From nobody Thu Apr 18 17:57:16 2024 X-Original-To: freebsd-hackers@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4VL58W6P3Pz5HJ8m for ; Thu, 18 Apr 2024 17:57:31 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from kib.kiev.ua (kib.kiev.ua [IPv6:2001:470:d5e7:1::1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 4VL58W2MjDz56lp for ; Thu, 18 Apr 2024 17:57:31 +0000 (UTC) (envelope-from kostikbel@gmail.com) Authentication-Results: mx1.freebsd.org; none Received: from tom.home (kib@localhost [127.0.0.1] (may be forged)) by kib.kiev.ua (8.18.1/8.18.1) with ESMTP id 43IHvG9n086861; Thu, 18 Apr 2024 20:57:19 +0300 (EEST) (envelope-from kostikbel@gmail.com) DKIM-Filter: OpenDKIM Filter v2.10.3 kib.kiev.ua 43IHvG9n086861 Received: (from kostik@localhost) by tom.home (8.18.1/8.18.1/Submit) id 43IHvGYe086860; Thu, 18 Apr 2024 20:57:16 +0300 (EEST) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: tom.home: kostik set sender to kostikbel@gmail.com using -f Date: Thu, 18 Apr 2024 20:57:16 +0300 From: Konstantin Belousov To: Wei Hu Cc: Warner Losh , "freebsd-hackers@FreeBSD.org" Subject: Re: How to add a -W flag in local Makefile Message-ID: References: List-Id: Technical discussions relating to FreeBSD List-Archive: https://lists.freebsd.org/archives/freebsd-hackers List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-hackers@FreeBSD.org MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Spam-Status: No, score=-1.0 required=5.0 tests=ALL_TRUSTED,BAYES_00, DKIM_ADSP_CUSTOM_MED,FORGED_GMAIL_RCVD,FREEMAIL_FROM, NML_ADSP_CUSTOM_MED autolearn=no autolearn_force=no version=4.0.0 X-Spam-Checker-Version: SpamAssassin 4.0.0 (2022-12-14) on tom.home X-Spamd-Bar: ---- X-Rspamd-Pre-Result: action=no action; module=replies; Message is reply to one we originated X-Spamd-Result: default: False [-4.00 / 15.00]; REPLY(-4.00)[]; ASN(0.00)[asn:6939, ipnet:2001:470::/32, country:US] X-Rspamd-Queue-Id: 4VL58W2MjDz56lp On Thu, Apr 18, 2024 at 03:27:13PM +0000, Wei Hu wrote: > I added something like: > > diff --git a/sys/dev/hyperv/vmbus/vmbus_var.h b/sys/dev/hyperv/vmbus/vmbus_var.h > index b598f782947e..6e3b7b040827 100644 > --- a/sys/dev/hyperv/vmbus/vmbus_var.h > +++ b/sys/dev/hyperv/vmbus/vmbus_var.h > @@ -193,4 +193,17 @@ struct hyperv_tlb_flush { > uint64_t hv_vm_tlb_flush(pmap_t pmap, vm_offset_t addr1, > vm_offset_t addr2, cpuset_t mask); > > +struct hv_vpset { > + uint64_t format; > + uint64_t valid_bank_mask; > + uint64_t bank_contents[]; > +} __packed; > + > +struct hv_tlb_flush_ex { > + uint64_t address_space; > + uint64_t flags; > + struct hv_vpset hv_vp_set; > + uint64_t gva_list[]; > +} __packed; > + > #endif /* !_VMBUS_VAR_H_ */ > > So, the struct hv_vpset is the second last member of struct hv_tlb_flush_ex. The member bank_contents[] in struct hv_vpset is of variable length. This would makes the last two members of struct hv_tlb_flush_ex both variable length. Therefore, the flag '-Wno-gnu-variable-sized-type-not-at-end' is needed, otherwise it would complain about this with errors like: > No, the compiler' complain is correct. The structure definition for hv_tlb_flush_ex does not make sense: you never can access gva_list (except for the case of bank_contents being zero-sized).