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From: Mark Rutland <mark.rutland@arm.com>
To: linux-arm-kernel@lists.infradead.org, will@kernel.org
Cc: mark.rutland@arm.com, elver@google.com, paulmck@kernel.org,
	peterz@infradead.org, catalin.marinas@arm.com,
	james.morse@arm.com, dvyukov@google.com
Subject: [PATCHv2 02/11] arm64: mark idle code as noinstr
Date: Mon, 30 Nov 2020 11:59:41 +0000	[thread overview]
Message-ID: <20201130115950.22492-3-mark.rutland@arm.com> (raw)
In-Reply-To: <20201130115950.22492-1-mark.rutland@arm.com>

Core code disables RCU when calling arch_cpu_idle(), so it's not safe
for arch_cpu_idle() or its calees to be instrumented, as the
instrumentation callbacks may attempt to use RCU or other features which
are unsafe to use in this context.

Mark them noinstr to prevent issues.

The use of local_irq_enable() in arch_cpu_idle() is similarly
problematic, and the "sched/idle: Fix arch_cpu_idle() vs tracing" patch
queued in the tip tree addresses that case.

Reported-by: Marco Elver <elver@google.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
---
 arch/arm64/kernel/process.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 4784011cecac..e6e2b8dc361e 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -72,13 +72,13 @@ EXPORT_SYMBOL_GPL(pm_power_off);
 
 void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd);
 
-static void __cpu_do_idle(void)
+static void noinstr __cpu_do_idle(void)
 {
 	dsb(sy);
 	wfi();
 }
 
-static void __cpu_do_idle_irqprio(void)
+static void noinstr __cpu_do_idle_irqprio(void)
 {
 	unsigned long pmr;
 	unsigned long daif_bits;
@@ -108,7 +108,7 @@ static void __cpu_do_idle_irqprio(void)
  *	ensure that interrupts are not masked at the PMR (because the core will
  *	not wake up if we block the wake up signal in the interrupt controller).
  */
-void cpu_do_idle(void)
+void noinstr cpu_do_idle(void)
 {
 	if (system_uses_irq_prio_masking())
 		__cpu_do_idle_irqprio();
@@ -119,7 +119,7 @@ void cpu_do_idle(void)
 /*
  * This is our default idle handler.
  */
-void arch_cpu_idle(void)
+void noinstr arch_cpu_idle(void)
 {
 	/*
 	 * This should do all the clock switching and wait for interrupt
-- 
2.11.0


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  parent reply	other threads:[~2020-11-30 12:01 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-30 11:59 [PATCHv2 00/11] arm64: entry lockdep/rcu/tracing fixes Mark Rutland
2020-11-30 11:59 ` [PATCHv2 01/11] arm64: syscall: exit userspace before unmasking exceptions Mark Rutland
2020-11-30 11:59 ` Mark Rutland [this message]
2020-11-30 11:59 ` [PATCHv2 03/11] arm64: entry: mark entry code as noinstr Mark Rutland
2020-11-30 11:59 ` [PATCHv2 04/11] arm64: entry: move enter_from_user_mode to entry-common.c Mark Rutland
2020-11-30 11:59 ` [PATCHv2 05/11] arm64: entry: prepare ret_to_user for function call Mark Rutland
2020-12-17 17:57   ` Guenter Roeck
2020-12-17 18:38     ` Catalin Marinas
2020-11-30 11:59 ` [PATCHv2 06/11] arm64: entry: move el1 irq/nmi logic to C Mark Rutland
2021-05-06  8:28   ` He Ying
2021-05-06  9:16     ` Mark Rutland
     [not found]       ` <e3843e03-173e-10a6-5b14-0d8c14219e09@huawei.com>
2021-05-06 10:58         ` Mark Rutland
2021-05-07  3:25           ` He Ying
2021-05-07  9:41             ` Mark Rutland
2021-05-07 10:02               ` He Ying
2020-11-30 11:59 ` [PATCHv2 07/11] arm64: entry: fix non-NMI user<->kernel transitions Mark Rutland
2020-11-30 11:59 ` [PATCHv2 08/11] arm64: ptrace: prepare for EL1 irq/rcu tracking Mark Rutland
2020-11-30 11:59 ` [PATCHv2 09/11] arm64: entry: fix non-NMI kernel<->kernel transitions Mark Rutland
2021-04-25  5:29   ` Zenghui Yu
2021-04-26  9:21     ` Mark Rutland
2021-04-26 13:39       ` Zenghui Yu
2021-04-27  7:15         ` Zenghui Yu
2021-04-27 14:43           ` Mark Rutland
2020-11-30 11:59 ` [PATCHv2 10/11] arm64: entry: fix NMI {user, kernel}->kernel transitions Mark Rutland
2020-11-30 11:59 ` [PATCHv2 11/11] arm64: entry: fix EL1 debug transitions Mark Rutland
2020-11-30 13:52 ` [PATCHv2 00/11] arm64: entry lockdep/rcu/tracing fixes Will Deacon

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