From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mx3-rdu2.redhat.com ([66.187.233.73] helo=mx1.redhat.com) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1f0lOp-0005K4-88 for kexec@lists.infradead.org; Tue, 27 Mar 2018 10:00:17 +0000 Date: Tue, 27 Mar 2018 17:59:55 +0800 From: Dave Young Subject: Re: [PATCH v5 4/5] kexec: Add option to fall back to KEXEC_LOAD when KEXEC_FILE_LOAD is not supported Message-ID: <20180327095955.GB4681@dhcp-128-65.nay.redhat.com> References: <20180302091706.GA15374@dhcp-128-65.nay.redhat.com> <9db6c165a0832796faf88b0cef8f296a896f5fa8.1521561315.git.msuchanek@suse.de> <20180326090832.GA24210@dhcp-128-65.nay.redhat.com> <20180326091210.GA4781@dhcp-128-65.nay.redhat.com> <20180326193810.028a94b5@kitsune.suse.cz> <87in9i3c08.fsf@morokweng.localdomain> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <87in9i3c08.fsf@morokweng.localdomain> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: Thiago Jung Bauermann Cc: Petr Tesarik , kexec@lists.infradead.org, Tony Jones , horms@verge.net.au, hbathini@linux.vnet.ibm.com, Michal =?iso-8859-1?Q?Such=E1nek?= On 03/26/18 at 03:52pm, Thiago Jung Bauermann wrote: > = > Michal Such=E1nek writes: > = > > On Mon, 26 Mar 2018 17:12:10 +0800 > > Dave Young wrote: > > > >> On 03/26/18 at 05:08pm, Dave Young wrote: > >> > On 03/20/18 at 04:56pm, Michal Suchanek wrote: = > >> > > Not all architectures implement KEXEC_FILE_LOAD. However, on some > >> > > archiectures KEXEC_FILE_LOAD is required when secure boot is > >> > > enabled in locked-down mode. Previously users had to select the > >> > > KEXEC_FILE_LOAD syscall with undocumented -s option. However, if > >> > > they did pass the option kexec would fail on architectures that > >> > > do not support it. > >> > > = > >> > > So add an -a option that tries KEXEC_FILE_LOAD and when it is not > >> > > supported tries KEXEC_LOAD. > >> > > = > >> > > Signed-off-by: Michal Suchanek > >> > > --- > >> > > v3: instead of changing the deafult add extra option > >> > > v4: actually check -ENOSYS as well > >> > > v5: add missing break > >> > > --- > >> > > kexec/kexec.c | 58 > >> > > +++++++++++++++++++++++++++++++++++++++++++++++++++++----- > >> > > kexec/kexec.h | 6 +++++- 2 files changed, 58 insertions(+), 6 > >> > > deletions(-) > >> > > = > >> > > diff --git a/kexec/kexec.c b/kexec/kexec.c > >> > > index 68ae0594d4a7..44042345a16e 100644 > >> > > --- a/kexec/kexec.c > >> > > +++ b/kexec/kexec.c > >> > > @@ -1243,6 +1243,7 @@ int main(int argc, char *argv[]) > >> > > int do_unload =3D 0; > >> > > int do_reuse_initrd =3D 0; > >> > > int do_kexec_file_syscall =3D 0; > >> > > + int do_kexec_fallback =3D 0; > >> > > int do_status =3D 0; > >> > > void *entry =3D 0; > >> > > char *type =3D 0; > >> > > @@ -1367,6 +1368,15 @@ int main(int argc, char *argv[]) > >> > > break; > >> > > case OPT_KEXEC_FILE_SYSCALL: > >> > > do_kexec_file_syscall =3D 1; > >> > > + do_kexec_fallback =3D 0; > >> > > + break; > >> > > + case OPT_KEXEC_SYSCALL: > >> > > + do_kexec_file_syscall =3D 0; > >> > > + do_kexec_fallback =3D 0; > >> > > + break; > >> > > + case OPT_KEXEC_SYSCALL_AUTO: > >> > > + do_kexec_file_syscall =3D 1; > >> > > + do_kexec_fallback =3D 1; > >> > > break; > >> > > case OPT_STATUS: > >> > > do_status =3D 1; > >> > > @@ -1433,7 +1443,7 @@ int main(int argc, char *argv[]) > >> > > } > >> > > } > >> > > if (do_kexec_file_syscall) { > >> > > - if (do_load_jump_back_helper) > >> > > + if (do_load_jump_back_helper > >> > > && !do_kexec_fallback) die("--load-jump-back-helper not supported > >> > > with kexec_file_load\n"); if (kexec_flags & > >> > > KEXEC_PRESERVE_CONTEXT) die("--load-preserve-context not > >> > > supported with kexec_file_load\n"); @@ -1447,16 +1457,54 @@ int > >> > > main(int argc, char *argv[]) result =3D k_status(kexec_flags); > >> > > } > >> > > if (do_unload) { > >> > > - if (do_kexec_file_syscall) > >> > > + if (do_kexec_file_syscall) { > >> > > result =3D > >> > > kexec_file_unload(kexec_file_flags); > >> > > - else > >> > > + if ((result =3D=3D -ENOSYS) && > >> > > do_kexec_fallback) > >> > > + do_kexec_file_syscall =3D 0; > >> > > + } > >> > > + if (!do_kexec_file_syscall) > >> > > result =3D k_unload(kexec_flags); > >> > > } > >> > > if (do_load && (result =3D=3D 0)) { > >> > > - if (do_kexec_file_syscall) > >> > > + if (do_kexec_file_syscall) { > >> > > result =3D do_kexec_file_load(fileind, > >> > > argc, argv, kexec_file_flags); > >> > > - else > >> > > + if (do_kexec_fallback) switch (result) { > >> > > + /* > >> > > + * Something failed with > >> > > signature verification. > >> > > + * Reject the image. > >> > > + */ > >> > > + case -ELIBBAD: > >> > > + case -EKEYREJECTED: > >> > > + case -ENOPKG: > >> > > + case -ENOKEY: > >> > > + case -EBADMSG: > >> > > + case -EMSGSIZE: > >> > > + /* > >> > > + * By default reject or > >> > > do nothing if > >> > > + * succeded > >> > > + */ > >> > > + default: break; > >> > > + case -ENOSYS: /* not implemented > >> > > */ > >> > > + /* > >> > > + * Parsing image or > >> > > other options failed > >> > > + * The image may be > >> > > invalid or image > >> > > + * type may not > >> > > supported by kernel so > >> > > + * retry parsing in > >> > > kexec-tools. > >> > > + */ > >> > > + case -EINVAL: > >> > > + case -ENOEXEC: > >> > > + /* > >> > > + * ENOTSUPP can be > >> > > unsupported image > >> > > + * type or unsupported > >> > > PE signature > >> > > + * wrapper type, duh > >> > > + */ > >> > > + case -ENOTSUP: = > >> > = > >> > Hmm, this is still used in latest version. kernel does not return > >> > such error number, I might not say clearly previously. Please > >> > check the kernel code, the only one place I know is because no > >> > kdump support in power kexec_file: > >> > arch/powerpc/kernel/machine_kexec_file_64.c > >> > = > >> > /* We don't support crash kernels yet. */ > >> > if (image->type =3D=3D KEXEC_TYPE_CRASH) > >> > return -ENOTSUPP; > >> > = > >> > So I suggest not checking this as well since -ENOTSUPP is not > >> > populated in userspace headers, and -ENOTSUP is not used at all. > >> > = > >> > Also as I mentioned in another reply -EINVAL and -ENOEXEC is also > >> > not ncessary. > >> > = > >> > For -ENOTSUP, maybe someone can submit a patch to switch to > >> > -ENOTSUPP so that userspace can check it. > >> > Ccing Thiago and Hari for the -ENOTSUPP errno issue. = > >> = > >> Oops for the hurry reply, I means -ENOTSUPP might be able to replaced > >> with -EOPNOTSUPP, a similar change like this: > >> https://patchwork.kernel.org/patch/8490791/ > > > > Thanks for catching this. In Linux ENOTSUPP with extra P is different > > from EOPNOTSUPP and ENOTSUP (single P). Since we are talking to the > > kernel and it returns the double P ENOTSUPP we need to define it in > > kexec as well. And we should check ENOTSUP with single P in case > > somebody some day thinks that returning undefined error codes to > > userspace is not nice like in the patch above. > = > I wasn't aware that ENOTSUPP was an in-kernel only errno. Should I > submit a patch for the kernel so that powerpc returns -EOPNOTSUPP in > case of trying to load kdump kernel with kexec_file_load()? This should be the easiest way and worth a try since userspace check it now. = > = > -- = > Thiago Jung Bauermann > IBM Linux Technology Center > = _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec