From: Dave Hansen <dave@sr71.net>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org,
dave.hansen@linux.intel.com
Subject: Re: [PATCH 17/37] x86, pkeys: add functions to fetch PKRU
Date: Mon, 30 Nov 2015 07:51:48 -0800 [thread overview]
Message-ID: <565C7094.8070706@sr71.net> (raw)
In-Reply-To: <alpine.DEB.2.11.1511271050400.3572@nanos>
On 11/27/2015 01:51 AM, Thomas Gleixner wrote:
> On Mon, 16 Nov 2015, Dave Hansen wrote:
>> +#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
>> +static inline u32 __read_pkru(void)
>> +{
>> + unsigned int eax, edx;
>> + unsigned int ecx = 0;
>> + unsigned int pkru;
>> +
>> + asm volatile(".byte 0x0f,0x01,0xee\n\t"
>> + : "=a" (eax), "=d" (edx)
>> + : "c" (ecx));
>> + pkru = eax;
>> + return pkru;
>
> Wouldn't a simple 'return eax;' be sufficient?
Yes. I wanted to make it clear that EAX specifically was where the data
we want was ending up. But, I guess the "=a" does that equally well.
I'll fix it up.
Also, looking at this, it also deserves a mention that this is the
"rdpkru" instruction. Otherwise, it's hard to figure out what
instruction this is.
next prev parent reply other threads:[~2015-11-30 15:51 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-17 3:35 [PATCH 00/37] x86: Memory Protection Keys Dave Hansen
2015-11-17 3:35 ` [PATCH 01/37] uprobes: dont pass around current->mm Dave Hansen
2015-11-17 3:35 ` [PATCH 02/37] mm, frame_vector: do not use get_user_pages_locked() Dave Hansen
2015-11-18 12:29 ` Jan Kara
2015-11-18 17:04 ` Andrea Arcangeli
2015-11-17 3:35 ` [PATCH 03/37] mm: kill get_user_pages_locked() Dave Hansen
2015-11-17 3:35 ` [PATCH 04/37] mm: simplify __get_user_pages() Dave Hansen
2015-11-17 3:35 ` [PATCH 05/37] mm, gup: introduce concept of "foreign" get_user_pages() Dave Hansen
2015-11-17 3:35 ` [PATCH 06/37] x86, fpu: add placeholder for Processor Trace XSAVE state Dave Hansen
2015-11-17 3:35 ` [PATCH 07/37] x86, pkeys: Add Kconfig option Dave Hansen
2015-11-17 3:35 ` [PATCH 08/37] x86, pkeys: cpuid bit definition Dave Hansen
2015-11-17 3:35 ` [PATCH 09/37] x86, pkeys: define new CR4 bit Dave Hansen
2015-11-17 3:35 ` [PATCH 10/37] x86, pkeys: add PKRU xsave fields and data structure(s) Dave Hansen
2015-11-27 9:23 ` Thomas Gleixner
2015-11-17 3:35 ` [PATCH 11/37] x86, pkeys: PTE bits for storing protection key Dave Hansen
2015-11-17 3:35 ` [PATCH 12/37] x86, pkeys: new page fault error code bit: PF_PK Dave Hansen
2015-11-17 3:35 ` [PATCH 13/37] x86, pkeys: store protection in high VMA flags Dave Hansen
2015-11-17 3:35 ` [PATCH 14/37] x86, pkeys: arch-specific protection bits Dave Hansen
2015-11-17 3:35 ` [PATCH 15/37] x86, pkeys: pass VMA down in to fault signal generation code Dave Hansen
2015-11-27 9:30 ` Thomas Gleixner
2015-11-17 3:35 ` [PATCH 16/37] x86, pkeys: notify userspace about protection key faults Dave Hansen
2015-11-27 9:49 ` Thomas Gleixner
2015-11-17 3:35 ` [PATCH 17/37] x86, pkeys: add functions to fetch PKRU Dave Hansen
2015-11-27 9:51 ` Thomas Gleixner
2015-11-30 15:51 ` Dave Hansen [this message]
2015-11-17 3:35 ` [PATCH 18/37] mm: factor out VMA fault permission checking Dave Hansen
2015-11-27 9:53 ` Thomas Gleixner
2015-11-17 3:35 ` [PATCH 19/37] x86, mm: simplify get_user_pages() PTE bit handling Dave Hansen
2015-11-27 10:12 ` Thomas Gleixner
2015-11-30 16:25 ` Dave Hansen
2015-11-17 3:35 ` [PATCH 20/37] x86, pkeys: check VMAs and PTEs for protection keys Dave Hansen
2015-11-17 3:35 ` [PATCH 21/37] mm: add gup flag to indicate "foreign" mm access Dave Hansen
2015-11-17 3:35 ` [PATCH 22/37] x86, pkeys: optimize fault handling in access_error() Dave Hansen
2015-11-17 3:35 ` [PATCH 23/37] x86, pkeys: differentiate instruction fetches Dave Hansen
2015-11-17 3:35 ` [PATCH 24/37] x86, pkeys: dump PKRU with other kernel registers Dave Hansen
2015-11-17 3:35 ` [PATCH 25/37] x86, pkeys: dump PTE pkey in /proc/pid/smaps Dave Hansen
2015-11-17 3:35 ` [PATCH 26/37] x86, pkeys: add Kconfig prompt to existing config option Dave Hansen
2015-11-17 3:35 ` [PATCH 27/37] mm, multi-arch: pass a protection key in to calc_vm_flag_bits() Dave Hansen
2015-11-17 3:35 ` [PATCH 28/37] x86, pkeys: add arch_validate_pkey() Dave Hansen
2015-11-17 3:35 ` [PATCH 29/37] mm: implement new mprotect_key() system call Dave Hansen
2015-11-17 3:35 ` [PATCH 30/37] x86, pkeys: make mprotect_key() mask off additional vm_flags Dave Hansen
2015-11-17 3:35 ` [PATCH 31/37] x86: wire up mprotect_key() system call Dave Hansen
2015-11-17 3:35 ` [PATCH 32/37] x86: separate out LDT init from context init Dave Hansen
2015-11-17 3:35 ` [PATCH 33/37] x86, fpu: allow setting of XSAVE state Dave Hansen
2015-11-17 3:35 ` [PATCH 34/37] x86, pkeys: allocation/free syscalls Dave Hansen
2015-11-17 3:36 ` [PATCH 35/37] x86, pkeys: add pkey set/get syscalls Dave Hansen
2015-11-17 3:36 ` [PATCH 36/37] x86, pkeys: actually enable Memory Protection Keys in CPU Dave Hansen
2015-11-17 3:36 ` [PATCH 37/37] x86, pkeys: Documentation Dave Hansen
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