forked from rpms/kernel
180 lines
4.9 KiB
Diff
180 lines
4.9 KiB
Diff
From 15a76d02ad4df4dbe37ed5bda874deeba2659843 Mon Sep 17 00:00:00 2001
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From: Borislav Petkov <bp@suse.de>
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Date: Wed, 19 Oct 2022 18:13:06 +0200
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Subject: [PATCH 09/36] x86/microcode: Rip out the subsys interface gunk
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This is a left-over from the old days when CPU hotplug wasn't as robust
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as it is now. Currently, microcode gets loaded early on the CPU init
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path and there's no need to attempt to load it again, which that subsys
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interface callback is doing.
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The only other thing that the subsys interface init path was doing is
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adding the
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/sys/devices/system/cpu/cpu*/microcode/
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hierarchy.
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So add a function which gets called on each CPU after all the necessary
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driver setup has happened. Use schedule_on_each_cpu() which can block
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because the sysfs creating code does kmem_cache_zalloc() which can block
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too and the initial version of this where it did that setup in an IPI
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handler of on_each_cpu() can cause a deadlock of the sort:
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lock(fs_reclaim);
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<Interrupt>
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lock(fs_reclaim);
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as the IPI handler runs in IRQ context.
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Signed-off-by: Borislav Petkov <bp@suse.de>
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Reviewed-by: Ashok Raj <ashok.raj@intel.com>
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Link: https://lore.kernel.org/r/20221028142638.28498-2-bp@alien8.de
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(cherry picked from commit b6f86689d5b740f2cc3ac3a1032c7374b24381cc)
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Signed-off-by: Mridula Shastry <mridula.c.shastry@oracle.com>
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Reviewed-by: Todd Vierling <todd.vierling@oracle.com>
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---
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arch/x86/kernel/cpu/microcode/core.c | 82 +++++++---------------------
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1 file changed, 21 insertions(+), 61 deletions(-)
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diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
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index 6affa814699d..8a7fc5d8db6e 100644
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--- a/arch/x86/kernel/cpu/microcode/core.c
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+++ b/arch/x86/kernel/cpu/microcode/core.c
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@@ -621,8 +621,8 @@ static enum ucode_state microcode_resume_cpu(int cpu)
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static enum ucode_state microcode_init_cpu(int cpu, bool refresh_fw)
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{
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- enum ucode_state ustate;
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struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
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+ enum ucode_state ustate;
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if (uci->valid)
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return UCODE_OK;
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@@ -656,44 +656,6 @@ static enum ucode_state microcode_update_cpu(int cpu)
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return microcode_init_cpu(cpu, false);
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}
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-static int mc_device_add(struct device *dev, struct subsys_interface *sif)
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-{
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- int err, cpu = dev->id;
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-
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- if (!cpu_online(cpu))
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- return 0;
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-
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- pr_debug("CPU%d added\n", cpu);
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-
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- err = sysfs_create_group(&dev->kobj, &mc_attr_group);
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- if (err)
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- return err;
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-
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- if (microcode_init_cpu(cpu, true) == UCODE_ERROR)
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- return -EINVAL;
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-
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- return err;
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-}
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-
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-static void mc_device_remove(struct device *dev, struct subsys_interface *sif)
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-{
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- int cpu = dev->id;
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-
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- if (!cpu_online(cpu))
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- return;
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-
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- pr_debug("CPU%d removed\n", cpu);
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- microcode_fini_cpu(cpu);
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- sysfs_remove_group(&dev->kobj, &mc_attr_group);
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-}
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-
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-static struct subsys_interface mc_cpu_interface = {
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- .name = "microcode",
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- .subsys = &cpu_subsys,
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- .add_dev = mc_device_add,
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- .remove_dev = mc_device_remove,
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-};
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-
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/**
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* microcode_bsp_resume - Update boot CPU microcode during resume.
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*/
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@@ -733,6 +695,9 @@ static int mc_cpu_down_prep(unsigned int cpu)
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struct device *dev;
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dev = get_cpu_device(cpu);
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+
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+ microcode_fini_cpu(cpu);
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+
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/* Suspend is in progress, only remove the interface */
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sysfs_remove_group(&dev->kobj, &mc_attr_group);
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pr_debug("CPU%d removed\n", cpu);
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@@ -740,6 +705,18 @@ static int mc_cpu_down_prep(unsigned int cpu)
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return 0;
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}
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+static void setup_online_cpu(struct work_struct *work)
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+{
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+ int cpu = smp_processor_id();
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+ struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
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+
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+ memset(uci, 0, sizeof(*uci));
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+
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+ microcode_ops->collect_cpu_info(cpu, &uci->cpu_sig);
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+
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+ mc_cpu_online(cpu);
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+}
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+
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static struct attribute *cpu_root_microcode_attrs[] = {
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#ifdef CONFIG_MICROCODE_LATE_LOADING
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&dev_attr_reload.attr,
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@@ -771,27 +748,19 @@ int __init microcode_init(void)
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return -ENODEV;
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microcode_pdev = platform_device_register_simple("microcode", -1,
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- NULL, 0);
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- if (IS_ERR(microcode_pdev))
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- return PTR_ERR(microcode_pdev);
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-
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- get_online_cpus();
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- mutex_lock(µcode_mutex);
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- error = subsys_interface_register(&mc_cpu_interface);
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- mutex_unlock(µcode_mutex);
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- put_online_cpus();
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-
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- if (error)
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- goto out_pdev;
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+ NULL, 0);
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error = sysfs_create_group(&cpu_subsys.dev_root->kobj,
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&cpu_root_microcode_group);
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if (error) {
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pr_err("Error creating microcode group!\n");
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- goto out_driver;
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+ goto out_pdev;
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}
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+ /* Do per-CPU setup */
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+ schedule_on_each_cpu(setup_online_cpu);
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+
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register_syscore_ops(&mc_syscore_ops);
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cpuhp_setup_state_nocalls(CPUHP_AP_MICROCODE_LOADER, "x86/microcode:starting",
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mc_cpu_starting, NULL);
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@@ -802,15 +771,6 @@ int __init microcode_init(void)
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return 0;
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- out_driver:
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- get_online_cpus();
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- mutex_lock(µcode_mutex);
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-
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- subsys_interface_unregister(&mc_cpu_interface);
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-
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- mutex_unlock(µcode_mutex);
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- put_online_cpus();
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-
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out_pdev:
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platform_device_unregister(microcode_pdev);
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return error;
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--
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2.39.3
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