From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ian Campbell Subject: Re: [PATCH for-4.5] xen/arm: Correct the opcode for BUG_INSTR on arm32 Date: Fri, 5 Dec 2014 10:54:38 +0000 Message-ID: <1417776878.22808.56.camel@citrix.com> References: <1417721215-32639-1-git-send-email-julien.grall@linaro.org> <20141204193434.GB6225@laptop.dumpdata.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta5.messagelabs.com ([195.245.231.135]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1XwqXe-0002lk-5l for xen-devel@lists.xenproject.org; Fri, 05 Dec 2014 10:55:18 +0000 In-Reply-To: <20141204193434.GB6225@laptop.dumpdata.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Konrad Rzeszutek Wilk Cc: xen-devel@lists.xenproject.org, Julien Grall , tim@xen.org, stefano.stabellini@citrix.com List-Id: xen-devel@lists.xenproject.org On Thu, 2014-12-04 at 14:34 -0500, Konrad Rzeszutek Wilk wrote: > On Thu, Dec 04, 2014 at 07:26:55PM +0000, Julien Grall wrote: > > A 0 was forgotten when the arm32 BUG instruction opcode has been added in commit > > 3e802c6ca1fb9a9549258c2855a57cad483f3cbd "xen/arm: Correctly support WARN_ON". > > > > This will result to use a valid instruction (mcreq 0, 3, r0, cr15, cr0, {7}), > > and inhibit usage of BUG/WARN_ON and co. Doh! > > > > Signed-off-by: Julien Grall > > > > --- > > > > Not sure, why I dropped the 0 when I implemented the patch... > > This is a bug fixed for Xen 4.5. This is only affected ARM32 where the > > BUG opcode was malformed. > > > > With the malformed opcode, the ASSERT/BUG_ON is skipped and the > > processor may execute another patch (because the compiler has optimized > > s/patch/path/ ? Will fix on commit. > > due the unreachable in both macro). > > > > The code modified is only executed when Xen is in bad state. > > Release-Acked-by: Konrad Rzeszutek Wilk Acked-by: Ian Campbell > > > --- > > xen/include/asm-arm/arm32/bug.h | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/xen/include/asm-arm/arm32/bug.h b/xen/include/asm-arm/arm32/bug.h > > index 155b420..3e66f35 100644 > > --- a/xen/include/asm-arm/arm32/bug.h > > +++ b/xen/include/asm-arm/arm32/bug.h > > @@ -6,7 +6,7 @@ > > /* ARMv7 provides a list of undefined opcode (see A8.8.247 DDI 0406C.b) > > * Use one them encoding A1 to go in exception mode > > */ > > -#define BUG_OPCODE 0xe7f00f0 > > +#define BUG_OPCODE 0xe7f000f0 > > > > #define BUG_INSTR ".word " __stringify(BUG_OPCODE) > > > > -- > > 2.1.3 > > > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xen.org > http://lists.xen.org/xen-devel