From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e23smtp01.au.ibm.com (e23smtp01.au.ibm.com [202.81.31.143]) (using TLSv1 with cipher CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 407FF1A07F5 for ; Thu, 16 Jul 2015 20:57:31 +1000 (AEST) Received: from /spool/local by e23smtp01.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 16 Jul 2015 20:57:31 +1000 Received: from d23relay08.au.ibm.com (d23relay08.au.ibm.com [9.185.71.33]) by d23dlp01.au.ibm.com (Postfix) with ESMTP id 857342CE8040 for ; Thu, 16 Jul 2015 20:57:30 +1000 (EST) Received: from d23av01.au.ibm.com (d23av01.au.ibm.com [9.190.234.96]) by d23relay08.au.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t6GAvJUL55443538 for ; Thu, 16 Jul 2015 20:57:27 +1000 Received: from d23av01.au.ibm.com (localhost [127.0.0.1]) by d23av01.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t6GAuv1n005245 for ; Thu, 16 Jul 2015 20:56:58 +1000 Subject: [PATCH] kprobes: Mark OPTPROBES n/a for powerpc From: Ananth N Mavinakayanahalli To: masami.hiramatsu.pt@hitachi.com, mpe@ellerman.id.au Cc: linuxppc-dev@lists.ozlabs.org Date: Thu, 16 Jul 2015 16:26:39 +0530 Message-ID: <20150716105639.9151.75671.stgit@thinktux.in.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Kprobes uses a breakpoint instruction to trap into execution flow and the probed instruction is single-stepped from an alternate location. On some architectures like x86, under certain conditions, the OPTPROBES feature enables replacing the probed instruction with a jump instead, resulting in a significant perfomance boost (one single-step exception is bypassed for each kprobe). Powerpc has an in-kernel instruction emulator. Kprobes on powerpc uses this emulator already and bypasses the single-step exception, with a lot less complexity. Hence, mark OPTPROBES n/a for powerpc. Signed-off-by: Ananth N Mavinakayanahalli --- .../features/debug/optprobes/arch-support.txt | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/Documentation/features/debug/optprobes/arch-support.txt b/Documentation/features/debug/optprobes/arch-support.txt index b8999d8..0a3ca33 100644 --- a/Documentation/features/debug/optprobes/arch-support.txt +++ b/Documentation/features/debug/optprobes/arch-support.txt @@ -27,7 +27,7 @@ | nios2: | TODO | | openrisc: | TODO | | parisc: | TODO | - | powerpc: | TODO | + | powerpc: | n/a | | s390: | TODO | | score: | TODO | | sh: | TODO |