From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-pa0-f48.google.com ([209.85.220.48]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZcQJ4-0001Tv-9x for kexec@lists.infradead.org; Thu, 17 Sep 2015 03:56:22 +0000 Received: by padhk3 with SMTP id hk3so7853519pad.3 for ; Wed, 16 Sep 2015 20:56:01 -0700 (PDT) Message-ID: <55fa39d0.2c1b450a.6854.4115@mx.google.com> Date: Wed, 16 Sep 2015 20:56:00 -0700 (PDT) From: Palmer Dabbelt Subject: Re: [PATCH 09/13] Move bp_type_idx to kernel/event/hw_breakpoint.c In-Reply-To: <20150915193910.GH16853@twins.programming.kicks-ass.net> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: peterz@infradead.org Cc: dave@sr71.net, linux-xtensa@linux-xtensa.org, fweisbec@gmail.com, dhowells@redhat.com, jcmvbkbc@gmail.com, hpa@zytor.com, mingo@kernel.org, ast@plumgrid.com, aarcange@redhat.com, bhe@redhat.com, x86@kernel.org, tomi.valkeinen@ti.com, 3chas3@gmail.com, paulmck@linux.vnet.ibm.com, dyoung@redhat.com, vgoyal@redhat.com, aishchuk@linux.vnet.ibm.com, linux-arch@vger.kernel.org, jikos@kernel.org, arnd@arndb.de, plagnioj@jcrosoft.com, josh@joshtriplett.org, acme@kernel.org, mathieu.desnoyers@efficios.com, viro@zeniv.linux.org.uk, luto@kernel.org, tglx@linutronix.de, drysdale@google.com, chris@zankel.net, iulia.manda21@gmail.com, geoff@infradead.org, gregkh@linuxfoundation.org, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, ebiederm@xmission.com, linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org, akpm@linux-foundation.org, davem@davemloft.net On Tue, 15 Sep 2015 12:39:10 PDT (-0700), peterz@infradead.org wrote: > On Tue, Sep 15, 2015 at 11:40:11AM -0700, Palmer Dabbelt wrote: >> On Tue, 15 Sep 2015 01:06:07 PDT (-0700), peterz@infradead.org wrote: >> > On Mon, Sep 14, 2015 at 03:50:43PM -0700, Palmer Dabbelt wrote: >> >> This has a "#ifdef CONFIG_*" that used to be exposed to userspace. >> >> >> >> The names in here are so generic that I don't think it's a good idea >> >> to expose them to userspace (or even the rest of the kernel). Since >> >> there's only one kernel user, it's been moved to that file. >> >> >> >> Signed-off-by: Palmer Dabbelt >> >> Reviewed-by: Andrew Waterman >> >> Reviewed-by: Albert Ou >> >> --- >> >> include/uapi/linux/hw_breakpoint.h | 10 ---------- >> >> kernel/events/hw_breakpoint.c | 10 ++++++++++ >> >> 2 files changed, 10 insertions(+), 10 deletions(-) >> >> >> >> diff --git a/include/uapi/linux/hw_breakpoint.h b/include/uapi/linux/hw_breakpoint.h >> >> index b04000a2296a..7a6a5a7f9511 100644 >> >> --- a/include/uapi/linux/hw_breakpoint.h >> >> +++ b/include/uapi/linux/hw_breakpoint.h >> >> @@ -17,14 +17,4 @@ enum { >> >> HW_BREAKPOINT_INVALID = HW_BREAKPOINT_RW | HW_BREAKPOINT_X, >> >> }; >> >> >> >> -enum bp_type_idx { >> >> - TYPE_INST = 0, >> >> -#ifdef CONFIG_HAVE_MIXED_BREAKPOINTS_REGS >> >> - TYPE_DATA = 0, >> >> -#else >> >> - TYPE_DATA = 1, >> >> -#endif >> >> - TYPE_MAX >> >> -}; >> > >> > This is rather unfortunate; you are correct that the naming is too >> > generic (and I tend to agree), but I think these values are required by >> > userspace to fill out: >> > >> > perf_event_attr::bp_type >> > >> > So removing them will break things. >> > >> > Frederic? >> >> perf_event_open(2) says >> >> bp_type (since Linux 2.6.33) >> This chooses the breakpoint type. It is one of: >> >> HW_BREAKPOINT_EMPTY >> No breakpoint. >> >> HW_BREAKPOINT_R >> Count when we read the memory location. >> >> HW_BREAKPOINT_W >> Count when we write the memory location. >> >> HW_BREAKPOINT_RW >> Count when we read or write the memory location. >> >> HW_BREAKPOINT_X >> Count when we execute code at the memory location. >> >> The values can be combined via a bitwise or, but the combination >> of HW_BREAKPOINT_R or HW_BREAKPOINT_W with HW_BREAKPOINT_X is >> not allowed. >> >> so I think removing this enum from userspace is OK. Did I miss >> something? > > Nah, could've just been me not being awake. Unless Frederic says > otherwise I'll chalk it up to not having drank enough morning juice. Well, I'm going to leave this alone, then -- as Arnd pointed out in a later email that got mis-threaded, this would be super tricky to fix if userspace actually relied on it (which is why I was scared I was wrong). v4 (which is hopefully the final version of the patch set) will leave this as it is. _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec