The following commit has been merged into the ras/core branch of tip: Commit-ID: 6e7a41c63abcfee28734c4c8872dae8d642329b6 Gitweb: https://git.kernel.org/tip/6e7a41c63abcfee28734c4c8872dae8d642329b6 Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx> AuthorDate: Mon, 30 Mar 2020 16:21:54 +02:00 Committer: Borislav Petkov <bp@xxxxxxx> CommitterDate: Tue, 14 Apr 2020 15:48:30 +02:00 x86/mce/amd: Sanitize thresholding device creation hotplug path Drop the stupid threshold_init_device() initcall iterating over all online CPUs in favor of properly setting up everything on the CPU hotplug path, when each CPU's callback is invoked. [ bp: Write commit message. ] Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Signed-off-by: Borislav Petkov <bp@xxxxxxx> Link: https://lkml.kernel.org/r/20200403161943.1458-5-bp@xxxxxxxxx --- arch/x86/kernel/cpu/mce/amd.c | 57 +++++++++------------------------ arch/x86/kernel/cpu/mce/core.c | 11 ++++++- 2 files changed, 27 insertions(+), 41 deletions(-) diff --git a/arch/x86/kernel/cpu/mce/amd.c b/arch/x86/kernel/cpu/mce/amd.c index 5639421..d3c416b 100644 --- a/arch/x86/kernel/cpu/mce/amd.c +++ b/arch/x86/kernel/cpu/mce/amd.c @@ -1474,12 +1474,22 @@ int mce_threshold_remove_device(unsigned int cpu) return 0; } -/* create dir/files for all valid threshold banks */ +/** + * mce_threshold_create_device - Create the per-CPU MCE threshold device + * @cpu: The plugged in CPU + * + * Create directories and files for all valid threshold banks. + * + * This is invoked from the CPU hotplug callback which was installed in + * mcheck_init_device(). The invocation happens in context of the hotplug + * thread running on @cpu. The callback is invoked on all CPUs which are + * online when the callback is installed or during a real hotplug event. + */ int mce_threshold_create_device(unsigned int cpu) { unsigned int bank; struct threshold_bank **bp; - int err = 0; + int err; if (!mce_flags.amd_threshold) return 0; @@ -1500,49 +1510,14 @@ int mce_threshold_create_device(unsigned int cpu) continue; err = threshold_create_bank(cpu, bank); if (err) - goto err; - } - return err; -err: - mce_threshold_remove_device(cpu); - return err; -} - -static __init int threshold_init_device(void) -{ - unsigned lcpu = 0; - - /* to hit CPUs online before the notifier is up */ - for_each_online_cpu(lcpu) { - int err = mce_threshold_create_device(lcpu); - - if (err) - return err; + goto out_err; } if (thresholding_irq_en) mce_threshold_vector = amd_threshold_interrupt; return 0; +out_err: + mce_threshold_remove_device(cpu); + return err; } -/* - * there are 3 funcs which need to be _initcalled in a logic sequence: - * 1. xen_late_init_mcelog - * 2. mcheck_init_device - * 3. threshold_init_device - * - * xen_late_init_mcelog must register xen_mce_chrdev_device before - * native mce_chrdev_device registration if running under xen platform; - * - * mcheck_init_device should be inited before threshold_init_device to - * initialize mce_device, otherwise a NULL ptr dereference will cause panic. - * - * so we use following _initcalls - * 1. device_initcall(xen_late_init_mcelog); - * 2. device_initcall_sync(mcheck_init_device); - * 3. late_initcall(threshold_init_device); - * - * when running under xen, the initcall order is 1,2,3; - * on baremetal, we skip 1 and we do only 2 and 3. - */ -late_initcall(threshold_init_device); diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c index 43ca91e..a6009ef 100644 --- a/arch/x86/kernel/cpu/mce/core.c +++ b/arch/x86/kernel/cpu/mce/core.c @@ -2481,6 +2481,13 @@ static __init void mce_init_banks(void) } } +/* + * When running on XEN, this initcall is ordered against the XEN mcelog + * initcall: + * + * device_initcall(xen_late_init_mcelog); + * device_initcall_sync(mcheck_init_device); + */ static __init int mcheck_init_device(void) { int err; @@ -2512,6 +2519,10 @@ static __init int mcheck_init_device(void) if (err) goto err_out_mem; + /* + * Invokes mce_cpu_online() on all CPUs which are online when + * the state is installed. + */ err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/mce:online", mce_cpu_online, mce_cpu_pre_down); if (err < 0)
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