From: Catalin Marinas <catalin.marinas@arm.com>
To: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com,
Andrew Morton <akpm@linux-foundation.org>,
Will Deacon <will@kernel.org>, Dmitry Vyukov <dvyukov@google.com>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
Alexander Potapenko <glider@google.com>,
Marco Elver <elver@google.com>,
Evgenii Stepanov <eugenis@google.com>,
Branislav Rankov <Branislav.Rankov@arm.com>,
Andrey Konovalov <andreyknvl@google.com>
Subject: Re: [PATCH v13 6/7] arm64: mte: Report async tag faults before suspend
Date: Fri, 12 Feb 2021 13:19:44 +0000 [thread overview]
Message-ID: <20210212131944.GB7718@arm.com> (raw)
In-Reply-To: <20210212120015.GA18281@e121166-lin.cambridge.arm.com>
On Fri, Feb 12, 2021 at 12:00:15PM +0000, Lorenzo Pieralisi wrote:
> On Thu, Feb 11, 2021 at 03:33:52PM +0000, Vincenzo Frascino wrote:
> > +void mte_suspend_enter(void)
> > +{
> > + if (!system_supports_mte())
> > + return;
> > +
> > + /*
> > + * The barriers are required to guarantee that the indirect writes
> > + * to TFSR_EL1 are synchronized before we report the state.
> > + */
> > + dsb(nsh);
> > + isb();
> > +
> > + /* Report SYS_TFSR_EL1 before suspend entry */
> > + mte_check_tfsr_el1();
> > +}
> > +
> > void mte_suspend_exit(void)
> > {
> > if (!system_supports_mte())
> > return;
> >
> > update_gcr_el1_excl(gcr_kernel_excl);
> > +
> > + /* Clear SYS_TFSR_EL1 after suspend exit */
> > + write_sysreg_s(0, SYS_TFSR_EL1);
>
> AFAICS it is not needed, it is done already in __cpu_setup() (that is
> called by cpu_resume on return from cpu_suspend() from firmware).
>
> However, I have a question. We are relying on context switch to set
> sctlr_el1_tfc0 right ? If that's the case, till the thread resuming from
> low power switches context we are running with SCTLR_EL1_TCF0 not
> reflecting the actual value.
I think you have a point here, though not for SCTLR_EL1 as it is already
restored. GCR_EL1 is only updated after some C code has run and may mess
up stack tagging when/if we ever support it. Anyway, something to worry
about later, I think even the boot path gets this wrong.
--
Catalin
next prev parent reply other threads:[~2021-02-12 13:20 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-11 15:33 [PATCH v13 0/7] arm64: ARMv8.5-A: MTE: Add async mode support Vincenzo Frascino
2021-02-11 15:33 ` [PATCH v13 1/7] arm64: mte: Add asynchronous " Vincenzo Frascino
2021-02-12 21:21 ` Andrey Konovalov
2021-02-22 11:14 ` Vincenzo Frascino
2021-02-11 15:33 ` [PATCH v13 2/7] kasan: Add KASAN mode kernel parameter Vincenzo Frascino
2021-02-11 17:50 ` Andrey Konovalov
2021-02-12 11:26 ` Vincenzo Frascino
2021-02-11 15:33 ` [PATCH v13 3/7] kasan: Add report for async mode Vincenzo Frascino
2021-02-11 20:03 ` kernel test robot
2021-02-11 20:13 ` Andrey Konovalov
2021-02-12 11:25 ` Vincenzo Frascino
2021-02-12 14:47 ` Andrey Konovalov
2021-02-11 23:03 ` kernel test robot
2021-02-11 15:33 ` [PATCH v13 4/7] arm64: mte: Enable TCO in functions that can read beyond buffer limits Vincenzo Frascino
2021-02-12 17:21 ` Catalin Marinas
2021-02-22 12:08 ` Vincenzo Frascino
2021-02-22 17:58 ` Catalin Marinas
2021-02-23 10:56 ` Vincenzo Frascino
2021-02-23 12:05 ` Catalin Marinas
2021-02-23 12:22 ` Vincenzo Frascino
2021-02-23 12:49 ` Will Deacon
2021-02-23 13:14 ` Catalin Marinas
2021-02-23 14:25 ` Vincenzo Frascino
2021-02-11 15:33 ` [PATCH v13 5/7] arm64: mte: Enable async tag check fault Vincenzo Frascino
2021-02-11 15:33 ` [PATCH v13 6/7] arm64: mte: Report async tag faults before suspend Vincenzo Frascino
2021-02-12 12:00 ` Lorenzo Pieralisi
2021-02-12 12:30 ` Lorenzo Pieralisi
2021-02-12 13:05 ` Vincenzo Frascino
2021-02-12 13:19 ` Catalin Marinas [this message]
2021-02-12 17:24 ` Catalin Marinas
2021-02-11 15:33 ` [PATCH v13 7/7] kasan: don't run tests in async mode Vincenzo Frascino
2021-02-12 0:49 ` kernel test robot
2021-02-12 17:22 ` Catalin Marinas
2021-02-12 21:44 ` Andrey Konovalov
2021-02-22 11:17 ` Vincenzo Frascino
2021-02-22 13:35 ` Andrey Konovalov
2021-02-11 15:45 ` [PATCH v13 0/7] arm64: ARMv8.5-A: MTE: Add async mode support Vincenzo Frascino
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