| Message ID | 157597242273.30329.4326721384243738456.tip-bot2@tip-bot2 (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [tip:,ras/core] x86/mce/AMD: Allow Reserved types to be overwritten in smca_banks[] | expand |
> -----Original Message----- > From: tip-bot2@linutronix.de <tip-bot2@linutronix.de> > Sent: Tuesday, December 10, 2019 5:07 AM > To: linux-tip-commits@vger.kernel.org > Cc: Ghannam, Yazen <Yazen.Ghannam@amd.com>; Borislav Petkov <bp@suse.de>; H. Peter Anvin <hpa@zytor.com>; Ingo Molnar > <mingo@kernel.org>; linux-edac <linux-edac@vger.kernel.org>; Thomas Gleixner <tglx@linutronix.de>; Tony Luck > <tony.luck@intel.com>; x86-ml <x86@kernel.org>; LKML <linux-kernel@vger.kernel.org> > Subject: [tip: ras/core] x86/mce/AMD: Allow Reserved types to be overwritten in smca_banks[] > > The following commit has been merged into the ras/core branch of tip: > > Commit-ID: a0cac35c1d83184151be4851ea90b5f920957967 > Gitweb: ... > Author: Yazen Ghannam <yazen.ghannam@amd.com> > AuthorDate: Thu, 21 Nov 2019 08:15:08 -06:00 > Committer: Borislav Petkov <bp@suse.de> > CommitterDate: Tue, 10 Dec 2019 09:27:59 +01:00 > > x86/mce/AMD: Allow Reserved types to be overwritten in smca_banks[] > Boris, Can this please be applied to ras/urgent? It fixes a boot issue on some recently released AMD systems. I had the Fixes tag, but I forgot to include CC:<stable>. Sorry about that. Thanks, Yazen
On Tue, Dec 17, 2019 at 01:49:13AM +0000, Ghannam, Yazen wrote: > Can this please be applied to ras/urgent? It fixes a boot issue on some > recently released AMD systems. > > I had the Fixes tag, but I forgot to include CC:<stable>. Sorry about that. Ok, I've reshuffled ras/core and ras/urgent and pushed them out. I'd appreciate it if you ran the urgent branch too, on your end. I tested on everything I have here but my hw doesn't trigger any boot hang issues anyway. If you have people reporting issues, now would be a good time for them to test it too. Thx.
diff --git a/arch/x86/kernel/cpu/mce/amd.c b/arch/x86/kernel/cpu/mce/amd.c index e41e3b4..d6cf5c1 100644 --- a/arch/x86/kernel/cpu/mce/amd.c +++ b/arch/x86/kernel/cpu/mce/amd.c @@ -266,7 +266,7 @@ static void smca_configure(unsigned int bank, unsigned int cpu) smca_set_misc_banks_map(bank, cpu); /* Return early if this bank was already initialized. */ - if (smca_banks[bank].hwid) + if (smca_banks[bank].hwid && smca_banks[bank].hwid->hwid_mcatype != 0) return; if (rdmsr_safe(MSR_AMD64_SMCA_MCx_IPID(bank), &low, &high)) {
The following commit has been merged into the ras/core branch of tip: Commit-ID: a0cac35c1d83184151be4851ea90b5f920957967 Gitweb: https://git.kernel.org/tip/a0cac35c1d83184151be4851ea90b5f920957967 Author: Yazen Ghannam <yazen.ghannam@amd.com> AuthorDate: Thu, 21 Nov 2019 08:15:08 -06:00 Committer: Borislav Petkov <bp@suse.de> CommitterDate: Tue, 10 Dec 2019 09:27:59 +01:00 x86/mce/AMD: Allow Reserved types to be overwritten in smca_banks[] Each logical CPU in Scalable MCA systems controls a unique set of MCA banks in the system. These banks are not shared between CPUs. The bank types and ordering will be the same across CPUs on currently available systems. However, some CPUs may see a bank as Reserved/Read-as-Zero (RAZ) while other CPUs do not. In this case, the bank seen as Reserved on one CPU is assumed to be the same type as the bank seen as a known type on another CPU. In general, this occurs when the hardware represented by the MCA bank is disabled, e.g. disabled memory controllers on certain models, etc. The MCA bank is disabled in the hardware, so there is no possibility of getting an MCA/MCE from it even if it is assumed to have a known type. For example: Full system: Bank | Type seen on CPU0 | Type seen on CPU1 ------------------------------------------------ 0 | LS | LS 1 | UMC | UMC 2 | CS | CS System with hardware disabled: Bank | Type seen on CPU0 | Type seen on CPU1 ------------------------------------------------ 0 | LS | LS 1 | UMC | RAZ 2 | CS | CS For this reason, there is a single, global struct smca_banks[] that is initialized at boot time. This array is initialized on each CPU as it comes online. However, the array will not be updated if an entry already exists. This works as expected when the first CPU (usually CPU0) has all possible MCA banks enabled. But if the first CPU has a subset, then it will save a "Reserved" type in smca_banks[]. Successive CPUs will then not be able to update smca_banks[] even if they encounter a known bank type. This may result in unexpected behavior. Depending on the system configuration, a user may observe issues enumerating the MCA thresholding sysfs interface. The issues may be as trivial as sysfs entries not being available, or as severe as system hangs. For example: Bank | Type seen on CPU0 | Type seen on CPU1 ------------------------------------------------ 0 | LS | LS 1 | RAZ | UMC 2 | CS | CS Extend the smca_banks[] entry check to return if the entry is a non-reserved type. Otherwise, continue so that CPUs that encounter a known bank type can update smca_banks[]. Fixes: 68627a697c19 ("x86/mce/AMD, EDAC/mce_amd: Enumerate Reserved SMCA bank type") Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: linux-edac <linux-edac@vger.kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: x86-ml <x86@kernel.org> Link: https://lkml.kernel.org/r/20191121141508.141273-1-Yazen.Ghannam@amd.com --- arch/x86/kernel/cpu/mce/amd.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)