Re: [PATCH v2] powerpc/rtas: Keep MSR[RI] set when calling RTAS
On 04/05/2022, 07:59:29, Michael Ellerman wrote:
> Laurent Dufour writes:
>> On 03/05/2022, 17:06:41, Michael Ellerman wrote:
>>> Laurent Dufour writes:
> ...
diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c
index 1f42aabbbab3..d7775b8c8853 100644
--- a/arch/powerpc/kernel/rtas.c
+++ b/arch/powerpc/kernel/rtas.c
@@ -49,6 +49,11 @@ void enter_rtas(unsigned long);
static inline void do_enter_rtas(unsigned long args)
{
+ unsigned long msr;
+
+ msr = mfmsr();
+ BUG_ON(!(msr & MSR_RI));
>>>
>>> I'm not sure about this.
>>>
>>> We call RTAS in some low-level places, so if we ever hit this BUG_ON
>>> then it might cause us to crash badly, or recursively BUG.
>>>
>>> A WARN_ON_ONCE() might be safer?
>>
>> I'm afraid a BUG_ON is required here. Since MSR[RI] is set on RTAS exit so
>> if it was not set when calling RTAS, that's a real issue and should
>> generate unexpected behaviour.
>>
>> Do you have places in mind where RTAS could be called with !MSR[RI]?
>
> The main one I can think of is if someone is using
> CONFIG_UDBG_RTAS_CONSOLE, then udbg_rtascon_putc() is wired up as
> udbg_putc() and that might be called from anywhere, including xmon.
>
> There's also RTAS calls in low-level xics interrupt code, that might get
> called during panic/crash.
>
> I don't expect any of those places to be called with MSR[RI] unset, but
> I'm worried that if we're already crashing and for some reason MSR[RI]
> is unset, then that BUG_ON will just make things worse.
>
> eg. imagine taking a BUG_ON() for every character we try to print as
> part of an oops.
>
> Admittedly CONFIG_UDBG_RTAS_CONSOLE is old and probably not used much
> anymore, but I'm still a bit paranoid :)
I think you're right to be paranoid :)
This part of code can be really sensitive.
I boot a kernel built with CONFIG_UDBG_RTAS_CONSOLE, xmon is working fine,
but I cannot pretend this is covering all the RTAS call cases.
My hope with BUG_ON() is to raise the issue, as soon as possible, so it can
be addressed during the test phase.
Re: [PATCH v2] powerpc/rtas: Keep MSR[RI] set when calling RTAS
Laurent Dufour writes:
> On 03/05/2022, 17:06:41, Michael Ellerman wrote:
>> Laurent Dufour writes:
...
>>> diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c
>>> index 1f42aabbbab3..d7775b8c8853 100644
>>> --- a/arch/powerpc/kernel/rtas.c
>>> +++ b/arch/powerpc/kernel/rtas.c
>>> @@ -49,6 +49,11 @@ void enter_rtas(unsigned long);
>>>
>>> static inline void do_enter_rtas(unsigned long args)
>>> {
>>> + unsigned long msr;
>>> +
>>> + msr = mfmsr();
>>> + BUG_ON(!(msr & MSR_RI));
>>
>> I'm not sure about this.
>>
>> We call RTAS in some low-level places, so if we ever hit this BUG_ON
>> then it might cause us to crash badly, or recursively BUG.
>>
>> A WARN_ON_ONCE() might be safer?
>
> I'm afraid a BUG_ON is required here. Since MSR[RI] is set on RTAS exit so
> if it was not set when calling RTAS, that's a real issue and should
> generate unexpected behaviour.
>
> Do you have places in mind where RTAS could be called with !MSR[RI]?
The main one I can think of is if someone is using
CONFIG_UDBG_RTAS_CONSOLE, then udbg_rtascon_putc() is wired up as
udbg_putc() and that might be called from anywhere, including xmon.
There's also RTAS calls in low-level xics interrupt code, that might get
called during panic/crash.
I don't expect any of those places to be called with MSR[RI] unset, but
I'm worried that if we're already crashing and for some reason MSR[RI]
is unset, then that BUG_ON will just make things worse.
eg. imagine taking a BUG_ON() for every character we try to print as
part of an oops.
Admittedly CONFIG_UDBG_RTAS_CONSOLE is old and probably not used much
anymore, but I'm still a bit paranoid :)
cheers
Re: [PATCH v2] powerpc/rtas: Keep MSR[RI] set when calling RTAS
Laurent Dufour writes: > On 03/05/2022, 18:16:29, Fabiano Rosas wrote: >> Michael Ellerman writes: >> diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S index 9581906b5ee9..65cb14b56f8d 100644 --- a/arch/powerpc/kernel/entry_64.S +++ b/arch/powerpc/kernel/entry_64.S @@ -330,22 +330,18 @@ _GLOBAL(enter_rtas) clrldi r4,r4,2 /* convert to realmode address */ mtlrr4 - li r0,0 - ori r0,r0,MSR_EE|MSR_SE|MSR_BE|MSR_RI - andcr0,r6,r0 - -li r9,1 -rldicr r9,r9,MSR_SF_LG,(63-MSR_SF_LG) - ori r9,r9,MSR_IR|MSR_DR|MSR_FE0|MSR_FE1|MSR_FP|MSR_RI|MSR_LE - andcr6,r0,r9 >>> >>> One advantage of the old method is it can adapt to new MSR bits being >>> set by the kernel. >>> >>> For example we used to use RTAS on powernv, and this code didn't need >>> updating to cater to MSR_HV being set. We will probably never use RTAS >>> on bare-metal again, so that's OK. >>> >>> But your change might break secure virtual machines, because it clears >>> MSR_S whereas the old code didn't. I think SVMs did use RTAS, but I >>> don't know whether it matters if it's called with MSR_S set or not? >>> >>> Not sure if anyone will remember, or has a working setup they can test. >>> Maybe for now we just copy MSR_S from the kernel MSR the way the >>> current code does. >> >> Would the kernel even be able to change the bit? I think only urfid can >> clear MSR_S. > > That's a good point, thanks Fabiano! > > The POWER ISA programming note about MSR[S] is explicit: > "MSR[S] can be set to 1 only by the System Call instruction and some > interrupts. It can be set to 0 only by urfid." > > Since RTAS is entered using rfid, MSR[S] should remain whatever is the > value in SRR1. > > And that's what POWER ISA is saying about the rfid instruction, in the > synopsis of the instruction the bit 41 of the resulting MSR (aka MSR[S]) is > not impacted. > > So there is no need to take care of this MSR bit in our code, but for sure, > this should be well commented. > > Michael, do you agree? Yep. Can you send a v3 with updated change log and comment mentioning MSR_S and MSR_LE, thanks. cheers
Re: [PATCH v2] powerpc/rtas: Keep MSR[RI] set when calling RTAS
Fabiano Rosas writes: > Michael Ellerman writes: >>> diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S >>> index 9581906b5ee9..65cb14b56f8d 100644 >>> --- a/arch/powerpc/kernel/entry_64.S >>> +++ b/arch/powerpc/kernel/entry_64.S >>> @@ -330,22 +330,18 @@ _GLOBAL(enter_rtas) >>> clrldi r4,r4,2 /* convert to realmode address */ >>> mtlrr4 >>> >>> - li r0,0 >>> - ori r0,r0,MSR_EE|MSR_SE|MSR_BE|MSR_RI >>> - andcr0,r6,r0 >>> - >>> -li r9,1 >>> -rldicr r9,r9,MSR_SF_LG,(63-MSR_SF_LG) >>> - ori r9,r9,MSR_IR|MSR_DR|MSR_FE0|MSR_FE1|MSR_FP|MSR_RI|MSR_LE >>> - andcr6,r0,r9 >> >> One advantage of the old method is it can adapt to new MSR bits being >> set by the kernel. >> >> For example we used to use RTAS on powernv, and this code didn't need >> updating to cater to MSR_HV being set. We will probably never use RTAS >> on bare-metal again, so that's OK. >> >> But your change might break secure virtual machines, because it clears >> MSR_S whereas the old code didn't. I think SVMs did use RTAS, but I >> don't know whether it matters if it's called with MSR_S set or not? >> >> Not sure if anyone will remember, or has a working setup they can test. >> Maybe for now we just copy MSR_S from the kernel MSR the way the >> current code does. > > Would the kernel even be able to change the bit? I think only urfid can > clear MSR_S. Good point :) cheers
Re: [PATCH v2] powerpc/rtas: Keep MSR[RI] set when calling RTAS
On 03/05/2022, 18:16:29, Fabiano Rosas wrote: > Michael Ellerman writes: > >>> diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S >>> index 9581906b5ee9..65cb14b56f8d 100644 >>> --- a/arch/powerpc/kernel/entry_64.S >>> +++ b/arch/powerpc/kernel/entry_64.S >>> @@ -330,22 +330,18 @@ _GLOBAL(enter_rtas) >>> clrldi r4,r4,2 /* convert to realmode address */ >>> mtlrr4 >>> >>> - li r0,0 >>> - ori r0,r0,MSR_EE|MSR_SE|MSR_BE|MSR_RI >>> - andcr0,r6,r0 >>> - >>> -li r9,1 >>> -rldicr r9,r9,MSR_SF_LG,(63-MSR_SF_LG) >>> - ori r9,r9,MSR_IR|MSR_DR|MSR_FE0|MSR_FE1|MSR_FP|MSR_RI|MSR_LE >>> - andcr6,r0,r9 >> >> One advantage of the old method is it can adapt to new MSR bits being >> set by the kernel. >> >> For example we used to use RTAS on powernv, and this code didn't need >> updating to cater to MSR_HV being set. We will probably never use RTAS >> on bare-metal again, so that's OK. >> >> But your change might break secure virtual machines, because it clears >> MSR_S whereas the old code didn't. I think SVMs did use RTAS, but I >> don't know whether it matters if it's called with MSR_S set or not? >> >> Not sure if anyone will remember, or has a working setup they can test. >> Maybe for now we just copy MSR_S from the kernel MSR the way the >> current code does. > > Would the kernel even be able to change the bit? I think only urfid can > clear MSR_S. That's a good point, thanks Fabiano! The POWER ISA programming note about MSR[S] is explicit: "MSR[S] can be set to 1 only by the System Call instruction and some interrupts. It can be set to 0 only by urfid." Since RTAS is entered using rfid, MSR[S] should remain whatever is the value in SRR1. And that's what POWER ISA is saying about the rfid instruction, in the synopsis of the instruction the bit 41 of the resulting MSR (aka MSR[S]) is not impacted. So there is no need to take care of this MSR bit in our code, but for sure, this should be well commented. Michael, do you agree? Cheers, Laurent.
Re: [PATCH v2] powerpc/rtas: Keep MSR[RI] set when calling RTAS
Thanks Michael for reviewing this. On 03/05/2022, 17:06:41, Michael Ellerman wrote: > Laurent Dufour writes: >> RTAS runs in real mode (MSR[DR] and MSR[IR] unset) and in 32bits >> mode (MSR[SF] unset). > > Probably also worth mentioning that it runs in big endian mode :) > > It is specified in PAPR (R1-7.2.1-6). Sure! > >> The change in MSR is done in enter_rtas() in a relatively complex way, >> since the MSR value could be hardcoded. >> >> Furthermore, a panic has been reported when hitting the watchdog interrupt >> while running in RTAS, this leads to the following stack trace: >> >> [69244.027433][ C24] watchdog: CPU 24 Hard LOCKUP >> [69244.027442][ C24] watchdog: CPU 24 TB:997512652051031, last heartbeat >> TB:997504470175378 (15980ms ago) >> [69244.027451][ C24] Modules linked in: chacha_generic(E) libchacha(E) >> xxhash_generic(E) wp512(E) sha3_generic(E) rmd160(E) poly1305_generic(E) >> libpoly1305(E) michael_mic(E) md4(E) crc32_generic(E) cmac(E) ccm(E) >> algif_rng(E) twofish_generic(E) twofish_common(E) serpent_generic(E) >> fcrypt(E) des_generic(E) libdes(E) cast6_generic(E) cast5_generic(E) >> cast_common(E) camellia_generic(E) blowfish_generic(E) blowfish_common(E) >> algif_skcipher(E) algif_hash(E) gcm(E) algif_aead(E) af_alg(E) tun(E) >> rpcsec_gss_krb5(E) auth_rpcgss(E) >> nfsv4(E) dns_resolver(E) rpadlpar_io(EX) rpaphp(EX) xsk_diag(E) tcp_diag(E) >> udp_diag(E) raw_diag(E) inet_diag(E) unix_diag(E) af_packet_diag(E) >> netlink_diag(E) nfsv3(E) nfs_acl(E) nfs(E) lockd(E) grace(E) sunrpc(E) >> fscache(E) netfs(E) af_packet(E) rfkill(E) bonding(E) tls(E) ibmveth(EX) >> crct10dif_vpmsum(E) rtc_generic(E) drm(E) drm_panel_orientation_quirks(E) >> fuse(E) configfs(E) backlight(E) ip_tables(E) x_tables(E) dm_service_time(E) >> sd_mod(E) t10_pi(E) >> [69244.027555][ C24] ibmvfc(EX) scsi_transport_fc(E) vmx_crypto(E) >> gf128mul(E) btrfs(E) blake2b_generic(E) libcrc32c(E) crc32c_vpmsum(E) xor(E) >> raid6_pq(E) dm_mirror(E) dm_region_hash(E) dm_log(E) sg(E) dm_multipath(E) >> dm_mod(E) scsi_dh_rdac(E) scsi_dh_emc(E) scsi_dh_alua(E) scsi_mod(E) >> [69244.027587][ C24] Supported: No, Unreleased kernel >> [69244.027600][ C24] CPU: 24 PID: 87504 Comm: drmgr Kdump: loaded Tainted: >> GE X5.14.21-150400.71.1.bz196362_2-default #1 SLE15-SP4 >> (unreleased) 0d821077ef4faa8dfaf370efb5fdca1fa35f4e2c >> [69244.027609][ C24] NIP: 1fb41050 LR: 1fb4104c CTR: >> >> [69244.027612][ C24] REGS: cfc33d60 TRAP: 0100 Tainted: G >> E X (5.14.21-150400.71.1.bz196362_2-default) >> [69244.027615][ C24] MSR: 82981000 CR: 4882 >> XER: 20040020 >> [69244.027625][ C24] CFAR: 011c IRQMASK: 1 >> [69244.027625][ C24] GPR00: 0003 >> 0001 50dc >> [69244.027625][ C24] GPR04: 1ffb6100 0020 >> 0001 1fb09010 >> [69244.027625][ C24] GPR08: 2000 >> >> [69244.027625][ C24] GPR12: 8004072a40a8 cff8b680 >> 0007 0034 >> [69244.027625][ C24] GPR16: 1fbf6e94 1fbf6d84 >> 1fbd1db0 1fb3f008 >> [69244.027625][ C24] GPR20: 1fb41018 >> 017f f68f >> [69244.027625][ C24] GPR24: 1fb18fe8 1fb3e000 >> 1fb1adc0 1fb1cf40 >> [69244.027625][ C24] GPR28: 1fb26000 1fb460f0 >> 1fb17f18 1fb17000 >> [69244.027663][ C24] NIP [1fb41050] 0x1fb41050 >> [69244.027696][ C24] LR [1fb4104c] 0x1fb4104c >> [69244.027699][ C24] Call Trace: >> [69244.027701][ C24] Instruction dump: >> [69244.027723][ C24] >> >> [69244.027728][ C24] >> >> [69244.027762][T87504] Oops: Unrecoverable System Reset, sig: 6 [#1] >> [69244.028044][T87504] LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA >> pSeries >> [69244.028089][T87504] Modules linked in: chacha_generic(E) libchacha(E) >> xxhash_generic(E) wp512(E) sha3_generic(E) rmd160(E) poly1305_generic(E) >> libpoly1305(E) michael_mic(E) md4(E) crc32_generic(E) cmac(E) ccm(E) >> algif_rng(E) twofish_generic(E) twofish_common(E) serpent_generic(E) >> fcrypt(E) des_generic(E) libdes(E) cast6_generic(E) cast5_generic(E) >> cast_common(E) camellia_generic(E) blowfish_generic(E) blowfish_common(E) >> algif_skcipher(E) algif_hash(E) gcm(E) algif_aead(E) af_alg(E) tun(E) >> rpcsec_gss_krb5(E) auth_rpcgss(E) >> nfsv4(E) dns_resolver(E) rpadlpar_io(EX) rpaphp(EX) xsk_diag(E) tcp_diag(E) >> udp_diag(E) raw_diag(E) inet_diag(E) unix_diag(E) af_packet_diag(E) >> netlink_diag(E) nfsv3(E) nfs_acl(E) nfs(E) lockd(E) grace(E) sunrpc(E) >> fscache(E) netfs(E) af_packet(E)
Re: [PATCH v2] powerpc/rtas: Keep MSR[RI] set when calling RTAS
Michael Ellerman writes: >> diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S >> index 9581906b5ee9..65cb14b56f8d 100644 >> --- a/arch/powerpc/kernel/entry_64.S >> +++ b/arch/powerpc/kernel/entry_64.S >> @@ -330,22 +330,18 @@ _GLOBAL(enter_rtas) >> clrldi r4,r4,2 /* convert to realmode address */ >> mtlrr4 >> >> -li r0,0 >> -ori r0,r0,MSR_EE|MSR_SE|MSR_BE|MSR_RI >> -andcr0,r6,r0 >> - >> -li r9,1 >> -rldicr r9,r9,MSR_SF_LG,(63-MSR_SF_LG) >> -ori r9,r9,MSR_IR|MSR_DR|MSR_FE0|MSR_FE1|MSR_FP|MSR_RI|MSR_LE >> -andcr6,r0,r9 > > One advantage of the old method is it can adapt to new MSR bits being > set by the kernel. > > For example we used to use RTAS on powernv, and this code didn't need > updating to cater to MSR_HV being set. We will probably never use RTAS > on bare-metal again, so that's OK. > > But your change might break secure virtual machines, because it clears > MSR_S whereas the old code didn't. I think SVMs did use RTAS, but I > don't know whether it matters if it's called with MSR_S set or not? > > Not sure if anyone will remember, or has a working setup they can test. > Maybe for now we just copy MSR_S from the kernel MSR the way the > current code does. Would the kernel even be able to change the bit? I think only urfid can clear MSR_S.
Re: [PATCH v2] powerpc/rtas: Keep MSR[RI] set when calling RTAS
Laurent Dufour writes: > RTAS runs in real mode (MSR[DR] and MSR[IR] unset) and in 32bits > mode (MSR[SF] unset). Probably also worth mentioning that it runs in big endian mode :) It is specified in PAPR (R1-7.2.1-6). > The change in MSR is done in enter_rtas() in a relatively complex way, > since the MSR value could be hardcoded. > > Furthermore, a panic has been reported when hitting the watchdog interrupt > while running in RTAS, this leads to the following stack trace: > > [69244.027433][ C24] watchdog: CPU 24 Hard LOCKUP > [69244.027442][ C24] watchdog: CPU 24 TB:997512652051031, last heartbeat > TB:997504470175378 (15980ms ago) > [69244.027451][ C24] Modules linked in: chacha_generic(E) libchacha(E) > xxhash_generic(E) wp512(E) sha3_generic(E) rmd160(E) poly1305_generic(E) > libpoly1305(E) michael_mic(E) md4(E) crc32_generic(E) cmac(E) ccm(E) > algif_rng(E) twofish_generic(E) twofish_common(E) serpent_generic(E) > fcrypt(E) des_generic(E) libdes(E) cast6_generic(E) cast5_generic(E) > cast_common(E) camellia_generic(E) blowfish_generic(E) blowfish_common(E) > algif_skcipher(E) algif_hash(E) gcm(E) algif_aead(E) af_alg(E) tun(E) > rpcsec_gss_krb5(E) auth_rpcgss(E) > nfsv4(E) dns_resolver(E) rpadlpar_io(EX) rpaphp(EX) xsk_diag(E) tcp_diag(E) > udp_diag(E) raw_diag(E) inet_diag(E) unix_diag(E) af_packet_diag(E) > netlink_diag(E) nfsv3(E) nfs_acl(E) nfs(E) lockd(E) grace(E) sunrpc(E) > fscache(E) netfs(E) af_packet(E) rfkill(E) bonding(E) tls(E) ibmveth(EX) > crct10dif_vpmsum(E) rtc_generic(E) drm(E) drm_panel_orientation_quirks(E) > fuse(E) configfs(E) backlight(E) ip_tables(E) x_tables(E) dm_service_time(E) > sd_mod(E) t10_pi(E) > [69244.027555][ C24] ibmvfc(EX) scsi_transport_fc(E) vmx_crypto(E) > gf128mul(E) btrfs(E) blake2b_generic(E) libcrc32c(E) crc32c_vpmsum(E) xor(E) > raid6_pq(E) dm_mirror(E) dm_region_hash(E) dm_log(E) sg(E) dm_multipath(E) > dm_mod(E) scsi_dh_rdac(E) scsi_dh_emc(E) scsi_dh_alua(E) scsi_mod(E) > [69244.027587][ C24] Supported: No, Unreleased kernel > [69244.027600][ C24] CPU: 24 PID: 87504 Comm: drmgr Kdump: loaded Tainted: > GE X5.14.21-150400.71.1.bz196362_2-default #1 SLE15-SP4 > (unreleased) 0d821077ef4faa8dfaf370efb5fdca1fa35f4e2c > [69244.027609][ C24] NIP: 1fb41050 LR: 1fb4104c CTR: > > [69244.027612][ C24] REGS: cfc33d60 TRAP: 0100 Tainted: G >E X (5.14.21-150400.71.1.bz196362_2-default) > [69244.027615][ C24] MSR: 82981000 CR: 4882 > XER: 20040020 > [69244.027625][ C24] CFAR: 011c IRQMASK: 1 > [69244.027625][ C24] GPR00: 0003 > 0001 50dc > [69244.027625][ C24] GPR04: 1ffb6100 0020 > 0001 1fb09010 > [69244.027625][ C24] GPR08: 2000 > > [69244.027625][ C24] GPR12: 8004072a40a8 cff8b680 > 0007 0034 > [69244.027625][ C24] GPR16: 1fbf6e94 1fbf6d84 > 1fbd1db0 1fb3f008 > [69244.027625][ C24] GPR20: 1fb41018 > 017f f68f > [69244.027625][ C24] GPR24: 1fb18fe8 1fb3e000 > 1fb1adc0 1fb1cf40 > [69244.027625][ C24] GPR28: 1fb26000 1fb460f0 > 1fb17f18 1fb17000 > [69244.027663][ C24] NIP [1fb41050] 0x1fb41050 > [69244.027696][ C24] LR [1fb4104c] 0x1fb4104c > [69244.027699][ C24] Call Trace: > [69244.027701][ C24] Instruction dump: > [69244.027723][ C24] > > [69244.027728][ C24] > > [69244.027762][T87504] Oops: Unrecoverable System Reset, sig: 6 [#1] > [69244.028044][T87504] LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries > [69244.028089][T87504] Modules linked in: chacha_generic(E) libchacha(E) > xxhash_generic(E) wp512(E) sha3_generic(E) rmd160(E) poly1305_generic(E) > libpoly1305(E) michael_mic(E) md4(E) crc32_generic(E) cmac(E) ccm(E) > algif_rng(E) twofish_generic(E) twofish_common(E) serpent_generic(E) > fcrypt(E) des_generic(E) libdes(E) cast6_generic(E) cast5_generic(E) > cast_common(E) camellia_generic(E) blowfish_generic(E) blowfish_common(E) > algif_skcipher(E) algif_hash(E) gcm(E) algif_aead(E) af_alg(E) tun(E) > rpcsec_gss_krb5(E) auth_rpcgss(E) > nfsv4(E) dns_resolver(E) rpadlpar_io(EX) rpaphp(EX) xsk_diag(E) tcp_diag(E) > udp_diag(E) raw_diag(E) inet_diag(E) unix_diag(E) af_packet_diag(E) > netlink_diag(E) nfsv3(E) nfs_acl(E) nfs(E) lockd(E) grace(E) sunrpc(E) > fscache(E) netfs(E) af_packet(E) rfkill(E) bonding(E) tls(E) ibmveth(EX) > crct10dif_vpmsum(E) rtc_generic(E) drm(E) drm_panel_orientation_quirks(E) > fuse(E) configfs(E) backlight(E) ip_tables(E) x_tables(E) dm_servic
Re: [PATCH v2] powerpc/rtas: Keep MSR[RI] set when calling RTAS
On 13/04/2022, 07:58:42, Nicholas Piggin wrote: > Excerpts from Laurent Dufour's message of April 2, 2022 12:06 am: >> RTAS runs in real mode (MSR[DR] and MSR[IR] unset) and in 32bits >> mode (MSR[SF] unset). >> >> The change in MSR is done in enter_rtas() in a relatively complex way, >> since the MSR value could be hardcoded. >> >> Furthermore, a panic has been reported when hitting the watchdog interrupt >> while running in RTAS, this leads to the following stack trace: >> >> [69244.027433][ C24] watchdog: CPU 24 Hard LOCKUP >> [69244.027442][ C24] watchdog: CPU 24 TB:997512652051031, last heartbeat >> TB:997504470175378 (15980ms ago) >> [69244.027451][ C24] Modules linked in: chacha_generic(E) libchacha(E) >> xxhash_generic(E) wp512(E) sha3_generic(E) rmd160(E) poly1305_generic(E) >> libpoly1305(E) michael_mic(E) md4(E) crc32_generic(E) cmac(E) ccm(E) >> algif_rng(E) twofish_generic(E) twofish_common(E) serpent_generic(E) >> fcrypt(E) des_generic(E) libdes(E) cast6_generic(E) cast5_generic(E) >> cast_common(E) camellia_generic(E) blowfish_generic(E) blowfish_common(E) >> algif_skcipher(E) algif_hash(E) gcm(E) algif_aead(E) af_alg(E) tun(E) >> rpcsec_gss_krb5(E) auth_rpcgss(E) >> nfsv4(E) dns_resolver(E) rpadlpar_io(EX) rpaphp(EX) xsk_diag(E) tcp_diag(E) >> udp_diag(E) raw_diag(E) inet_diag(E) unix_diag(E) af_packet_diag(E) >> netlink_diag(E) nfsv3(E) nfs_acl(E) nfs(E) lockd(E) grace(E) sunrpc(E) >> fscache(E) netfs(E) af_packet(E) rfkill(E) bonding(E) tls(E) ibmveth(EX) >> crct10dif_vpmsum(E) rtc_generic(E) drm(E) drm_panel_orientation_quirks(E) >> fuse(E) configfs(E) backlight(E) ip_tables(E) x_tables(E) dm_service_time(E) >> sd_mod(E) t10_pi(E) >> [69244.027555][ C24] ibmvfc(EX) scsi_transport_fc(E) vmx_crypto(E) >> gf128mul(E) btrfs(E) blake2b_generic(E) libcrc32c(E) crc32c_vpmsum(E) xor(E) >> raid6_pq(E) dm_mirror(E) dm_region_hash(E) dm_log(E) sg(E) dm_multipath(E) >> dm_mod(E) scsi_dh_rdac(E) scsi_dh_emc(E) scsi_dh_alua(E) scsi_mod(E) >> [69244.027587][ C24] Supported: No, Unreleased kernel >> [69244.027600][ C24] CPU: 24 PID: 87504 Comm: drmgr Kdump: loaded Tainted: >> GE X5.14.21-150400.71.1.bz196362_2-default #1 SLE15-SP4 >> (unreleased) 0d821077ef4faa8dfaf370efb5fdca1fa35f4e2c >> [69244.027609][ C24] NIP: 1fb41050 LR: 1fb4104c CTR: >> >> [69244.027612][ C24] REGS: cfc33d60 TRAP: 0100 Tainted: G >> E X (5.14.21-150400.71.1.bz196362_2-default) >> [69244.027615][ C24] MSR: 82981000 CR: 4882 >> XER: 20040020 >> [69244.027625][ C24] CFAR: 011c IRQMASK: 1 >> [69244.027625][ C24] GPR00: 0003 >> 0001 50dc >> [69244.027625][ C24] GPR04: 1ffb6100 0020 >> 0001 1fb09010 >> [69244.027625][ C24] GPR08: 2000 >> >> [69244.027625][ C24] GPR12: 8004072a40a8 cff8b680 >> 0007 0034 >> [69244.027625][ C24] GPR16: 1fbf6e94 1fbf6d84 >> 1fbd1db0 1fb3f008 >> [69244.027625][ C24] GPR20: 1fb41018 >> 017f f68f >> [69244.027625][ C24] GPR24: 1fb18fe8 1fb3e000 >> 1fb1adc0 1fb1cf40 >> [69244.027625][ C24] GPR28: 1fb26000 1fb460f0 >> 1fb17f18 1fb17000 >> [69244.027663][ C24] NIP [1fb41050] 0x1fb41050 >> [69244.027696][ C24] LR [1fb4104c] 0x1fb4104c >> [69244.027699][ C24] Call Trace: >> [69244.027701][ C24] Instruction dump: >> [69244.027723][ C24] >> >> [69244.027728][ C24] >> >> [69244.027762][T87504] Oops: Unrecoverable System Reset, sig: 6 [#1] >> [69244.028044][T87504] LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA >> pSeries >> [69244.028089][T87504] Modules linked in: chacha_generic(E) libchacha(E) >> xxhash_generic(E) wp512(E) sha3_generic(E) rmd160(E) poly1305_generic(E) >> libpoly1305(E) michael_mic(E) md4(E) crc32_generic(E) cmac(E) ccm(E) >> algif_rng(E) twofish_generic(E) twofish_common(E) serpent_generic(E) >> fcrypt(E) des_generic(E) libdes(E) cast6_generic(E) cast5_generic(E) >> cast_common(E) camellia_generic(E) blowfish_generic(E) blowfish_common(E) >> algif_skcipher(E) algif_hash(E) gcm(E) algif_aead(E) af_alg(E) tun(E) >> rpcsec_gss_krb5(E) auth_rpcgss(E) >> nfsv4(E) dns_resolver(E) rpadlpar_io(EX) rpaphp(EX) xsk_diag(E) tcp_diag(E) >> udp_diag(E) raw_diag(E) inet_diag(E) unix_diag(E) af_packet_diag(E) >> netlink_diag(E) nfsv3(E) nfs_acl(E) nfs(E) lockd(E) grace(E) sunrpc(E) >> fscache(E) netfs(E) af_packet(E) rfkill(E) bonding(E) tls(E) ibmveth(EX) >> crct10dif_vpmsum(E) rtc_generic(E) drm(E) drm_panel_orientation_quirks(E
Re: [PATCH v2] powerpc/rtas: Keep MSR[RI] set when calling RTAS
Excerpts from Laurent Dufour's message of April 2, 2022 12:06 am: > RTAS runs in real mode (MSR[DR] and MSR[IR] unset) and in 32bits > mode (MSR[SF] unset). > > The change in MSR is done in enter_rtas() in a relatively complex way, > since the MSR value could be hardcoded. > > Furthermore, a panic has been reported when hitting the watchdog interrupt > while running in RTAS, this leads to the following stack trace: > > [69244.027433][ C24] watchdog: CPU 24 Hard LOCKUP > [69244.027442][ C24] watchdog: CPU 24 TB:997512652051031, last heartbeat > TB:997504470175378 (15980ms ago) > [69244.027451][ C24] Modules linked in: chacha_generic(E) libchacha(E) > xxhash_generic(E) wp512(E) sha3_generic(E) rmd160(E) poly1305_generic(E) > libpoly1305(E) michael_mic(E) md4(E) crc32_generic(E) cmac(E) ccm(E) > algif_rng(E) twofish_generic(E) twofish_common(E) serpent_generic(E) > fcrypt(E) des_generic(E) libdes(E) cast6_generic(E) cast5_generic(E) > cast_common(E) camellia_generic(E) blowfish_generic(E) blowfish_common(E) > algif_skcipher(E) algif_hash(E) gcm(E) algif_aead(E) af_alg(E) tun(E) > rpcsec_gss_krb5(E) auth_rpcgss(E) > nfsv4(E) dns_resolver(E) rpadlpar_io(EX) rpaphp(EX) xsk_diag(E) tcp_diag(E) > udp_diag(E) raw_diag(E) inet_diag(E) unix_diag(E) af_packet_diag(E) > netlink_diag(E) nfsv3(E) nfs_acl(E) nfs(E) lockd(E) grace(E) sunrpc(E) > fscache(E) netfs(E) af_packet(E) rfkill(E) bonding(E) tls(E) ibmveth(EX) > crct10dif_vpmsum(E) rtc_generic(E) drm(E) drm_panel_orientation_quirks(E) > fuse(E) configfs(E) backlight(E) ip_tables(E) x_tables(E) dm_service_time(E) > sd_mod(E) t10_pi(E) > [69244.027555][ C24] ibmvfc(EX) scsi_transport_fc(E) vmx_crypto(E) > gf128mul(E) btrfs(E) blake2b_generic(E) libcrc32c(E) crc32c_vpmsum(E) xor(E) > raid6_pq(E) dm_mirror(E) dm_region_hash(E) dm_log(E) sg(E) dm_multipath(E) > dm_mod(E) scsi_dh_rdac(E) scsi_dh_emc(E) scsi_dh_alua(E) scsi_mod(E) > [69244.027587][ C24] Supported: No, Unreleased kernel > [69244.027600][ C24] CPU: 24 PID: 87504 Comm: drmgr Kdump: loaded Tainted: > GE X5.14.21-150400.71.1.bz196362_2-default #1 SLE15-SP4 > (unreleased) 0d821077ef4faa8dfaf370efb5fdca1fa35f4e2c > [69244.027609][ C24] NIP: 1fb41050 LR: 1fb4104c CTR: > > [69244.027612][ C24] REGS: cfc33d60 TRAP: 0100 Tainted: G >E X (5.14.21-150400.71.1.bz196362_2-default) > [69244.027615][ C24] MSR: 82981000 CR: 4882 > XER: 20040020 > [69244.027625][ C24] CFAR: 011c IRQMASK: 1 > [69244.027625][ C24] GPR00: 0003 > 0001 50dc > [69244.027625][ C24] GPR04: 1ffb6100 0020 > 0001 1fb09010 > [69244.027625][ C24] GPR08: 2000 > > [69244.027625][ C24] GPR12: 8004072a40a8 cff8b680 > 0007 0034 > [69244.027625][ C24] GPR16: 1fbf6e94 1fbf6d84 > 1fbd1db0 1fb3f008 > [69244.027625][ C24] GPR20: 1fb41018 > 017f f68f > [69244.027625][ C24] GPR24: 1fb18fe8 1fb3e000 > 1fb1adc0 1fb1cf40 > [69244.027625][ C24] GPR28: 1fb26000 1fb460f0 > 1fb17f18 1fb17000 > [69244.027663][ C24] NIP [1fb41050] 0x1fb41050 > [69244.027696][ C24] LR [1fb4104c] 0x1fb4104c > [69244.027699][ C24] Call Trace: > [69244.027701][ C24] Instruction dump: > [69244.027723][ C24] > > [69244.027728][ C24] > > [69244.027762][T87504] Oops: Unrecoverable System Reset, sig: 6 [#1] > [69244.028044][T87504] LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries > [69244.028089][T87504] Modules linked in: chacha_generic(E) libchacha(E) > xxhash_generic(E) wp512(E) sha3_generic(E) rmd160(E) poly1305_generic(E) > libpoly1305(E) michael_mic(E) md4(E) crc32_generic(E) cmac(E) ccm(E) > algif_rng(E) twofish_generic(E) twofish_common(E) serpent_generic(E) > fcrypt(E) des_generic(E) libdes(E) cast6_generic(E) cast5_generic(E) > cast_common(E) camellia_generic(E) blowfish_generic(E) blowfish_common(E) > algif_skcipher(E) algif_hash(E) gcm(E) algif_aead(E) af_alg(E) tun(E) > rpcsec_gss_krb5(E) auth_rpcgss(E) > nfsv4(E) dns_resolver(E) rpadlpar_io(EX) rpaphp(EX) xsk_diag(E) tcp_diag(E) > udp_diag(E) raw_diag(E) inet_diag(E) unix_diag(E) af_packet_diag(E) > netlink_diag(E) nfsv3(E) nfs_acl(E) nfs(E) lockd(E) grace(E) sunrpc(E) > fscache(E) netfs(E) af_packet(E) rfkill(E) bonding(E) tls(E) ibmveth(EX) > crct10dif_vpmsum(E) rtc_generic(E) drm(E) drm_panel_orientation_quirks(E) > fuse(E) configfs(E) backlight(E) ip_tables(E) x_tables(E) dm_service_time(E) > sd_mod(E) t10_pi(E) > [69244.028171][T87504] i
[PATCH v2] powerpc/rtas: Keep MSR[RI] set when calling RTAS
RTAS runs in real mode (MSR[DR] and MSR[IR] unset) and in 32bits mode (MSR[SF] unset). The change in MSR is done in enter_rtas() in a relatively complex way, since the MSR value could be hardcoded. Furthermore, a panic has been reported when hitting the watchdog interrupt while running in RTAS, this leads to the following stack trace: [69244.027433][ C24] watchdog: CPU 24 Hard LOCKUP [69244.027442][ C24] watchdog: CPU 24 TB:997512652051031, last heartbeat TB:997504470175378 (15980ms ago) [69244.027451][ C24] Modules linked in: chacha_generic(E) libchacha(E) xxhash_generic(E) wp512(E) sha3_generic(E) rmd160(E) poly1305_generic(E) libpoly1305(E) michael_mic(E) md4(E) crc32_generic(E) cmac(E) ccm(E) algif_rng(E) twofish_generic(E) twofish_common(E) serpent_generic(E) fcrypt(E) des_generic(E) libdes(E) cast6_generic(E) cast5_generic(E) cast_common(E) camellia_generic(E) blowfish_generic(E) blowfish_common(E) algif_skcipher(E) algif_hash(E) gcm(E) algif_aead(E) af_alg(E) tun(E) rpcsec_gss_krb5(E) auth_rpcgss(E) nfsv4(E) dns_resolver(E) rpadlpar_io(EX) rpaphp(EX) xsk_diag(E) tcp_diag(E) udp_diag(E) raw_diag(E) inet_diag(E) unix_diag(E) af_packet_diag(E) netlink_diag(E) nfsv3(E) nfs_acl(E) nfs(E) lockd(E) grace(E) sunrpc(E) fscache(E) netfs(E) af_packet(E) rfkill(E) bonding(E) tls(E) ibmveth(EX) crct10dif_vpmsum(E) rtc_generic(E) drm(E) drm_panel_orientation_quirks(E) fuse(E) configfs(E) backlight(E) ip_tables(E) x_tables(E) dm_service_time(E) sd_mod(E) t10_pi(E) [69244.027555][ C24] ibmvfc(EX) scsi_transport_fc(E) vmx_crypto(E) gf128mul(E) btrfs(E) blake2b_generic(E) libcrc32c(E) crc32c_vpmsum(E) xor(E) raid6_pq(E) dm_mirror(E) dm_region_hash(E) dm_log(E) sg(E) dm_multipath(E) dm_mod(E) scsi_dh_rdac(E) scsi_dh_emc(E) scsi_dh_alua(E) scsi_mod(E) [69244.027587][ C24] Supported: No, Unreleased kernel [69244.027600][ C24] CPU: 24 PID: 87504 Comm: drmgr Kdump: loaded Tainted: G E X5.14.21-150400.71.1.bz196362_2-default #1 SLE15-SP4 (unreleased) 0d821077ef4faa8dfaf370efb5fdca1fa35f4e2c [69244.027609][ C24] NIP: 1fb41050 LR: 1fb4104c CTR: [69244.027612][ C24] REGS: cfc33d60 TRAP: 0100 Tainted: G E X (5.14.21-150400.71.1.bz196362_2-default) [69244.027615][ C24] MSR: 82981000 CR: 4882 XER: 20040020 [69244.027625][ C24] CFAR: 011c IRQMASK: 1 [69244.027625][ C24] GPR00: 0003 0001 50dc [69244.027625][ C24] GPR04: 1ffb6100 0020 0001 1fb09010 [69244.027625][ C24] GPR08: 2000 [69244.027625][ C24] GPR12: 8004072a40a8 cff8b680 0007 0034 [69244.027625][ C24] GPR16: 1fbf6e94 1fbf6d84 1fbd1db0 1fb3f008 [69244.027625][ C24] GPR20: 1fb41018 017f f68f [69244.027625][ C24] GPR24: 1fb18fe8 1fb3e000 1fb1adc0 1fb1cf40 [69244.027625][ C24] GPR28: 1fb26000 1fb460f0 1fb17f18 1fb17000 [69244.027663][ C24] NIP [1fb41050] 0x1fb41050 [69244.027696][ C24] LR [1fb4104c] 0x1fb4104c [69244.027699][ C24] Call Trace: [69244.027701][ C24] Instruction dump: [69244.027723][ C24] [69244.027728][ C24] [69244.027762][T87504] Oops: Unrecoverable System Reset, sig: 6 [#1] [69244.028044][T87504] LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries [69244.028089][T87504] Modules linked in: chacha_generic(E) libchacha(E) xxhash_generic(E) wp512(E) sha3_generic(E) rmd160(E) poly1305_generic(E) libpoly1305(E) michael_mic(E) md4(E) crc32_generic(E) cmac(E) ccm(E) algif_rng(E) twofish_generic(E) twofish_common(E) serpent_generic(E) fcrypt(E) des_generic(E) libdes(E) cast6_generic(E) cast5_generic(E) cast_common(E) camellia_generic(E) blowfish_generic(E) blowfish_common(E) algif_skcipher(E) algif_hash(E) gcm(E) algif_aead(E) af_alg(E) tun(E) rpcsec_gss_krb5(E) auth_rpcgss(E) nfsv4(E) dns_resolver(E) rpadlpar_io(EX) rpaphp(EX) xsk_diag(E) tcp_diag(E) udp_diag(E) raw_diag(E) inet_diag(E) unix_diag(E) af_packet_diag(E) netlink_diag(E) nfsv3(E) nfs_acl(E) nfs(E) lockd(E) grace(E) sunrpc(E) fscache(E) netfs(E) af_packet(E) rfkill(E) bonding(E) tls(E) ibmveth(EX) crct10dif_vpmsum(E) rtc_generic(E) drm(E) drm_panel_orientation_quirks(E) fuse(E) configfs(E) backlight(E) ip_tables(E) x_tables(E) dm_service_time(E) sd_mod(E) t10_pi(E) [69244.028171][T87504] ibmvfc(EX) scsi_transport_fc(E) vmx_crypto(E) gf128mul(E) btrfs(E) blake2b_generic(E) libcrc32c(E) crc32c_vpmsum(E) xor(E) raid6_pq(E) dm_mirror(E) dm_region_hash(E) dm_log(E) sg(E) dm_multipath(E) dm_mod(E) scsi_dh_rdac(E) scsi_dh_
