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b=QIuMw6kCPkNDcegay066toqhxHLFsDVAPpT7lfQSgz4qNfV3fp17wvADDAGzcdR5DKUQuW 2yQhohLfxUd3zveQLvE9ZReyrTdvJ3SyCOEGmcUq0a/yaDvSFFjeepZ7a3rLbXElN9/GJ+ E04TnC8r1mKr0ESIHG6XVsxDjTJJpS4= X-MC-Unique: FnUjs0XsMvK945Sa9hkyGA-1 From: Thomas Huth To: qemu-devel@nongnu.org, Cornelia Huck , Christian Borntraeger Subject: [PATCH] pc-bios/s390-ccw: Use reset_psw pointer instead of hard-coded null pointer Date: Fri, 23 Apr 2021 10:36:04 +0200 Message-Id: <20210423083604.526367-1-thuth@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=thuth@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=216.205.24.124; envelope-from=thuth@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: qemu-s390x@nongnu.org, Janosch Frank Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @redhat.com) Content-Type: text/plain; charset="utf-8" When compiling the s390-ccw bios with clang, it emits a warning like this: pc-bios/s390-ccw/jump2ipl.c:86:9: warning: indirection of non-volatile null pointer will be deleted, not trap [-Wnull-dereference] if (*((uint64_t *)0) & RESET_PSW_MASK) { ^~~~~~~~~~~~~~~~ pc-bios/s390-ccw/jump2ipl.c:86:9: note: consider using __builtin_trap() or qualifying pointer with 'volatile' We could add a "volatile" here to shut it up, but on the other hand, we also have a pointer variable called "reset_psw" in this file already that points to the PSW at address 0, so we can simply use that pointer variable instead. Signed-off-by: Thomas Huth Reviewed-by: Philippe Mathieu-Daud=C3=A9 --- pc-bios/s390-ccw/jump2ipl.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/pc-bios/s390-ccw/jump2ipl.c b/pc-bios/s390-ccw/jump2ipl.c index b9c70d64a5..de1541ea5d 100644 --- a/pc-bios/s390-ccw/jump2ipl.c +++ b/pc-bios/s390-ccw/jump2ipl.c @@ -83,7 +83,7 @@ void jump_to_low_kernel(void) } =20 /* Trying to get PSW at zero address */ - if (*((uint64_t *)0) & RESET_PSW_MASK) { + if (*reset_psw & RESET_PSW_MASK) { /* * Surely nobody will try running directly from lowcore, so * let's use 0 as an indication that we want to load the reset --=20 2.27.0