From: Mark Rutland <mark.rutland@arm.com>
To: Zenghui Yu <yuzenghui@huawei.com>, maz@kernel.org
Cc: linux-arm-kernel@lists.infradead.org, will@kernel.org,
elver@google.com, paulmck@kernel.org, peterz@infradead.org,
catalin.marinas@arm.com, james.morse@arm.com, dvyukov@google.com,
wanghaibin.wang@huawei.com
Subject: Re: [PATCHv2 09/11] arm64: entry: fix non-NMI kernel<->kernel transitions
Date: Tue, 27 Apr 2021 15:43:33 +0100 [thread overview]
Message-ID: <20210427144333.GD37475@C02TD0UTHF1T.local> (raw)
In-Reply-To: <d7ee0514-9be0-1c38-c280-045989e5778a@huawei.com>
On Tue, Apr 27, 2021 at 03:15:39PM +0800, Zenghui Yu wrote:
> On 2021/4/26 21:39, Zenghui Yu wrote:
> > Hi Mark,
> >
> > On 2021/4/26 17:21, Mark Rutland wrote:
> >
> > > diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
> > > index 6acfc5e6b5e0..7d46c74a8706 100644
> > > --- a/arch/arm64/kernel/entry.S
> > > +++ b/arch/arm64/kernel/entry.S
> > > @@ -292,6 +292,8 @@ alternative_else_nop_endif
> > > alternative_if ARM64_HAS_IRQ_PRIO_MASKING
> > > mrs_s x20, SYS_ICC_PMR_EL1
> > > str x20, [sp, #S_PMR_SAVE]
> > > + orr x20, x20, #GIC_PRIO_PSR_I_SET
> > > + msr_s SYS_ICC_PMR_EL1, x20
> > > alternative_else_nop_endif
> >
> > While this does fix the lockdep part, it breaks something else. The
> > sleep-in-atomic one stands out (which says, I've seen other splats
> > triggered with this diff), where irqs_disabled() in do_mem_abort() now
> > gets confused by the updated PMR (GIC_PRIO_IRQON | GIC_PRIO_PSR_I_SET).
>
> Seem that this can be addressed by restoring pt_regs->pmr_save into PMR
> in local_daif_inherit() (before we restore the DAIF bits)?
I think so, yes.
Looking at this some more, I'm not sure whether the entry code should:
* ORR in GIC_PRIO_PSR_I_SET, matching gic_prio_irq_setup
* MOV in (GIC_PRIO_IRQON | GIC_PRIO_PSR_I_SET) matching
gic_prio_kentry_setup
... as it's not clear to me why the two differ, nor whether we can
follow the same approach in both cases.
I'll dig a bit more through the history and see what I can dredge up,
unless Marc has any ideas.
Thanks,
Mark.
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next prev parent reply other threads:[~2021-04-27 14:45 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 ` [PATCHv2 02/11] arm64: mark idle code as noinstr Mark Rutland
2020-11-30 11:59 ` [PATCHv2 03/11] arm64: entry: mark entry " 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 [this message]
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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