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=-13.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 B7BB6C433DF for ; Wed, 15 Jul 2020 23:35:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9819F20656 for ; Wed, 15 Jul 2020 23:35:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726776AbgGOXfd (ORCPT ); Wed, 15 Jul 2020 19:35:33 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:8124 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726770AbgGOXfd (ORCPT ); Wed, 15 Jul 2020 19:35:33 -0400 Received: from pps.filterd (m0098394.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 06FNWS1x078659; Wed, 15 Jul 2020 19:35:21 -0400 Received: from ppma02fra.de.ibm.com (47.49.7a9f.ip4.static.sl-reverse.com [159.122.73.71]) by mx0a-001b2d01.pphosted.com with ESMTP id 32a45awau3-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 15 Jul 2020 19:35:21 -0400 Received: from pps.filterd (ppma02fra.de.ibm.com [127.0.0.1]) by ppma02fra.de.ibm.com (8.16.0.42/8.16.0.42) with SMTP id 06FNJnOs014446; Wed, 15 Jul 2020 23:35:18 GMT Received: from b06cxnps4076.portsmouth.uk.ibm.com (d06relay13.portsmouth.uk.ibm.com [9.149.109.198]) by ppma02fra.de.ibm.com with ESMTP id 327527w34g-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 15 Jul 2020 23:35:18 +0000 Received: from b06wcsmtp001.portsmouth.uk.ibm.com (b06wcsmtp001.portsmouth.uk.ibm.com [9.149.105.160]) by b06cxnps4076.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 06FNXwU953805244 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 15 Jul 2020 23:33:59 GMT Received: from b06wcsmtp001.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id CD45BA4060; Wed, 15 Jul 2020 23:33:58 +0000 (GMT) Received: from b06wcsmtp001.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 423A4A4066; Wed, 15 Jul 2020 23:33:58 +0000 (GMT) Received: from localhost.localdomain (unknown [9.145.186.215]) by b06wcsmtp001.portsmouth.uk.ibm.com (Postfix) with ESMTP; Wed, 15 Jul 2020 23:33:58 +0000 (GMT) From: Ilya Leoshkevich To: Alexei Starovoitov , Daniel Borkmann Cc: bpf@vger.kernel.org, Heiko Carstens , Vasily Gorbik , Ilya Leoshkevich , Heiko Carstens Subject: [PATCH v2 2/4] s390/kernel: expand the exception table logic to allow new handling options Date: Thu, 16 Jul 2020 01:32:59 +0200 Message-Id: <20200715233301.933201-3-iii@linux.ibm.com> X-Mailer: git-send-email 2.25.4 In-Reply-To: <20200715233301.933201-1-iii@linux.ibm.com> References: <20200715233301.933201-1-iii@linux.ibm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235,18.0.687 definitions=2020-07-15_12:2020-07-15,2020-07-15 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 spamscore=0 priorityscore=1501 lowpriorityscore=0 suspectscore=0 impostorscore=0 mlxscore=0 bulkscore=0 adultscore=0 malwarescore=0 mlxlogscore=999 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2007150171 Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org This is a s390 port of commit 548acf19234d ("x86/mm: Expand the exception table logic to allow new handling options"), which is needed for implementing BPF_PROBE_MEM on s390. The new handler field is made 64-bit in order to allow pointing from dynamically allocated entries to handlers in kernel text. Unlike on x86, NULL is used instead of ex_handler_default. This is because exception tables are used by boot/text_dma.S, and it would be a pain to preserve ex_handler_default. The new infrastructure is ignored in early_pgm_check_handler, since there is no pt_regs. Signed-off-by: Ilya Leoshkevich Reviewed-by: Heiko Carstens --- arch/s390/include/asm/extable.h | 50 +++++++++++++++++++++++++++++---- arch/s390/include/asm/linkage.h | 3 +- arch/s390/kernel/kprobes.c | 4 +-- arch/s390/kernel/traps.c | 7 ++--- arch/s390/mm/fault.c | 4 +-- scripts/sorttable.c | 25 +++++++++++++++++ 6 files changed, 76 insertions(+), 17 deletions(-) diff --git a/arch/s390/include/asm/extable.h b/arch/s390/include/asm/extable.h index ae27f756b409..8f0c60f2fe3a 100644 --- a/arch/s390/include/asm/extable.h +++ b/arch/s390/include/asm/extable.h @@ -1,12 +1,20 @@ /* SPDX-License-Identifier: GPL-2.0 */ #ifndef __S390_EXTABLE_H #define __S390_EXTABLE_H + +#include +#include + /* - * The exception table consists of pairs of addresses: the first is the - * address of an instruction that is allowed to fault, and the second is - * the address at which the program should continue. No registers are - * modified, so it is entirely up to the continuation code to figure out - * what to do. + * The exception table consists of three addresses: + * + * - Address of an instruction that is allowed to fault. + * - Address at which the program should continue. + * - Optional address of handler that takes pt_regs * argument and runs in + * interrupt context. + * + * No registers are modified, so it is entirely up to the continuation code + * to figure out what to do. * * All the routines below use bits of fixup code that are out of line * with the main instruction path. This means when everything is well, @@ -17,6 +25,7 @@ struct exception_table_entry { int insn, fixup; + long handler; }; extern struct exception_table_entry *__start_dma_ex_table; @@ -29,6 +38,37 @@ static inline unsigned long extable_fixup(const struct exception_table_entry *x) return (unsigned long)&x->fixup + x->fixup; } +typedef bool (*ex_handler_t)(const struct exception_table_entry *, + struct pt_regs *); + +static inline ex_handler_t +ex_fixup_handler(const struct exception_table_entry *x) +{ + return (ex_handler_t)((unsigned long)&x->handler + x->handler); +} + +static inline bool ex_handle(const struct exception_table_entry *x, + struct pt_regs *regs) +{ + ex_handler_t handler = ex_fixup_handler(x); + + if (unlikely(handler)) + return handler(x, regs); + regs->psw.addr = extable_fixup(x); + return true; +} + #define ARCH_HAS_RELATIVE_EXTABLE +static inline void swap_ex_entry_fixup(struct exception_table_entry *a, + struct exception_table_entry *b, + struct exception_table_entry tmp, + int delta) +{ + a->fixup = b->fixup + delta; + b->fixup = tmp.fixup - delta; + a->handler = b->handler + delta; + b->handler = tmp.handler - delta; +} + #endif diff --git a/arch/s390/include/asm/linkage.h b/arch/s390/include/asm/linkage.h index 1b52c07b5642..83ff5a35d522 100644 --- a/arch/s390/include/asm/linkage.h +++ b/arch/s390/include/asm/linkage.h @@ -14,9 +14,10 @@ #define __EX_TABLE(_section, _fault, _target) \ stringify_in_c(.section _section,"a";) \ - stringify_in_c(.align 4;) \ + stringify_in_c(.align 8;) \ stringify_in_c(.long (_fault) - .;) \ stringify_in_c(.long (_target) - .;) \ + stringify_in_c(.quad 0 - .;) \ stringify_in_c(.previous) #define EX_TABLE(_fault, _target) \ diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c index 548d0ea9808d..d2a71d872638 100644 --- a/arch/s390/kernel/kprobes.c +++ b/arch/s390/kernel/kprobes.c @@ -523,10 +523,8 @@ static int kprobe_trap_handler(struct pt_regs *regs, int trapnr) * zero, try to fix up. */ entry = s390_search_extables(regs->psw.addr); - if (entry) { - regs->psw.addr = extable_fixup(entry); + if (entry && ex_handle(entry, regs)) return 1; - } /* * fixup_exception() could not handle it, diff --git a/arch/s390/kernel/traps.c b/arch/s390/kernel/traps.c index ff9cc4c3290e..8d1e8a1a97df 100644 --- a/arch/s390/kernel/traps.c +++ b/arch/s390/kernel/traps.c @@ -50,11 +50,8 @@ void do_report_trap(struct pt_regs *regs, int si_signo, int si_code, char *str) } else { const struct exception_table_entry *fixup; fixup = s390_search_extables(regs->psw.addr); - if (fixup) - regs->psw.addr = extable_fixup(fixup); - else { + if (!fixup || !ex_handle(fixup, regs)) die(regs, str); - } } } @@ -251,7 +248,7 @@ void monitor_event_exception(struct pt_regs *regs) case BUG_TRAP_TYPE_NONE: fixup = s390_search_extables(regs->psw.addr); if (fixup) - regs->psw.addr = extable_fixup(fixup); + ex_handle(fixup, regs); break; case BUG_TRAP_TYPE_WARN: break; diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c index d53c2e2ea1fd..c4c6cafef3f4 100644 --- a/arch/s390/mm/fault.c +++ b/arch/s390/mm/fault.c @@ -255,10 +255,8 @@ static noinline void do_no_context(struct pt_regs *regs) /* Are we prepared to handle this kernel fault? */ fixup = s390_search_extables(regs->psw.addr); - if (fixup) { - regs->psw.addr = extable_fixup(fixup); + if (fixup && ex_handle(fixup, regs)) return; - } /* * Oops. The kernel tried to access some bad page. We'll have to diff --git a/scripts/sorttable.c b/scripts/sorttable.c index ec6b5e81eba1..a4b8415ba71c 100644 --- a/scripts/sorttable.c +++ b/scripts/sorttable.c @@ -255,6 +255,29 @@ static void x86_sort_relative_table(char *extab_image, int image_size) } } +static void s390_sort_relative_table(char *extab_image, int image_size) +{ + int i; + + for (i = 0; i < image_size; i += 16) { + char *loc = extab_image + i; + + w(r((uint32_t *)loc) + i, (uint32_t *)loc); + w(r((uint32_t *)(loc + 4)) + (i + 4), (uint32_t *)(loc + 4)); + w8(r8((uint64_t *)(loc + 8)) + (i + 8), (uint64_t *)(loc + 8)); + } + + qsort(extab_image, image_size / 16, 16, compare_relative_table); + + for (i = 0; i < image_size; i += 16) { + char *loc = extab_image + i; + + w(r((uint32_t *)loc) - i, (uint32_t *)loc); + w(r((uint32_t *)(loc + 4)) - (i + 4), (uint32_t *)(loc + 4)); + w8(r8((uint64_t *)(loc + 8)) - (i + 8), (uint64_t *)(loc + 8)); + } +} + static int do_file(char const *const fname, void *addr) { int rc = -1; @@ -297,6 +320,8 @@ static int do_file(char const *const fname, void *addr) custom_sort = x86_sort_relative_table; break; case EM_S390: + custom_sort = s390_sort_relative_table; + break; case EM_AARCH64: case EM_PARISC: case EM_PPC: -- 2.25.4