From: Ira Weiny <ira.weiny@intel.com>
To: Dave Hansen <dave.hansen@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, 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 7/9] x86/entry: Preserve PKRS MSR across exceptions
Date: Wed, 14 Oct 2020 20:46:45 -0700 [thread overview]
Message-ID: <20201015034645.GQ2046448@iweiny-DESK2.sc.intel.com> (raw)
In-Reply-To: <6006a4c8-32bd-04ca-95cc-b2736a5cef72@intel.com>
On Tue, Oct 13, 2020 at 11:52:32AM -0700, Dave Hansen wrote:
> On 10/9/20 12:42 PM, ira.weiny@intel.com wrote:
> > @@ -341,6 +341,9 @@ noinstr void irqentry_enter(struct pt_regs *regs, irqentry_state_t *state)
> > /* Use the combo lockdep/tracing function */
> > trace_hardirqs_off();
> > instrumentation_end();
> > +
> > +done:
> > + irq_save_pkrs(state);
> > }
>
> One nit: This saves *and* sets PKRS. It's not obvious from the call
> here that PKRS is altered at this site. Seems like there could be a
> better name.
>
> Even if we did:
>
> irq_save_set_pkrs(state, INIT_VAL);
>
> It would probably compile down to the same thing, but be *really*
> obvious what's going on.
I suppose that is true. But I think it is odd having a parameter which is the
same for every call site.
But I'm not going to quibble over something like this.
Changed,
Ira
>
> > void irqentry_exit_cond_resched(void)
> > @@ -362,7 +365,12 @@ noinstr void irqentry_exit(struct pt_regs *regs, irqentry_state_t *state)
> > /* Check whether this returns to user mode */
> > if (user_mode(regs)) {
> > irqentry_exit_to_user_mode(regs);
> > - } else if (!regs_irqs_disabled(regs)) {
> > + return;
> > + }
> > +
> > + irq_restore_pkrs(state);
> > +
> > + if (!regs_irqs_disabled(regs)) {
> > /*
> > * If RCU was not watching on entry this needs to be done
> > * carefully and needs the same ordering of lockdep/tracing
> >
>
next prev parent reply other threads:[~2020-10-15 3:46 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
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 [this message]
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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