From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9B71A34D4D8; Wed, 7 Jan 2026 16:03:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=216.40.44.13 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767801822; cv=none; b=gFhe0rCLRZM8r6LmyBTQTRQe5gQz4XMQJT/zh/ZIs3nGTINYqTPClOV1U5nCT18UhIBJqJq/WiIR4pgabvhDIqLLR20rwHTzSx6TtGqdmlOF68vbBWA4EfRr4j7pG9aFXCBJ40qQcdqIGismbP8GDLNFTaS1fS3D2DcL0HTzljM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767801822; c=relaxed/simple; bh=0/LOXatsbH7F3/lbi5zwi6kK9oqM1E1EsqV+tVAbn7c=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=sTURO8I4e3HRxlC6bv6sWlm3Ij/IVmdPVadUCAy39CTMnQVXZpSH/IiIhLfgRIZHS79IX/52H/h4VkDSP1fKr2Af9Zk/9wjwUuw+O6he3USVFLLOQP9XAOU8vlVbZipSx+lyKRYzsKSQpgHoZD+5s7iht/U7CKHGweD8Op7a4Dw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=goodmis.org; spf=pass smtp.mailfrom=goodmis.org; arc=none smtp.client-ip=216.40.44.13 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=goodmis.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=goodmis.org Received: from omf04.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id BDE121A5130; Wed, 7 Jan 2026 16:03:28 +0000 (UTC) Received: from [HIDDEN] (Authenticated sender: rostedt@goodmis.org) by omf04.hostedemail.com (Postfix) with ESMTPA id E70AC20023; Wed, 7 Jan 2026 16:03:25 +0000 (UTC) Date: Wed, 7 Jan 2026 11:03:52 -0500 From: Steven Rostedt To: Jiri Olsa Cc: Masami Hiramatsu , Will Deacon , Mahe Tardy , Peter Zijlstra , bpf@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, x86@kernel.org, Yonghong Song , Song Liu , Andrii Nakryiko , Mark Rutland Subject: Re: [PATCH bpf-next 1/2] arm64/ftrace,bpf: Fix partial regs after bpf_prog_run Message-ID: <20260107110352.3fd7ddda@gandalf.local.home> In-Reply-To: <20260107093256.54616-1-jolsa@kernel.org> References: <20260107093256.54616-1-jolsa@kernel.org> X-Mailer: Claws Mail 3.20.0git84 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspamout07 X-Rspamd-Queue-Id: E70AC20023 X-Stat-Signature: 13qo46g6zpia7f3nofbp81nnodino9w7 X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Session-ID: U2FsdGVkX1957k6O/UsmSN3vUac32Bo7sXZIZwwkaaU= X-HE-Tag: 1767801805-671253 X-HE-Meta: U2FsdGVkX18RsKY0dngVyvOKbOnb578X+xSZkEOG7hLLVWfcT997CreYeXdTXjiUBbrnEpEplun5zUoX/yIde/2G7I0khiiwc2+9R3i83hE5x9MaXQsj752xyWlfb1torPzACnrRGbNQRBs76gmyhpH81bHqH6l5Ph89iZObGEZbEZGFPfhDP4wmX4UEQOSAmpy+EanvESqs05MZHmkt+EhdhXlEt4bxk4hAlAIcQw42HV/JXn0BV2+43E+XurhE5vtIgIOTTqPOPf6C1dvfnCE7BZArazcQzYY63MXPU9eCBeI0YhZEhYxCQn/Q3+/MgFzPmaLc5W8Wh67jl6agKZJpPxz16ltc On Wed, 7 Jan 2026 10:32:55 +0100 Jiri Olsa wrote: > diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h > index 1621c84f44b3..177c7bbf3b84 100644 > --- a/arch/arm64/include/asm/ftrace.h > +++ b/arch/arm64/include/asm/ftrace.h > @@ -157,6 +157,30 @@ ftrace_partial_regs(const struct ftrace_regs *fregs, struct pt_regs *regs) > return regs; > } > See my reply in the other email thread: https://lore.kernel.org/all/20260107105316.2b70a308@gandalf.local.home/ -- Steve > +/* > + * ftrace_partial_regs_update - update the original ftrace_regs from regs > + * @fregs: The ftrace_regs to update from @regs > + * @regs: The partial regs from ftrace_partial_regs() that was updated > + * > + * Some architectures have the partial regs living in the ftrace_regs > + * structure, whereas other architectures need to make a different copy > + * of the @regs. If a partial @regs is retrieved by ftrace_partial_regs() and > + * if the code using @regs updates a field (like the instruction pointer or > + * stack pointer) it may need to propagate that change to the original @fregs > + * it retrieved the partial @regs from. Use this function to guarantee that > + * update happens. > + */ > +static __always_inline void > +ftrace_partial_regs_update(const struct ftrace_regs *fregs, struct pt_regs *regs) > +{ > + struct __arch_ftrace_regs *afregs = arch_ftrace_regs(fregs); > + > + if (afregs->pc != regs->pc) { > + afregs->pc = regs->pc; > + afregs->regs[0] = regs->regs[0]; > + } > +}