From patchwork Wed Jan 22 14:11:18 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jean Pihet X-Patchwork-Id: 3523351 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 [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 9983C9F2E9 for ; Wed, 22 Jan 2014 14:13:38 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id ED7E12013D for ; Wed, 22 Jan 2014 14:13:33 +0000 (UTC) Received: from casper.infradead.org (casper.infradead.org [85.118.1.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 9A41820138 for ; Wed, 22 Jan 2014 14:13:32 +0000 (UTC) Received: from merlin.infradead.org ([2001:4978:20e::2]) by casper.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1W5yY3-0006bm-Vn; Wed, 22 Jan 2014 14:12:56 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1W5yXu-0007ad-2l; Wed, 22 Jan 2014 14:12:46 +0000 Received: from mail-ea0-f176.google.com ([209.85.215.176]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1W5yXJ-0007RK-O3 for linux-arm-kernel@lists.infradead.org; Wed, 22 Jan 2014 14:12:13 +0000 Received: by mail-ea0-f176.google.com with SMTP id h14so4521072eaj.21 for ; Wed, 22 Jan 2014 06:11:39 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=wfIUPnOLBnHvHPMvtGyNoUD0tnx2AHwy9041tfujAuU=; b=Y/BZyE92xBudYFmIixlEtES0uruOlFEgEwarxm0V/T/1QatIEXBD6MLaTmvMpGe/6R JUl1c7RvwRs929UuFezbU08AMoB5QB3aiQNDRb06YlcPIyDB62doNadCxY7MfQe/8NqL MRIT3QpSg/SHwp862U9cVQJqbF8+n6/Zl/Fc6gluV201kuViMINB0ja5MVnmKDGajqg6 wfOj39v7peoVZuikYLWUzaYIVKQrxGzQyrWLIF7hwFbI/fAMsuPl7gwrWpW+qyI0fxpT 49K3CElydtfz+yZLS6UBYn07enRVat904oY4H/u3d/jF05FyqpCB2E7U1VewM8p4AHTT VuZw== X-Gm-Message-State: ALoCoQmG+GLCg27teryCrsRZXcssmXLjb4s4QZ3MJtRXzdfi+wUuRezV6/5vl97kx8qWceHtwl0E X-Received: by 10.14.201.68 with SMTP id a44mr1779687eeo.46.1390399899796; Wed, 22 Jan 2014 06:11:39 -0800 (PST) Received: from localhost.localdomain (80.58-241-81.adsl-dyn.isp.belgacom.be. [81.241.58.80]) by mx.google.com with ESMTPSA id d43sm27572324eeo.12.2014.01.22.06.11.37 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Wed, 22 Jan 2014 06:11:38 -0800 (PST) From: Jean Pihet To: linux-kernel@vger.kernel.org, linaro-kernel@lists.linaro.org, linux-arm-kernel@lists.infradead.org, Arnaldo , Ingo Molnar , Jiri Olsa , Will Deacon Subject: [PATCH 3/4] ARM64: perf: add support for frame pointer unwinding in compat mode Date: Wed, 22 Jan 2014 15:11:18 +0100 Message-Id: <1390399879-5109-4-git-send-email-jean.pihet@linaro.org> X-Mailer: git-send-email 1.7.11.7 In-Reply-To: <1390399879-5109-1-git-send-email-jean.pihet@linaro.org> References: <1390399879-5109-1-git-send-email-jean.pihet@linaro.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20140122_091209_920686_CAB9C09C X-CRM114-Status: GOOD ( 15.84 ) X-Spam-Score: -2.6 (--) Cc: Jean Pihet , patches@linaro.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.8 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 When profiling a 32-bit application, user space callchain unwinding using the frame pointer is performed in compat mode. The code is taken over from the AARCH32 code and adapted to work on AARCH64. Signed-off-by: Jean Pihet --- arch/arm64/kernel/perf_event.c | 75 +++++++++++++++++++++++++++++++++++++----- 1 file changed, 67 insertions(+), 8 deletions(-) diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c index 5b1cd79..e868c72 100644 --- a/arch/arm64/kernel/perf_event.c +++ b/arch/arm64/kernel/perf_event.c @@ -1348,8 +1348,8 @@ early_initcall(init_hw_perf_events); * Callchain handling code. */ struct frame_tail { - struct frame_tail __user *fp; - unsigned long lr; + struct frame_tail __user *fp; + unsigned long lr; } __attribute__((packed)); /* @@ -1386,22 +1386,80 @@ user_backtrace(struct frame_tail __user *tail, return buftail.fp; } +/* + * The registers we're interested in are at the end of the variable + * length saved register structure. The fp points at the end of this + * structure so the address of this struct is: + * (struct compat_frame_tail *)(xxx->fp)-1 + * + * This code has been adapted from the ARM OProfile support. + */ +struct compat_frame_tail { + compat_uptr_t fp; /* a (struct compat_frame_tail *) in compat mode */ + u32 sp; + u32 lr; +} __attribute__((packed)); + +static struct compat_frame_tail __user * +compat_user_backtrace(struct compat_frame_tail __user *tail, + struct perf_callchain_entry *entry) +{ + struct compat_frame_tail buftail; + unsigned long err; + + /* Also check accessibility of one struct frame_tail beyond */ + if (!access_ok(VERIFY_READ, tail, sizeof(buftail))) + return NULL; + + pagefault_disable(); + err = __copy_from_user_inatomic(&buftail, tail, sizeof(buftail)); + pagefault_enable(); + + if (err) + return NULL; + + perf_callchain_store(entry, buftail.lr); + + /* + * Frame pointers should strictly progress back up the stack + * (towards higher addresses). + */ + if (tail + 1 >= (struct compat_frame_tail __user *) + compat_ptr(buftail.fp)) + return NULL; + + return (struct compat_frame_tail __user *)compat_ptr(buftail.fp) - 1; +} + void perf_callchain_user(struct perf_callchain_entry *entry, struct pt_regs *regs) { - struct frame_tail __user *tail; - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { /* We don't support guest os callchain now */ return; } perf_callchain_store(entry, regs->pc); - tail = (struct frame_tail __user *)regs->regs[29]; - while (entry->nr < PERF_MAX_STACK_DEPTH && - tail && !((unsigned long)tail & 0xf)) - tail = user_backtrace(tail, entry); + if (!compat_user_mode(regs)) { + /* AARCH64 mode */ + struct frame_tail __user *tail; + + tail = (struct frame_tail __user *)regs->regs[29]; + + while (entry->nr < PERF_MAX_STACK_DEPTH && + tail && !((unsigned long)tail & 0xf)) + tail = user_backtrace(tail, entry); + } else { + /* AARCH32 compat mode */ + struct compat_frame_tail __user *tail; + + tail = (struct compat_frame_tail __user *)regs->compat_fp - 1; + + while ((entry->nr < PERF_MAX_STACK_DEPTH) && + tail && !((unsigned long)tail & 0x3)) + tail = compat_user_backtrace(tail, entry); + } } /* @@ -1429,6 +1487,7 @@ void perf_callchain_kernel(struct perf_callchain_entry *entry, frame.fp = regs->regs[29]; frame.sp = regs->sp; frame.pc = regs->pc; + walk_stackframe(&frame, callchain_trace, entry); }