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arm64: abort counter_read_on_cpu() when irqs_disabled() 

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: Will Deacon <will@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20201113155328.4194-1-ionela.voinescu@arm.com
[catalin.marinas@arm.com: modified following Mark's comment]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Ionela Voinescu 2020-11-13 15:53:28 +00:00 committed by Catalin Marinas
parent 68c5debcc0
commit 7449042252
1 changed files with 7 additions and 0 deletions
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7
arch/arm64/kernel/topology.c
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@ -343,9 +343,16 @@ static void cpu_read_constcnt(void *val)
static inline
int counters_read_on_cpu(int cpu, smp_call_func_t func, u64 *val)
{
/*
* Abort call on counterless CPU or when interrupts are
* disabled - can lead to deadlock in smp sync call.
*/
if (!cpu_has_amu_feat(cpu))
return -EOPNOTSUPP;
if (WARN_ON_ONCE(irqs_disabled()))
return -EPERM;
smp_call_function_single(cpu, func, val, 1);
return 0;