From owner-svn-src-head@freebsd.org Sun Oct 18 16:16:23 2020 Return-Path: Delivered-To: svn-src-head@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 4315443607C; Sun, 18 Oct 2020 16:16:23 +0000 (UTC) (envelope-from trasz@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (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-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4CDlPg12Z6z4gYL; Sun, 18 Oct 2020 16:16:23 +0000 (UTC) (envelope-from trasz@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 083321551F; Sun, 18 Oct 2020 16:16:23 +0000 (UTC) (envelope-from trasz@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id 09IGGMZt030566; Sun, 18 Oct 2020 16:16:22 GMT (envelope-from trasz@FreeBSD.org) Received: (from trasz@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id 09IGGMnk030565; Sun, 18 Oct 2020 16:16:22 GMT (envelope-from trasz@FreeBSD.org) Message-Id: <202010181616.09IGGMnk030565@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: trasz set sender to trasz@FreeBSD.org using -f From: Edward Tomasz Napierala Date: Sun, 18 Oct 2020 16:16:22 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r366810 - head/sys/amd64/linux X-SVN-Group: head X-SVN-Commit-Author: trasz X-SVN-Commit-Paths: head/sys/amd64/linux X-SVN-Commit-Revision: 366810 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.33 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 18 Oct 2020 16:16:23 -0000 Author: trasz Date: Sun Oct 18 16:16:22 2020 New Revision: 366810 URL: https://svnweb.freebsd.org/changeset/base/366810 Log: Stop calling set_syscall_retval() from linux_set_syscall_retval(). The former clobbers some registers that shouldn't be touched. Reviewed by: kib (earlier version) MFC after: 2 weeks Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D26406 Modified: head/sys/amd64/linux/linux_sysvec.c Modified: head/sys/amd64/linux/linux_sysvec.c ============================================================================== --- head/sys/amd64/linux/linux_sysvec.c Sun Oct 18 15:58:16 2020 (r366809) +++ head/sys/amd64/linux/linux_sysvec.c Sun Oct 18 16:16:22 2020 (r366810) @@ -206,24 +206,45 @@ linux_fetch_syscall_args(struct thread *td) static void linux_set_syscall_retval(struct thread *td, int error) { - struct trapframe *frame = td->td_frame; + struct trapframe *frame; - /* - * On Linux only %rcx and %r11 values are not preserved across - * the syscall. So, do not clobber %rdx and %r10. - */ - td->td_retval[1] = frame->tf_rdx; - if (error != EJUSTRETURN) - frame->tf_r10 = frame->tf_rcx; + frame = td->td_frame; - cpu_set_syscall_retval(td, error); + switch (error) { + case 0: + frame->tf_rax = td->td_retval[0]; + frame->tf_r10 = frame->tf_rcx; + break; - if (__predict_false(error != 0)) { - if (error != ERESTART && error != EJUSTRETURN) - frame->tf_rax = linux_to_bsd_errno(error); + case ERESTART: + /* + * Reconstruct pc, we know that 'syscall' is 2 bytes, + * lcall $X,y is 7 bytes, int 0x80 is 2 bytes. + * We saved this in tf_err. + * + */ + frame->tf_rip -= frame->tf_err; + frame->tf_r10 = frame->tf_rcx; + break; + + case EJUSTRETURN: + break; + + default: + frame->tf_rax = linux_to_bsd_errno(error); + frame->tf_r10 = frame->tf_rcx; + break; } - /* Restore all registers. */ + /* + * Differently from FreeBSD native ABI, on Linux only %rcx + * and %r11 values are not preserved across the syscall. + * Require full context restore to get all registers except + * those two restored at return to usermode. + * + * XXX: Would be great to be able to avoid PCB_FULL_IRET + * for the error == 0 case. + */ set_pcb_flags(td->td_pcb, PCB_FULL_IRET); }