From patchwork Fri Oct 30 08:31:04 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Li Bin X-Patchwork-Id: 7525521 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id C6BAB9F2F7 for ; Fri, 30 Oct 2015 08:35:56 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id DD67C20671 for ; Fri, 30 Oct 2015 08:35:55 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 024B52067D for ; Fri, 30 Oct 2015 08:35:55 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1Zs58p-0005t8-6e; Fri, 30 Oct 2015 08:34:31 +0000 Received: from szxga02-in.huawei.com ([119.145.14.65]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Zs57M-0004NC-2Z for linux-arm-kernel@lists.infradead.org; Fri, 30 Oct 2015 08:33:05 +0000 Received: from 172.24.1.51 (EHLO szxeml430-hub.china.huawei.com) ([172.24.1.51]) by szxrg02-dlp.huawei.com (MOS 4.3.7-GA FastPath queued) with ESMTP id CVJ50735; Fri, 30 Oct 2015 16:32:09 +0800 (CST) Received: from localhost.localdomain (10.175.100.166) by szxeml430-hub.china.huawei.com (10.82.67.185) with Microsoft SMTP Server id 14.3.235.1; Fri, 30 Oct 2015 16:32:01 +0800 From: Li Bin To: , , , , Subject: [PATCH 3/3] recordmcount: arm64: replace the ignored mcount call into nop Date: Fri, 30 Oct 2015 16:31:04 +0800 Message-ID: <1446193864-24593-4-git-send-email-huawei.libin@huawei.com> X-Mailer: git-send-email 1.7.1 In-Reply-To: <1446193864-24593-1-git-send-email-huawei.libin@huawei.com> References: <1446193864-24593-1-git-send-email-huawei.libin@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.175.100.166] X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20151030_013300_925299_BBA35465 X-CRM114-Status: GOOD ( 14.63 ) X-Spam-Score: -4.2 (----) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: zhouchengming1@huawei.com, xiexiuqi@huawei.com, guohanjun@huawei.com, linux-kernel@vger.kernel.org, huawei.libin@huawei.com, dingtianhong@huawei.com, linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-5.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP By now, the recordmcount only records the function that in following sections: .text/.ref.text/.sched.text/.spinlock.text/.irqentry.text/ .kprobes.text/.text.unlikely For the function that not in these sections, the call mcount will be in place and not be replaced when kernel boot up. And it will bring performance overhead, such as do_mem_abort (in .exception.text section). This patch make the call mcount to nop for this case in recordmcount. Cc: # 3.18+ Signed-off-by: Li Bin Acked-by: Will Deacon --- scripts/recordmcount.c | 24 +++++++++++++++++++++++- 1 file changed, 23 insertions(+), 1 deletion(-) diff --git a/scripts/recordmcount.c b/scripts/recordmcount.c index 8cc020b..698768b 100644 --- a/scripts/recordmcount.c +++ b/scripts/recordmcount.c @@ -42,6 +42,7 @@ #ifndef EM_AARCH64 #define EM_AARCH64 183 +#define R_AARCH64_NONE 0 #define R_AARCH64_ABS64 257 #endif @@ -160,6 +161,22 @@ static int make_nop_x86(void *map, size_t const offset) return 0; } +static unsigned char ideal_nop4_arm64[4] = {0x1f, 0x20, 0x03, 0xd5}; +static int make_nop_arm64(void *map, size_t const offset) +{ + uint32_t *ptr; + + ptr = map + offset; + /* bl <_mcount> is 0x94000000 before relocation */ + if (*ptr != 0x94000000) + return -1; + + /* Convert to nop */ + ulseek(fd_map, offset, SEEK_SET); + uwrite(fd_map, ideal_nop, 4); + return 0; +} + /* * Get the whole file as a programming convenience in order to avoid * malloc+lseek+read+free of many pieces. If successful, then mmap @@ -354,7 +371,12 @@ do_file(char const *const fname) altmcount = "__gnu_mcount_nc"; break; case EM_AARCH64: - reltype = R_AARCH64_ABS64; gpfx = '_'; break; + reltype = R_AARCH64_ABS64; + make_nop = make_nop_arm64; + rel_type_nop = R_AARCH64_NONE; + ideal_nop = ideal_nop4_arm64; + gpfx = '_'; + break; case EM_IA_64: reltype = R_IA64_IMM64; gpfx = '_'; break; case EM_METAG: reltype = R_METAG_ADDR32; altmcount = "_mcount_wrapper";