From patchwork Mon Feb 3 18:18:28 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jean Pihet X-Patchwork-Id: 3570321 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 14FBDC02DC for ; Mon, 3 Feb 2014 18:21:08 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 2B6BA20160 for ; Mon, 3 Feb 2014 18:21:07 +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 29CF0200D4 for ; Mon, 3 Feb 2014 18:21:06 +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 1WAO7a-00064k-IB; Mon, 03 Feb 2014 18:19:51 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1WAO7B-00048f-59; Mon, 03 Feb 2014 18:19:25 +0000 Received: from mail-ee0-f49.google.com ([74.125.83.49]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1WAO6t-000443-BM for linux-arm-kernel@lists.infradead.org; Mon, 03 Feb 2014 18:19:08 +0000 Received: by mail-ee0-f49.google.com with SMTP id d17so3802994eek.22 for ; Mon, 03 Feb 2014 10:18:45 -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=lJb5jQX/g8u65cHRtQUh6mzFTIKYW14X3Dm8annCSQ8=; b=ZqZXLueWKLtk2WJ387YI8TdDA9ucP4zDEmAeP6u1KHoB4Up2HES+w4txm+iZENK9e+ ppLTg6DHpPVNNIs0Bk1Gvl1UbXcwDaT5IKdEESF3GY0UmSijRwXZqATlnsjt2SH0LKGM L4011bGUov0ZDXtVdy4ZE3kT7TpQroct79JDSAlT4MiQSD7eeqS5n5r5to2fVyeF3zCP Je4tEBF9ODctAok78hBlCiDiZZEARR1353BijQBCxZgOLTEEAq6mxImkybkow0XbuxDR Ks0xOh7Y6PMrnMcin4MADw12seqNlVoJITONRmD/2W6IOyH52E9dWZ+Xv5WVubwujtef F5xA== X-Gm-Message-State: ALoCoQmFjR9EMj28Dr8gSd8LCe/qccA0E5GJkS7Z7Pxi/GPfh8CTGlXSnW6Y7Mb0dDTjqsTYvir1 X-Received: by 10.14.241.142 with SMTP id g14mr45468023eer.40.1391451525747; Mon, 03 Feb 2014 10:18:45 -0800 (PST) Received: from localhost.localdomain (193.52-245-81.adsl-dyn.isp.belgacom.be. [81.245.52.193]) by mx.google.com with ESMTPSA id k41sm67692577een.19.2014.02.03.10.18.43 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Mon, 03 Feb 2014 10:18:45 -0800 (PST) From: Jean Pihet To: linux-kernel@vger.kernel.org, linaro-kernel@lists.linaro.org, linux-arm-kernel@lists.infradead.org, Will Deacon Subject: [PATCH 2/3] ARM64: perf: add support for frame pointer unwinding in compat mode Date: Mon, 3 Feb 2014 19:18:28 +0100 Message-Id: <1391451509-31265-3-git-send-email-jean.pihet@linaro.org> X-Mailer: git-send-email 1.7.11.7 In-Reply-To: <1391451509-31265-1-git-send-email-jean.pihet@linaro.org> References: <1391451509-31265-1-git-send-email-jean.pihet@linaro.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20140203_131907_524487_87248EFD X-CRM114-Status: GOOD ( 15.83 ) X-Spam-Score: -2.6 (--) Cc: Jean Pihet , Jiri Olsa , Ingo Molnar , Arnaldo , 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=-4.7 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 Acked-by: Will Deacon --- 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); }