From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751980AbeCMGUX (ORCPT ); Tue, 13 Mar 2018 02:20:23 -0400 Received: from terminus.zytor.com ([198.137.202.136]:50157 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751391AbeCMGUW (ORCPT ); Tue, 13 Mar 2018 02:20:22 -0400 Date: Mon, 12 Mar 2018 23:19:53 -0700 From: tip-bot for Jiri Olsa Message-ID: Cc: will.deacon@arm.com, chabbi.milind@gmail.com, fweisbec@gmail.com, yao.jin@linux.intel.com, jolsa@kernel.org, onestero@redhat.com, tglx@linutronix.de, kan.liang@intel.com, namhyung@kernel.org, dsahern@gmail.com, mpe@ellerman.id.au, hbathini@linux.vnet.ibm.com, jolsa@redhat.com, sukadev@linux.vnet.ibm.com, alexander.shishkin@linux.intel.com, mingo@kernel.org, torvalds@linux-foundation.org, acme@redhat.com, linux-kernel@vger.kernel.org, hpa@zytor.com, peterz@infradead.org Reply-To: kan.liang@intel.com, mpe@ellerman.id.au, dsahern@gmail.com, namhyung@kernel.org, jolsa@kernel.org, onestero@redhat.com, tglx@linutronix.de, yao.jin@linux.intel.com, fweisbec@gmail.com, will.deacon@arm.com, chabbi.milind@gmail.com, hbathini@linux.vnet.ibm.com, sukadev@linux.vnet.ibm.com, mingo@kernel.org, alexander.shishkin@linux.intel.com, jolsa@redhat.com, peterz@infradead.org, hpa@zytor.com, linux-kernel@vger.kernel.org, acme@redhat.com, torvalds@linux-foundation.org In-Reply-To: <20180312134548.31532-4-jolsa@kernel.org> References: <20180312134548.31532-4-jolsa@kernel.org> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/core] hw_breakpoint: Add modify_bp_slot() function Git-Commit-ID: ea6a9d530c1779b9bd30944b803820c462f01eac X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: ea6a9d530c1779b9bd30944b803820c462f01eac Gitweb: https://git.kernel.org/tip/ea6a9d530c1779b9bd30944b803820c462f01eac Author: Jiri Olsa AuthorDate: Mon, 12 Mar 2018 14:45:43 +0100 Committer: Ingo Molnar CommitDate: Tue, 13 Mar 2018 06:56:07 +0100 hw_breakpoint: Add modify_bp_slot() function Add the modify_bp_slot() function to keep slot numbers correct when changing the breakpoint type. Using existing __release_bp_slot()/__reserve_bp_slot() call sequence to update the slot counts. Signed-off-by: Jiri Olsa Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: David Ahern Cc: Frederic Weisbecker Cc: Hari Bathini Cc: Jin Yao Cc: Jiri Olsa Cc: Kan Liang Cc: Linus Torvalds Cc: Michael Ellerman Cc: Milind Chabbi Cc: Namhyung Kim Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Sukadev Bhattiprolu Cc: Thomas Gleixner Cc: Will Deacon Link: http://lkml.kernel.org/r/20180312134548.31532-4-jolsa@kernel.org Signed-off-by: Ingo Molnar --- kernel/events/hw_breakpoint.c | 46 ++++++++++++++++++++++++++++++++++++------- 1 file changed, 39 insertions(+), 7 deletions(-) diff --git a/kernel/events/hw_breakpoint.c b/kernel/events/hw_breakpoint.c index 9b31fbcc3305..776948beb4ac 100644 --- a/kernel/events/hw_breakpoint.c +++ b/kernel/events/hw_breakpoint.c @@ -44,6 +44,7 @@ #include #include #include +#include #include /* @@ -344,6 +345,38 @@ void release_bp_slot(struct perf_event *bp) mutex_unlock(&nr_bp_mutex); } +static int __modify_bp_slot(struct perf_event *bp, u64 old_type) +{ + int err; + + __release_bp_slot(bp, old_type); + + err = __reserve_bp_slot(bp, bp->attr.bp_type); + if (err) { + /* + * Reserve the old_type slot back in case + * there's no space for the new type. + * + * This must succeed, because we just released + * the old_type slot in the __release_bp_slot + * call above. If not, something is broken. + */ + WARN_ON(__reserve_bp_slot(bp, old_type)); + } + + return err; +} + +static int modify_bp_slot(struct perf_event *bp, u64 old_type) +{ + int ret; + + mutex_lock(&nr_bp_mutex); + ret = __modify_bp_slot(bp, old_type); + mutex_unlock(&nr_bp_mutex); + return ret; +} + /* * Allow the kernel debugger to reserve breakpoint slots without * taking a lock using the dbg_* variant of for the reserve and @@ -435,6 +468,7 @@ int modify_user_hw_breakpoint(struct perf_event *bp, struct perf_event_attr *att u64 old_addr = bp->attr.bp_addr; u64 old_len = bp->attr.bp_len; int old_type = bp->attr.bp_type; + bool modify = attr->bp_type != old_type; int err = 0; /* @@ -452,12 +486,9 @@ int modify_user_hw_breakpoint(struct perf_event *bp, struct perf_event_attr *att bp->attr.bp_type = attr->bp_type; bp->attr.bp_len = attr->bp_len; - if (attr->disabled) - goto end; - err = validate_hw_breakpoint(bp); - if (!err) - perf_event_enable(bp); + if (!err && modify) + err = modify_bp_slot(bp, old_type); if (err) { bp->attr.bp_addr = old_addr; @@ -469,9 +500,10 @@ int modify_user_hw_breakpoint(struct perf_event *bp, struct perf_event_attr *att return err; } -end: - bp->attr.disabled = attr->disabled; + if (!attr->disabled) + perf_event_enable(bp); + bp->attr.disabled = attr->disabled; return 0; } EXPORT_SYMBOL_GPL(modify_user_hw_breakpoint);