From: Ira Weiny <ira.weiny@intel.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Andy Lutomirski <luto@kernel.org>,
x86@kernel.org, Dave Hansen <dave.hansen@linux.intel.com>,
Dan Williams <dan.j.williams@intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
Fenghua Yu <fenghua.yu@intel.com>,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-nvdimm@lists.01.org, linux-fsdevel@vger.kernel.org,
linux-mm@kvack.org, linux-kselftest@vger.kernel.org
Subject: Re: [PATCH RFC V3 6/9] x86/entry: Pass irqentry_state_t by reference
Date: Sun, 18 Oct 2020 22:37:36 -0700 [thread overview]
Message-ID: <20201019053639.GA3713473@iweiny-DESK2.sc.intel.com> (raw)
In-Reply-To: <87lfg6tjnq.fsf@nanos.tec.linutronix.de>
On Fri, Oct 16, 2020 at 02:55:21PM +0200, Thomas Gleixner wrote:
> On Fri, Oct 16 2020 at 13:45, Peter Zijlstra wrote:
> > On Fri, Oct 09, 2020 at 12:42:55PM -0700, ira.weiny@intel.com wrote:
> >> @@ -238,7 +236,7 @@ noinstr void idtentry_exit_nmi(struct pt_regs *regs, bool restore)
> >>
> >> rcu_nmi_exit();
> >> lockdep_hardirq_exit();
> >> - if (restore)
> >> + if (irq_state->exit_rcu)
> >> lockdep_hardirqs_on(CALLER_ADDR0);
> >> __nmi_exit();
> >> }
> >
> > That's not nice.. The NMI path is different from the IRQ path and has a
> > different variable. Yes, this works, but *groan*.
> >
> > Maybe union them if you want to avoid bloating the structure, but the
> > above makes it really hard to read.
>
> Right, and also that nmi entry thing should not be in x86. Something
> like the untested below as first cleanup.
Ok, I see what Peter was talking about. I've added this patch to the series.
>
> Thanks,
>
> tglx
> ----
> Subject: x86/entry: Move nmi entry/exit into common code
> From: Thomas Gleixner <tglx@linutronix.de>
> Date: Fri, 11 Sep 2020 10:09:56 +0200
>
> Add blurb here.
How about:
To prepare for saving PKRS values across NMI's we lift the
idtentry_[enter|exit]_nmi() to the common code. Rename them to
irqentry_nmi_[enter|exit]() to reflect the new generic nature and store the
state in the same irqentry_state_t structure as the other irqentry_*()
functions. Finally, differentiate the state being stored between the NMI and
IRQ path by adding 'lockdep' to irqentry_state_t.
?
>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> ---
> arch/x86/entry/common.c | 34 ----------------------------------
> arch/x86/include/asm/idtentry.h | 3 ---
> arch/x86/kernel/cpu/mce/core.c | 6 +++---
> arch/x86/kernel/nmi.c | 6 +++---
> arch/x86/kernel/traps.c | 13 +++++++------
> include/linux/entry-common.h | 20 ++++++++++++++++++++
> kernel/entry/common.c | 36 ++++++++++++++++++++++++++++++++++++
> 7 files changed, 69 insertions(+), 49 deletions(-)
>
[snip]
> --- a/include/linux/entry-common.h
> +++ b/include/linux/entry-common.h
> @@ -343,6 +343,7 @@ void irqentry_exit_to_user_mode(struct p
> #ifndef irqentry_state
> typedef struct irqentry_state {
> bool exit_rcu;
> + bool lockdep;
> } irqentry_state_t;
Building on what Peter said do you agree this should be made into a union?
It may not be strictly necessary in this patch but I think it would reflect the
mutual exclusivity better and could be changed easy enough in the follow on
patch which adds the pkrs state.
Ira
next prev parent reply other threads:[~2020-10-19 5:37 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-09 19:42 [PATCH RFC V3 0/9] PKS: Add Protection Keys Supervisor (PKS) support RFC v3 ira.weiny
2020-10-09 19:42 ` [PATCH RFC V3 1/9] x86/pkeys: Create pkeys_common.h ira.weiny
2020-10-13 17:46 ` Dave Hansen
2020-10-13 19:44 ` Ira Weiny
2020-10-09 19:42 ` [PATCH RFC V3 2/9] x86/fpu: Refactor arch_set_user_pkey_access() for PKS support ira.weiny
2020-10-13 17:50 ` Dave Hansen
2020-10-13 23:56 ` Ira Weiny
2020-10-16 10:57 ` Peter Zijlstra
2020-10-17 3:32 ` Ira Weiny
2020-10-19 9:35 ` Peter Zijlstra
2020-10-09 19:42 ` [PATCH RFC V3 3/9] x86/pks: Enable Protection Keys Supervisor (PKS) ira.weiny
2020-10-13 18:23 ` Dave Hansen
2020-10-14 2:08 ` Ira Weiny
2020-10-09 19:42 ` [PATCH RFC V3 4/9] x86/pks: Preserve the PKRS MSR on context switch ira.weiny
2020-10-13 18:31 ` Dave Hansen
2020-10-14 22:36 ` Ira Weiny
2020-10-16 11:12 ` Peter Zijlstra
2020-10-17 5:14 ` Ira Weiny
2020-10-19 9:37 ` Peter Zijlstra
2020-10-19 18:48 ` Ira Weiny
2020-10-16 11:06 ` Peter Zijlstra
2020-10-17 5:37 ` Ira Weiny
2020-10-09 19:42 ` [PATCH RFC V3 5/9] x86/pks: Add PKS kernel API ira.weiny
2020-10-13 18:43 ` Dave Hansen
2020-10-15 1:08 ` Ira Weiny
2020-10-16 11:07 ` Peter Zijlstra
2020-10-17 5:42 ` Ira Weiny
2020-10-09 19:42 ` [PATCH RFC V3 6/9] x86/entry: Pass irqentry_state_t by reference ira.weiny
2020-10-16 11:45 ` Peter Zijlstra
2020-10-16 12:55 ` Thomas Gleixner
2020-10-19 5:37 ` Ira Weiny [this message]
2020-10-19 9:32 ` Thomas Gleixner
2020-10-19 20:26 ` Ira Weiny
2020-10-19 21:12 ` Thomas Gleixner
2020-10-20 14:10 ` Ira Weiny
2020-10-09 19:42 ` [PATCH RFC V3 7/9] x86/entry: Preserve PKRS MSR across exceptions ira.weiny
2020-10-13 18:52 ` Dave Hansen
2020-10-15 3:46 ` Ira Weiny
2020-10-15 4:06 ` Dave Hansen
2020-10-15 4:18 ` Ira Weiny
2020-10-09 19:42 ` [PATCH RFC V3 8/9] x86/fault: Report the PKRS state on fault ira.weiny
2020-10-13 18:56 ` Dave Hansen
2020-10-15 4:13 ` Ira Weiny
2020-10-09 19:42 ` [PATCH RFC V3 9/9] x86/pks: Add PKS test code ira.weiny
2020-10-13 19:02 ` Dave Hansen
2020-10-15 4:46 ` Ira Weiny
2020-10-09 20:18 ` [PATCH RFC V3 0/9] PKS: Add Protection Keys Supervisor (PKS) support RFC v3 Ira Weiny
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