semaphore: Add might_sleep() to down_*() family

PATCH Applied Xiaoming Ni 8 participants 17 messages Aug 9, 2021 – Sep 1, 2021

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Xiaoming Ni

author

2021-08-09 02:12 UTC #0 lore raw

PATCH 1/1 semaphore: Add might_sleep() to down_*() family

Semaphore is sleeping lock. Add might_sleep() to down*() family (with exception of down_trylock()) to detect atomic context sleep.

Previously discussed with Peter Zijlstra, see link:
https://lore.kernel.org/lkml/[email protected]

Signed-off-by Xiaoming Ni <[email protected]>

---
 kernel/locking/semaphore.c | 4 ++++
 1 file changed, 4 insertions(+)

kernel/locking/semaphore.c +4 -0

index 9aa855a96c4a..9ee381e4d2a4 100644
@@ -54,6 +54,7 @@ void down(struct semaphore *sem)
 {
 	unsigned long flags;
 
+	might_sleep();
 	raw_spin_lock_irqsave(&sem->lock, flags);
 	if (likely(sem->count > 0))
 		sem->count--;

@@ -77,6 +78,7 @@ int down_interruptible(struct semaphore *sem)
 	unsigned long flags;
 	int result = 0;
 
+	might_sleep();
 	raw_spin_lock_irqsave(&sem->lock, flags);
 	if (likely(sem->count > 0))
 		sem->count--;

@@ -103,6 +105,7 @@ int down_killable(struct semaphore *sem)
 	unsigned long flags;
 	int result = 0;
 
+	might_sleep();
 	raw_spin_lock_irqsave(&sem->lock, flags);
 	if (likely(sem->count > 0))
 		sem->count--;

@@ -157,6 +160,7 @@ int down_timeout(struct semaphore *sem, long timeout)
 	unsigned long flags;
 	int result = 0;
 
+	might_sleep();
 	raw_spin_lock_irqsave(&sem->lock, flags);
 	if (likely(sem->count > 0))
 		sem->count--;

Signature · 1 line

2.27.0

Waiman Long

2021-08-09 03:01 UTC #1 lore raw

Quoted 40 lines · Xiaoming Ni

Semaphore is sleeping lock. Add might_sleep() to down*() family (with exception of down_trylock()) to detect atomic context sleep.

Previously discussed with Peter Zijlstra, see link:
https://lore.kernel.org/lkml/[email protected]

Signed-off-by Xiaoming Ni <[email protected]>

---
  kernel/locking/semaphore.c | 4 ++++
  1 file changed, 4 insertions(+)

kernel/locking/semaphore.c +3 -0

index 9aa855a96c4a..9ee381e4d2a4 100644
@@ -54,6 +54,7 @@ void down(struct semaphore *sem)
  {
  	unsigned long flags;
 
+	might_sleep();
  	raw_spin_lock_irqsave(&sem->lock, flags);
  	if (likely(sem->count > 0))
  		sem->count--;

@@ -77,6 +78,7 @@ int down_interruptible(struct semaphore *sem)
  	unsigned long flags;
  	int result = 0;
 
+	might_sleep();
  	raw_spin_lock_irqsave(&sem->lock, flags);
  	if (likely(sem->count > 0))
  		sem->count--;

@@ -103,6 +105,7 @@ int down_killable(struct semaphore *sem)
  	unsigned long flags;
  	int result = 0;
 
+	might_sleep();
  	raw_spin_lock_irqsave(&sem->lock, flags);
  	if (likely(sem->count > 0))
  		sem->count--;

kernel/locking/semaphore.c int down_timeout(struct semaphore *sem, long timeout) · line 166

Quoted 7 lines

kernel/locking/semaphore.c +1 -0

@@ -157,6 +160,7 @@ int down_timeout(struct semaphore *sem, long timeout)
  	unsigned long flags;
  	int result = 0;
 
+	might_sleep();
  	raw_spin_lock_irqsave(&sem->lock, flags);
  	if (likely(sem->count > 0))
  		sem->count--;

I think it is simpler to just put a "might_sleep()" in __down_common() which is the function where sleep can actually happen.

Cheers,
Longman

Xiaoming Ni

author

2021-08-09 03:51 UTC #2 lore raw

Quoted 40 lines · Waiman Long

Quoted 39 lines · Xiaoming Ni

Semaphore is sleeping lock. Add might_sleep() to down*() family (with exception of down_trylock()) to detect atomic context sleep.

Previously discussed with Peter Zijlstra, see link:

https://lore.kernel.org/lkml/[email protected]

Signed-off-by Xiaoming Ni <[email protected]>

---
kernel/locking/semaphore.c | 4 ++++

  1 file changed, 4 insertions(+)

kernel/locking/semaphore.c +3 -0

index 9aa855a96c4a..9ee381e4d2a4 100644
@@ -54,6 +54,7 @@ void down(struct semaphore *sem)
   {
       unsigned long flags;
+    might_sleep();
       raw_spin_lock_irqsave(&sem->lock, flags);
       if (likely(sem->count > 0))
           sem->count--;

@@ -77,6 +78,7 @@ int down_interruptible(struct semaphore *sem)
       unsigned long flags;
       int result = 0;
+    might_sleep();
       raw_spin_lock_irqsave(&sem->lock, flags);
       if (likely(sem->count > 0))
           sem->count--;

@@ -103,6 +105,7 @@ int down_killable(struct semaphore *sem)
       unsigned long flags;
       int result = 0;
+    might_sleep();
       raw_spin_lock_irqsave(&sem->lock, flags);
       if (likely(sem->count > 0))
           sem->count--;

@@ -157,6 +160,7 @@ int down_timeout(struct semaphore *sem, long timeout)

Quoted 9 lines

kernel/locking/semaphore.c int down_interruptible(struct semaphore *sem) · line 84
Quoted 6 lines
kernel/locking/semaphore.c +1 -0
       unsigned long flags;
       int result = 0;
+    might_sleep();
       raw_spin_lock_irqsave(&sem->lock, flags);
       if (likely(sem->count > 0))
           sem->count--;
I think it is simpler to just put a "might_sleep()" in __down_common() which is the function where sleep can actually happen.

If the actual atomic context hibernation occurs, the corresponding alarm log is generated in __schedule_bug().

	__schedule()
		--> schedule_debug()
			--> __schedule_bug()

However, "might_sleep()" indicates the possibility of sleep, so that code writers can identify and fix the problem as soon as possible, but does not trigger atomic context sleep.

Is it better to put "might_sleep()" in each down API entry than __down_common() to help identify potential code problems?

Thanks
Xiaoming Ni

Waiman Long

2021-08-09 12:52 UTC #3 lore raw

Quoted 5 lines · Xiaoming Ni

Quoted 3 lines · Waiman Long
I think it is simpler to just put a "might_sleep()" in __down_common() which is the function where sleep can actually happen.

Quoted 8 lines

If the actual atomic context hibernation occurs, the corresponding alarm log is generated in __schedule_bug(). __schedule()
--> schedule_debug()
--> __schedule_bug()
However, "might_sleep()" indicates the possibility of sleep, so that code writers can identify and fix the problem as soon as possible, but does not trigger atomic context sleep.
Is it better to put "might_sleep()" in each down API entry than __down_common() to help identify potential code problems?

Putting "might_sleep()" in each down_*() functions mean that whenever we add a new API function, we have to remember to add "might_sleep()". If we put it in down_common(), it will work for any newly added API function in the future even though I doubt we will add any.

Cheers,
Longman

Xiaoming Ni

author

2021-08-09 14:36 UTC #4 lore raw

Quoted 11 lines · Waiman Long

Quoted 10 lines · Xiaoming Ni
Quoted 3 lines · Waiman Long
I think it is simpler to just put a "might_sleep()" in __down_common() which is the function where sleep can actually happen.
If the actual atomic context hibernation occurs, the corresponding alarm log is generated in __schedule_bug(). __schedule()
--> schedule_debug()
--> __schedule_bug()

Quoted 7 lines

Quoted 3 lines
However, "might_sleep()" indicates the possibility of sleep, so that code writers can identify and fix the problem as soon as possible, but does not trigger atomic context sleep.
Is it better to put "might_sleep()" in each down API entry than __down_common() to help identify potential code problems?
Putting "might_sleep()" in each down_*() functions mean that whenever we add a new API function, we have to remember to add "might_sleep()". If we put it in down_common(), it will work for any newly added API function in the future even though I doubt we will add any.

If the code enters down_common(), it is not "might" sleep but "will" sleep, and an alarm is printed in __schedule_bug() later.

"might_sleep()" is used to check potential problems, and "_schedule_bug()" is used to check actual faults.

So, I still think we should add "might_sleep()" to each down_*() function to alert code owner to potential problems early.

Thanks
Xiaoming Ni

Thomas Gleixner

2021-08-13 17:27 UTC #5 lore raw

In reply to Waiman Long

Quoted 7 lines · Waiman Long

Quoted 6 lines · Xiaoming Ni
Semaphore is sleeping lock. Add might_sleep() to down*() family (with exception of down_trylock()) to detect atomic context sleep.
kernel/locking/semaphore.c +0 -0
@@ -157,6 +160,7 @@ int down_timeout(struct semaphore *sem, long timeout)
  	unsigned long flags;
  	int result = 0;
 

Quoted 7 lines

kernel/locking/semaphore.c void down(struct semaphore *sem) · line 60
Quoted 4 lines
kernel/locking/semaphore.c +1 -0
+	might_sleep();
  	raw_spin_lock_irqsave(&sem->lock, flags);
  	if (likely(sem->count > 0))
  		sem->count--;
I think it is simpler to just put a "might_sleep()" in __down_common() which is the function where sleep can actually happen.

No. Putting it in __down_common() is wrong, because that covers only the contended case.

But we want to cover the potential sleep, i.e. checking even in the non-contended case, which is what might_sleep() is about.

Thanks,

tglx

Waiman Long

2021-08-13 18:47 UTC #6 lore raw

Quoted 14 lines · Thomas Gleixner

Quoted 7 lines · Waiman Long
Quoted 6 lines · Xiaoming Ni
Semaphore is sleeping lock. Add might_sleep() to down*() family (with exception of down_trylock()) to detect atomic context sleep.
kernel/locking/semaphore.c +0 -0
@@ -157,6 +160,7 @@ int down_timeout(struct semaphore *sem, long timeout)
   	unsigned long flags;
   	int result = 0;
 
Quoted 6 lines
kernel/locking/semaphore.c void down(struct semaphore *sem) · line 60
Quoted 4 lines
kernel/locking/semaphore.c +1 -0
+	might_sleep();
   	raw_spin_lock_irqsave(&sem->lock, flags);
   	if (likely(sem->count > 0))
   		sem->count--;
I think it is simpler to just put a "might_sleep()" in __down_common() which is the function where sleep can actually happen.

Quoted 5 lines

No. Putting it in __down_common() is wrong, because that covers only the contended case.
But we want to cover the potential sleep, i.e. checking even in the non-contended case, which is what might_sleep() is about.

You are right. Thanks for the correction.

Cheers,
Longman

Will Deacon

maintainer Acked-by on v1 1/1

2021-08-13 14:43 UTC #7 lore raw

In reply to Xiaoming Ni

Quoted 5 lines · Xiaoming Ni

Semaphore is sleeping lock. Add might_sleep() to down*() family (with exception of down_trylock()) to detect atomic context sleep.
Previously discussed with Peter Zijlstra, see link:
https://lore.kernel.org/lkml/[email protected]

You can use a Link: tag here.

Quoted 4 lines

Signed-off-by Xiaoming Ni <[email protected]>
---
 kernel/locking/semaphore.c | 4 ++++
 1 file changed, 4 insertions(+)

Acked-by Will Deacon <[email protected]>

Will

tip-bot2 for Xiaoming Ni

merge bot Applied

2021-08-23 09:39 UTC #8 lore raw

[tip: locking/core] locking/semaphore: Add might_sleep() to down_*() family

In reply to Xiaoming Ni

The following commit has been merged into the locking/core branch of tip:

Commit-ID:     99409b935c9ac5ea36ab5218954115c52449234d
Gitweb:        https://git.kernel.org/tip/99409b935c9ac5ea36ab5218954115c52449234d
Author:        Xiaoming Ni <[email protected]>
AuthorDate:    Mon, 09 Aug 2021 10:12:15 +08:00
Committer:     Peter Zijlstra <[email protected]>
CommitterDate: Fri, 20 Aug 2021 12:33:17 +02:00

locking/semaphore: Add might_sleep() to down_*() family

Semaphore is sleeping lock. Add might_sleep() to down*() family (with exception of down_trylock()) to detect atomic context sleep.

Signed-off-by Xiaoming Ni <[email protected]>

Signed-off-by Peter Zijlstra (Intel) <[email protected]>

Acked-by Will Deacon <[email protected]>

Link https://lore.kernel.org/r/[email protected] open here

---
 kernel/locking/semaphore.c | 4 ++++
 1 file changed, 4 insertions(+)

kernel/locking/semaphore.c +4 -0

index 9aa855a..9ee381e 100644
@@ -54,6 +54,7 @@ void down(struct semaphore *sem)
 {
 	unsigned long flags;
 
+	might_sleep();
 	raw_spin_lock_irqsave(&sem->lock, flags);
 	if (likely(sem->count > 0))
 		sem->count--;

@@ -77,6 +78,7 @@ int down_interruptible(struct semaphore *sem)
 	unsigned long flags;
 	int result = 0;
 
+	might_sleep();
 	raw_spin_lock_irqsave(&sem->lock, flags);
 	if (likely(sem->count > 0))
 		sem->count--;

@@ -103,6 +105,7 @@ int down_killable(struct semaphore *sem)
 	unsigned long flags;
 	int result = 0;
 
+	might_sleep();
 	raw_spin_lock_irqsave(&sem->lock, flags);
 	if (likely(sem->count > 0))
 		sem->count--;

@@ -157,6 +160,7 @@ int down_timeout(struct semaphore *sem, long timeout)
 	unsigned long flags;
 	int result = 0;
 
+	might_sleep();
 	raw_spin_lock_irqsave(&sem->lock, flags);
 	if (likely(sem->count > 0))
 		sem->count--;

Guenter Roeck

2021-08-31 11:13 UTC #9 lore raw

In reply to Xiaoming Ni

Hi,

Quoted 8 lines · Xiaoming Ni

Semaphore is sleeping lock. Add might_sleep() to down*() family (with exception of down_trylock()) to detect atomic context sleep.
Previously discussed with Peter Zijlstra, see link:
https://lore.kernel.org/lkml/[email protected]
Signed-off-by Xiaoming Ni <[email protected]>
Acked-by Will Deacon <[email protected]>

This patch results in the following traceback on all arm64 boots with EFI BIOS.

The problem is only seen with CONFIG_ACPI_PPTT=y, and thus only on arm64.

Guenter

---

[   14.048540] BUG: sleeping function called from invalid context at kernel/locking/semaphore.c:163
[   14.048700] in_atomic(): 1, irqs_disabled(): 128, non_block: 0, pid: 14, name: cpuhp/0
[   14.048865] 2 locks held by cpuhp/0/14:
[   14.048943]  #0: ffff8000125799b0 (cpu_hotplug_lock){++++}-{0:0}, at: cpuhp_thread_fun+0x38/0x254
[   14.049320]  #1: ffff8000125799d8 (cpuhp_state-up){+.+.}-{0:0}, at: cpuhp_thread_fun+0x38/0x254
[   14.049523] irq event stamp: 62
[   14.049580] hardirqs last  enabled at (61): [<ffff800010269690>] finish_task_switch.isra.0+0xd0/0x2f0
[   14.049689] hardirqs last disabled at (62): [<ffff800010313ce8>] generic_exec_single+0x138/0x190
[   14.049785] softirqs last  enabled at (0): [<ffff8000102245d4>] copy_process+0x634/0x1af4
[   14.049876] softirqs last disabled at (0): [<0000000000000000>] 0x0
[   14.050299] CPU: 0 PID: 14 Comm: cpuhp/0 Not tainted 5.14.0-01100-gb91db6a0b52e #1
[   14.050452] Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015
[   14.050694] Call trace:
[   14.050753]  dump_backtrace+0x0/0x19c
[   14.050839]  show_stack+0x1c/0x30
[   14.050892]  dump_stack_lvl+0x9c/0xd8
[   14.050949]  dump_stack+0x1c/0x38
[   14.050999]  ___might_sleep+0x154/0x200
[   14.051053]  __might_sleep+0x54/0x90
[   14.051106]  down_timeout+0x34/0x90
[   14.051159]  acpi_os_wait_semaphore+0x68/0x9c
[   14.051218]  acpi_ut_acquire_mutex+0x50/0xbc
[   14.051277]  acpi_get_table+0x3c/0xc0
[   14.051330]  acpi_find_last_cache_level+0x44/0x12c
[   14.051391]  _init_cache_level+0xd8/0xe4
[   14.051446]  generic_exec_single+0xf8/0x190
[   14.051502]  smp_call_function_single+0x174/0x1e0
[   14.051561]  init_cache_level+0x30/0x60
[   14.051614]  cacheinfo_cpu_online+0x28/0x840
[   14.051675]  cpuhp_invoke_callback+0x168/0x2ac
[   14.051751]  cpuhp_thread_fun+0x198/0x254
[   14.051810]  smpboot_thread_fn+0x200/0x2c0
[   14.051867]  kthread+0x164/0x170
[   14.051921]  ret_from_fork+0x10/0x18

Hanjun Guo

2021-08-31 11:39 UTC #10 lore raw

Hi Guenter,

Quoted 9 lines · Guenter Roeck

Hi,
Quoted 6 lines · Xiaoming Ni
Semaphore is sleeping lock. Add might_sleep() to down*() family (with exception of down_trylock()) to detect atomic context sleep.
Previously discussed with Peter Zijlstra, see link:
https://lore.kernel.org/lkml/[email protected]

Quoted 7 lines

Quoted 2 lines
Signed-off-by Xiaoming Ni <[email protected]>
Acked-by Will Deacon <[email protected]>
This patch results in the following traceback on all arm64 boots with EFI BIOS.
The problem is only seen with CONFIG_ACPI_PPTT=y, and thus only on arm64.

I Cced Xiongfeng, he sent a patch to fix this issue over a month ago:

https://lore.kernel.org/linux-arm-kernel/[email protected]/T/

and the calltrace is exactly the same as below.

Sudeep, would you mind take a look again?

Quoted 27 lines

---

[   14.048540] BUG: sleeping function called from invalid context at kernel/locking/semaphore.c:163
[   14.048700] in_atomic(): 1, irqs_disabled(): 128, non_block: 0, pid: 14, name: cpuhp/0
[   14.048865] 2 locks held by cpuhp/0/14:
[   14.048943]  #0: ffff8000125799b0 (cpu_hotplug_lock){++++}-{0:0}, at: cpuhp_thread_fun+0x38/0x254
[   14.049320]  #1: ffff8000125799d8 (cpuhp_state-up){+.+.}-{0:0}, at: cpuhp_thread_fun+0x38/0x254
[   14.049523] irq event stamp: 62
[   14.049580] hardirqs last  enabled at (61): [<ffff800010269690>] finish_task_switch.isra.0+0xd0/0x2f0
[   14.049689] hardirqs last disabled at (62): [<ffff800010313ce8>] generic_exec_single+0x138/0x190
[   14.049785] softirqs last  enabled at (0): [<ffff8000102245d4>] copy_process+0x634/0x1af4
[   14.049876] softirqs last disabled at (0): [<0000000000000000>] 0x0
[   14.050299] CPU: 0 PID: 14 Comm: cpuhp/0 Not tainted 5.14.0-01100-gb91db6a0b52e #1
[   14.050452] Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015
[   14.050694] Call trace:
[   14.050753]  dump_backtrace+0x0/0x19c
[   14.050839]  show_stack+0x1c/0x30
[   14.050892]  dump_stack_lvl+0x9c/0xd8
[   14.050949]  dump_stack+0x1c/0x38
[   14.050999]  ___might_sleep+0x154/0x200
[   14.051053]  __might_sleep+0x54/0x90
[   14.051106]  down_timeout+0x34/0x90
[   14.051159]  acpi_os_wait_semaphore+0x68/0x9c
[   14.051218]  acpi_ut_acquire_mutex+0x50/0xbc
[   14.051277]  acpi_get_table+0x3c/0xc0
[   14.051330]  acpi_find_last_cache_level+0x44/0x12c
[   14.051391]  _init_cache_level+0xd8/0xe4
[   14.051446]  generic_exec_single+0xf8/0x190

Quoted 8 lines

[   14.051502]  smp_call_function_single+0x174/0x1e0
[   14.051561]  init_cache_level+0x30/0x60
[   14.051614]  cacheinfo_cpu_online+0x28/0x840
[   14.051675]  cpuhp_invoke_callback+0x168/0x2ac
[   14.051751]  cpuhp_thread_fun+0x198/0x254
[   14.051810]  smpboot_thread_fn+0x200/0x2c0
[   14.051867]  kthread+0x164/0x170
[   14.051921]  ret_from_fork+0x10/0x18

Thanks
Hanjun

Thomas Gleixner

2021-08-31 12:20 UTC #11 lore raw

Quoted 9 lines · Hanjun Guo

Quoted 4 lines · Guenter Roeck
This patch results in the following traceback on all arm64 boots with EFI BIOS.
The problem is only seen with CONFIG_ACPI_PPTT=y, and thus only on arm64.
I Cced Xiongfeng, he sent a patch to fix this issue over a month ago:
https://lore.kernel.org/linux-arm-kernel/[email protected]/T/

OMG. None of this is necessary.

Peter Zijlstra

maintainer

2021-08-31 11:41 UTC #12 lore raw

In reply to Guenter Roeck

Quoted 39 lines · Guenter Roeck

Hi,

Quoted 8 lines · Xiaoming Ni

Semaphore is sleeping lock. Add might_sleep() to down*() family (with exception of down_trylock()) to detect atomic context sleep.
Previously discussed with Peter Zijlstra, see link:
https://lore.kernel.org/lkml/[email protected]
Signed-off-by Xiaoming Ni <[email protected]>
Acked-by Will Deacon <[email protected]>

This patch results in the following traceback on all arm64 boots with EFI BIOS.

The problem is only seen with CONFIG_ACPI_PPTT=y, and thus only on arm64.

Guenter

---

[   14.048540] BUG: sleeping function called from invalid context at kernel/locking/semaphore.c:163
[   14.048700] in_atomic(): 1, irqs_disabled(): 128, non_block: 0, pid: 14, name: cpuhp/0
[   14.048865] 2 locks held by cpuhp/0/14:
[   14.048943]  #0: ffff8000125799b0 (cpu_hotplug_lock){++++}-{0:0}, at: cpuhp_thread_fun+0x38/0x254
[   14.049320]  #1: ffff8000125799d8 (cpuhp_state-up){+.+.}-{0:0}, at: cpuhp_thread_fun+0x38/0x254
[   14.049523] irq event stamp: 62
[   14.049580] hardirqs last  enabled at (61): [<ffff800010269690>] finish_task_switch.isra.0+0xd0/0x2f0
[   14.049689] hardirqs last disabled at (62): [<ffff800010313ce8>] generic_exec_single+0x138/0x190
[   14.049785] softirqs last  enabled at (0): [<ffff8000102245d4>] copy_process+0x634/0x1af4
[   14.049876] softirqs last disabled at (0): [<0000000000000000>] 0x0
[   14.050299] CPU: 0 PID: 14 Comm: cpuhp/0 Not tainted 5.14.0-01100-gb91db6a0b52e #1
[   14.050452] Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015
[   14.050694] Call trace:
[   14.050753]  dump_backtrace+0x0/0x19c
[   14.050839]  show_stack+0x1c/0x30
[   14.050892]  dump_stack_lvl+0x9c/0xd8
[   14.050949]  dump_stack+0x1c/0x38
[   14.050999]  ___might_sleep+0x154/0x200
[   14.051053]  __might_sleep+0x54/0x90

Quoted 8 lines

[   14.051106]  down_timeout+0x34/0x90
[   14.051159]  acpi_os_wait_semaphore+0x68/0x9c
[   14.051218]  acpi_ut_acquire_mutex+0x50/0xbc
[   14.051277]  acpi_get_table+0x3c/0xc0
[   14.051330]  acpi_find_last_cache_level+0x44/0x12c
[   14.051391]  _init_cache_level+0xd8/0xe4
[   14.051446]  generic_exec_single+0xf8/0x190
[   14.051502]  smp_call_function_single+0x174/0x1e0

This is the patch working as intended.. You simply cannot schedule with interrupts disabled as per the callchain.

Thomas Gleixner

2021-08-31 12:16 UTC #13 lore raw

In reply to Guenter Roeck

Quoted 6 lines · Guenter Roeck

Hi,
Quoted 3 lines · Xiaoming Ni
Semaphore is sleeping lock. Add might_sleep() to down*() family (with exception of down_trylock()) to detect atomic context sleep.

Quoted 8 lines

Quoted 5 lines
Previously discussed with Peter Zijlstra, see link:
https://lore.kernel.org/lkml/[email protected]
Signed-off-by Xiaoming Ni <[email protected]>
Acked-by Will Deacon <[email protected]>
This patch results in the following traceback on all arm64 boots with EFI BIOS.

That's what this change was supposed to catch :)

Quoted 1 line

The problem is only seen with CONFIG_ACPI_PPTT=y, and thus only on arm64.

The below should fix this.

Thanks,

tglx
---
Subject: drivers: base: cacheinfo: Get rid of DEFINE_SMP_CALL_CACHE_FUNCTION()
From: Thomas Gleixner <[email protected]>
Date: Tue, 31 Aug 2021 13:48:34 +0200

DEFINE_SMP_CALL_CACHE_FUNCTION() was usefel before the CPU hotplug rework to ensure that the cache related functions are called on the upcoming CPU because the notifier itself could run on any online CPU.

The hotplug state machine guarantees that the callbacks are invoked on the upcoming CPU. So there is no need to have this SMP function call obfuscation. That indirection was missed when the hotplug notifiers were converted.

This also solves the problem of ARM64 init_cache_level() invoking ACPI functions which take a semaphore in that context. That's invalid as SMP function calls run with interrupts disabled. Running it just from the callback in context of the CPU hotplug thread solves this.

Reported-by Guenter Roeck <[email protected]>

Fixes 8571890e1513 ("arm64: Add support for ACPI based firmware tables")

Signed-off-by Thomas Gleixner <[email protected]>

---
 arch/arm64/kernel/cacheinfo.c   |    7 ++-----
 arch/mips/kernel/cacheinfo.c    |    7 ++-----
 arch/riscv/kernel/cacheinfo.c   |    7 ++-----
 arch/x86/kernel/cpu/cacheinfo.c |    7 ++-----
 include/linux/cacheinfo.h       |   18 ------------------
 5 files changed, 8 insertions(+), 38 deletions(-)

arch/arm64/kernel/cacheinfo.c +2 -5

@@ -43,7 +43,7 @@ static void ci_leaf_init(struct cacheinf
 	this_leaf->type = type;
 }
 
-static int __init_cache_level(unsigned int cpu)
+int init_cache_level(unsigned int cpu)
 {
 	unsigned int ctype, level, leaves, fw_level;
 	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);

@@ -78,7 +78,7 @@ static int __init_cache_level(unsigned i
 	return 0;
 }
 
-static int __populate_cache_leaves(unsigned int cpu)
+int populate_cache_leaves(unsigned int cpu)
 {
 	unsigned int level, idx;
 	enum cache_type type;

@@ -97,6 +97,3 @@ static int __populate_cache_leaves(unsig
 	}
 	return 0;
 }
-
-DEFINE_SMP_CALL_CACHE_FUNCTION(init_cache_level)
-DEFINE_SMP_CALL_CACHE_FUNCTION(populate_cache_leaves)

arch/mips/kernel/cacheinfo.c +2 -5

@@ -17,7 +17,7 @@ do {								\
 	leaf++;							\
 } while (0)
 
-static int __init_cache_level(unsigned int cpu)
+int init_cache_level(unsigned int cpu)
 {
 	struct cpuinfo_mips *c = &current_cpu_data;
 	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);

@@ -74,7 +74,7 @@ static void fill_cpumask_cluster(int cpu
 			cpumask_set_cpu(cpu1, cpu_map);
 }
 
-static int __populate_cache_leaves(unsigned int cpu)
+int populate_cache_leaves(unsigned int cpu)
 {
 	struct cpuinfo_mips *c = &current_cpu_data;
 	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);

@@ -114,6 +114,3 @@ static int __populate_cache_leaves(unsig
 
 	return 0;
 }
-
-DEFINE_SMP_CALL_CACHE_FUNCTION(init_cache_level)
-DEFINE_SMP_CALL_CACHE_FUNCTION(populate_cache_leaves)

arch/riscv/kernel/cacheinfo.c +2 -5

@@ -113,7 +113,7 @@ static void fill_cacheinfo(struct cachei
 	}
 }
 
-static int __init_cache_level(unsigned int cpu)
+int init_cache_level(unsigned int cpu)
 {
 	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
 	struct device_node *np = of_cpu_device_node_get(cpu);

@@ -155,7 +155,7 @@ static int __init_cache_level(unsigned i
 	return 0;
 }
 
-static int __populate_cache_leaves(unsigned int cpu)
+int populate_cache_leaves(unsigned int cpu)
 {
 	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
 	struct cacheinfo *this_leaf = this_cpu_ci->info_list;

@@ -187,6 +187,3 @@ static int __populate_cache_leaves(unsig
 
 	return 0;
 }
-
-DEFINE_SMP_CALL_CACHE_FUNCTION(init_cache_level)
-DEFINE_SMP_CALL_CACHE_FUNCTION(populate_cache_leaves)

arch/x86/kernel/cpu/cacheinfo.c +2 -5

@@ -985,7 +985,7 @@ static void ci_leaf_init(struct cacheinf
 	this_leaf->priv = base->nb;
 }
 
-static int __init_cache_level(unsigned int cpu)
+int init_cache_level(unsigned int cpu)
 {
 	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);

@@ -1014,7 +1014,7 @@ static void get_cache_id(int cpu, struct
 	id4_regs->id = c->apicid >> index_msb;
 }
 
-static int __populate_cache_leaves(unsigned int cpu)
+int populate_cache_leaves(unsigned int cpu)
 {
 	unsigned int idx, ret;
 	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);

@@ -1033,6 +1033,3 @@ static int __populate_cache_leaves(unsig
 
 	return 0;
 }
-
-DEFINE_SMP_CALL_CACHE_FUNCTION(init_cache_level)
-DEFINE_SMP_CALL_CACHE_FUNCTION(populate_cache_leaves)

include/linux/cacheinfo.h +0 ~~-18~~

@@ -79,24 +79,6 @@ struct cpu_cacheinfo {
 	bool cpu_map_populated;
 };
 
-/*
- * Helpers to make sure "func" is executed on the cpu whose cache
- * attributes are being detected
- */
-#define DEFINE_SMP_CALL_CACHE_FUNCTION(func)			\
-static inline void _##func(void *ret)				\
-{								\
-	int cpu = smp_processor_id();				\
-	*(int *)ret = __##func(cpu);				\
-}								\
-								\
-int func(unsigned int cpu)					\
-{								\
-	int ret;						\
-	smp_call_function_single(cpu, _##func, &ret, true);	\
-	return ret;						\
-}
-
 struct cpu_cacheinfo *get_cpu_cacheinfo(unsigned int cpu);
 int init_cache_level(unsigned int cpu);
 int populate_cache_leaves(unsigned int cpu);

Will Deacon

maintainer Acked-by

2021-08-31 12:34 UTC #14 lore raw

Quoted 22 lines · Thomas Gleixner

Quoted 4 lines · Guenter Roeck
Quoted 3 lines · Xiaoming Ni
Semaphore is sleeping lock. Add might_sleep() to down*() family (with exception of down_trylock()) to detect atomic context sleep.
Quoted 8 lines
Quoted 5 lines
Previously discussed with Peter Zijlstra, see link:
https://lore.kernel.org/lkml/[email protected]
Signed-off-by Xiaoming Ni <[email protected]>
Acked-by Will Deacon <[email protected]>
This patch results in the following traceback on all arm64 boots with EFI BIOS.
That's what this change was supposed to catch :)
Quoted 1 line
The problem is only seen with CONFIG_ACPI_PPTT=y, and thus only on arm64.
The below should fix this.
Thanks,

Quoted 7 lines

tglx
---
Subject: drivers: base: cacheinfo: Get rid of DEFINE_SMP_CALL_CACHE_FUNCTION()
From: Thomas Gleixner <[email protected]>
Date: Tue, 31 Aug 2021 13:48:34 +0200
DEFINE_SMP_CALL_CACHE_FUNCTION() was usefel before the CPU hotplug rework

typo: "usefel"

Quoted 45 lines

to ensure that the cache related functions are called on the upcoming CPU because the notifier itself could run on any online CPU.
The hotplug state machine guarantees that the callbacks are invoked on the upcoming CPU. So there is no need to have this SMP function call obfuscation. That indirection was missed when the hotplug notifiers were converted.
This also solves the problem of ARM64 init_cache_level() invoking ACPI functions which take a semaphore in that context. That's invalid as SMP function calls run with interrupts disabled. Running it just from the callback in context of the CPU hotplug thread solves this.
Reported-by Guenter Roeck <[email protected]>
Fixes 8571890e1513 ("arm64: Add support for ACPI based firmware tables")
Signed-off-by Thomas Gleixner <[email protected]>
---
 arch/arm64/kernel/cacheinfo.c   |    7 ++-----
 arch/mips/kernel/cacheinfo.c    |    7 ++-----
 arch/riscv/kernel/cacheinfo.c   |    7 ++-----
 arch/x86/kernel/cpu/cacheinfo.c |    7 ++-----
 include/linux/cacheinfo.h       |   18 ------------------
 5 files changed, 8 insertions(+), 38 deletions(-)
arch/arm64/kernel/cacheinfo.c +2 -2
@@ -43,7 +43,7 @@ static void ci_leaf_init(struct cacheinf
 	this_leaf->type = type;
 }
 
-static int __init_cache_level(unsigned int cpu)
+int init_cache_level(unsigned int cpu)
 {
 	unsigned int ctype, level, leaves, fw_level;
 	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
@@ -78,7 +78,7 @@ static int __init_cache_level(unsigned i
 	return 0;
 }
 
-static int __populate_cache_leaves(unsigned int cpu)
+int populate_cache_leaves(unsigned int cpu)
 {
 	unsigned int level, idx;
 	enum cache_type type;

arch/arm64/kernel/cacheinfo.c static int __populate_cache_leaves(unsig · line 102

Quoted 6 lines

arch/arm64/kernel/cacheinfo.c +0 -3

@@ -97,6 +97,3 @@ static int __populate_cache_leaves(unsig
 	}
 	return 0;
 }
-
-DEFINE_SMP_CALL_CACHE_FUNCTION(init_cache_level)
-DEFINE_SMP_CALL_CACHE_FUNCTION(populate_cache_leaves)

Glad to see the back of this:

Acked-by Will Deacon <[email protected]>

Will

Guenter Roeck

Tested-by

2021-08-31 17:42 UTC #15 lore raw

In reply to Thomas Gleixner

Quoted 40 lines · Thomas Gleixner

Quoted 6 lines · Guenter Roeck
Hi,
Quoted 3 lines · Xiaoming Ni
Semaphore is sleeping lock. Add might_sleep() to down*() family (with exception of down_trylock()) to detect atomic context sleep.
Quoted 8 lines
Quoted 5 lines
Previously discussed with Peter Zijlstra, see link:
https://lore.kernel.org/lkml/[email protected]
Signed-off-by Xiaoming Ni <[email protected]>
Acked-by Will Deacon <[email protected]>
This patch results in the following traceback on all arm64 boots with EFI BIOS.
That's what this change was supposed to catch :)
Quoted 1 line
The problem is only seen with CONFIG_ACPI_PPTT=y, and thus only on arm64.
The below should fix this.
Thanks,
tglx
---
Subject: drivers: base: cacheinfo: Get rid of DEFINE_SMP_CALL_CACHE_FUNCTION()
From: Thomas Gleixner <[email protected]>
Date: Tue, 31 Aug 2021 13:48:34 +0200
DEFINE_SMP_CALL_CACHE_FUNCTION() was usefel before the CPU hotplug rework to ensure that the cache related functions are called on the upcoming CPU because the notifier itself could run on any online CPU.
The hotplug state machine guarantees that the callbacks are invoked on the upcoming CPU. So there is no need to have this SMP function call obfuscation. That indirection was missed when the hotplug notifiers were converted.

Quoted 8 lines

This also solves the problem of ARM64 init_cache_level() invoking ACPI functions which take a semaphore in that context. That's invalid as SMP function calls run with interrupts disabled. Running it just from the callback in context of the CPU hotplug thread solves this.
Reported-by Guenter Roeck <[email protected]>
Fixes 8571890e1513 ("arm64: Add support for ACPI based firmware tables")
Signed-off-by Thomas Gleixner <[email protected]>

The warning is no longer seen with this patch applied on top of v5.14-1100-gb91db6a0b52e, and I don't see any new problems on riscv, x86/x86_64, or mips.

Tested-by Guenter Roeck <[email protected]>

Thanks,
Guenter

Quoted 143 lines

---
 arch/arm64/kernel/cacheinfo.c   |    7 ++-----
 arch/mips/kernel/cacheinfo.c    |    7 ++-----
 arch/riscv/kernel/cacheinfo.c   |    7 ++-----
 arch/x86/kernel/cpu/cacheinfo.c |    7 ++-----
 include/linux/cacheinfo.h       |   18 ------------------
 5 files changed, 8 insertions(+), 38 deletions(-)

arch/arm64/kernel/cacheinfo.c +2 -5

@@ -43,7 +43,7 @@ static void ci_leaf_init(struct cacheinf
 	this_leaf->type = type;
 }
 
-static int __init_cache_level(unsigned int cpu)
+int init_cache_level(unsigned int cpu)
 {
 	unsigned int ctype, level, leaves, fw_level;
 	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);

@@ -78,7 +78,7 @@ static int __init_cache_level(unsigned i
 	return 0;
 }
 
-static int __populate_cache_leaves(unsigned int cpu)
+int populate_cache_leaves(unsigned int cpu)
 {
 	unsigned int level, idx;
 	enum cache_type type;

@@ -97,6 +97,3 @@ static int __populate_cache_leaves(unsig
 	}
 	return 0;
 }
-
-DEFINE_SMP_CALL_CACHE_FUNCTION(init_cache_level)
-DEFINE_SMP_CALL_CACHE_FUNCTION(populate_cache_leaves)

arch/mips/kernel/cacheinfo.c +2 -5

@@ -17,7 +17,7 @@ do {								\
 	leaf++;							\
 } while (0)
 
-static int __init_cache_level(unsigned int cpu)
+int init_cache_level(unsigned int cpu)
 {
 	struct cpuinfo_mips *c = &current_cpu_data;
 	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);

@@ -74,7 +74,7 @@ static void fill_cpumask_cluster(int cpu
 			cpumask_set_cpu(cpu1, cpu_map);
 }
 
-static int __populate_cache_leaves(unsigned int cpu)
+int populate_cache_leaves(unsigned int cpu)
 {
 	struct cpuinfo_mips *c = &current_cpu_data;
 	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);

@@ -114,6 +114,3 @@ static int __populate_cache_leaves(unsig
 
 	return 0;
 }
-
-DEFINE_SMP_CALL_CACHE_FUNCTION(init_cache_level)
-DEFINE_SMP_CALL_CACHE_FUNCTION(populate_cache_leaves)

arch/riscv/kernel/cacheinfo.c +2 -5

@@ -113,7 +113,7 @@ static void fill_cacheinfo(struct cachei
 	}
 }
 
-static int __init_cache_level(unsigned int cpu)
+int init_cache_level(unsigned int cpu)
 {
 	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
 	struct device_node *np = of_cpu_device_node_get(cpu);

@@ -155,7 +155,7 @@ static int __init_cache_level(unsigned i
 	return 0;
 }
 
-static int __populate_cache_leaves(unsigned int cpu)
+int populate_cache_leaves(unsigned int cpu)
 {
 	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
 	struct cacheinfo *this_leaf = this_cpu_ci->info_list;

@@ -187,6 +187,3 @@ static int __populate_cache_leaves(unsig
 
 	return 0;
 }
-
-DEFINE_SMP_CALL_CACHE_FUNCTION(init_cache_level)
-DEFINE_SMP_CALL_CACHE_FUNCTION(populate_cache_leaves)

arch/x86/kernel/cpu/cacheinfo.c +2 -5

@@ -985,7 +985,7 @@ static void ci_leaf_init(struct cacheinf
 	this_leaf->priv = base->nb;
 }
 
-static int __init_cache_level(unsigned int cpu)
+int init_cache_level(unsigned int cpu)
 {
 	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);

@@ -1014,7 +1014,7 @@ static void get_cache_id(int cpu, struct
 	id4_regs->id = c->apicid >> index_msb;
 }
 
-static int __populate_cache_leaves(unsigned int cpu)
+int populate_cache_leaves(unsigned int cpu)
 {
 	unsigned int idx, ret;
 	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);

@@ -1033,6 +1033,3 @@ static int __populate_cache_leaves(unsig
 
 	return 0;
 }
-
-DEFINE_SMP_CALL_CACHE_FUNCTION(init_cache_level)
-DEFINE_SMP_CALL_CACHE_FUNCTION(populate_cache_leaves)

include/linux/cacheinfo.h +0 ~~-18~~

@@ -79,24 +79,6 @@ struct cpu_cacheinfo {
 	bool cpu_map_populated;
 };
 
-/*
- * Helpers to make sure "func" is executed on the cpu whose cache
- * attributes are being detected
- */
-#define DEFINE_SMP_CALL_CACHE_FUNCTION(func)			\
-static inline void _##func(void *ret)				\
-{								\
-	int cpu = smp_processor_id();				\
-	*(int *)ret = __##func(cpu);				\
-}								\
-								\
-int func(unsigned int cpu)					\
-{								\
-	int ret;						\
-	smp_call_function_single(cpu, _##func, &ret, true);	\
-	return ret;						\
-}
-
 struct cpu_cacheinfo *get_cpu_cacheinfo(unsigned int cpu);
 int init_cache_level(unsigned int cpu);
 int populate_cache_leaves(unsigned int cpu);

tip-bot2 for Thomas Gleixner

merge bot Applied

2021-09-01 08:37 UTC #16 lore raw

[tip: smp/urgent] drivers: base: cacheinfo: Get rid of DEFINE_SMP_CALL_CACHE_FUNCTION()

In reply to Thomas Gleixner

The following commit has been merged into the smp/urgent branch of tip:

Commit-ID:     4b92d4add5f6dcf21275185c997d6ecb800054cd
Gitweb:        https://git.kernel.org/tip/4b92d4add5f6dcf21275185c997d6ecb800054cd
Author:        Thomas Gleixner <[email protected]>
AuthorDate:    Tue, 31 Aug 2021 13:48:34 +02:00
Committer:     Thomas Gleixner <[email protected]>
CommitterDate: Wed, 01 Sep 2021 10:29:10 +02:00

drivers: base: cacheinfo: Get rid of DEFINE_SMP_CALL_CACHE_FUNCTION()

Fixes 8571890e1513 ("arm64: Add support for ACPI based firmware tables")

Reported-by Guenter Roeck <[email protected]>

Signed-off-by Thomas Gleixner <[email protected]>

Tested-by Guenter Roeck <[email protected]>

Acked-by Will Deacon <[email protected]>

Acked-by Peter Zijlstra <[email protected]>

Link https://lore.kernel.org/r/871r69ersb.ffs@tglx open here

---
 arch/arm64/kernel/cacheinfo.c   |  7 ++-----
 arch/mips/kernel/cacheinfo.c    |  7 ++-----
 arch/riscv/kernel/cacheinfo.c   |  7 ++-----
 arch/x86/kernel/cpu/cacheinfo.c |  7 ++-----
 include/linux/cacheinfo.h       | 18 ------------------
 5 files changed, 8 insertions(+), 38 deletions(-)

arch/arm64/kernel/cacheinfo.c +2 -5

index 7fa6828..587543c 100644
@@ -43,7 +43,7 @@ static void ci_leaf_init(struct cacheinfo *this_leaf,
 	this_leaf->type = type;
 }
 
-static int __init_cache_level(unsigned int cpu)
+int init_cache_level(unsigned int cpu)
 {
 	unsigned int ctype, level, leaves, fw_level;
 	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);

@@ -78,7 +78,7 @@ static int __init_cache_level(unsigned int cpu)
 	return 0;
 }
 
-static int __populate_cache_leaves(unsigned int cpu)
+int populate_cache_leaves(unsigned int cpu)
 {
 	unsigned int level, idx;
 	enum cache_type type;

@@ -97,6 +97,3 @@ static int __populate_cache_leaves(unsigned int cpu)
 	}
 	return 0;
 }
-
-DEFINE_SMP_CALL_CACHE_FUNCTION(init_cache_level)
-DEFINE_SMP_CALL_CACHE_FUNCTION(populate_cache_leaves)

arch/mips/kernel/cacheinfo.c +2 -5

index 53d8ea7..495dd05 100644
@@ -17,7 +17,7 @@ do {								\
 	leaf++;							\
 } while (0)
 
-static int __init_cache_level(unsigned int cpu)
+int init_cache_level(unsigned int cpu)
 {
 	struct cpuinfo_mips *c = &current_cpu_data;
 	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);

@@ -74,7 +74,7 @@ static void fill_cpumask_cluster(int cpu, cpumask_t *cpu_map)
 			cpumask_set_cpu(cpu1, cpu_map);
 }
 
-static int __populate_cache_leaves(unsigned int cpu)
+int populate_cache_leaves(unsigned int cpu)
 {
 	struct cpuinfo_mips *c = &current_cpu_data;
 	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);

@@ -114,6 +114,3 @@ static int __populate_cache_leaves(unsigned int cpu)
 
 	return 0;
 }
-
-DEFINE_SMP_CALL_CACHE_FUNCTION(init_cache_level)
-DEFINE_SMP_CALL_CACHE_FUNCTION(populate_cache_leaves)

arch/riscv/kernel/cacheinfo.c +2 -5

index d867813..90deabf 100644
@@ -113,7 +113,7 @@ static void fill_cacheinfo(struct cacheinfo **this_leaf,
 	}
 }
 
-static int __init_cache_level(unsigned int cpu)
+int init_cache_level(unsigned int cpu)
 {
 	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
 	struct device_node *np = of_cpu_device_node_get(cpu);

@@ -155,7 +155,7 @@ static int __init_cache_level(unsigned int cpu)
 	return 0;
 }
 
-static int __populate_cache_leaves(unsigned int cpu)
+int populate_cache_leaves(unsigned int cpu)
 {
 	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
 	struct cacheinfo *this_leaf = this_cpu_ci->info_list;

@@ -187,6 +187,3 @@ static int __populate_cache_leaves(unsigned int cpu)
 
 	return 0;
 }
-
-DEFINE_SMP_CALL_CACHE_FUNCTION(init_cache_level)
-DEFINE_SMP_CALL_CACHE_FUNCTION(populate_cache_leaves)

arch/x86/kernel/cpu/cacheinfo.c +2 -5

index d66af29..b5e36bd 100644
@@ -985,7 +985,7 @@ static void ci_leaf_init(struct cacheinfo *this_leaf,
 	this_leaf->priv = base->nb;
 }
 
-static int __init_cache_level(unsigned int cpu)
+int init_cache_level(unsigned int cpu)
 {
 	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);

@@ -1014,7 +1014,7 @@ static void get_cache_id(int cpu, struct _cpuid4_info_regs *id4_regs)
 	id4_regs->id = c->apicid >> index_msb;
 }
 
-static int __populate_cache_leaves(unsigned int cpu)
+int populate_cache_leaves(unsigned int cpu)
 {
 	unsigned int idx, ret;
 	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);

@@ -1033,6 +1033,3 @@ static int __populate_cache_leaves(unsigned int cpu)
 
 	return 0;
 }
-
-DEFINE_SMP_CALL_CACHE_FUNCTION(init_cache_level)
-DEFINE_SMP_CALL_CACHE_FUNCTION(populate_cache_leaves)

include/linux/cacheinfo.h +0 ~~-18~~

index 4f72b47..2f909ed 100644
@@ -79,24 +79,6 @@ struct cpu_cacheinfo {
 	bool cpu_map_populated;
 };
 
-/*
- * Helpers to make sure "func" is executed on the cpu whose cache
- * attributes are being detected
- */
-#define DEFINE_SMP_CALL_CACHE_FUNCTION(func)			\
-static inline void _##func(void *ret)				\
-{								\
-	int cpu = smp_processor_id();				\
-	*(int *)ret = __##func(cpu);				\
-}								\
-								\
-int func(unsigned int cpu)					\
-{								\
-	int ret;						\
-	smp_call_function_single(cpu, _##func, &ret, true);	\
-	return ret;						\
-}
-
 struct cpu_cacheinfo *get_cpu_cacheinfo(unsigned int cpu);
 int init_cache_level(unsigned int cpu);
 int populate_cache_leaves(unsigned int cpu);