From: Borislav Petkov <bp@alien8.de>
To: James Morse <james.morse@arm.com>
Cc: jonathan.zhang@cavium.com, Rafael Wysocki <rjw@rjwysocki.net>,
Tony Luck <tony.luck@intel.com>,
linux-mm@kvack.org, Marc Zyngier <marc.zyngier@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Tyler Baicar <tbaicar@codeaurora.org>,
Will Deacon <will.deacon@arm.com>,
Dongjiu Geng <gengdongjiu@huawei.com>,
linux-acpi@vger.kernel.org, Punit Agrawal <punit.agrawal@arm.com>,
Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
kvmarm@lists.cs.columbia.edu,
linux-arm-kernel@lists.infradead.org, Len Brown <lenb@kernel.org>
Subject: Re: [PATCH v6 07/18] arm64: KVM/mm: Move SEA handling behind a single 'claim' interface
Date: Fri, 12 Oct 2018 12:02:12 +0200 [thread overview]
Message-ID: <20181012100212.GA580@zn.tnic> (raw)
In-Reply-To: <20180921221705.6478-8-james.morse@arm.com>
On Fri, Sep 21, 2018 at 11:16:54PM +0100, James Morse wrote:
> To split up APEIs in_nmi() path, we need the nmi-like callers to always
> be in_nmi(). Add a helper to do the work and claim the notification.
>
> When KVM or the arch code takes an exception that might be a RAS
> notification, it asks the APEI firmware-first code whether it wants
> to claim the exception. We can then go on to see if (a future)
> kernel-first mechanism wants to claim the notification, before
> falling through to the existing default behaviour.
>
> The NOTIFY_SEA code was merged before we had multiple, possibly
> interacting, NMI-like notifications and the need to consider kernel
> first in the future. Make the 'claiming' behaviour explicit.
>
> As we're restructuring the APEI code to allow multiple NMI-like
> notifications, any notification that might interrupt interrupts-masked
> code must always be wrapped in nmi_enter()/nmi_exit(). This allows APEI
> to use in_nmi() to use the right fixmap entries.
>
> We mask SError over this window to prevent an asynchronous RAS error
> arriving and tripping 'nmi_enter()'s BUG_ON(in_nmi()).
>
> Signed-off-by: James Morse <james.morse@arm.com>
> Acked-by: Marc Zyngier <marc.zyngier@arm.com>
> Tested-by: Tyler Baicar <tbaicar@codeaurora.org>
...
> diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
> index ed46dc188b22..a9b8bba014b5 100644
> --- a/arch/arm64/kernel/acpi.c
> +++ b/arch/arm64/kernel/acpi.c
> @@ -28,8 +28,10 @@
> #include <linux/smp.h>
> #include <linux/serial_core.h>
>
> +#include <acpi/ghes.h>
> #include <asm/cputype.h>
> #include <asm/cpu_ops.h>
> +#include <asm/daifflags.h>
> #include <asm/pgtable.h>
> #include <asm/smp_plat.h>
>
> @@ -257,3 +259,30 @@ pgprot_t __acpi_get_mem_attribute(phys_addr_t addr)
> return __pgprot(PROT_NORMAL_NC);
> return __pgprot(PROT_DEVICE_nGnRnE);
> }
> +
> +/*
> + * Claim Synchronous External Aborts as a firmware first notification.
> + *
> + * Used by KVM and the arch do_sea handler.
> + * @regs may be NULL when called from process context.
> + */
> +int apei_claim_sea(struct pt_regs *regs)
> +{
> + int err = -ENOENT;
> + unsigned long current_flags = arch_local_save_flags();
> +
> + if (!IS_ENABLED(CONFIG_ACPI_APEI_SEA))
> + return err;
I don't know what side effects arch_local_save_flags() has on ARM but if
we return here, it looks to me like useless work.
--
Regards/Gruss,
Boris.
Good mailing practices for 400: avoid top-posting and trim the reply.
WARNING: multiple messages have this Message-ID (diff)
From: Borislav Petkov <bp@alien8.de>
To: James Morse <james.morse@arm.com>
Cc: linux-acpi@vger.kernel.org, kvmarm@lists.cs.columbia.edu,
linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org,
Marc Zyngier <marc.zyngier@arm.com>,
Christoffer Dall <christoffer.dall@arm.com>,
Will Deacon <will.deacon@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
Rafael Wysocki <rjw@rjwysocki.net>, Len Brown <lenb@kernel.org>,
Tony Luck <tony.luck@intel.com>,
Tyler Baicar <tbaicar@codeaurora.org>,
Dongjiu Geng <gengdongjiu@huawei.com>,
Xie XiuQi <xiexiuqi@huawei.com>,
Punit Agrawal <punit.agrawal@arm.com>,
jonathan.zhang@cavium.com
Subject: Re: [PATCH v6 07/18] arm64: KVM/mm: Move SEA handling behind a single 'claim' interface
Date: Fri, 12 Oct 2018 12:02:12 +0200 [thread overview]
Message-ID: <20181012100212.GA580@zn.tnic> (raw)
In-Reply-To: <20180921221705.6478-8-james.morse@arm.com>
On Fri, Sep 21, 2018 at 11:16:54PM +0100, James Morse wrote:
> To split up APEIs in_nmi() path, we need the nmi-like callers to always
> be in_nmi(). Add a helper to do the work and claim the notification.
>
> When KVM or the arch code takes an exception that might be a RAS
> notification, it asks the APEI firmware-first code whether it wants
> to claim the exception. We can then go on to see if (a future)
> kernel-first mechanism wants to claim the notification, before
> falling through to the existing default behaviour.
>
> The NOTIFY_SEA code was merged before we had multiple, possibly
> interacting, NMI-like notifications and the need to consider kernel
> first in the future. Make the 'claiming' behaviour explicit.
>
> As we're restructuring the APEI code to allow multiple NMI-like
> notifications, any notification that might interrupt interrupts-masked
> code must always be wrapped in nmi_enter()/nmi_exit(). This allows APEI
> to use in_nmi() to use the right fixmap entries.
>
> We mask SError over this window to prevent an asynchronous RAS error
> arriving and tripping 'nmi_enter()'s BUG_ON(in_nmi()).
>
> Signed-off-by: James Morse <james.morse@arm.com>
> Acked-by: Marc Zyngier <marc.zyngier@arm.com>
> Tested-by: Tyler Baicar <tbaicar@codeaurora.org>
...
> diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
> index ed46dc188b22..a9b8bba014b5 100644
> --- a/arch/arm64/kernel/acpi.c
> +++ b/arch/arm64/kernel/acpi.c
> @@ -28,8 +28,10 @@
> #include <linux/smp.h>
> #include <linux/serial_core.h>
>
> +#include <acpi/ghes.h>
> #include <asm/cputype.h>
> #include <asm/cpu_ops.h>
> +#include <asm/daifflags.h>
> #include <asm/pgtable.h>
> #include <asm/smp_plat.h>
>
> @@ -257,3 +259,30 @@ pgprot_t __acpi_get_mem_attribute(phys_addr_t addr)
> return __pgprot(PROT_NORMAL_NC);
> return __pgprot(PROT_DEVICE_nGnRnE);
> }
> +
> +/*
> + * Claim Synchronous External Aborts as a firmware first notification.
> + *
> + * Used by KVM and the arch do_sea handler.
> + * @regs may be NULL when called from process context.
> + */
> +int apei_claim_sea(struct pt_regs *regs)
> +{
> + int err = -ENOENT;
> + unsigned long current_flags = arch_local_save_flags();
> +
> + if (!IS_ENABLED(CONFIG_ACPI_APEI_SEA))
> + return err;
I don't know what side effects arch_local_save_flags() has on ARM but if
we return here, it looks to me like useless work.
--
Regards/Gruss,
Boris.
Good mailing practices for 400: avoid top-posting and trim the reply.
WARNING: multiple messages have this Message-ID (diff)
From: bp@alien8.de (Borislav Petkov)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v6 07/18] arm64: KVM/mm: Move SEA handling behind a single 'claim' interface
Date: Fri, 12 Oct 2018 12:02:12 +0200 [thread overview]
Message-ID: <20181012100212.GA580@zn.tnic> (raw)
In-Reply-To: <20180921221705.6478-8-james.morse@arm.com>
On Fri, Sep 21, 2018 at 11:16:54PM +0100, James Morse wrote:
> To split up APEIs in_nmi() path, we need the nmi-like callers to always
> be in_nmi(). Add a helper to do the work and claim the notification.
>
> When KVM or the arch code takes an exception that might be a RAS
> notification, it asks the APEI firmware-first code whether it wants
> to claim the exception. We can then go on to see if (a future)
> kernel-first mechanism wants to claim the notification, before
> falling through to the existing default behaviour.
>
> The NOTIFY_SEA code was merged before we had multiple, possibly
> interacting, NMI-like notifications and the need to consider kernel
> first in the future. Make the 'claiming' behaviour explicit.
>
> As we're restructuring the APEI code to allow multiple NMI-like
> notifications, any notification that might interrupt interrupts-masked
> code must always be wrapped in nmi_enter()/nmi_exit(). This allows APEI
> to use in_nmi() to use the right fixmap entries.
>
> We mask SError over this window to prevent an asynchronous RAS error
> arriving and tripping 'nmi_enter()'s BUG_ON(in_nmi()).
>
> Signed-off-by: James Morse <james.morse@arm.com>
> Acked-by: Marc Zyngier <marc.zyngier@arm.com>
> Tested-by: Tyler Baicar <tbaicar@codeaurora.org>
...
> diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
> index ed46dc188b22..a9b8bba014b5 100644
> --- a/arch/arm64/kernel/acpi.c
> +++ b/arch/arm64/kernel/acpi.c
> @@ -28,8 +28,10 @@
> #include <linux/smp.h>
> #include <linux/serial_core.h>
>
> +#include <acpi/ghes.h>
> #include <asm/cputype.h>
> #include <asm/cpu_ops.h>
> +#include <asm/daifflags.h>
> #include <asm/pgtable.h>
> #include <asm/smp_plat.h>
>
> @@ -257,3 +259,30 @@ pgprot_t __acpi_get_mem_attribute(phys_addr_t addr)
> return __pgprot(PROT_NORMAL_NC);
> return __pgprot(PROT_DEVICE_nGnRnE);
> }
> +
> +/*
> + * Claim Synchronous External Aborts as a firmware first notification.
> + *
> + * Used by KVM and the arch do_sea handler.
> + * @regs may be NULL when called from process context.
> + */
> +int apei_claim_sea(struct pt_regs *regs)
> +{
> + int err = -ENOENT;
> + unsigned long current_flags = arch_local_save_flags();
> +
> + if (!IS_ENABLED(CONFIG_ACPI_APEI_SEA))
> + return err;
I don't know what side effects arch_local_save_flags() has on ARM but if
we return here, it looks to me like useless work.
--
Regards/Gruss,
Boris.
Good mailing practices for 400: avoid top-posting and trim the reply.
next prev parent reply other threads:[~2018-10-12 10:02 UTC|newest]
Thread overview: 123+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-21 22:16 [PATCH v6 00/18] APEI in_nmi() rework James Morse
2018-09-21 22:16 ` James Morse
2018-09-21 22:16 ` James Morse
2018-09-21 22:16 ` [PATCH v6 01/18] ACPI / APEI: Move the estatus queue code up, and under its own ifdef James Morse
2018-09-21 22:16 ` James Morse
2018-09-21 22:16 ` James Morse
2018-09-21 22:16 ` [PATCH v6 02/18] ACPI / APEI: Generalise the estatus queue's add/remove and notify code James Morse
2018-09-21 22:16 ` James Morse
2018-09-21 22:16 ` James Morse
2018-09-21 22:16 ` [PATCH v6 03/18] ACPI / APEI: don't wait to serialise with oops messages when panic()ing James Morse
2018-09-21 22:16 ` James Morse
2018-09-21 22:16 ` James Morse
2018-09-21 22:16 ` [PATCH v6 04/18] ACPI / APEI: Switch NOTIFY_SEA to use the estatus queue James Morse
2018-09-21 22:16 ` James Morse
2018-09-21 22:16 ` James Morse
2018-09-28 17:04 ` Borislav Petkov
2018-09-28 17:04 ` Borislav Petkov
2018-09-28 17:04 ` Borislav Petkov
2018-09-21 22:16 ` [PATCH v6 05/18] ACPI / APEI: Make estatus queue a Kconfig symbol James Morse
2018-09-21 22:16 ` James Morse
2018-09-21 22:16 ` James Morse
2018-10-01 17:59 ` Borislav Petkov
2018-10-01 17:59 ` Borislav Petkov
2018-10-01 17:59 ` Borislav Petkov
2018-10-03 17:50 ` James Morse
2018-10-03 17:50 ` James Morse
2018-10-03 17:50 ` James Morse
2018-10-04 17:34 ` Borislav Petkov
2018-10-04 17:34 ` Borislav Petkov
2018-10-04 17:34 ` Borislav Petkov
2018-10-12 17:17 ` James Morse
2018-10-12 17:17 ` James Morse
2018-10-12 17:17 ` James Morse
2018-10-12 18:10 ` Borislav Petkov
2018-10-12 18:10 ` Borislav Petkov
2018-10-12 18:10 ` Borislav Petkov
2018-09-21 22:16 ` [PATCH v6 06/18] KVM: arm/arm64: Add kvm_ras.h to collect kvm specific RAS plumbing James Morse
2018-09-21 22:16 ` James Morse
2018-09-21 22:16 ` James Morse
2018-10-12 9:57 ` Borislav Petkov
2018-10-12 9:57 ` Borislav Petkov
2018-10-12 9:57 ` Borislav Petkov
2018-10-12 17:18 ` James Morse
2018-10-12 17:18 ` James Morse
2018-10-12 17:18 ` James Morse
2018-09-21 22:16 ` [PATCH v6 07/18] arm64: KVM/mm: Move SEA handling behind a single 'claim' interface James Morse
2018-09-21 22:16 ` James Morse
2018-09-21 22:16 ` James Morse
2018-10-12 10:02 ` Borislav Petkov [this message]
2018-10-12 10:02 ` Borislav Petkov
2018-10-12 10:02 ` Borislav Petkov
2018-10-12 17:18 ` James Morse
2018-10-12 17:18 ` James Morse
2018-10-12 17:18 ` James Morse
2018-09-21 22:16 ` [PATCH v6 08/18] ACPI / APEI: Move locking to the notification helper James Morse
2018-09-21 22:16 ` James Morse
2018-09-21 22:16 ` James Morse
2018-10-12 11:08 ` Borislav Petkov
2018-10-12 11:08 ` Borislav Petkov
2018-10-12 11:08 ` Borislav Petkov
2018-09-21 22:16 ` [PATCH v6 09/18] ACPI / APEI: Let the notification helper specify the fixmap slot James Morse
2018-09-21 22:16 ` James Morse
2018-09-21 22:16 ` James Morse
2018-10-12 11:14 ` Borislav Petkov
2018-10-12 11:14 ` Borislav Petkov
2018-10-12 11:14 ` Borislav Petkov
2018-09-21 22:16 ` [PATCH v6 10/18] ACPI / APEI: preparatory split of ghes->estatus James Morse
2018-09-21 22:16 ` James Morse
2018-09-21 22:16 ` James Morse
2018-10-12 16:37 ` Borislav Petkov
2018-10-12 16:37 ` Borislav Petkov
2018-10-12 16:37 ` Borislav Petkov
2018-09-21 22:16 ` [PATCH v6 11/18] ACPI / APEI: Remove silent flag from ghes_read_estatus() James Morse
2018-09-21 22:16 ` James Morse
2018-09-21 22:16 ` James Morse
2018-10-12 16:55 ` Borislav Petkov
2018-10-12 16:55 ` Borislav Petkov
2018-10-12 16:55 ` Borislav Petkov
2018-09-21 22:16 ` [PATCH v6 12/18] ACPI / APEI: Don't store CPER records physical address in struct ghes James Morse
2018-09-21 22:16 ` James Morse
2018-09-21 22:16 ` James Morse
2018-09-21 22:17 ` [PATCH v6 13/18] ACPI / APEI: Don't update struct ghes' flags in read/clear estatus James Morse
2018-09-21 22:17 ` James Morse
2018-09-21 22:17 ` James Morse
2018-10-12 17:14 ` Borislav Petkov
2018-10-12 17:14 ` Borislav Petkov
2018-10-12 17:14 ` Borislav Petkov
2018-09-21 22:17 ` [PATCH v6 14/18] ACPI / APEI: Split ghes_read_estatus() to read CPER length James Morse
2018-09-21 22:17 ` James Morse
2018-09-21 22:17 ` James Morse
2018-10-12 17:25 ` Borislav Petkov
2018-10-12 17:25 ` Borislav Petkov
2018-10-12 17:25 ` Borislav Petkov
2018-09-21 22:17 ` [PATCH v6 15/18] ACPI / APEI: Only use queued estatus entry during _in_nmi_notify_one() James Morse
2018-09-21 22:17 ` James Morse
2018-09-21 22:17 ` James Morse
2018-10-12 17:34 ` Borislav Petkov
2018-10-12 17:34 ` Borislav Petkov
2018-10-12 17:34 ` Borislav Petkov
2018-09-21 22:17 ` [PATCH v6 16/18] ACPI / APEI: Split fixmap pages for arm64 NMI-like notifications James Morse
2018-09-21 22:17 ` James Morse
2018-09-21 22:17 ` James Morse
2018-09-21 22:17 ` [PATCH v6 17/18] mm/memory-failure: increase queued recovery work's priority James Morse
2018-09-21 22:17 ` James Morse
2018-09-21 22:17 ` James Morse
2018-10-15 16:49 ` Borislav Petkov
2018-10-15 16:49 ` Borislav Petkov
2018-10-15 16:49 ` Borislav Petkov
2018-10-16 7:43 ` Peter Zijlstra
2018-10-16 7:43 ` Peter Zijlstra
2018-10-16 7:43 ` Peter Zijlstra
2018-09-21 22:17 ` [PATCH v6 18/18] arm64: acpi: Make apei_claim_sea() synchronise with APEI's irq work James Morse
2018-09-21 22:17 ` James Morse
2018-09-21 22:17 ` James Morse
2018-09-25 12:45 ` [PATCH v6 00/18] APEI in_nmi() rework Borislav Petkov
2018-09-25 12:45 ` Borislav Petkov
2018-09-25 12:45 ` Borislav Petkov
2018-10-03 17:50 ` James Morse
2018-10-03 17:50 ` James Morse
2018-10-03 17:50 ` James Morse
2018-10-04 15:15 ` Borislav Petkov
2018-10-04 15:15 ` Borislav Petkov
2018-10-04 15:15 ` Borislav Petkov
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