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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
commit | ace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch) | |
tree | b2d64bc10158fdd5497876388cd68142ca374ed3 /arch/x86/kernel/cpu/microcode/core.c | |
parent | Initial commit. (diff) | |
download | linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip |
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/x86/kernel/cpu/microcode/core.c')
-rw-r--r-- | arch/x86/kernel/cpu/microcode/core.c | 684 |
1 files changed, 684 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c new file mode 100644 index 0000000000..a4ebd5e0ae --- /dev/null +++ b/arch/x86/kernel/cpu/microcode/core.c @@ -0,0 +1,684 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * CPU Microcode Update Driver for Linux + * + * Copyright (C) 2000-2006 Tigran Aivazian <aivazian.tigran@gmail.com> + * 2006 Shaohua Li <shaohua.li@intel.com> + * 2013-2016 Borislav Petkov <bp@alien8.de> + * + * X86 CPU microcode early update for Linux: + * + * Copyright (C) 2012 Fenghua Yu <fenghua.yu@intel.com> + * H Peter Anvin" <hpa@zytor.com> + * (C) 2015 Borislav Petkov <bp@alien8.de> + * + * This driver allows to upgrade microcode on x86 processors. + */ + +#define pr_fmt(fmt) "microcode: " fmt + +#include <linux/platform_device.h> +#include <linux/stop_machine.h> +#include <linux/syscore_ops.h> +#include <linux/miscdevice.h> +#include <linux/capability.h> +#include <linux/firmware.h> +#include <linux/kernel.h> +#include <linux/delay.h> +#include <linux/mutex.h> +#include <linux/cpu.h> +#include <linux/nmi.h> +#include <linux/fs.h> +#include <linux/mm.h> + +#include <asm/cpu_device_id.h> +#include <asm/perf_event.h> +#include <asm/processor.h> +#include <asm/cmdline.h> +#include <asm/setup.h> + +#include "internal.h" + +#define DRIVER_VERSION "2.2" + +static struct microcode_ops *microcode_ops; +static bool dis_ucode_ldr = true; + +bool initrd_gone; + +LIST_HEAD(microcode_cache); + +/* + * Synchronization. + * + * All non cpu-hotplug-callback call sites use: + * + * - cpus_read_lock/unlock() to synchronize with + * the cpu-hotplug-callback call sites. + * + * We guarantee that only a single cpu is being + * updated at any particular moment of time. + */ +struct ucode_cpu_info ucode_cpu_info[NR_CPUS]; + +struct cpu_info_ctx { + struct cpu_signature *cpu_sig; + int err; +}; + +/* + * Those patch levels cannot be updated to newer ones and thus should be final. + */ +static u32 final_levels[] = { + 0x01000098, + 0x0100009f, + 0x010000af, + 0, /* T-101 terminator */ +}; + +/* + * Check the current patch level on this CPU. + * + * Returns: + * - true: if update should stop + * - false: otherwise + */ +static bool amd_check_current_patch_level(void) +{ + u32 lvl, dummy, i; + u32 *levels; + + native_rdmsr(MSR_AMD64_PATCH_LEVEL, lvl, dummy); + + if (IS_ENABLED(CONFIG_X86_32)) + levels = (u32 *)__pa_nodebug(&final_levels); + else + levels = final_levels; + + for (i = 0; levels[i]; i++) { + if (lvl == levels[i]) + return true; + } + return false; +} + +static bool __init check_loader_disabled_bsp(void) +{ + static const char *__dis_opt_str = "dis_ucode_ldr"; + +#ifdef CONFIG_X86_32 + const char *cmdline = (const char *)__pa_nodebug(boot_command_line); + const char *option = (const char *)__pa_nodebug(__dis_opt_str); + bool *res = (bool *)__pa_nodebug(&dis_ucode_ldr); + +#else /* CONFIG_X86_64 */ + const char *cmdline = boot_command_line; + const char *option = __dis_opt_str; + bool *res = &dis_ucode_ldr; +#endif + + /* + * CPUID(1).ECX[31]: reserved for hypervisor use. This is still not + * completely accurate as xen pv guests don't see that CPUID bit set but + * that's good enough as they don't land on the BSP path anyway. + */ + if (native_cpuid_ecx(1) & BIT(31)) + return *res; + + if (x86_cpuid_vendor() == X86_VENDOR_AMD) { + if (amd_check_current_patch_level()) + return *res; + } + + if (cmdline_find_option_bool(cmdline, option) <= 0) + *res = false; + + return *res; +} + +void __init load_ucode_bsp(void) +{ + unsigned int cpuid_1_eax; + bool intel = true; + + if (!have_cpuid_p()) + return; + + cpuid_1_eax = native_cpuid_eax(1); + + switch (x86_cpuid_vendor()) { + case X86_VENDOR_INTEL: + if (x86_family(cpuid_1_eax) < 6) + return; + break; + + case X86_VENDOR_AMD: + if (x86_family(cpuid_1_eax) < 0x10) + return; + intel = false; + break; + + default: + return; + } + + if (check_loader_disabled_bsp()) + return; + + if (intel) + load_ucode_intel_bsp(); + else + load_ucode_amd_early(cpuid_1_eax); +} + +static bool check_loader_disabled_ap(void) +{ +#ifdef CONFIG_X86_32 + return *((bool *)__pa_nodebug(&dis_ucode_ldr)); +#else + return dis_ucode_ldr; +#endif +} + +void load_ucode_ap(void) +{ + unsigned int cpuid_1_eax; + + if (check_loader_disabled_ap()) + return; + + cpuid_1_eax = native_cpuid_eax(1); + + switch (x86_cpuid_vendor()) { + case X86_VENDOR_INTEL: + if (x86_family(cpuid_1_eax) >= 6) + load_ucode_intel_ap(); + break; + case X86_VENDOR_AMD: + if (x86_family(cpuid_1_eax) >= 0x10) + load_ucode_amd_early(cpuid_1_eax); + break; + default: + break; + } +} + +static int __init save_microcode_in_initrd(void) +{ + struct cpuinfo_x86 *c = &boot_cpu_data; + int ret = -EINVAL; + + if (dis_ucode_ldr) { + ret = 0; + goto out; + } + + switch (c->x86_vendor) { + case X86_VENDOR_INTEL: + if (c->x86 >= 6) + ret = save_microcode_in_initrd_intel(); + break; + case X86_VENDOR_AMD: + if (c->x86 >= 0x10) + ret = save_microcode_in_initrd_amd(cpuid_eax(1)); + break; + default: + break; + } + +out: + initrd_gone = true; + + return ret; +} + +struct cpio_data find_microcode_in_initrd(const char *path, bool use_pa) +{ +#ifdef CONFIG_BLK_DEV_INITRD + unsigned long start = 0; + size_t size; + +#ifdef CONFIG_X86_32 + struct boot_params *params; + + if (use_pa) + params = (struct boot_params *)__pa_nodebug(&boot_params); + else + params = &boot_params; + + size = params->hdr.ramdisk_size; + + /* + * Set start only if we have an initrd image. We cannot use initrd_start + * because it is not set that early yet. + */ + if (size) + start = params->hdr.ramdisk_image; + +# else /* CONFIG_X86_64 */ + size = (unsigned long)boot_params.ext_ramdisk_size << 32; + size |= boot_params.hdr.ramdisk_size; + + if (size) { + start = (unsigned long)boot_params.ext_ramdisk_image << 32; + start |= boot_params.hdr.ramdisk_image; + + start += PAGE_OFFSET; + } +# endif + + /* + * Fixup the start address: after reserve_initrd() runs, initrd_start + * has the virtual address of the beginning of the initrd. It also + * possibly relocates the ramdisk. In either case, initrd_start contains + * the updated address so use that instead. + * + * initrd_gone is for the hotplug case where we've thrown out initrd + * already. + */ + if (!use_pa) { + if (initrd_gone) + return (struct cpio_data){ NULL, 0, "" }; + if (initrd_start) + start = initrd_start; + } else { + /* + * The picture with physical addresses is a bit different: we + * need to get the *physical* address to which the ramdisk was + * relocated, i.e., relocated_ramdisk (not initrd_start) and + * since we're running from physical addresses, we need to access + * relocated_ramdisk through its *physical* address too. + */ + u64 *rr = (u64 *)__pa_nodebug(&relocated_ramdisk); + if (*rr) + start = *rr; + } + + return find_cpio_data(path, (void *)start, size, NULL); +#else /* !CONFIG_BLK_DEV_INITRD */ + return (struct cpio_data){ NULL, 0, "" }; +#endif +} + +static void reload_early_microcode(unsigned int cpu) +{ + int vendor, family; + + vendor = x86_cpuid_vendor(); + family = x86_cpuid_family(); + + switch (vendor) { + case X86_VENDOR_INTEL: + if (family >= 6) + reload_ucode_intel(); + break; + case X86_VENDOR_AMD: + if (family >= 0x10) + reload_ucode_amd(cpu); + break; + default: + break; + } +} + +/* fake device for request_firmware */ +static struct platform_device *microcode_pdev; + +#ifdef CONFIG_MICROCODE_LATE_LOADING +/* + * Late loading dance. Why the heavy-handed stomp_machine effort? + * + * - HT siblings must be idle and not execute other code while the other sibling + * is loading microcode in order to avoid any negative interactions caused by + * the loading. + * + * - In addition, microcode update on the cores must be serialized until this + * requirement can be relaxed in the future. Right now, this is conservative + * and good. + */ +#define SPINUNIT 100 /* 100 nsec */ + +static int check_online_cpus(void) +{ + unsigned int cpu; + + /* + * Make sure all CPUs are online. It's fine for SMT to be disabled if + * all the primary threads are still online. + */ + for_each_present_cpu(cpu) { + if (topology_is_primary_thread(cpu) && !cpu_online(cpu)) { + pr_err("Not all CPUs online, aborting microcode update.\n"); + return -EINVAL; + } + } + + return 0; +} + +static atomic_t late_cpus_in; +static atomic_t late_cpus_out; + +static int __wait_for_cpus(atomic_t *t, long long timeout) +{ + int all_cpus = num_online_cpus(); + + atomic_inc(t); + + while (atomic_read(t) < all_cpus) { + if (timeout < SPINUNIT) { + pr_err("Timeout while waiting for CPUs rendezvous, remaining: %d\n", + all_cpus - atomic_read(t)); + return 1; + } + + ndelay(SPINUNIT); + timeout -= SPINUNIT; + + touch_nmi_watchdog(); + } + return 0; +} + +/* + * Returns: + * < 0 - on error + * 0 - success (no update done or microcode was updated) + */ +static int __reload_late(void *info) +{ + int cpu = smp_processor_id(); + enum ucode_state err; + int ret = 0; + + /* + * Wait for all CPUs to arrive. A load will not be attempted unless all + * CPUs show up. + * */ + if (__wait_for_cpus(&late_cpus_in, NSEC_PER_SEC)) + return -1; + + /* + * On an SMT system, it suffices to load the microcode on one sibling of + * the core because the microcode engine is shared between the threads. + * Synchronization still needs to take place so that no concurrent + * loading attempts happen on multiple threads of an SMT core. See + * below. + */ + if (cpumask_first(topology_sibling_cpumask(cpu)) == cpu) + err = microcode_ops->apply_microcode(cpu); + else + goto wait_for_siblings; + + if (err >= UCODE_NFOUND) { + if (err == UCODE_ERROR) { + pr_warn("Error reloading microcode on CPU %d\n", cpu); + ret = -1; + } + } + +wait_for_siblings: + if (__wait_for_cpus(&late_cpus_out, NSEC_PER_SEC)) + panic("Timeout during microcode update!\n"); + + /* + * At least one thread has completed update on each core. + * For others, simply call the update to make sure the + * per-cpu cpuinfo can be updated with right microcode + * revision. + */ + if (cpumask_first(topology_sibling_cpumask(cpu)) != cpu) + err = microcode_ops->apply_microcode(cpu); + + return ret; +} + +/* + * Reload microcode late on all CPUs. Wait for a sec until they + * all gather together. + */ +static int microcode_reload_late(void) +{ + int old = boot_cpu_data.microcode, ret; + struct cpuinfo_x86 prev_info; + + pr_err("Attempting late microcode loading - it is dangerous and taints the kernel.\n"); + pr_err("You should switch to early loading, if possible.\n"); + + atomic_set(&late_cpus_in, 0); + atomic_set(&late_cpus_out, 0); + + /* + * Take a snapshot before the microcode update in order to compare and + * check whether any bits changed after an update. + */ + store_cpu_caps(&prev_info); + + ret = stop_machine_cpuslocked(__reload_late, NULL, cpu_online_mask); + if (!ret) { + pr_info("Reload succeeded, microcode revision: 0x%x -> 0x%x\n", + old, boot_cpu_data.microcode); + microcode_check(&prev_info); + } else { + pr_info("Reload failed, current microcode revision: 0x%x\n", + boot_cpu_data.microcode); + } + + return ret; +} + +static ssize_t reload_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t size) +{ + enum ucode_state tmp_ret = UCODE_OK; + int bsp = boot_cpu_data.cpu_index; + unsigned long val; + ssize_t ret = 0; + + ret = kstrtoul(buf, 0, &val); + if (ret || val != 1) + return -EINVAL; + + cpus_read_lock(); + + ret = check_online_cpus(); + if (ret) + goto put; + + tmp_ret = microcode_ops->request_microcode_fw(bsp, µcode_pdev->dev); + if (tmp_ret != UCODE_NEW) + goto put; + + ret = microcode_reload_late(); +put: + cpus_read_unlock(); + + if (ret == 0) + ret = size; + + add_taint(TAINT_CPU_OUT_OF_SPEC, LOCKDEP_STILL_OK); + + return ret; +} + +static DEVICE_ATTR_WO(reload); +#endif + +static ssize_t version_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct ucode_cpu_info *uci = ucode_cpu_info + dev->id; + + return sprintf(buf, "0x%x\n", uci->cpu_sig.rev); +} + +static ssize_t processor_flags_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct ucode_cpu_info *uci = ucode_cpu_info + dev->id; + + return sprintf(buf, "0x%x\n", uci->cpu_sig.pf); +} + +static DEVICE_ATTR_RO(version); +static DEVICE_ATTR_RO(processor_flags); + +static struct attribute *mc_default_attrs[] = { + &dev_attr_version.attr, + &dev_attr_processor_flags.attr, + NULL +}; + +static const struct attribute_group mc_attr_group = { + .attrs = mc_default_attrs, + .name = "microcode", +}; + +static void microcode_fini_cpu(int cpu) +{ + if (microcode_ops->microcode_fini_cpu) + microcode_ops->microcode_fini_cpu(cpu); +} + +static enum ucode_state microcode_init_cpu(int cpu) +{ + struct ucode_cpu_info *uci = ucode_cpu_info + cpu; + + memset(uci, 0, sizeof(*uci)); + + microcode_ops->collect_cpu_info(cpu, &uci->cpu_sig); + + return microcode_ops->apply_microcode(cpu); +} + +/** + * microcode_bsp_resume - Update boot CPU microcode during resume. + */ +void microcode_bsp_resume(void) +{ + int cpu = smp_processor_id(); + struct ucode_cpu_info *uci = ucode_cpu_info + cpu; + + if (uci->mc) + microcode_ops->apply_microcode(cpu); + else + reload_early_microcode(cpu); +} + +static struct syscore_ops mc_syscore_ops = { + .resume = microcode_bsp_resume, +}; + +static int mc_cpu_starting(unsigned int cpu) +{ + enum ucode_state err = microcode_ops->apply_microcode(cpu); + + pr_debug("%s: CPU%d, err: %d\n", __func__, cpu, err); + + return err == UCODE_ERROR; +} + +static int mc_cpu_online(unsigned int cpu) +{ + struct device *dev = get_cpu_device(cpu); + + if (sysfs_create_group(&dev->kobj, &mc_attr_group)) + pr_err("Failed to create group for CPU%d\n", cpu); + return 0; +} + +static int mc_cpu_down_prep(unsigned int cpu) +{ + struct device *dev; + + dev = get_cpu_device(cpu); + + microcode_fini_cpu(cpu); + + /* Suspend is in progress, only remove the interface */ + sysfs_remove_group(&dev->kobj, &mc_attr_group); + pr_debug("%s: CPU%d\n", __func__, cpu); + + return 0; +} + +static void setup_online_cpu(struct work_struct *work) +{ + int cpu = smp_processor_id(); + enum ucode_state err; + + err = microcode_init_cpu(cpu); + if (err == UCODE_ERROR) { + pr_err("Error applying microcode on CPU%d\n", cpu); + return; + } + + mc_cpu_online(cpu); +} + +static struct attribute *cpu_root_microcode_attrs[] = { +#ifdef CONFIG_MICROCODE_LATE_LOADING + &dev_attr_reload.attr, +#endif + NULL +}; + +static const struct attribute_group cpu_root_microcode_group = { + .name = "microcode", + .attrs = cpu_root_microcode_attrs, +}; + +static int __init microcode_init(void) +{ + struct device *dev_root; + struct cpuinfo_x86 *c = &boot_cpu_data; + int error; + + if (dis_ucode_ldr) + return -EINVAL; + + if (c->x86_vendor == X86_VENDOR_INTEL) + microcode_ops = init_intel_microcode(); + else if (c->x86_vendor == X86_VENDOR_AMD) + microcode_ops = init_amd_microcode(); + else + pr_err("no support for this CPU vendor\n"); + + if (!microcode_ops) + return -ENODEV; + + microcode_pdev = platform_device_register_simple("microcode", -1, NULL, 0); + if (IS_ERR(microcode_pdev)) + return PTR_ERR(microcode_pdev); + + dev_root = bus_get_dev_root(&cpu_subsys); + if (dev_root) { + error = sysfs_create_group(&dev_root->kobj, &cpu_root_microcode_group); + put_device(dev_root); + if (error) { + pr_err("Error creating microcode group!\n"); + goto out_pdev; + } + } + + /* Do per-CPU setup */ + schedule_on_each_cpu(setup_online_cpu); + + register_syscore_ops(&mc_syscore_ops); + cpuhp_setup_state_nocalls(CPUHP_AP_MICROCODE_LOADER, "x86/microcode:starting", + mc_cpu_starting, NULL); + cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "x86/microcode:online", + mc_cpu_online, mc_cpu_down_prep); + + pr_info("Microcode Update Driver: v%s.", DRIVER_VERSION); + + return 0; + + out_pdev: + platform_device_unregister(microcode_pdev); + return error; + +} +fs_initcall(save_microcode_in_initrd); +late_initcall(microcode_init); |