From: Thomas Gleixner <tglx@linutronix.de>
To: Dave Hansen <dave.hansen@linux.intel.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
Andy Lutomirski <luto@kernel.org>, Ingo Molnar <mingo@kernel.org>,
Borislav Petkov <bp@alien8.de>, Brian Gerst <brgerst@gmail.com>,
Denys Vlasenko <dvlasenk@redhat.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Peter Zijlstra <peterz@infradead.org>,
Rik van Riel <riel@redhat.com>,
daniel.gruss@iaik.tugraz.at, hughd@google.com,
keescook@google.com, linux-mm@kvack.org,
michael.schwarz@iaik.tugraz.at, moritz.lipp@iaik.tugraz.at,
richard.fellner@student.tugraz.at
Subject: Re: [patch V2 2/5] x86/kaiser: Simplify disabling of global pages
Date: Mon, 27 Nov 2017 21:28:49 +0100 (CET) [thread overview]
Message-ID: <alpine.DEB.2.20.1711272128360.2333@nanos> (raw)
In-Reply-To: <0b5a64f1-9979-ae56-99f8-72c3802a9c60@linux.intel.com>
On Mon, 27 Nov 2017, Dave Hansen wrote:
> On 11/26/2017 03:14 PM, Thomas Gleixner wrote:
> > +static void enable_global_pages(void)
> > +{
> > +#ifndef CONFIG_KAISER
> > + __supported_pte_mask |= _PAGE_GLOBAL;
> > +#endif
> > +}
> > +
> > static void __init probe_page_size_mask(void)
> > {
> > /*
> > @@ -179,11 +186,11 @@ static void __init probe_page_size_mask(
> > cr4_set_bits_and_update_boot(X86_CR4_PSE);
> >
> > /* Enable PGE if available */
> > + __supported_pte_mask |= _PAGE_GLOBAL;
> > if (boot_cpu_has(X86_FEATURE_PGE)) {
> > cr4_set_bits_and_update_boot(X86_CR4_PGE);
> > - __supported_pte_mask |= _PAGE_GLOBAL;
> > - } else
> > - __supported_pte_mask &= ~_PAGE_GLOBAL;
> > + enable_global_pages();
> > + }
>
> This looks a little funky. Doesn't this or _PAGE_GLOBAL into
> __supported_pte_mask twice? Once before the if(), and then a second
> time via enable_global_pages() inside the if?
>
> Did you intend for it to be masked *out* in the first one and then or'd
> back in via enable_global_pages()?
It's fixed already ...
next prev parent reply other threads:[~2017-11-27 20:28 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-26 23:14 [patch V2 0/5] x86/kaiser: Boot time disabling and debug support Thomas Gleixner
2017-11-26 23:14 ` [patch V2 1/5] x86/kaiser: Respect disabled CPU features Thomas Gleixner
2017-11-27 9:57 ` Peter Zijlstra
2017-11-27 11:47 ` Thomas Gleixner
2017-11-27 12:31 ` Brian Gerst
2017-11-27 13:18 ` Thomas Gleixner
2017-11-27 18:11 ` Dave Hansen
2017-11-27 18:37 ` Kees Cook
2017-11-26 23:14 ` [patch V2 2/5] x86/kaiser: Simplify disabling of global pages Thomas Gleixner
2017-11-27 11:49 ` Thomas Gleixner
2017-11-27 18:15 ` Dave Hansen
2017-11-27 20:28 ` Thomas Gleixner [this message]
2017-11-26 23:14 ` [patch V2 3/5] x86/dump_pagetables: Check KAISER shadow page table for WX pages Thomas Gleixner
2017-11-27 18:17 ` Dave Hansen
2017-11-26 23:14 ` [patch V2 4/5] x86/mm/debug_pagetables: Allow dumping current pagetables Thomas Gleixner
2017-11-27 9:41 ` Peter Zijlstra
2017-11-27 10:06 ` [PATCH] vfs: Add PERM_* symbolic helpers for common file mode/permissions Ingo Molnar
2017-11-27 19:21 ` Linus Torvalds
2017-11-28 10:54 ` Ingo Molnar
2017-11-28 11:12 ` Ingo Molnar
2017-11-29 8:52 ` Michael Ellerman
2017-11-27 18:18 ` [patch V2 4/5] x86/mm/debug_pagetables: Allow dumping current pagetables Dave Hansen
2017-11-26 23:14 ` [patch V2 5/5] x86/kaiser: Add boottime disable switch Thomas Gleixner
2017-11-27 9:48 ` Peter Zijlstra
2017-11-27 10:22 ` Peter Zijlstra
2017-11-27 11:50 ` Thomas Gleixner
2017-11-27 12:49 ` Peter Zijlstra
2017-11-27 21:43 ` Peter Zijlstra
2017-11-27 18:22 ` Dave Hansen
2017-11-27 19:00 ` Thomas Gleixner
2017-11-27 19:18 ` Josh Poimboeuf
2017-11-27 20:47 ` Thomas Gleixner
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