From: Ionela Voinescu <ionela.voinescu@arm.com>
To: catalin.marinas@arm.com, mark.rutland@arm.com,
sudeep.holla@arm.com, will@kernel.org
Cc: morten.rasmussen@arm.com, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, ionela.voinescu@arm.com
Subject: [PATCH] arm64: abort counter_read_on_cpu() when irqs_disabled()
Date: Fri, 13 Nov 2020 15:53:28 +0000 [thread overview]
Message-ID: <20201113155328.4194-1-ionela.voinescu@arm.com> (raw)
In-Reply-To: <20201106125334.21570-1-ionela.voinescu@arm.com>
Given that smp_call_function_single() can deadlock when interrupts are
disabled, abort the SMP call if irqs_disabled(). This scenario is
currently not possible given the function's uses, but safeguard this for
potential future uses.
Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
---
arch/arm64/kernel/topology.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c
index 3a083a9a8ef2..e387188741f2 100644
--- a/arch/arm64/kernel/topology.c
+++ b/arch/arm64/kernel/topology.c
@@ -343,7 +343,11 @@ static void cpu_read_constcnt(void *val)
static inline
int counters_read_on_cpu(int cpu, smp_call_func_t func, u64 *val)
{
- if (!cpu_has_amu_feat(cpu))
+ /*
+ * Abort call on counterless CPU or when interrupts are
+ * disabled - can lead to deadlock in smp sync call.
+ */
+ if (!cpu_has_amu_feat(cpu) || unlikely(irqs_disabled()))
return -EOPNOTSUPP;
smp_call_function_single(cpu, func, val, 1);
--
2.17.1
next prev parent reply other threads:[~2020-11-13 15:53 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-06 12:53 [PATCH v4 0/3] arm64: cppc: add FFH support using AMUs Ionela Voinescu
2020-11-06 12:53 ` [PATCH v4 1/3] arm64: wrap and generalise counter read functions Ionela Voinescu
2020-11-13 14:11 ` Sudeep Holla
2020-11-06 12:53 ` [PATCH v4 2/3] arm64: split counter validation function Ionela Voinescu
2020-11-13 14:12 ` Sudeep Holla
2020-11-06 12:53 ` [PATCH v4 3/3] arm64: implement CPPC FFH support using AMUs Ionela Voinescu
2020-11-12 18:00 ` Catalin Marinas
2020-11-13 12:28 ` Ionela Voinescu
2020-11-13 12:54 ` Catalin Marinas
2020-11-13 14:16 ` Sudeep Holla
2020-11-13 16:37 ` Ionela Voinescu
2020-11-13 20:03 ` Catalin Marinas
2020-11-13 15:53 ` Ionela Voinescu [this message]
2020-11-13 16:02 ` [PATCH] arm64: abort counter_read_on_cpu() when irqs_disabled() Mark Rutland
2020-11-13 16:58 ` Ionela Voinescu
2020-11-13 17:30 ` Mark Rutland
2020-11-13 19:55 ` Catalin Marinas
2020-11-13 20:26 ` [PATCH v4 0/3] arm64: cppc: add FFH support using AMUs Catalin Marinas
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