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From: Alexei Lozovsky <me@ilammy.net>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Alexey Dobriyan <adobriyan@gmail.com>,
	Christoph Lameter <cl@linux.com>,
	LKML <linux-kernel@vger.kernel.org>,
	linux-fsdevel@vger.kernel.org
Subject: [PATCH v2 03/12] powerpc/irq: Use READ_ONCE for IRQ counter reads
Date: Thu, 16 Sep 2021 02:58:39 +0900	[thread overview]
Message-ID: <20210915175848.162260-4-me@ilammy.net> (raw)
In-Reply-To: <20210915175848.162260-1-me@ilammy.net>

Just like with generic IRQ counters in the previous commit,
wrap accesses to per-CPU counters from irq_cpustat_t in READ_ONCE.
Grab that one "hmi_irqs" oddball from struct paca_struct as well.
These memory loads should not be torn, let's make it explicit.

Signed-off-by: Alexei Lozovsky <me@ilammy.net>
---
 arch/powerpc/kernel/irq.c | 40 +++++++++++++++++++--------------------
 1 file changed, 20 insertions(+), 20 deletions(-)

diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 551b653228c4..e5082d8be700 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -581,52 +581,52 @@ int arch_show_interrupts(struct seq_file *p, int prec)
 
 	seq_printf(p, "%*s: ", prec, "LOC");
 	for_each_online_cpu(j)
-		seq_printf(p, "%10u ", per_cpu(irq_stat, j).timer_irqs_event);
+		seq_printf(p, "%10u ", READ_ONCE(per_cpu(irq_stat, j).timer_irqs_event));
         seq_printf(p, "  Local timer interrupts for timer event device\n");
 
 	seq_printf(p, "%*s: ", prec, "BCT");
 	for_each_online_cpu(j)
-		seq_printf(p, "%10u ", per_cpu(irq_stat, j).broadcast_irqs_event);
+		seq_printf(p, "%10u ", READ_ONCE(per_cpu(irq_stat, j).broadcast_irqs_event));
 	seq_printf(p, "  Broadcast timer interrupts for timer event device\n");
 
 	seq_printf(p, "%*s: ", prec, "LOC");
 	for_each_online_cpu(j)
-		seq_printf(p, "%10u ", per_cpu(irq_stat, j).timer_irqs_others);
+		seq_printf(p, "%10u ", READ_ONCE(per_cpu(irq_stat, j).timer_irqs_others));
         seq_printf(p, "  Local timer interrupts for others\n");
 
 	seq_printf(p, "%*s: ", prec, "SPU");
 	for_each_online_cpu(j)
-		seq_printf(p, "%10u ", per_cpu(irq_stat, j).spurious_irqs);
+		seq_printf(p, "%10u ", READ_ONCE(per_cpu(irq_stat, j).spurious_irqs));
 	seq_printf(p, "  Spurious interrupts\n");
 
 	seq_printf(p, "%*s: ", prec, "PMI");
 	for_each_online_cpu(j)
-		seq_printf(p, "%10u ", per_cpu(irq_stat, j).pmu_irqs);
+		seq_printf(p, "%10u ", READ_ONCE(per_cpu(irq_stat, j).pmu_irqs));
 	seq_printf(p, "  Performance monitoring interrupts\n");
 
 	seq_printf(p, "%*s: ", prec, "MCE");
 	for_each_online_cpu(j)
-		seq_printf(p, "%10u ", per_cpu(irq_stat, j).mce_exceptions);
+		seq_printf(p, "%10u ", READ_ONCE(per_cpu(irq_stat, j).mce_exceptions));
 	seq_printf(p, "  Machine check exceptions\n");
 
 #ifdef CONFIG_PPC_BOOK3S_64
 	if (cpu_has_feature(CPU_FTR_HVMODE)) {
 		seq_printf(p, "%*s: ", prec, "HMI");
 		for_each_online_cpu(j)
-			seq_printf(p, "%10u ", paca_ptrs[j]->hmi_irqs);
+			seq_printf(p, "%10u ", READ_ONCE(paca_ptrs[j]->hmi_irqs));
 		seq_printf(p, "  Hypervisor Maintenance Interrupts\n");
 	}
 #endif
 
 	seq_printf(p, "%*s: ", prec, "NMI");
 	for_each_online_cpu(j)
-		seq_printf(p, "%10u ", per_cpu(irq_stat, j).sreset_irqs);
+		seq_printf(p, "%10u ", READ_ONCE(per_cpu(irq_stat, j).sreset_irqs));
 	seq_printf(p, "  System Reset interrupts\n");
 
 #ifdef CONFIG_PPC_WATCHDOG
 	seq_printf(p, "%*s: ", prec, "WDG");
 	for_each_online_cpu(j)
-		seq_printf(p, "%10u ", per_cpu(irq_stat, j).soft_nmi_irqs);
+		seq_printf(p, "%10u ", READ_ONCE(per_cpu(irq_stat, j).soft_nmi_irqs));
 	seq_printf(p, "  Watchdog soft-NMI interrupts\n");
 #endif
 
@@ -634,7 +634,7 @@ int arch_show_interrupts(struct seq_file *p, int prec)
 	if (cpu_has_feature(CPU_FTR_DBELL)) {
 		seq_printf(p, "%*s: ", prec, "DBL");
 		for_each_online_cpu(j)
-			seq_printf(p, "%10u ", per_cpu(irq_stat, j).doorbell_irqs);
+			seq_printf(p, "%10u ", READ_ONCE(per_cpu(irq_stat, j).doorbell_irqs));
 		seq_printf(p, "  Doorbell interrupts\n");
 	}
 #endif
@@ -647,22 +647,22 @@ int arch_show_interrupts(struct seq_file *p, int prec)
  */
 u64 arch_irq_stat_cpu(unsigned int cpu)
 {
-	u64 sum = per_cpu(irq_stat, cpu).timer_irqs_event;
+	u64 sum = READ_ONCE(per_cpu(irq_stat, cpu).timer_irqs_event);
 
-	sum += per_cpu(irq_stat, cpu).broadcast_irqs_event;
-	sum += per_cpu(irq_stat, cpu).pmu_irqs;
-	sum += per_cpu(irq_stat, cpu).mce_exceptions;
-	sum += per_cpu(irq_stat, cpu).spurious_irqs;
-	sum += per_cpu(irq_stat, cpu).timer_irqs_others;
+	sum += READ_ONCE(per_cpu(irq_stat, cpu).broadcast_irqs_event);
+	sum += READ_ONCE(per_cpu(irq_stat, cpu).pmu_irqs);
+	sum += READ_ONCE(per_cpu(irq_stat, cpu).mce_exceptions);
+	sum += READ_ONCE(per_cpu(irq_stat, cpu).spurious_irqs);
+	sum += READ_ONCE(per_cpu(irq_stat, cpu).timer_irqs_others);
 #ifdef CONFIG_PPC_BOOK3S_64
-	sum += paca_ptrs[cpu]->hmi_irqs;
+	sum += READ_ONCE(paca_ptrs[cpu]->hmi_irqs);
 #endif
-	sum += per_cpu(irq_stat, cpu).sreset_irqs;
+	sum += READ_ONCE(per_cpu(irq_stat, cpu).sreset_irqs);
 #ifdef CONFIG_PPC_WATCHDOG
-	sum += per_cpu(irq_stat, cpu).soft_nmi_irqs;
+	sum += READ_ONCE(per_cpu(irq_stat, cpu).soft_nmi_irqs);
 #endif
 #ifdef CONFIG_PPC_DOORBELL
-	sum += per_cpu(irq_stat, cpu).doorbell_irqs;
+	sum += READ_ONCE(per_cpu(irq_stat, cpu).doorbell_irqs);
 #endif
 
 	return sum;
-- 
2.25.1


  parent reply	other threads:[~2021-09-15 17:59 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-10  8:53 /proc/stat interrupt counter wrap-around Alexei Lozovsky
2021-09-11  3:48 ` [PATCH 0/7] proc/stat: Maintain monotonicity of "intr" and "softirq" Alexei Lozovsky
2021-09-11  3:48   ` [PATCH 1/7] genirq: Use unsigned int for irqs_sum Alexei Lozovsky
2021-09-11  3:48   ` [PATCH 2/7] powerpc/irq: arch_irq_stat_cpu() returns unsigned int Alexei Lozovsky
2021-09-11  3:48   ` [PATCH 3/7] x86/irq: " Alexei Lozovsky
2021-09-11  3:48   ` [PATCH 4/7] x86/irq: arch_irq_stat() " Alexei Lozovsky
2021-09-11  3:48   ` [PATCH 5/7] proc/stat: Use unsigned int for "intr" sum Alexei Lozovsky
2021-09-11  3:48   ` [PATCH 6/7] proc/stat: Use unsigned int for "softirq" sum Alexei Lozovsky
2021-09-11  3:48   ` [PATCH 7/7] docs: proc.rst: stat: Note the interrupt counter wrap-around Alexei Lozovsky
2021-09-11  3:59     ` Randy Dunlap
2021-09-12  9:30   ` [PATCH 0/7] proc/stat: Maintain monotonicity of "intr" and "softirq" Alexey Dobriyan
2021-09-12 12:37     ` Alexei Lozovsky
2021-09-14 14:11       ` Thomas Gleixner
2021-09-15  4:24         ` Alexei Lozovsky
2021-09-15 17:58   ` [PATCH v2 00/12] " Alexei Lozovsky
2021-09-15 17:58     ` [PATCH v2 01/12] genirq: Use READ_ONCE for IRQ counter reads Alexei Lozovsky
2021-09-15 17:58     ` [PATCH v2 02/12] genirq: Use unsigned long for IRQ counters Alexei Lozovsky
2021-09-15 17:58     ` Alexei Lozovsky [this message]
2021-09-15 17:58     ` [PATCH v2 04/12] powerpc/irq: " Alexei Lozovsky
2021-09-15 17:58     ` [PATCH v2 05/12] powerpc/irq: Use unsigned long for IRQ counter sum Alexei Lozovsky
2021-09-15 17:58     ` [PATCH v2 06/12] x86/irq: Use READ_ONCE for IRQ counter reads Alexei Lozovsky
2021-09-15 17:58     ` [PATCH v2 07/12] x86/irq: Use unsigned long for IRQ counters Alexei Lozovsky
2021-09-15 17:58     ` [PATCH v2 08/12] x86/irq: Use unsigned long for IRQ counters more Alexei Lozovsky
2021-09-15 17:58     ` [PATCH v2 09/12] x86/irq: Use unsigned long for IRQ counter sum Alexei Lozovsky
2021-09-15 17:58     ` [PATCH v2 10/12] proc/stat: Use unsigned long for "intr" sum Alexei Lozovsky
2021-09-15 17:58     ` [PATCH v2 11/12] proc/stat: Use unsigned long for "softirq" sum Alexei Lozovsky
2021-09-15 17:58     ` [PATCH v2 12/12] docs: proc.rst: stat: Note the interrupt counter wrap-around Alexei Lozovsky

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