From: Michael Matz <matz@suse.de>
To: Borislav Petkov <bp@alien8.de>
Cc: mingo@kernel.org, luto@amacapital.net, tglx@linutronix.de,
oleg@redhat.com, brgerst@gmail.com, mcgrof@suse.com,
dave.hansen@linux.intel.com, akpm@linux-foundation.org,
dvlasenk@redhat.com, peterz@infradead.org,
torvalds@linux-foundation.org, linux-kernel@vger.kernel.org,
toshi.kani@hp.com, luto@kernel.org, aryabinin@virtuozzo.com,
hpa@zytor.com, linux-tip-commits@vger.kernel.org
Subject: Re: [tip:x86/mm] x86/mm: Add INVPCID helpers
Date: Wed, 10 Feb 2016 14:48:02 +0100 (CET) [thread overview]
Message-ID: <alpine.LSU.2.20.1602101439540.20277@wotan.suse.de> (raw)
In-Reply-To: <20160210120827.GA11832@pd.tnic>
Hi,
On Wed, 10 Feb 2016, Borislav Petkov wrote:
> --- a/arch/x86/include/asm/tlbflush.h
> +++ b/arch/x86/include/asm/tlbflush.h
> @@ -23,7 +23,7 @@ static inline void __invpcid(unsigned long pcid, unsigned long addr,
> * invpcid (%rcx), %rax in long mode.
> */
> asm volatile (".byte 0x66, 0x0f, 0x38, 0x82, 0x01"
> - : : "m" (desc), "a" (type), "c" (desc) : "memory");
> + : : "m" (*desc), "a" (type), "c" (desc) : "memory");
That still doesn't do what you want. Arrays in C are funny. *desc is
exactly equivalent to desc[0], _not_ to the whole array, indeed there's no
C syntax to name an lvalue of array type in normal expressions. You need
to jump through hoops for this:
"m" (*(struct {unsigned long x[2];} *)desc)
It'd probably be easier to simply declare the descriptor as a struct,
rather than an array, then the original syntax would have been mostly
correct:
struct {u64 d[2];} desc = { pcid, addr };
asm ... "m" (desc), "c" (&desc)
Ciao,
Michael.
next prev parent reply other threads:[~2016-02-10 13:48 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-29 19:42 [PATCH v3 0/3] x86/mm: INVPCID support Andy Lutomirski
2016-01-29 19:42 ` Andy Lutomirski
2016-01-29 19:42 ` [PATCH v3 1/3] x86/mm: Add INVPCID helpers Andy Lutomirski
2016-01-29 19:42 ` Andy Lutomirski
2016-02-09 16:07 ` [tip:x86/mm] " tip-bot for Andy Lutomirski
2016-02-10 12:08 ` Borislav Petkov
2016-02-10 13:48 ` Michael Matz [this message]
2016-02-10 14:51 ` [PATCH -v1.1] x86/mm: Fix INVPCID asm constraint Borislav Petkov
2016-02-11 2:48 ` Andy Lutomirski
2016-01-29 19:42 ` [PATCH v3 2/3] x86/mm: Add a noinvpcid option to turn off INVPCID Andy Lutomirski
2016-01-29 19:42 ` Andy Lutomirski
2016-02-09 16:07 ` [tip:x86/mm] x86/mm: Add a 'noinvpcid' boot " tip-bot for Andy Lutomirski
2016-01-29 19:42 ` [PATCH v3 3/3] x86/mm: If INVPCID is available, use it to flush global mappings Andy Lutomirski
2016-01-29 19:42 ` Andy Lutomirski
2016-02-09 16:08 ` [tip:x86/mm] " tip-bot for Andy Lutomirski
2016-02-01 10:51 ` [PATCH v3 0/3] x86/mm: INVPCID support Borislav Petkov
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