From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Fri, 26 Oct 2018 11:05:43 +0200 From: Pavel Machek To: Sasha Levin Cc: stable@vger.kernel.org, linux-kernel@vger.kernel.org, Gerald Schaefer , Martin Schwidefsky Subject: Re: [PATCH AUTOSEL 4.14 02/15] s390/hibernate: fix error handling when suspend cpu != resume cpu Message-ID: <20181026090543.GC20200@amd> References: <20181022102026.40869-1-sashal@kernel.org> <20181022102026.40869-2-sashal@kernel.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="3siQDZowHQqNOShm" Content-Disposition: inline In-Reply-To: <20181022102026.40869-2-sashal@kernel.org> List-ID: --3siQDZowHQqNOShm Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon 2018-10-22 06:20:13, Sasha Levin wrote: > From: Gerald Schaefer >=20 > [ Upstream commit 55a5542a546238354d1f209f794414168cf8c71d ] >=20 > The resume code checks if the resume cpu is the same as the suspend cpu. > If not, and if it is also not possible to switch to the suspend cpu, an > error message should be printed and the resume process should be stopped > by loading a disabled wait psw. >=20 > The current logic is broken in multiple ways, the message is never printe= d, > and the disabled wait psw never loaded because the kernel panics before t= hat: > - sam31 and SIGP_SET_ARCHITECTURE to ESA mode is wrong, this will break > on the first 64bit instruction in sclp_early_printk(). > - The init stack should be used, but the stack pointer is not set up corr= ectly > (missing aghi %r15,-STACK_FRAME_OVERHEAD). > - __sclp_early_printk() checks the sclp_init_state. If it is not > sclp_init_state_uninitialized, it simply returns w/o printing anything. > In the resumed kernel however, sclp_init_state will never be uninitiali= zed. Stable patches should fix one bug, and one bug only. pavel > --- > arch/s390/include/asm/sclp.h | 3 ++- > arch/s390/kernel/early_printk.c | 2 +- > arch/s390/kernel/swsusp.S | 8 +++----- > drivers/s390/char/sclp_early_core.c | 11 ++++++++--- > 4 files changed, 14 insertions(+), 10 deletions(-) >=20 > diff --git a/arch/s390/include/asm/sclp.h b/arch/s390/include/asm/sclp.h > index d3c1a8a2e3ad..d90a84770ce5 100644 > --- a/arch/s390/include/asm/sclp.h > +++ b/arch/s390/include/asm/sclp.h > @@ -107,7 +107,8 @@ int sclp_early_get_core_info(struct sclp_core_info *i= nfo); > void sclp_early_get_ipl_info(struct sclp_ipl_info *info); > void sclp_early_detect(void); > void sclp_early_printk(const char *s); > -void __sclp_early_printk(const char *s, unsigned int len); > +void sclp_early_printk_force(const char *s); > +void __sclp_early_printk(const char *s, unsigned int len, unsigned int f= orce); > =20 > int _sclp_get_core_info(struct sclp_core_info *info); > int sclp_core_configure(u8 core); > diff --git a/arch/s390/kernel/early_printk.c b/arch/s390/kernel/early_pri= ntk.c > index 9431784d7796..40c1dfec944e 100644 > --- a/arch/s390/kernel/early_printk.c > +++ b/arch/s390/kernel/early_printk.c > @@ -10,7 +10,7 @@ > =20 > static void sclp_early_write(struct console *con, const char *s, unsigne= d int len) > { > - __sclp_early_printk(s, len); > + __sclp_early_printk(s, len, 0); > } > =20 > static struct console sclp_early_console =3D { > diff --git a/arch/s390/kernel/swsusp.S b/arch/s390/kernel/swsusp.S > index a049a7b9d6e8..c1a080b11ae9 100644 > --- a/arch/s390/kernel/swsusp.S > +++ b/arch/s390/kernel/swsusp.S > @@ -198,12 +198,10 @@ pgm_check_entry: > =20 > /* Suspend CPU not available -> panic */ > larl %r15,init_thread_union > - ahi %r15,1<<(PAGE_SHIFT+THREAD_SIZE_ORDER) > + aghi %r15,1<<(PAGE_SHIFT+THREAD_SIZE_ORDER) > + aghi %r15,-STACK_FRAME_OVERHEAD > larl %r2,.Lpanic_string > - lghi %r1,0 > - sam31 > - sigp %r1,%r0,SIGP_SET_ARCHITECTURE > - brasl %r14,sclp_early_printk > + brasl %r14,sclp_early_printk_force > larl %r3,.Ldisabled_wait_31 > lpsw 0(%r3) > 4: > diff --git a/drivers/s390/char/sclp_early_core.c b/drivers/s390/char/sclp= _early_core.c > index edeb2597b0b8..4daf797a6423 100644 > --- a/drivers/s390/char/sclp_early_core.c > +++ b/drivers/s390/char/sclp_early_core.c > @@ -188,11 +188,11 @@ static int sclp_early_setup(int disable, int *have_= linemode, int *have_vt220) > * Output one or more lines of text on the SCLP console (VT220 and / > * or line-mode). > */ > -void __sclp_early_printk(const char *str, unsigned int len) > +void __sclp_early_printk(const char *str, unsigned int len, unsigned int= force) > { > int have_linemode, have_vt220; > =20 > - if (sclp_init_state !=3D sclp_init_state_uninitialized) > + if (!force && sclp_init_state !=3D sclp_init_state_uninitialized) > return; > if (sclp_early_setup(0, &have_linemode, &have_vt220) !=3D 0) > return; > @@ -205,5 +205,10 @@ void __sclp_early_printk(const char *str, unsigned i= nt len) > =20 > void sclp_early_printk(const char *str) > { > - __sclp_early_printk(str, strlen(str)); > + __sclp_early_printk(str, strlen(str), 0); > +} > + > +void sclp_early_printk_force(const char *str) > +{ > + __sclp_early_printk(str, strlen(str), 1); > } --=20 (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo= g.html --3siQDZowHQqNOShm Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAlvS2OcACgkQMOfwapXb+vIZ0wCguIpVQeN2lRWaGkbVeIza//0/ je0AnjqVJ5PkubMO0vMvHHHwBIJA3Dpt =l/ve -----END PGP SIGNATURE----- --3siQDZowHQqNOShm--