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From: Thomas Gleixner <tglx@linutronix.de>
To: Dave Hansen <dave@sr71.net>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org,
	dave.hansen@linux.intel.com
Subject: Re: [PATCH 29/31] x86, pkeys: allow kernel to modify user pkey rights register
Date: Fri, 8 Jan 2016 20:40:14 +0100 (CET)	[thread overview]
Message-ID: <alpine.DEB.2.11.1601082039570.3575@nanos> (raw)
In-Reply-To: <20160107000145.96AD9FDD@viggo.jf.intel.com>

On Wed, 6 Jan 2016, Dave Hansen wrote:
> From: Dave Hansen <dave.hansen@linux.intel.com>
> 
> The Protection Key Rights for User memory (PKRU) is a 32-bit
> user-accessible register.  It contains two bits for each
> protection key: one to write-disable (WD) access to memory
> covered by the key and another to access-disable (AD).
> 
> Userspace can read/write the register with the RDPKRU and WRPKRU
> instructions.  But, the register is saved and restored with the
> XSAVE family of instructions, which means we have to treat it
> like a floating point register.
> 
> The kernel needs to write to the register if it wants to
> implement execute-only memory or if it implements a system call
> to change PKRU.
> 
> To do this, we need to create a 'pkru_state' buffer, read the old
> contents in to it, modify it, and then tell the FPU code that
> there is modified data in there so it can (possibly) move the
> buffer back in to the registers.
> 
> This uses the fpu__xfeature_set_state() function that we defined
> in the previous patch.
> 
> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>

Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

  reply	other threads:[~2016-01-08 19:41 UTC|newest]

Thread overview: 87+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-07  0:01 [PATCH 00/31] x86: Memory Protection Keys (v8) Dave Hansen
2016-01-07  0:01 ` Dave Hansen
2016-01-07  0:01 ` [PATCH 01/31] mm, gup: introduce concept of "foreign" get_user_pages() Dave Hansen
2016-01-07  0:01   ` Dave Hansen
2016-01-13 19:00   ` Vlastimil Babka
2016-01-13 19:00     ` Vlastimil Babka
2016-01-13 19:16     ` Dave Hansen
2016-01-13 19:16       ` Dave Hansen
2016-01-07  0:01 ` [PATCH 02/31] x86, fpu: add placeholder for Processor Trace XSAVE state Dave Hansen
2016-01-07  0:01   ` Dave Hansen
2016-01-07  0:01 ` [PATCH 03/31] x86, pkeys: Add Kconfig option Dave Hansen
2016-01-07  0:01   ` Dave Hansen
2016-01-07  0:01 ` [PATCH 04/31] x86, pkeys: cpuid bit definition Dave Hansen
2016-01-07  0:01   ` Dave Hansen
2016-01-07  0:01 ` [PATCH 05/31] x86, pkeys: define new CR4 bit Dave Hansen
2016-01-07  0:01   ` Dave Hansen
2016-01-07  0:01 ` [PATCH 06/31] x86, pkeys: add PKRU xsave fields and data structure(s) Dave Hansen
2016-01-07  0:01   ` Dave Hansen
2016-01-07  0:01 ` [PATCH 07/31] x86, pkeys: PTE bits for storing protection key Dave Hansen
2016-01-07  0:01   ` Dave Hansen
2016-01-07  0:01 ` [PATCH 08/31] x86, pkeys: new page fault error code bit: PF_PK Dave Hansen
2016-01-07  0:01   ` Dave Hansen
2016-01-07  0:01 ` [PATCH 09/31] x86, pkeys: store protection in high VMA flags Dave Hansen
2016-01-07  0:01   ` Dave Hansen
2016-01-07  0:01 ` [PATCH 10/31] x86, pkeys: arch-specific protection bits Dave Hansen
2016-01-07  0:01   ` Dave Hansen
2016-01-08 19:31   ` Thomas Gleixner
2016-01-07  0:01 ` [PATCH 11/31] x86, pkeys: pass VMA down in to fault signal generation code Dave Hansen
2016-01-07  0:01   ` Dave Hansen
2016-01-07  0:01 ` [PATCH 12/31] signals, pkeys: notify userspace about protection key faults Dave Hansen
2016-01-07  0:01   ` Dave Hansen
2016-01-07  0:01 ` [PATCH 13/31] x86, pkeys: fill in pkey field in siginfo Dave Hansen
2016-01-07  0:01   ` Dave Hansen
2016-01-07  0:01 ` [PATCH 14/31] x86, pkeys: add functions to fetch PKRU Dave Hansen
2016-01-07  0:01   ` Dave Hansen
2016-01-08 19:32   ` Thomas Gleixner
2016-01-07  0:01 ` [PATCH 15/31] mm: factor out VMA fault permission checking Dave Hansen
2016-01-07  0:01   ` Dave Hansen
2016-01-07  0:01 ` [PATCH 16/31] x86, mm: simplify get_user_pages() PTE bit handling Dave Hansen
2016-01-07  0:01   ` Dave Hansen
2016-01-07  0:01 ` [PATCH 17/31] x86, pkeys: check VMAs and PTEs for protection keys Dave Hansen
2016-01-07  0:01   ` Dave Hansen
2016-01-07  0:01 ` [PATCH 18/31] mm: add gup flag to indicate "foreign" mm access Dave Hansen
2016-01-07  0:01   ` Dave Hansen
2016-01-07  0:01 ` [PATCH 19/31] x86, pkeys: optimize fault handling in access_error() Dave Hansen
2016-01-07  0:01   ` Dave Hansen
2016-01-07  0:01 ` [PATCH 20/31] x86, pkeys: differentiate instruction fetches Dave Hansen
2016-01-07  0:01   ` Dave Hansen
2016-01-07  0:01 ` [PATCH 21/31] x86, pkeys: dump PKRU with other kernel registers Dave Hansen
2016-01-07  0:01   ` Dave Hansen
2016-01-07  0:01 ` [PATCH 22/31] x86, pkeys: dump pkey from VMA in /proc/pid/smaps Dave Hansen
2016-01-07  0:01   ` Dave Hansen
2016-01-07  0:01 ` [PATCH 23/31] x86, pkeys: add Kconfig prompt to existing config option Dave Hansen
2016-01-07  0:01   ` Dave Hansen
2016-01-07  0:01 ` [PATCH 24/31] x86, pkeys: actually enable Memory Protection Keys in CPU Dave Hansen
2016-01-07  0:01   ` Dave Hansen
2016-01-07  0:01 ` [PATCH 25/31] mm, multi-arch: pass a protection key in to calc_vm_flag_bits() Dave Hansen
2016-01-07  0:01   ` Dave Hansen
2016-01-07  0:01 ` [PATCH 26/31] x86, pkeys: add arch_validate_pkey() Dave Hansen
2016-01-07  0:01   ` Dave Hansen
2016-01-08 19:34   ` Thomas Gleixner
2016-01-07  0:01 ` [PATCH 27/31] x86: separate out LDT init from context init Dave Hansen
2016-01-07  0:01   ` Dave Hansen
2016-01-07  0:01 ` [PATCH 28/31] x86, fpu: allow setting of XSAVE state Dave Hansen
2016-01-07  0:01   ` Dave Hansen
2016-01-07  0:01 ` [PATCH 29/31] x86, pkeys: allow kernel to modify user pkey rights register Dave Hansen
2016-01-07  0:01   ` Dave Hansen
2016-01-08 19:40   ` Thomas Gleixner [this message]
2016-01-07  0:01 ` [PATCH 30/31] x86, pkeys: create an x86 arch_calc_vm_prot_bits() for VMA flags Dave Hansen
2016-01-07  0:01   ` Dave Hansen
2016-01-08 19:40   ` Thomas Gleixner
2016-01-07  0:01 ` [PATCH 31/31] x86, pkeys: execute-only support Dave Hansen
2016-01-07  0:01   ` Dave Hansen
2016-01-07 21:02   ` Kees Cook
2016-01-07 21:02     ` Kees Cook
2016-01-07 22:25     ` Dave Hansen
2016-01-07 22:25       ` Dave Hansen
2016-01-07 21:10   ` Andy Lutomirski
2016-01-07 21:10     ` Andy Lutomirski
2016-01-07 22:13     ` Dave Hansen
2016-01-07 22:13       ` Dave Hansen
2016-01-07 22:44       ` Andy Lutomirski
2016-01-07 22:44         ` Andy Lutomirski
2016-01-08 19:51   ` Thomas Gleixner
2016-01-08 19:51     ` Thomas Gleixner
2016-01-29 18:16 [PATCH 00/31] x86: Memory Protection Keys (v9) Dave Hansen
2016-01-29 18:17 ` [PATCH 29/31] x86, pkeys: allow kernel to modify user pkey rights register Dave Hansen
2016-01-29 18:17   ` Dave Hansen

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