diff options
| author | Julien Thierry <julien.thierry@arm.com> | 2019-06-11 10:38:10 +0100 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2019-06-21 15:50:10 +0100 |
| commit | bd82d4bd21880b7c4d5f5756be435095d6ae07b5 (patch) | |
| tree | fdc4ec809f5d0991d9932cebddf7b5821f970f9d /arch/arm64/kernel/smp.c | |
| parent | 17ce302f3117e9518395847a3120c8a108b587b8 (diff) | |
arm64: Fix incorrect irqflag restore for priority masking
When using IRQ priority masking to disable interrupts, in order to deal
with the PSR.I state, local_irq_save() would convert the I bit into a
PMR value (GIC_PRIO_IRQOFF). This resulted in local_irq_restore()
potentially modifying the value of PMR in undesired location due to the
state of PSR.I upon flag saving [1].
In an attempt to solve this issue in a less hackish manner, introduce
a bit (GIC_PRIO_IGNORE_PMR) for the PMR values that can represent
whether PSR.I is being used to disable interrupts, in which case it
takes precedence of the status of interrupt masking via PMR.
GIC_PRIO_PSR_I_SET is chosen such that (<pmr_value> |
GIC_PRIO_PSR_I_SET) does not mask more interrupts than <pmr_value> as
some sections (e.g. arch_cpu_idle(), interrupt acknowledge path)
requires PMR not to mask interrupts that could be signaled to the
CPU when using only PSR.I.
[1] https://www.spinics.net/lists/arm-kernel/msg716956.html
Fixes: 4a503217ce37 ("arm64: irqflags: Use ICC_PMR_EL1 for interrupt masking")
Cc: <stable@vger.kernel.org> # 5.1.x-
Reported-by: Zenghui Yu <yuzenghui@huawei.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Wei Li <liwei391@huawei.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Christoffer Dall <christoffer.dall@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Suzuki K Pouloze <suzuki.poulose@arm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/kernel/smp.c')
| -rw-r--r-- | arch/arm64/kernel/smp.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index bb4b3f07761a..4deaee3c2a33 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -192,11 +192,13 @@ static void init_gic_priority_masking(void) WARN_ON(!(cpuflags & PSR_I_BIT)); - gic_write_pmr(GIC_PRIO_IRQOFF); - /* We can only unmask PSR.I if we can take aborts */ - if (!(cpuflags & PSR_A_BIT)) + if (!(cpuflags & PSR_A_BIT)) { + gic_write_pmr(GIC_PRIO_IRQOFF); write_sysreg(cpuflags & ~PSR_I_BIT, daif); + } else { + gic_write_pmr(GIC_PRIO_IRQON | GIC_PRIO_PSR_I_SET); + } } /* |