From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752255AbcHQJgo (ORCPT ); Wed, 17 Aug 2016 05:36:44 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:35973 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750787AbcHQJgk (ORCPT ); Wed, 17 Aug 2016 05:36:40 -0400 X-IBM-Helo: d28dlp02.in.ibm.com X-IBM-MailFrom: maddy@linux.vnet.ibm.com X-IBM-RcptTo: linux-kernel@vger.kernel.org From: Madhavan Srinivasan To: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, peterz@infradead.org, acme@kernel.org Cc: Madhavan Srinivasan , Yury Norov , Ingo Molnar , Alexander Shishkin , Jiri Olsa , Adrian Hunter , Kan Liang , Wang Nan , Michael Ellerman Subject: [PATCH v6 1/2] tools/perf: Fix the mask in regs_dump__printf and print_sample_iregs Date: Wed, 17 Aug 2016 15:06:07 +0530 X-Mailer: git-send-email 2.7.4 X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16081709-0048-0000-0000-000002E9A6FB X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16081709-0049-0000-0000-00000E5E202D Message-Id: <1471426568-31051-1-git-send-email-maddy@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-08-17_06:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1604210000 definitions=main-1608170108 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When decoding the perf_regs mask in regs_dump__printf(), we loop through the mask using find_first_bit and find_next_bit functions. "mask" is of type "u64", but sent as a "unsigned long *" to lib functions along with sizeof(). While the exisitng code works fine in most of the case, the logic is broken when using a 32bit perf on a 64bit kernel (Big Endian). When reading u64 using (u32 *)(&val)[0], perf (lib/find_*_bit()) assumes it gets lower 32bits of u64 which is wrong. Proposed fix is to swap the words of the u64 to handle this case. This is _not_ endianess swap. Suggested-by: Yury Norov Reviewed-by: Yury Norov Acked-by: Jiri Olsa Cc: Yury Norov Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Arnaldo Carvalho de Melo Cc: Alexander Shishkin Cc: Jiri Olsa Cc: Adrian Hunter Cc: Kan Liang Cc: Wang Nan Cc: Michael Ellerman Signed-off-by: Madhavan Srinivasan --- Changelog v5: 1)No logic change, just upstream rebasing Changelog v4: 1) Removed the new macro and resued the DECLARE_BITMAP Changelog v3: 1)Moved the swap function to lib/bitmap.c 2)Added a macro for declaration 3)Added the comments Changelog v2: 1)Moved the swap code to a common function 2)Added more comments in the code Changelog v1: 1)updated commit message and patch subject 2)Add the fix to print_sample_iregs() in builtin-script.c tools/include/linux/bitmap.h | 2 ++ tools/lib/bitmap.c | 18 ++++++++++++++++++ tools/perf/builtin-script.c | 4 +++- tools/perf/util/session.c | 4 +++- 4 files changed, 26 insertions(+), 2 deletions(-) diff --git a/tools/include/linux/bitmap.h b/tools/include/linux/bitmap.h index 43c1c5021e4b..998ac95a8ddd 100644 --- a/tools/include/linux/bitmap.h +++ b/tools/include/linux/bitmap.h @@ -4,10 +4,12 @@ #include #include #include +#include #define DECLARE_BITMAP(name,bits) \ unsigned long name[BITS_TO_LONGS(bits)] +void bitmap_from_u64(unsigned long *dst, u64 mask); int __bitmap_weight(const unsigned long *bitmap, int bits); void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1, const unsigned long *bitmap2, int bits); diff --git a/tools/lib/bitmap.c b/tools/lib/bitmap.c index 38748b0e342f..21e17730c35f 100644 --- a/tools/lib/bitmap.c +++ b/tools/lib/bitmap.c @@ -73,3 +73,21 @@ int __bitmap_and(unsigned long *dst, const unsigned long *bitmap1, BITMAP_LAST_WORD_MASK(bits)); return result != 0; } + +/* + * bitmap_from_u64 - Check and swap words within u64. + * @mask: source bitmap + * @dst: destination bitmap + * + * In 32 bit big endian userspace on a 64bit kernel, 'unsigned long' is 32 bits. + * When reading u64 using (u32 *)(&val)[0] and (u32 *)(&val)[1], + * we will get wrong value for the mask. That is "(u32 *)(&val)[0]" + * gets upper 32 bits of u64, but perf may expect lower 32bits of u64. + */ +void bitmap_from_u64(unsigned long *dst, u64 mask) +{ + dst[0] = mask & ULONG_MAX; + + if (sizeof(mask) > sizeof(unsigned long)) + dst[1] = mask >> 32; +} diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c index 9c640a8081c7..4b8de4f99a11 100644 --- a/tools/perf/builtin-script.c +++ b/tools/perf/builtin-script.c @@ -418,11 +418,13 @@ static void print_sample_iregs(struct perf_sample *sample, struct regs_dump *regs = &sample->intr_regs; uint64_t mask = attr->sample_regs_intr; unsigned i = 0, r; + DECLARE_BITMAP(_mask, 64); if (!regs) return; - for_each_set_bit(r, (unsigned long *) &mask, sizeof(mask) * 8) { + bitmap_from_u64(_mask, mask); + for_each_set_bit(r, _mask, sizeof(mask) * 8) { u64 val = regs->regs[i++]; printf("%5s:0x%"PRIx64" ", perf_reg_name(r), val); } diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c index 5d61242a6e64..440a9fb2a6fb 100644 --- a/tools/perf/util/session.c +++ b/tools/perf/util/session.c @@ -944,8 +944,10 @@ static void branch_stack__printf(struct perf_sample *sample) static void regs_dump__printf(u64 mask, u64 *regs) { unsigned rid, i = 0; + DECLARE_BITMAP(_mask, 64); - for_each_set_bit(rid, (unsigned long *) &mask, sizeof(mask) * 8) { + bitmap_from_u64(_mask, mask); + for_each_set_bit(rid, _mask, sizeof(mask) * 8) { u64 val = regs[i++]; printf(".... %-5s 0x%" PRIx64 "\n", -- 2.7.4