From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 535C7CA9EB9 for ; Tue, 22 Oct 2019 11:38:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 18122218AE for ; Tue, 22 Oct 2019 11:38:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388744AbfJVLit (ORCPT ); Tue, 22 Oct 2019 07:38:49 -0400 Received: from mail-wm1-f65.google.com ([209.85.128.65]:36267 "EHLO mail-wm1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387871AbfJVLit (ORCPT ); Tue, 22 Oct 2019 07:38:49 -0400 Received: by mail-wm1-f65.google.com with SMTP id c22so6714417wmd.1; Tue, 22 Oct 2019 04:38:46 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:autocrypt :message-id:date:user-agent:mime-version:in-reply-to :content-language:content-transfer-encoding; bh=H4XHYqow4rWm5szIAWV5ylZxrQNb9J+QDV/Ex9kAv0Y=; b=SgD20YDE+/6l37I1jIjKBbZoFyZfhe6b58UML64rAMe89hiiS5XRewxX22ywknxOky YMlXK5T5On7UbqekNwOAj9/jhUfDN0juJIlkoay+Hfc3pkeXWknc4Zy4N+EuPun6MxXp j3zS5q5gskdoATj7AlD7hGcNzH7JWsjLHd/JXc+7R46fJAyuCtoFIaBHj1j8te4bqVNt 38ZsMmqo+nuW7fVgXALpFmhytczXBxY0rnsCECw2vzbOMZYaNqHhSoK+R0lyvq11Tldw 5HSFjEUd8YxwykdlDL25pgsBw0LhKaX3B7krv/wAsDPL2G/zJUZh+asgYDReS+i8EgfA tuiQ== X-Gm-Message-State: APjAAAXbANpAsvmThuAgtkMeU3kNusz5jyeGY72W2l0YNuRkmIhLUY77 ZXhPFs7P0D0OFoU1DRzX7Mw= X-Google-Smtp-Source: APXvYqzWW8cBeW5KJZJ14BkS8q1bBVAJppXvnNoimiMDRZ/j4pBjN2CJfQ/+9cvDjRSx1A80au14AQ== X-Received: by 2002:a1c:1a4b:: with SMTP id a72mr2609572wma.17.1571744325690; Tue, 22 Oct 2019 04:38:45 -0700 (PDT) Received: from ?IPv6:2a0b:e7c0:0:107::49? ([2a0b:e7c0:0:107::49]) by smtp.gmail.com with ESMTPSA id l18sm16340820wrc.18.2019.10.22.04.38.43 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 22 Oct 2019 04:38:44 -0700 (PDT) Subject: Re: [PATCH] x86/ftrace: Get rid of function_hook To: Borislav Petkov , Steven Rostedt Cc: tip-bot2 for Jiri Slaby , linux-kernel@vger.kernel.org, linux-tip-commits@vger.kernel.org, "H. Peter Anvin" , Ingo Molnar , Josh Poimboeuf , linux-arch@vger.kernel.org, Masami Hiramatsu , Peter Zijlstra , Thomas Gleixner , x86-ml , Ingo Molnar References: <20191011115108.12392-22-jslaby@suse.cz> <157141622788.29376.4016565749507481510.tip-bot2@tip-bot2> <20191018124800.0a7006bb@gandalf.local.home> <20191018124956.764ac42e@gandalf.local.home> <20191018171354.GB20368@zn.tnic> <20191018133735.77e90e36@gandalf.local.home> <20191018194856.GC20368@zn.tnic> <20191018163125.346e078d@gandalf.local.home> <20191019073424.GA27353@zn.tnic> <20191021141038.GC7014@zn.tnic> From: Jiri Slaby Autocrypt: addr=jslaby@suse.cz; prefer-encrypt=mutual; keydata= mQINBE6S54YBEACzzjLwDUbU5elY4GTg/NdotjA0jyyJtYI86wdKraekbNE0bC4zV+ryvH4j rrcDwGs6tFVrAHvdHeIdI07s1iIx5R/ndcHwt4fvI8CL5PzPmn5J+h0WERR5rFprRh6axhOk rSD5CwQl19fm4AJCS6A9GJtOoiLpWn2/IbogPc71jQVrupZYYx51rAaHZ0D2KYK/uhfc6neJ i0WqPlbtIlIrpvWxckucNu6ZwXjFY0f3qIRg3Vqh5QxPkojGsq9tXVFVLEkSVz6FoqCHrUTx wr+aw6qqQVgvT/McQtsI0S66uIkQjzPUrgAEtWUv76rM4ekqL9stHyvTGw0Fjsualwb0Gwdx ReTZzMgheAyoy/umIOKrSEpWouVoBt5FFSZUyjuDdlPPYyPav+hpI6ggmCTld3u2hyiHji2H cDpcLM2LMhlHBipu80s9anNeZhCANDhbC5E+NZmuwgzHBcan8WC7xsPXPaiZSIm7TKaVoOcL 9tE5aN3jQmIlrT7ZUX52Ff/hSdx/JKDP3YMNtt4B0cH6ejIjtqTd+Ge8sSttsnNM0CQUkXps w98jwz+Lxw/bKMr3NSnnFpUZaxwji3BC9vYyxKMAwNelBCHEgS/OAa3EJoTfuYOK6wT6nadm YqYjwYbZE5V/SwzMbpWu7Jwlvuwyfo5mh7w5iMfnZE+vHFwp/wARAQABtBtKaXJpIFNsYWJ5 IDxqc2xhYnlAc3VzZS5jej6JAjgEEwECACIFAk6S6NgCGwMGCwkIBwMCBhUIAgkKCwQWAgMB Ah4BAheAAAoJEL0lsQQGtHBJgDsP/j9wh0vzWXsOPO3rDpHjeC3BT5DKwjVN/KtP7uZttlkB duReCYMTZGzSrmK27QhCflZ7Tw0Naq4FtmQSH8dkqVFugirhlCOGSnDYiZAAubjTrNLTqf7e 5poQxE8mmniH/Asg4KufD9bpxSIi7gYIzaY3hqvYbVF1vYwaMTujojlixvesf0AFlE4x8WKs wpk43fmo0ZLcwObTnC3Hl1JBsPujCVY8t4E7zmLm7kOB+8EHaHiRZ4fFDWweuTzRDIJtVmrH LWvRDAYg+IH3SoxtdJe28xD9KoJw4jOX1URuzIU6dklQAnsKVqxz/rpp1+UVV6Ky6OBEFuoR 613qxHCFuPbkRdpKmHyE0UzmniJgMif3v0zm/+1A/VIxpyN74cgwxjhxhj/XZWN/LnFuER1W zTHcwaQNjq/I62AiPec5KgxtDeV+VllpKmFOtJ194nm9QM9oDSRBMzrG/2AY/6GgOdZ0+qe+ 4BpXyt8TmqkWHIsVpE7I5zVDgKE/YTyhDuqYUaWMoI19bUlBBUQfdgdgSKRMJX4vE72dl8BZ +/ONKWECTQ0hYntShkmdczcUEsWjtIwZvFOqgGDbev46skyakWyod6vSbOJtEHmEq04NegUD al3W7Y/FKSO8NqcfrsRNFWHZ3bZ2Q5X0tR6fc6gnZkNEtOm5fcWLY+NVz4HLaKrJuQINBE6S 54YBEADPnA1iy/lr3PXC4QNjl2f4DJruzW2Co37YdVMjrgXeXpiDvneEXxTNNlxUyLeDMcIQ K8obCkEHAOIkDZXZG8nr4mKzyloy040V0+XA9paVs6/ice5l+yJ1eSTs9UKvj/pyVmCAY1Co SNN7sfPaefAmIpduGacp9heXF+1Pop2PJSSAcCzwZ3PWdAJ/w1Z1Dg/tMCHGFZ2QCg4iFzg5 Bqk4N34WcG24vigIbRzxTNnxsNlU1H+tiB81fngUp2pszzgXNV7CWCkaNxRzXi7kvH+MFHu2 1m/TuujzxSv0ZHqjV+mpJBQX/VX62da0xCgMidrqn9RCNaJWJxDZOPtNCAWvgWrxkPFFvXRl t52z637jleVFL257EkMI+u6UnawUKopa+Tf+R/c+1Qg0NHYbiTbbw0pU39olBQaoJN7JpZ99 T1GIlT6zD9FeI2tIvarTv0wdNa0308l00bas+d6juXRrGIpYiTuWlJofLMFaaLYCuP+e4d8x rGlzvTxoJ5wHanilSE2hUy2NSEoPj7W+CqJYojo6wTJkFEiVbZFFzKwjAnrjwxh6O9/V3O+Z XB5RrjN8hAf/4bSo8qa2y3i39cuMT8k3nhec4P9M7UWTSmYnIBJsclDQRx5wSh0Mc9Y/psx9 B42WbV4xrtiiydfBtO6tH6c9mT5Ng+d1sN/VTSPyfQARAQABiQIfBBgBAgAJBQJOkueGAhsM AAoJEL0lsQQGtHBJN7UQAIDvgxaW8iGuEZZ36XFtewH56WYvVUefs6+Pep9ox/9ZXcETv0vk DUgPKnQAajG/ViOATWqADYHINAEuNvTKtLWmlipAI5JBgE+5g9UOT4i69OmP/is3a/dHlFZ3 qjNk1EEGyvioeycJhla0RjakKw5PoETbypxsBTXk5EyrSdD/I2Hez9YGW/RcI/WC8Y4Z/7FS ITZhASwaCOzy/vX2yC6iTx4AMFt+a6Z6uH/xGE8pG5NbGtd02r+m7SfuEDoG3Hs1iMGecPyV XxCVvSV6dwRQFc0UOZ1a6ywwCWfGOYqFnJvfSbUiCMV8bfRSWhnNQYLIuSv/nckyi8CzCYIg c21cfBvnwiSfWLZTTj1oWyj5a0PPgGOdgGoIvVjYXul3yXYeYOqbYjiC5t99JpEeIFupxIGV ciMk6t3pDrq7n7Vi/faqT+c4vnjazJi0UMfYnnAzYBa9+NkfW0w5W9Uy7kW/v7SffH/2yFiK 9HKkJqkN9xYEYaxtfl5pelF8idoxMZpTvCZY7jhnl2IemZCBMs6s338wS12Qro5WEAxV6cjD VSdmcD5l9plhKGLmgVNCTe8DPv81oDn9s0cIRLg9wNnDtj8aIiH8lBHwfUkpn32iv0uMV6Ae sLxhDWfOR4N+wu1gzXWgLel4drkCJcuYK5IL1qaZDcuGR8RPo3jbFO7Y Message-ID: Date: Tue, 22 Oct 2019 13:38:42 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.1.1 MIME-Version: 1.0 In-Reply-To: <20191021141038.GC7014@zn.tnic> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 21. 10. 19, 16:10, Borislav Petkov wrote: > From: Borislav Petkov > > function_hook is used as a better name than the default __fentry__ > which is the profiling counter which gcc adds before every function's > prologue. Thus, it is not called from C and cannot have the same > semantics as a pure C function - it saves/restores regs so that a C > function can be called. > > Drop the function_hook symbol and use __fentry__ directly for better > alignment with gcc's documentation. > > Switch the marking to SYM_CODE_START/_END which is reserved for > non-standard, special functions. > > Signed-off-by: Borislav Petkov > Cc: "H. Peter Anvin" > Cc: Ingo Molnar > Cc: Jiri Slaby On the top of Steven's comment: Acked-by: Jiri Slaby Thanks for taking care of this while my tooth was causing me pain. > Cc: Jonathan Corbet > Cc: Josh Poimboeuf > Cc: linux-doc@vger.kernel.org > Cc: linux-kernel@vger.kernel.org > Cc: Peter Zijlstra > Cc: "Steven Rostedt (VMware)" > Cc: Thomas Gleixner > Cc: x86@kernel.org > --- > Documentation/asm-annotations.rst | 4 ++-- > arch/x86/kernel/ftrace_32.S | 8 +++----- > arch/x86/kernel/ftrace_64.S | 13 ++++++------- > 3 files changed, 11 insertions(+), 14 deletions(-) > > diff --git a/Documentation/asm-annotations.rst b/Documentation/asm-annotations.rst > index 29ccd6e61fe5..f55c2bb74d00 100644 > --- a/Documentation/asm-annotations.rst > +++ b/Documentation/asm-annotations.rst > @@ -117,9 +117,9 @@ This section covers ``SYM_FUNC_*`` and ``SYM_CODE_*`` enumerated above. > So in most cases, developers should write something like in the following > example, having some asm instructions in between the macros, of course:: > > - SYM_FUNC_START(function_hook) > + SYM_FUNC_START(memset) > ... asm insns ... > - SYM_FUNC_END(function_hook) > + SYM_FUNC_END(memset) > > In fact, this kind of annotation corresponds to the now deprecated ``ENTRY`` > and ``ENDPROC`` macros. > diff --git a/arch/x86/kernel/ftrace_32.S b/arch/x86/kernel/ftrace_32.S > index 8ed1f5d371f0..77be7e7e5e59 100644 > --- a/arch/x86/kernel/ftrace_32.S > +++ b/arch/x86/kernel/ftrace_32.S > @@ -12,18 +12,16 @@ > #include > #include > > -# define function_hook __fentry__ > -EXPORT_SYMBOL(__fentry__) > - > #ifdef CONFIG_FRAME_POINTER > # define MCOUNT_FRAME 1 /* using frame = true */ > #else > # define MCOUNT_FRAME 0 /* using frame = false */ > #endif > > -SYM_FUNC_START(function_hook) > +SYM_CODE_START(__fentry__) > ret > -SYM_FUNC_END(function_hook) > +SYM_CODE_END(__fentry__) > +EXPORT_SYMBOL(__fentry__) > > SYM_CODE_START(ftrace_caller) > > diff --git a/arch/x86/kernel/ftrace_64.S b/arch/x86/kernel/ftrace_64.S > index 69c8d1b9119e..3029fe4f8547 100644 > --- a/arch/x86/kernel/ftrace_64.S > +++ b/arch/x86/kernel/ftrace_64.S > @@ -14,9 +14,6 @@ > .code64 > .section .entry.text, "ax" > > -# define function_hook __fentry__ > -EXPORT_SYMBOL(__fentry__) > - > #ifdef CONFIG_FRAME_POINTER > /* Save parent and function stack frames (rip and rbp) */ > # define MCOUNT_FRAME_SIZE (8+16*2) > @@ -132,9 +129,10 @@ EXPORT_SYMBOL(__fentry__) > > #ifdef CONFIG_DYNAMIC_FTRACE > > -SYM_FUNC_START(function_hook) > +SYM_CODE_START(__fentry__) > retq > -SYM_FUNC_END(function_hook) > +SYM_CODE_END(__fentry__) > +EXPORT_SYMBOL(__fentry__) > > SYM_FUNC_START(ftrace_caller) > /* save_mcount_regs fills in first two parameters */ > @@ -248,7 +246,7 @@ SYM_FUNC_END(ftrace_regs_caller) > > #else /* ! CONFIG_DYNAMIC_FTRACE */ > > -SYM_FUNC_START(function_hook) > +SYM_CODE_START(__fentry__) > cmpq $ftrace_stub, ftrace_trace_function > jnz trace > > @@ -279,7 +277,8 @@ trace: > restore_mcount_regs > > jmp fgraph_trace > -SYM_FUNC_END(function_hook) > +SYM_CODE_END(__fentry__) > +EXPORT_SYMBOL(__fentry__) > #endif /* CONFIG_DYNAMIC_FTRACE */ > > #ifdef CONFIG_FUNCTION_GRAPH_TRACER > -- js suse labs