[patch V3 11/32] hwtracing/coresight-etm3x: Use cpuhp_setup_state_nocalls_cpuslocked()

[patch V3 11/32] hwtracing/coresight-etm3x: Use cpuhp_setup_state_nocalls_cpuslocked()

[Thomas Gleixner]

From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

etm_probe() holds get_online_cpus() while invoking
cpuhp_setup_state_nocalls().

cpuhp_setup_state_nocalls() invokes get_online_cpus() as well. This is
correct, but prevents the conversion of the hotplug locking to a percpu
rwsem.

Use cpuhp_setup_state_nocalls_cpuslocked() to avoid the nested
call. Convert *_online_cpus() to the new interfaces while at it.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-arm-kernel at lists.infradead.org

---
 drivers/hwtracing/coresight/coresight-etm3x.c |   20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

--- a/drivers/hwtracing/coresight/coresight-etm3x.c
+++ b/drivers/hwtracing/coresight/coresight-etm3x.c
@@ -587,7 +587,7 @@ static void etm_disable_sysfs(struct cor
 	 * after cpu online mask indicates the cpu is offline but before the
 	 * DYING hotplug callback is serviced by the ETM driver.
 	 */
-	get_online_cpus();
+	cpus_read_lock();
 	spin_lock(&drvdata->spinlock);
 
 	/*
@@ -597,7 +597,7 @@ static void etm_disable_sysfs(struct cor
 	smp_call_function_single(drvdata->cpu, etm_disable_hw, drvdata, 1);
 
 	spin_unlock(&drvdata->spinlock);
-	put_online_cpus();
+	cpus_read_unlock();
 
 	dev_info(drvdata->dev, "ETM tracing disabled\n");
 }
@@ -795,7 +795,7 @@ static int etm_probe(struct amba_device
 
 	drvdata->cpu = pdata ? pdata->cpu : 0;
 
-	get_online_cpus();
+	cpus_read_lock();
 	etmdrvdata[drvdata->cpu] = drvdata;
 
 	if (smp_call_function_single(drvdata->cpu,
@@ -803,17 +803,17 @@ static int etm_probe(struct amba_device
 		dev_err(dev, "ETM arch init failed\n");
 
 	if (!etm_count++) {
-		cpuhp_setup_state_nocalls(CPUHP_AP_ARM_CORESIGHT_STARTING,
-					  "arm/coresight:starting",
-					  etm_starting_cpu, etm_dying_cpu);
-		ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
-						"arm/coresight:online",
-						etm_online_cpu, NULL);
+		cpuhp_setup_state_nocalls_cpuslocked(CPUHP_AP_ARM_CORESIGHT_STARTING,
+						     "arm/coresight:starting",
+						     etm_starting_cpu, etm_dying_cpu);
+		ret = cpuhp_setup_state_nocalls_cpuslocked(CPUHP_AP_ONLINE_DYN,
+							   "arm/coresight:online",
+							   etm_online_cpu, NULL);
 		if (ret < 0)
 			goto err_arch_supported;
 		hp_online = ret;
 	}
-	put_online_cpus();
+	cpus_read_unlock();
 
 	if (etm_arch_supported(drvdata->arch) == false) {
 		ret = -EINVAL;

[patch V3 12/32] hwtracing/coresight-etm4x: Use cpuhp_setup_state_nocalls_cpuslocked()

[Thomas Gleixner]

From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

etm_probe4() holds get_online_cpus() while invoking
cpuhp_setup_state_nocalls().

cpuhp_setup_state_nocalls() invokes get_online_cpus() as well. This is
correct, but prevents the conversion of the hotplug locking to a percpu
rwsem.

Use cpuhp_setup_state_nocalls_cpuslocked() to avoid the nested
call. Convert *_online_cpus() to the new interfaces while at it.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-arm-kernel at lists.infradead.org

---
 drivers/hwtracing/coresight/coresight-etm4x.c |   20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

--- a/drivers/hwtracing/coresight/coresight-etm4x.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x.c
@@ -371,7 +371,7 @@ static void etm4_disable_sysfs(struct co
 	 * after cpu online mask indicates the cpu is offline but before the
 	 * DYING hotplug callback is serviced by the ETM driver.
 	 */
-	get_online_cpus();
+	cpus_read_lock();
 	spin_lock(&drvdata->spinlock);
 
 	/*
@@ -381,7 +381,7 @@ static void etm4_disable_sysfs(struct co
 	smp_call_function_single(drvdata->cpu, etm4_disable_hw, drvdata, 1);
 
 	spin_unlock(&drvdata->spinlock);
-	put_online_cpus();
+	cpus_read_unlock();
 
 	dev_info(drvdata->dev, "ETM tracing disabled\n");
 }
@@ -982,7 +982,7 @@ static int etm4_probe(struct amba_device
 
 	drvdata->cpu = pdata ? pdata->cpu : 0;
 
-	get_online_cpus();
+	cpus_read_lock();
 	etmdrvdata[drvdata->cpu] = drvdata;
 
 	if (smp_call_function_single(drvdata->cpu,
@@ -990,18 +990,18 @@ static int etm4_probe(struct amba_device
 		dev_err(dev, "ETM arch init failed\n");
 
 	if (!etm4_count++) {
-		cpuhp_setup_state_nocalls(CPUHP_AP_ARM_CORESIGHT_STARTING,
-					  "arm/coresight4:starting",
-					  etm4_starting_cpu, etm4_dying_cpu);
-		ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
-						"arm/coresight4:online",
-						etm4_online_cpu, NULL);
+		cpuhp_setup_state_nocalls_cpuslocked(CPUHP_AP_ARM_CORESIGHT_STARTING,
+						     "arm/coresight4:starting",
+						     etm4_starting_cpu, etm4_dying_cpu);
+		ret = cpuhp_setup_state_nocalls_cpuslocked(CPUHP_AP_ONLINE_DYN,
+							   "arm/coresight4:online",
+							   etm4_online_cpu, NULL);
 		if (ret < 0)
 			goto err_arch_supported;
 		hp_online = ret;
 	}
 
-	put_online_cpus();
+	cpus_read_unlock();
 
 	if (etm4_arch_supported(drvdata->arch) == false) {
 		ret = -EINVAL;

[patch V3 14/32] ARM/hw_breakpoint: Use cpuhp_setup_state_cpuslocked()

[Thomas Gleixner]

From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

arch_hw_breakpoint_init() holds get_online_cpus() while registerring the
hotplug callbacks.

cpuhp_setup_state() invokes get_online_cpus() as well. This is correct, but
prevents the conversion of the hotplug locking to a percpu rwsem.

Use cpuhp_setup_state_cpuslocked() to avoid the nested call. Convert
*_online_cpus() to the new interfaces while at it.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: linux-arm-kernel at lists.infradead.org


---
 arch/arm/kernel/hw_breakpoint.c |   11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

--- a/arch/arm/kernel/hw_breakpoint.c
+++ b/arch/arm/kernel/hw_breakpoint.c
@@ -1090,7 +1090,7 @@ static int __init arch_hw_breakpoint_ini
 	 * driven low on this core and there isn't an architected way to
 	 * determine that.
 	 */
-	get_online_cpus();
+	cpus_read_lock();
 	register_undef_hook(&debug_reg_hook);
 
 	/*
@@ -1098,15 +1098,16 @@ static int __init arch_hw_breakpoint_ini
 	 * assume that a halting debugger will leave the world in a nice state
 	 * for us.
 	 */
-	ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "arm/hw_breakpoint:online",
-				dbg_reset_online, NULL);
+	ret = cpuhp_setup_state_cpuslocked(CPUHP_AP_ONLINE_DYN,
+					   "arm/hw_breakpoint:online",
+					   dbg_reset_online, NULL);
 	unregister_undef_hook(&debug_reg_hook);
 	if (WARN_ON(ret < 0) || !cpumask_empty(&debug_err_mask)) {
 		core_num_brps = 0;
 		core_num_wrps = 0;
 		if (ret > 0)
 			cpuhp_remove_state_nocalls(ret);
-		put_online_cpus();
+		cpus_read_unlock();
 		return 0;
 	}
 
@@ -1124,7 +1125,7 @@ static int __init arch_hw_breakpoint_ini
 			TRAP_HWBKPT, "watchpoint debug exception");
 	hook_ifault_code(FAULT_CODE_DEBUG, hw_breakpoint_pending, SIGTRAP,
 			TRAP_HWBKPT, "breakpoint debug exception");
-	put_online_cpus();
+	cpus_read_unlock();
 
 	/* Register PM notifiers. */
 	pm_init();

[patch V3 26/32] arm64: Prevent cpu hotplug rwsem recursion

[Thomas Gleixner]

The text patching functions which are invoked from jump_label and kprobes
code are protected against cpu hotplug at the call sites.

Use stop_machine_cpuslocked() to avoid recursion on the cpu hotplug
rwsem. stop_machine_cpuslocked() contains a lockdep assertion to catch any
unprotected callers.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: linux-arm-kernel at lists.infradead.org
---
 arch/arm64/include/asm/insn.h |    1 -
 arch/arm64/kernel/insn.c      |    5 +++--
 2 files changed, 3 insertions(+), 3 deletions(-)

--- a/arch/arm64/include/asm/insn.h
+++ b/arch/arm64/include/asm/insn.h
@@ -433,7 +433,6 @@ u32 aarch64_set_branch_offset(u32 insn,
 bool aarch64_insn_hotpatch_safe(u32 old_insn, u32 new_insn);
 
 int aarch64_insn_patch_text_nosync(void *addr, u32 insn);
-int aarch64_insn_patch_text_sync(void *addrs[], u32 insns[], int cnt);
 int aarch64_insn_patch_text(void *addrs[], u32 insns[], int cnt);
 
 s32 aarch64_insn_adrp_get_offset(u32 insn);
--- a/arch/arm64/kernel/insn.c
+++ b/arch/arm64/kernel/insn.c
@@ -255,6 +255,7 @@ static int __kprobes aarch64_insn_patch_
 	return ret;
 }
 
+static
 int __kprobes aarch64_insn_patch_text_sync(void *addrs[], u32 insns[], int cnt)
 {
 	struct aarch64_insn_patch patch = {
@@ -267,8 +268,8 @@ int __kprobes aarch64_insn_patch_text_sy
 	if (cnt <= 0)
 		return -EINVAL;
 
-	return stop_machine(aarch64_insn_patch_text_cb, &patch,
-			    cpu_online_mask);
+	return stop_machine_cpuslocked(aarch64_insn_patch_text_cb, &patch,
+				       cpu_online_mask);
 }
 
 int __kprobes aarch64_insn_patch_text(void *addrs[], u32 insns[], int cnt)

[patch V3 27/32] arm: Prevent hotplug rwsem recursion

[Thomas Gleixner]

The text patching functions which are invoked from jump_label and kprobes
code are protected against cpu hotplug at the call sites.

Use stop_machine_cpuslocked() to avoid recursion on the cpu hotplug
rwsem. stop_machine_cpuslocked() contains a lockdep assertion to catch any
unprotected callers.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arm-kernel at lists.infradead.org
Cc: Russell King <linux@armlinux.org.uk>
---
 arch/arm/kernel/patch.c        |    2 +-
 arch/arm/probes/kprobes/core.c |    3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

--- a/arch/arm/kernel/patch.c
+++ b/arch/arm/kernel/patch.c
@@ -124,5 +124,5 @@ void __kprobes patch_text(void *addr, un
 		.insn = insn,
 	};
 
-	stop_machine(patch_text_stop_machine, &patch, NULL);
+	stop_machine_cpuslocked(patch_text_stop_machine, &patch, NULL);
 }
--- a/arch/arm/probes/kprobes/core.c
+++ b/arch/arm/probes/kprobes/core.c
@@ -182,7 +182,8 @@ void __kprobes kprobes_remove_breakpoint
 		.addr = addr,
 		.insn = insn,
 	};
-	stop_machine(__kprobes_remove_breakpoint, &p, cpu_online_mask);
+	stop_machine_cpuslocked(__kprobes_remove_breakpoint, &p,
+				cpu_online_mask);
 }
 
 void __kprobes arch_disarm_kprobe(struct kprobe *p)

[patch V3 11/32] hwtracing/coresight-etm3x: Use cpuhp_setup_state_nocalls_cpuslocked()

[Mathieu Poirier]

On Wed, May 24, 2017 at 10:15:22AM +0200, Thomas Gleixner wrote:
> From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> 
> etm_probe() holds get_online_cpus() while invoking
> cpuhp_setup_state_nocalls().
> 
> cpuhp_setup_state_nocalls() invokes get_online_cpus() as well. This is
> correct, but prevents the conversion of the hotplug locking to a percpu
> rwsem.
> 
> Use cpuhp_setup_state_nocalls_cpuslocked() to avoid the nested
> call. Convert *_online_cpus() to the new interfaces while at it.
> 
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Steven Rostedt <rostedt@goodmis.org>
> Cc: linux-arm-kernel at lists.infradead.org

Acked-by: Mathieu Poirier <mathieu.poirier@linaro.org>

> 
> ---
>  drivers/hwtracing/coresight/coresight-etm3x.c |   20 ++++++++++----------
>  1 file changed, 10 insertions(+), 10 deletions(-)
> 
> --- a/drivers/hwtracing/coresight/coresight-etm3x.c
> +++ b/drivers/hwtracing/coresight/coresight-etm3x.c
> @@ -587,7 +587,7 @@ static void etm_disable_sysfs(struct cor
>  	 * after cpu online mask indicates the cpu is offline but before the
>  	 * DYING hotplug callback is serviced by the ETM driver.
>  	 */
> -	get_online_cpus();
> +	cpus_read_lock();
>  	spin_lock(&drvdata->spinlock);
>  
>  	/*
> @@ -597,7 +597,7 @@ static void etm_disable_sysfs(struct cor
>  	smp_call_function_single(drvdata->cpu, etm_disable_hw, drvdata, 1);
>  
>  	spin_unlock(&drvdata->spinlock);
> -	put_online_cpus();
> +	cpus_read_unlock();
>  
>  	dev_info(drvdata->dev, "ETM tracing disabled\n");
>  }
> @@ -795,7 +795,7 @@ static int etm_probe(struct amba_device
>  
>  	drvdata->cpu = pdata ? pdata->cpu : 0;
>  
> -	get_online_cpus();
> +	cpus_read_lock();
>  	etmdrvdata[drvdata->cpu] = drvdata;
>  
>  	if (smp_call_function_single(drvdata->cpu,
> @@ -803,17 +803,17 @@ static int etm_probe(struct amba_device
>  		dev_err(dev, "ETM arch init failed\n");
>  
>  	if (!etm_count++) {
> -		cpuhp_setup_state_nocalls(CPUHP_AP_ARM_CORESIGHT_STARTING,
> -					  "arm/coresight:starting",
> -					  etm_starting_cpu, etm_dying_cpu);
> -		ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
> -						"arm/coresight:online",
> -						etm_online_cpu, NULL);
> +		cpuhp_setup_state_nocalls_cpuslocked(CPUHP_AP_ARM_CORESIGHT_STARTING,
> +						     "arm/coresight:starting",
> +						     etm_starting_cpu, etm_dying_cpu);
> +		ret = cpuhp_setup_state_nocalls_cpuslocked(CPUHP_AP_ONLINE_DYN,
> +							   "arm/coresight:online",
> +							   etm_online_cpu, NULL);
>  		if (ret < 0)
>  			goto err_arch_supported;
>  		hp_online = ret;
>  	}
> -	put_online_cpus();
> +	cpus_read_unlock();
>  
>  	if (etm_arch_supported(drvdata->arch) == false) {
>  		ret = -EINVAL;
> 
> 

[patch V3 12/32] hwtracing/coresight-etm4x: Use cpuhp_setup_state_nocalls_cpuslocked()

[Mathieu Poirier]

On Wed, May 24, 2017 at 10:15:23AM +0200, Thomas Gleixner wrote:
> From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> 
> etm_probe4() holds get_online_cpus() while invoking
> cpuhp_setup_state_nocalls().
> 
> cpuhp_setup_state_nocalls() invokes get_online_cpus() as well. This is
> correct, but prevents the conversion of the hotplug locking to a percpu
> rwsem.
> 
> Use cpuhp_setup_state_nocalls_cpuslocked() to avoid the nested
> call. Convert *_online_cpus() to the new interfaces while at it.
> 
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Steven Rostedt <rostedt@goodmis.org>
> Cc: linux-arm-kernel at lists.infradead.org

Acked-by: Mathieu Poirier <mathieu.poirier@linaro.org>

> 
> ---
>  drivers/hwtracing/coresight/coresight-etm4x.c |   20 ++++++++++----------
>  1 file changed, 10 insertions(+), 10 deletions(-)
> 
> --- a/drivers/hwtracing/coresight/coresight-etm4x.c
> +++ b/drivers/hwtracing/coresight/coresight-etm4x.c
> @@ -371,7 +371,7 @@ static void etm4_disable_sysfs(struct co
>  	 * after cpu online mask indicates the cpu is offline but before the
>  	 * DYING hotplug callback is serviced by the ETM driver.
>  	 */
> -	get_online_cpus();
> +	cpus_read_lock();
>  	spin_lock(&drvdata->spinlock);
>  
>  	/*
> @@ -381,7 +381,7 @@ static void etm4_disable_sysfs(struct co
>  	smp_call_function_single(drvdata->cpu, etm4_disable_hw, drvdata, 1);
>  
>  	spin_unlock(&drvdata->spinlock);
> -	put_online_cpus();
> +	cpus_read_unlock();
>  
>  	dev_info(drvdata->dev, "ETM tracing disabled\n");
>  }
> @@ -982,7 +982,7 @@ static int etm4_probe(struct amba_device
>  
>  	drvdata->cpu = pdata ? pdata->cpu : 0;
>  
> -	get_online_cpus();
> +	cpus_read_lock();
>  	etmdrvdata[drvdata->cpu] = drvdata;
>  
>  	if (smp_call_function_single(drvdata->cpu,
> @@ -990,18 +990,18 @@ static int etm4_probe(struct amba_device
>  		dev_err(dev, "ETM arch init failed\n");
>  
>  	if (!etm4_count++) {
> -		cpuhp_setup_state_nocalls(CPUHP_AP_ARM_CORESIGHT_STARTING,
> -					  "arm/coresight4:starting",
> -					  etm4_starting_cpu, etm4_dying_cpu);
> -		ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
> -						"arm/coresight4:online",
> -						etm4_online_cpu, NULL);
> +		cpuhp_setup_state_nocalls_cpuslocked(CPUHP_AP_ARM_CORESIGHT_STARTING,
> +						     "arm/coresight4:starting",
> +						     etm4_starting_cpu, etm4_dying_cpu);
> +		ret = cpuhp_setup_state_nocalls_cpuslocked(CPUHP_AP_ONLINE_DYN,
> +							   "arm/coresight4:online",
> +							   etm4_online_cpu, NULL);
>  		if (ret < 0)
>  			goto err_arch_supported;
>  		hp_online = ret;
>  	}
>  
> -	put_online_cpus();
> +	cpus_read_unlock();
>  
>  	if (etm4_arch_supported(drvdata->arch) == false) {
>  		ret = -EINVAL;
> 
>