_classes;
+ return (*pos > max_lock_class_idx) ? NULL : class;
}
static void *l_start(struct seq_file *m, loff_t *pos)
{
- return seq_list_start_head(&all_lock_classes, *pos);
+ unsigned long idx = *pos;
+
+ if (idx > max_lock_class_idx)
+ return NULL;
+ return lock_classes + idx;
}
static void l_stop(struct seq_file *m, void *v)
@@ -57,14 +76,16 @@ static void print_name(struct seq_file *m, struct lock_class *class)
static int l_show(struct seq_file *m, void *v)
{
- struct lock_class *class = list_entry(v, struct lock_class, lock_entry);
+ struct lock_class *class = v;
struct lock_list *entry;
char usage[LOCK_USAGE_CHARS];
+ int idx = class - lock_classes;
- if (v == &all_lock_classes) {
+ if (v == lock_classes)
seq_printf(m, "all lock classes:\n");
+
+ if (!test_bit(idx, lock_classes_in_use))
return 0;
- }
seq_printf(m, "%p", class->key);
#ifdef CONFIG_DEBUG_LOCKDEP
@@ -220,8 +241,11 @@ static int lockdep_stats_show(struct seq_file *m, void *v)
#ifdef CONFIG_PROVE_LOCKING
struct lock_class *class;
+ unsigned long idx;
- list_for_each_entry(class, &all_lock_classes, lock_entry) {
+ iterate_lock_classes(idx, class) {
+ if (!test_bit(idx, lock_classes_in_use))
+ continue;
if (class->usage_mask == 0)
nr_unused++;
@@ -254,6 +278,7 @@ static int lockdep_stats_show(struct seq_file *m, void *v)
sum_forward_deps += lockdep_count_forward_deps(class);
}
+
#ifdef CONFIG_DEBUG_LOCKDEP
DEBUG_LOCKS_WARN_ON(debug_atomic_read(nr_unused_locks) != nr_unused);
#endif
@@ -345,6 +370,8 @@ static int lockdep_stats_show(struct seq_file *m, void *v)
seq_printf(m, " max bfs queue depth: %11u\n",
max_bfs_queue_depth);
#endif
+ seq_printf(m, " max lock class index: %11lu\n",
+ max_lock_class_idx);
lockdep_stats_debug_show(m);
seq_printf(m, " debug_locks: %11u\n",
debug_locks);
@@ -622,12 +649,16 @@ static int lock_stat_open(struct inode *inode, struct file *file)
if (!res) {
struct lock_stat_data *iter = data->stats;
struct seq_file *m = file->private_data;
+ unsigned long idx;
- list_for_each_entry(class, &all_lock_classes, lock_entry) {
+ iterate_lock_classes(idx, class) {
+ if (!test_bit(idx, lock_classes_in_use))
+ continue;
iter->class = class;
iter->stats = lock_stats(class);
iter++;
}
+
data->iter_end = iter;
sort(data->stats, data->iter_end - data->stats,
@@ -645,6 +676,7 @@ static ssize_t lock_stat_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
struct lock_class *class;
+ unsigned long idx;
char c;
if (count) {
@@ -654,8 +686,11 @@ static ssize_t lock_stat_write(struct file *file, const char __user *buf,
if (c != '0')
return count;
- list_for_each_entry(class, &all_lock_classes, lock_entry)
+ iterate_lock_classes(idx, class) {
+ if (!test_bit(idx, lock_classes_in_use))
+ continue;
clear_lock_stats(class);
+ }
}
return count;
}
From fe65deb56e552a8c9bf7f27860dbdeac12a36116 Mon Sep 17 00:00:00 2001
From: Masahiro Yamada <masahiroy@kernel.org>
Date: Mon, 14 Feb 2022 01:57:16 +0900
Subject: [PATCH 13/14] jump_label: Avoid unneeded casts in
STATIC_KEY_INIT_{TRUE,FALSE}
Commit 3821fd35b58d ("jump_label: Reduce the size of struct static_key")
introduced the union to struct static_key.
It is more natual to set JUMP_TYPE_* to the .type field without casting.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220213165717.2354046-1-masahiroy@kernel.org
---
include/linux/jump_label.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h
index 48b9b2a82767..6924e6837e6d 100644
--- a/include/linux/jump_label.h
+++ b/include/linux/jump_label.h
@@ -251,10 +251,10 @@ extern void static_key_disable_cpuslocked(struct static_key *key);
*/
#define STATIC_KEY_INIT_TRUE \
{ .enabled = { 1 }, \
- { .entries = (void *)JUMP_TYPE_TRUE } }
+ { .type = JUMP_TYPE_TRUE } }
#define STATIC_KEY_INIT_FALSE \
{ .enabled = { 0 }, \
- { .entries = (void *)JUMP_TYPE_FALSE } }
+ { .type = JUMP_TYPE_FALSE } }
#else /* !CONFIG_JUMP_LABEL */
From cd27ccfc727e99352321c0c75012ab9c5a90321e Mon Sep 17 00:00:00 2001
From: Masahiro Yamada <masahiroy@kernel.org>
Date: Mon, 14 Feb 2022 01:57:17 +0900
Subject: [PATCH 14/14] jump_label: Refactor #ifdef of struct static_key
Move #ifdef CONFIG_JUMP_LABEL inside the struct static_key.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220213165717.2354046-2-masahiroy@kernel.org
---
include/linux/jump_label.h | 9 ++-------
1 file changed, 2 insertions(+), 7 deletions(-)
diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h
index 6924e6837e6d..107751cc047b 100644
--- a/include/linux/jump_label.h
+++ b/include/linux/jump_label.h
@@ -82,10 +82,9 @@ extern bool static_key_initialized;
"%s(): static key '%pS' used before call to jump_label_init()", \
__func__, (key))
-#ifdef CONFIG_JUMP_LABEL
-
struct static_key {
atomic_t enabled;
+#ifdef CONFIG_JUMP_LABEL
/*
* Note:
* To make anonymous unions work with old compilers, the static
@@ -104,13 +103,9 @@ struct static_key {
struct jump_entry *entries;
struct static_key_mod *next;
};
+#endif /* CONFIG_JUMP_LABEL */
};
-#else
-struct static_key {
- atomic_t enabled;
-};
-#endif /* CONFIG_JUMP_LABEL */
#endif /* __ASSEMBLY__ */
#ifdef CONFIG_JUMP_LABEL