From 246ff09f89e54fdf740a8d496176c86743db3ec7 Mon Sep 17 00:00:00 2001 From: Konstantin Khlebnikov Date: Thu, 31 Oct 2019 16:04:48 +0300 Subject: x86/MCE/AMD: Do not use rdmsr_safe_on_cpu() in smca_configure() ... because interrupts are disabled that early and sending IPIs can deadlock: BUG: sleeping function called from invalid context at kernel/sched/completion.c:99 in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 0, name: swapper/1 no locks held by swapper/1/0. irq event stamp: 0 hardirqs last enabled at (0): [<0000000000000000>] 0x0 hardirqs last disabled at (0): [] copy_process+0x8b9/0x1ca0 softirqs last enabled at (0): [] copy_process+0x8b9/0x1ca0 softirqs last disabled at (0): [<0000000000000000>] 0x0 Preemption disabled at: [] start_secondary+0x3b/0x190 CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.5.0-rc2+ #1 Hardware name: GIGABYTE MZ01-CE1-00/MZ01-CE1-00, BIOS F02 08/29/2018 Call Trace: dump_stack ___might_sleep.cold.92 wait_for_completion ? generic_exec_single rdmsr_safe_on_cpu ? wrmsr_on_cpus mce_amd_feature_init mcheck_cpu_init identify_cpu identify_secondary_cpu smp_store_cpu_info start_secondary secondary_startup_64 The function smca_configure() is called only on the current CPU anyway, therefore replace rdmsr_safe_on_cpu() with atomic rdmsr_safe() and avoid the IPI. [ bp: Update commit message. ] Signed-off-by: Konstantin Khlebnikov Signed-off-by: Borislav Petkov Reviewed-by: Yazen Ghannam Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: linux-edac Cc: Cc: Thomas Gleixner Cc: Tony Luck Cc: x86-ml Link: https://lkml.kernel.org/r/157252708836.3876.4604398213417262402.stgit@buzz --- arch/x86/kernel/cpu/mce/amd.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch') diff --git a/arch/x86/kernel/cpu/mce/amd.c b/arch/x86/kernel/cpu/mce/amd.c index 5167bd2bb6b1..e41e3b40aa48 100644 --- a/arch/x86/kernel/cpu/mce/amd.c +++ b/arch/x86/kernel/cpu/mce/amd.c @@ -269,7 +269,7 @@ static void smca_configure(unsigned int bank, unsigned int cpu) if (smca_banks[bank].hwid) return; - if (rdmsr_safe_on_cpu(cpu, MSR_AMD64_SMCA_MCx_IPID(bank), &low, &high)) { + if (rdmsr_safe(MSR_AMD64_SMCA_MCx_IPID(bank), &low, &high)) { pr_warn("Failed to read MCA_IPID for bank %d\n", bank); return; } -- cgit v1.2.3 From 966af20929ac24360ba3fac5533eb2ab003747da Mon Sep 17 00:00:00 2001 From: Yazen Ghannam Date: Thu, 21 Nov 2019 08:15:08 -0600 Subject: 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 Signed-off-by: Borislav Petkov Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: linux-edac Cc: Cc: Thomas Gleixner Cc: Tony Luck Cc: x86-ml 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(-) (limited to 'arch') diff --git a/arch/x86/kernel/cpu/mce/amd.c b/arch/x86/kernel/cpu/mce/amd.c index e41e3b40aa48..d6cf5c18a7e0 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)) { -- cgit v1.2.3 From a3a57ddad061acc90bef39635caf2b2330ce8f21 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Jan=20H=2E=20Sch=C3=B6nherr?= Date: Tue, 10 Dec 2019 01:07:30 +0100 Subject: x86/mce: Fix possibly incorrect severity calculation on AMD MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The function mce_severity_amd_smca() requires m->bank to be initialized for correct operation. Fix the one case, where mce_severity() is called without doing so. Fixes: 6bda529ec42e ("x86/mce: Grade uncorrected errors for SMCA-enabled systems") Fixes: d28af26faa0b ("x86/MCE: Initialize mce.bank in the case of a fatal error in mce_no_way_out()") Signed-off-by: Jan H. Schönherr Signed-off-by: Borislav Petkov Reviewed-by: Tony Luck Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: linux-edac Cc: Cc: Thomas Gleixner Cc: x86-ml Cc: Yazen Ghannam Link: https://lkml.kernel.org/r/20191210000733.17979-4-jschoenh@amazon.de --- arch/x86/kernel/cpu/mce/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch') diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c index 5f42f25bac8f..2e2a421c8528 100644 --- a/arch/x86/kernel/cpu/mce/core.c +++ b/arch/x86/kernel/cpu/mce/core.c @@ -819,8 +819,8 @@ static int mce_no_way_out(struct mce *m, char **msg, unsigned long *validp, if (quirk_no_way_out) quirk_no_way_out(i, m, regs); + m->bank = i; if (mce_severity(m, mca_cfg.tolerant, &tmp, true) >= MCE_PANIC_SEVERITY) { - m->bank = i; mce_read_aux(m, i); *msg = tmp; return 1; -- cgit v1.2.3