From: Borislav Petkov <bp@alien8.de>
To: Dave Hansen <dave@sr71.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>,
linux-kernel@vger.kernel.org, brgerst@gmail.com,
tglx@linutronix.de, torvalds@linux-foundation.org, hpa@zytor.com,
akpm@linux-foundation.org, peterz@infradead.org,
mingo@kernel.org, luto@amacapital.net, dvlasenk@redhat.com,
riel@redhat.com
Subject: Re: [PATCH] x86/mm/pkeys: Do not enable them by default
Date: Fri, 19 Feb 2016 19:31:28 +0100 [thread overview]
Message-ID: <20160219183128.GH8918@pd.tnic> (raw)
In-Reply-To: <56C7558E.2060603@sr71.net>
On Fri, Feb 19, 2016 at 09:49:02AM -0800, Dave Hansen wrote:
> For gains that small, we should barely even allow this thing to be
> configurable, much less default it to off.
Well, it's not about size gains only - it is also about adding code to
the kernel which is never going to be executed and also building it each
time on !pkey machines.
> Yes, agreed. Distros _can_ override things. But, In general,
> *especially* with user-visible effects, I'd really like defconfig (or
> other build defaults) to be reasonably close to what distributions do.
You can always add it to arch/x86/configs/x86_64_defconfig.
> My view has always been that the folks that really care about binary
> size are the ones that will be the ones digging through their .configs
> turning things off.
Except when automating "make oldconfig" and then wondering why all of a
sudden new features are enabled.
In my experience, it has always been the case that new features are
default off. What you want to achieve can easily be done without the
"def_bool y" thing.
--
Regards/Gruss,
Boris.
ECO tip #101: Trim your mails when you reply.
next prev parent reply other threads:[~2016-02-19 18:31 UTC|newest]
Thread overview: 84+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-12 21:01 [PATCH 00/33] x86: Memory Protection Keys (v10) Dave Hansen
2016-02-12 21:01 ` [PATCH 01/33] mm: introduce get_user_pages_remote() Dave Hansen
2016-02-15 6:09 ` Balbir Singh
2016-02-15 16:29 ` Dave Hansen
2016-02-15 6:14 ` Srikar Dronamraju
2016-02-16 12:14 ` [tip:x86/pkeys] mm/gup: Introduce get_user_pages_remote() tip-bot for Dave Hansen
2016-02-20 6:25 ` Konstantin Khlebnikov
2016-02-12 21:01 ` [PATCH 02/33] mm: overload get_user_pages() functions Dave Hansen
2016-02-16 8:36 ` Ingo Molnar
2016-02-17 18:15 ` Dave Hansen
2016-02-18 20:15 ` [tip:mm/pkeys] mm/gup: Overload " tip-bot for Dave Hansen
2016-02-12 21:01 ` [PATCH 03/33] mm, gup: switch callers of get_user_pages() to not pass tsk/mm Dave Hansen
2016-02-18 20:16 ` [tip:mm/pkeys] mm/gup: Switch all " tip-bot for Dave Hansen
2016-02-12 21:01 ` [PATCH 04/33] x86, fpu: add placeholder for Processor Trace XSAVE state Dave Hansen
2016-02-18 20:16 ` [tip:mm/pkeys] x86/fpu: Add placeholder for 'Processor Trace' " tip-bot for Dave Hansen
2016-02-12 21:02 ` [PATCH 05/33] x86, pkeys: Add Kconfig option Dave Hansen
2016-02-18 20:16 ` [tip:mm/pkeys] x86/mm/pkeys: " tip-bot for Dave Hansen
2016-02-19 11:27 ` [PATCH] x86/mm/pkeys: Do not enable them by default Borislav Petkov
2016-02-19 17:11 ` Dave Hansen
2016-02-19 17:23 ` Borislav Petkov
2016-02-19 17:49 ` Dave Hansen
2016-02-19 18:31 ` Borislav Petkov [this message]
2016-02-12 21:02 ` [PATCH 06/33] x86, pkeys: cpuid bit definition Dave Hansen
2016-02-18 20:17 ` [tip:mm/pkeys] x86/cpufeature, x86/mm/pkeys: Add protection keys related CPUID definitions tip-bot for Dave Hansen
2016-02-12 21:02 ` [PATCH 07/33] x86, pkeys: define new CR4 bit Dave Hansen
2016-02-18 20:17 ` [tip:mm/pkeys] x86/cpu, x86/mm/pkeys: Define " tip-bot for Dave Hansen
2016-02-12 21:02 ` [PATCH 08/33] x86, pkeys: add PKRU xsave fields and data structure(s) Dave Hansen
2016-02-18 20:17 ` [tip:mm/pkeys] x86/fpu, x86/mm/pkeys: Add PKRU xsave fields and data structures tip-bot for Dave Hansen
2016-02-12 21:02 ` [PATCH 09/33] x86, pkeys: PTE bits for storing protection key Dave Hansen
2016-02-18 20:18 ` [tip:mm/pkeys] x86/mm/pkeys: Add " tip-bot for Dave Hansen
2016-02-12 21:02 ` [PATCH 10/33] x86, pkeys: new page fault error code bit: PF_PK Dave Hansen
2016-02-18 20:18 ` [tip:mm/pkeys] x86/mm/pkeys: Add new 'PF_PK' page fault error code bit tip-bot for Dave Hansen
2016-02-12 21:02 ` [PATCH 11/33] x86, pkeys: store protection in high VMA flags Dave Hansen
2016-02-18 20:19 ` [tip:mm/pkeys] mm/core, x86/mm/pkeys: Store protection bits " tip-bot for Dave Hansen
2016-02-12 21:02 ` [PATCH 12/33] x86, pkeys: arch-specific protection bits Dave Hansen
2016-02-18 20:19 ` [tip:mm/pkeys] x86/mm/pkeys: Add arch-specific VMA " tip-bot for Dave Hansen
2016-02-12 21:02 ` [PATCH 13/33] x86, pkeys: pass VMA down in to fault signal generation code Dave Hansen
2016-02-18 20:19 ` [tip:mm/pkeys] x86/mm/pkeys: Pass " tip-bot for Dave Hansen
2016-02-12 21:02 ` [PATCH 14/33] signals, pkeys: notify userspace about protection key faults Dave Hansen
2016-02-18 20:20 ` [tip:mm/pkeys] signals, pkeys: Notify " tip-bot for Dave Hansen
2016-02-12 21:02 ` [PATCH 15/33] x86, pkeys: fill in pkey field in siginfo Dave Hansen
2016-02-18 20:20 ` [tip:mm/pkeys] x86/mm/pkeys: Fill " tip-bot for Dave Hansen
2016-02-12 21:02 ` [PATCH 16/33] x86, pkeys: add functions to fetch PKRU Dave Hansen
2016-02-18 20:21 ` [tip:mm/pkeys] x86/mm/pkeys: Add " tip-bot for Dave Hansen
2016-02-12 21:02 ` [PATCH 17/33] mm: factor out VMA fault permission checking Dave Hansen
2016-02-18 20:21 ` [tip:mm/pkeys] mm/gup: Factor " tip-bot for Dave Hansen
2016-02-12 21:02 ` [PATCH 18/33] x86, mm: simplify get_user_pages() PTE bit handling Dave Hansen
2016-02-18 20:21 ` [tip:mm/pkeys] x86/mm/gup: Simplify " tip-bot for Dave Hansen
2016-02-12 21:02 ` [PATCH 19/33] x86, pkeys: check VMAs and PTEs for protection keys Dave Hansen
2016-02-18 20:22 ` [tip:mm/pkeys] mm/gup, x86/mm/pkeys: Check " tip-bot for Dave Hansen
2016-02-12 21:02 ` [PATCH 20/33] mm: do not enforce PKEY permissions on "foreign" mm access Dave Hansen
2016-02-12 21:02 ` [PATCH 21/33] x86, pkeys: optimize fault handling in access_error() Dave Hansen
2016-02-18 20:23 ` [tip:mm/pkeys] x86/mm/pkeys: Optimize " tip-bot for Dave Hansen
2016-02-12 21:02 ` [PATCH 22/33] x86, pkeys: differentiate instruction fetches Dave Hansen
2016-02-18 20:23 ` [tip:mm/pkeys] mm/core, x86/mm/pkeys: Differentiate " tip-bot for Dave Hansen
2016-02-12 21:02 ` [PATCH 23/33] x86, pkeys: dump PKRU with other kernel registers Dave Hansen
2016-02-18 20:24 ` [tip:mm/pkeys] x86/mm/pkeys: Dump " tip-bot for Dave Hansen
2016-02-12 21:02 ` [PATCH 24/33] x86, pkeys: dump pkey from VMA in /proc/pid/smaps Dave Hansen
2016-02-18 20:24 ` [tip:mm/pkeys] x86/mm/pkeys: Dump pkey from VMA in /proc/pid/ smaps tip-bot for Dave Hansen
2016-02-12 21:02 ` [PATCH 25/33] x86, pkeys: add Kconfig prompt to existing config option Dave Hansen
2016-02-18 20:24 ` [tip:mm/pkeys] x86/mm/pkeys: Add " tip-bot for Dave Hansen
2016-02-12 21:02 ` [PATCH 26/33] x86, pkeys: actually enable Memory Protection Keys in CPU Dave Hansen
2016-02-18 20:25 ` [tip:mm/pkeys] x86/mm/pkeys: Actually enable Memory Protection Keys in the CPU tip-bot for Dave Hansen
2016-02-12 21:02 ` [PATCH 27/33] mm, multi-arch: pass a protection key in to calc_vm_flag_bits() Dave Hansen
2016-02-18 20:25 ` [tip:mm/pkeys] mm/core, arch, powerpc: Pass " tip-bot for Dave Hansen
2016-02-12 21:02 ` [PATCH 28/33] x86, pkeys: add arch_validate_pkey() Dave Hansen
2016-02-18 20:25 ` [tip:mm/pkeys] mm/core, x86/mm/pkeys: Add arch_validate_pkey() tip-bot for Dave Hansen
2016-02-12 21:02 ` [PATCH 29/33] x86: separate out LDT init from context init Dave Hansen
2016-02-18 20:26 ` [tip:mm/pkeys] x86/mm: Factor " tip-bot for Dave Hansen
2016-02-12 21:02 ` [PATCH 30/33] x86, fpu: allow setting of XSAVE state Dave Hansen
2016-02-18 20:26 ` [tip:mm/pkeys] x86/fpu: Allow " tip-bot for Dave Hansen
2016-02-12 21:02 ` [PATCH 31/33] x86, pkeys: allow kernel to modify user pkey rights register Dave Hansen
2016-02-18 20:27 ` [tip:mm/pkeys] x86/mm/pkeys: Allow " tip-bot for Dave Hansen
2016-02-12 21:02 ` [PATCH 32/33] x86, pkeys: create an x86 arch_calc_vm_prot_bits() for VMA flags Dave Hansen
2016-02-18 20:27 ` [tip:mm/pkeys] x86/mm/pkeys: Create an x86 arch_calc_vm_prot_bits () " tip-bot for Dave Hansen
2016-02-12 21:02 ` [PATCH 33/33] x86, pkeys: execute-only support Dave Hansen
2016-02-17 21:27 ` Kees Cook
2016-02-17 21:33 ` Dave Hansen
2016-02-17 21:36 ` Kees Cook
2016-02-17 22:17 ` Andy Lutomirski
2016-02-17 22:53 ` Dave Hansen
2016-02-18 0:46 ` Andy Lutomirski
2016-02-18 20:27 ` [tip:mm/pkeys] mm/core, x86/mm/pkeys: Add execute-only protection keys support tip-bot for Dave Hansen
2016-02-16 9:29 ` [PATCH 00/33] x86: Memory Protection Keys (v10) Ingo Molnar
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