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=-3.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 2A26EC2BB55 for ; Thu, 16 Apr 2020 13:17:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ED01D206E9 for ; Thu, 16 Apr 2020 13:17:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Zfju2v+h" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2894973AbgDPNRc (ORCPT ); Thu, 16 Apr 2020 09:17:32 -0400 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:31960 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2895032AbgDPNQ7 (ORCPT ); Thu, 16 Apr 2020 09:16:59 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1587043004; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=walCYN4WkDNtTgYLVIJ9g+ufVPDd3WAeg5aHW/gs+FQ=; b=Zfju2v+hIMLw+T3VeykfqesMm4fjTgmvUpreBL43ZquSNtY5yhRIHSSyl/2awEXblw20tU Gnb883zOmELa/SCQxOGuqk+ZEpebFhzbHQqOYO1F8xQG5eFBtgUyaPnNrDuu8Pu/xtV0pn EaFIq70Cc265fMlgcRQ40M5MZasUlwo= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-26-AUkX1xh4N-G2HhfxHPoJ2Q-1; Thu, 16 Apr 2020 09:16:40 -0400 X-MC-Unique: AUkX1xh4N-G2HhfxHPoJ2Q-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 72B4980256B; Thu, 16 Apr 2020 13:16:38 +0000 (UTC) Received: from treble (ovpn-116-146.rdu2.redhat.com [10.10.116.146]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 7945C10372C0; Thu, 16 Apr 2020 13:16:37 +0000 (UTC) Date: Thu, 16 Apr 2020 08:16:35 -0500 From: Josh Poimboeuf To: Miroslav Benes Cc: live-patching@vger.kernel.org, linux-kernel@vger.kernel.org, Peter Zijlstra , Jessica Yu , linux-s390@vger.kernel.org, heiko.carstens@de.ibm.com Subject: Re: [PATCH 4/7] s390/module: Use s390_kernel_write() for relocations Message-ID: <20200416131635.scbpuued6l4xb6qq@treble> References: <20200416120651.wqmoaa35jft4prox@treble> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20200416120651.wqmoaa35jft4prox@treble> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Sender: live-patching-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: live-patching@vger.kernel.org On Thu, Apr 16, 2020 at 07:06:51AM -0500, Josh Poimboeuf wrote: > On Thu, Apr 16, 2020 at 10:56:02AM +0200, Miroslav Benes wrote: > > > + bool early = me->state == MODULE_STATE_UNFORMED; > > > + > > > + return __apply_relocate_add(sechdrs, strtab, symindex, relsec, me, > > > + early ? memcpy : s390_kernel_write); > > > > The compiler warns about > > > > arch/s390/kernel/module.c: In function 'apply_relocate_add': > > arch/s390/kernel/module.c:453:24: warning: pointer type mismatch in conditional expression > > early ? memcpy : s390_kernel_write); > > Thanks, I'll get all that cleaned up. > > I could have sworn I got a SUCCESS message from the kbuild bot. Does it > ignore warnings nowadays? Here's a fix on top of the original patch. I changed s390_kernel_write() to return "void *" to match memcpy() (probably a separate patch). I also grabbed the text_mutex for the !early case in apply_relocate_add() -- will do something similar for x86. Will try to test this on a 390 box. diff --git a/arch/s390/include/asm/uaccess.h b/arch/s390/include/asm/uaccess.h index a470f1fa9f2a..324438889fe1 100644 --- a/arch/s390/include/asm/uaccess.h +++ b/arch/s390/include/asm/uaccess.h @@ -276,6 +276,6 @@ static inline unsigned long __must_check clear_user(void __user *to, unsigned lo } int copy_to_user_real(void __user *dest, void *src, unsigned long count); -void s390_kernel_write(void *dst, const void *src, size_t size); +void *s390_kernel_write(void *dst, const void *src, size_t size); #endif /* __S390_UACCESS_H */ diff --git a/arch/s390/kernel/module.c b/arch/s390/kernel/module.c index e85e378f876e..2b30ed0ce14f 100644 --- a/arch/s390/kernel/module.c +++ b/arch/s390/kernel/module.c @@ -19,6 +19,7 @@ #include #include #include +#include #include #include #include @@ -175,10 +176,11 @@ int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, static int apply_rela_bits(Elf_Addr loc, Elf_Addr val, int sign, int bits, int shift, - void (*write)(void *dest, const void *src, size_t len)) + void *(*write)(void *dest, const void *src, size_t len)) { unsigned long umax; long min, max; + void *dest = (void *)loc; if (val & ((1UL << shift) - 1)) return -ENOEXEC; @@ -196,28 +198,28 @@ static int apply_rela_bits(Elf_Addr loc, Elf_Addr val, } if (bits == 8) { - write(loc, &val, 1); + write(dest, &val, 1); } else if (bits == 12) { unsigned short tmp = (val & 0xfff) | (*(unsigned short *) loc & 0xf000); - write(loc, &tmp, 2); + write(dest, &tmp, 2); } else if (bits == 16) { - write(loc, &val, 2); + write(dest, &val, 2); } else if (bits == 20) { unsigned int tmp = (val & 0xfff) << 16 | (val & 0xff000) >> 4 | (*(unsigned int *) loc & 0xf00000ff); - write(loc, &tmp, 4); + write(dest, &tmp, 4); } else if (bits == 32) { - write(loc, &val, 4); + write(dest, &val, 4); } else if (bits == 64) { - write(loc, &val, 8); + write(dest, &val, 8); } return 0; } static int apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab, const char *strtab, struct module *me, - void (*write)(void *dest, const void *src, size_t len)) + void *(*write)(void *dest, const void *src, size_t len)) { struct mod_arch_syminfo *info; Elf_Addr loc, val; @@ -419,7 +421,7 @@ static int apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab, static int __apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, unsigned int symindex, unsigned int relsec, struct module *me, - void (*write)(void *dest, const void *src, size_t len)) + void *(*write)(void *dest, const void *src, size_t len)) { Elf_Addr base; Elf_Sym *symtab; @@ -435,7 +437,7 @@ static int __apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, n = sechdrs[relsec].sh_size / sizeof(Elf_Rela); for (i = 0; i < n; i++, rela++) { - rc = apply_rela(rela, base, symtab, strtab, me); + rc = apply_rela(rela, base, symtab, strtab, me, write); if (rc) return rc; } @@ -449,8 +451,16 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, int ret; bool early = me->state == MODULE_STATE_UNFORMED; - return __apply_relocate_add(sechdrs, strtab, symindex, relsec, me, - early ? memcpy : s390_kernel_write); + if (!early) + mutex_lock(&text_mutex); + + ret = __apply_relocate_add(sechdrs, strtab, symindex, relsec, me, + early ? memcpy : s390_kernel_write); + + if (!early) + mutex_unlock(&text_mutex); + + return ret; } int module_finalize(const Elf_Ehdr *hdr, diff --git a/arch/s390/mm/maccess.c b/arch/s390/mm/maccess.c index de7ca4b6718f..22a0be655f27 100644 --- a/arch/s390/mm/maccess.c +++ b/arch/s390/mm/maccess.c @@ -55,19 +55,22 @@ static notrace long s390_kernel_write_odd(void *dst, const void *src, size_t siz */ static DEFINE_SPINLOCK(s390_kernel_write_lock); -void notrace s390_kernel_write(void *dst, const void *src, size_t size) +notrace void *s390_kernel_write(void *dst, const void *src, size_t size) { + void *tmp = dst; unsigned long flags; long copied; spin_lock_irqsave(&s390_kernel_write_lock, flags); while (size) { - copied = s390_kernel_write_odd(dst, src, size); - dst += copied; + copied = s390_kernel_write_odd(tmp, src, size); + tmp += copied; src += copied; size -= copied; } spin_unlock_irqrestore(&s390_kernel_write_lock, flags); + + return dst; } static int __no_sanitize_address __memcpy_real(void *dest, void *src, size_t count)