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2fb08b672e
commit 8076fcde01 upstream.
RFDS is a CPU vulnerability that may allow userspace to infer kernel
stale data previously used in floating point registers, vector registers
and integer registers. RFDS only affects certain Intel Atom processors.
Intel released a microcode update that uses VERW instruction to clear
the affected CPU buffers. Unlike MDS, none of the affected cores support
SMT.
Add RFDS bug infrastructure and enable the VERW based mitigation by
default, that clears the affected buffers just before exiting to
userspace. Also add sysfs reporting and cmdline parameter
"reg_file_data_sampling" to control the mitigation.
For details see:
Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst
[ pawan: - Resolved conflicts in sysfs reporting.
- s/ATOM_GRACEMONT/ALDERLAKE_N/ATOM_GRACEMONT is called
ALDERLAKE_N in 6.6. ]
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
247 lines
8 KiB
C
247 lines
8 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* include/linux/cpu.h - generic cpu definition
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*
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* This is mainly for topological representation. We define the
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* basic 'struct cpu' here, which can be embedded in per-arch
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* definitions of processors.
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*
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* Basic handling of the devices is done in drivers/base/cpu.c
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*
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* CPUs are exported via sysfs in the devices/system/cpu
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* directory.
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*/
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#ifndef _LINUX_CPU_H_
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#define _LINUX_CPU_H_
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#include <linux/node.h>
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#include <linux/compiler.h>
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#include <linux/cpumask.h>
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#include <linux/cpuhotplug.h>
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struct device;
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struct device_node;
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struct attribute_group;
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struct cpu {
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int node_id; /* The node which contains the CPU */
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int hotpluggable; /* creates sysfs control file if hotpluggable */
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struct device dev;
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};
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extern void boot_cpu_init(void);
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extern void boot_cpu_hotplug_init(void);
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extern void cpu_init(void);
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extern void trap_init(void);
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extern int register_cpu(struct cpu *cpu, int num);
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extern struct device *get_cpu_device(unsigned cpu);
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extern bool cpu_is_hotpluggable(unsigned cpu);
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extern bool arch_match_cpu_phys_id(int cpu, u64 phys_id);
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extern bool arch_find_n_match_cpu_physical_id(struct device_node *cpun,
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int cpu, unsigned int *thread);
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extern int cpu_add_dev_attr(struct device_attribute *attr);
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extern void cpu_remove_dev_attr(struct device_attribute *attr);
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extern int cpu_add_dev_attr_group(struct attribute_group *attrs);
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extern void cpu_remove_dev_attr_group(struct attribute_group *attrs);
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extern ssize_t cpu_show_meltdown(struct device *dev,
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struct device_attribute *attr, char *buf);
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extern ssize_t cpu_show_spectre_v1(struct device *dev,
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struct device_attribute *attr, char *buf);
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extern ssize_t cpu_show_spectre_v2(struct device *dev,
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struct device_attribute *attr, char *buf);
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extern ssize_t cpu_show_spec_store_bypass(struct device *dev,
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struct device_attribute *attr, char *buf);
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extern ssize_t cpu_show_l1tf(struct device *dev,
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struct device_attribute *attr, char *buf);
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extern ssize_t cpu_show_mds(struct device *dev,
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struct device_attribute *attr, char *buf);
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extern ssize_t cpu_show_tsx_async_abort(struct device *dev,
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struct device_attribute *attr,
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char *buf);
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extern ssize_t cpu_show_itlb_multihit(struct device *dev,
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struct device_attribute *attr, char *buf);
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extern ssize_t cpu_show_srbds(struct device *dev, struct device_attribute *attr, char *buf);
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extern ssize_t cpu_show_mmio_stale_data(struct device *dev,
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struct device_attribute *attr,
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char *buf);
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extern ssize_t cpu_show_retbleed(struct device *dev,
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struct device_attribute *attr, char *buf);
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extern ssize_t cpu_show_spec_rstack_overflow(struct device *dev,
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struct device_attribute *attr, char *buf);
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extern ssize_t cpu_show_gds(struct device *dev,
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struct device_attribute *attr, char *buf);
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extern ssize_t cpu_show_reg_file_data_sampling(struct device *dev,
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struct device_attribute *attr, char *buf);
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extern __printf(4, 5)
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struct device *cpu_device_create(struct device *parent, void *drvdata,
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const struct attribute_group **groups,
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const char *fmt, ...);
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#ifdef CONFIG_HOTPLUG_CPU
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extern void unregister_cpu(struct cpu *cpu);
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extern ssize_t arch_cpu_probe(const char *, size_t);
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extern ssize_t arch_cpu_release(const char *, size_t);
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#endif
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/*
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* These states are not related to the core CPU hotplug mechanism. They are
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* used by various (sub)architectures to track internal state
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*/
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#define CPU_ONLINE 0x0002 /* CPU is up */
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#define CPU_UP_PREPARE 0x0003 /* CPU coming up */
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#define CPU_DEAD 0x0007 /* CPU dead */
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#define CPU_DEAD_FROZEN 0x0008 /* CPU timed out on unplug */
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#define CPU_POST_DEAD 0x0009 /* CPU successfully unplugged */
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#define CPU_BROKEN 0x000B /* CPU did not die properly */
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#ifdef CONFIG_SMP
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extern bool cpuhp_tasks_frozen;
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int add_cpu(unsigned int cpu);
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int cpu_device_up(struct device *dev);
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void notify_cpu_starting(unsigned int cpu);
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extern void cpu_maps_update_begin(void);
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extern void cpu_maps_update_done(void);
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int bringup_hibernate_cpu(unsigned int sleep_cpu);
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void bringup_nonboot_cpus(unsigned int setup_max_cpus);
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#else /* CONFIG_SMP */
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#define cpuhp_tasks_frozen 0
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static inline void cpu_maps_update_begin(void)
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{
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}
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static inline void cpu_maps_update_done(void)
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{
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}
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static inline int add_cpu(unsigned int cpu) { return 0;}
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#endif /* CONFIG_SMP */
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extern struct bus_type cpu_subsys;
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extern int lockdep_is_cpus_held(void);
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#ifdef CONFIG_HOTPLUG_CPU
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extern void cpus_write_lock(void);
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extern void cpus_write_unlock(void);
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extern void cpus_read_lock(void);
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extern void cpus_read_unlock(void);
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extern int cpus_read_trylock(void);
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extern void lockdep_assert_cpus_held(void);
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extern void cpu_hotplug_disable(void);
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extern void cpu_hotplug_enable(void);
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void clear_tasks_mm_cpumask(int cpu);
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int remove_cpu(unsigned int cpu);
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int cpu_device_down(struct device *dev);
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extern void smp_shutdown_nonboot_cpus(unsigned int primary_cpu);
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#else /* CONFIG_HOTPLUG_CPU */
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static inline void cpus_write_lock(void) { }
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static inline void cpus_write_unlock(void) { }
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static inline void cpus_read_lock(void) { }
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static inline void cpus_read_unlock(void) { }
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static inline int cpus_read_trylock(void) { return true; }
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static inline void lockdep_assert_cpus_held(void) { }
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static inline void cpu_hotplug_disable(void) { }
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static inline void cpu_hotplug_enable(void) { }
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static inline int remove_cpu(unsigned int cpu) { return -EPERM; }
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static inline void smp_shutdown_nonboot_cpus(unsigned int primary_cpu) { }
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#endif /* !CONFIG_HOTPLUG_CPU */
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#ifdef CONFIG_PM_SLEEP_SMP
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extern int freeze_secondary_cpus(int primary);
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extern void thaw_secondary_cpus(void);
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static inline int suspend_disable_secondary_cpus(void)
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{
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int cpu = 0;
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if (IS_ENABLED(CONFIG_PM_SLEEP_SMP_NONZERO_CPU))
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cpu = -1;
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return freeze_secondary_cpus(cpu);
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}
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static inline void suspend_enable_secondary_cpus(void)
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{
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return thaw_secondary_cpus();
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}
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#else /* !CONFIG_PM_SLEEP_SMP */
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static inline void thaw_secondary_cpus(void) {}
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static inline int suspend_disable_secondary_cpus(void) { return 0; }
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static inline void suspend_enable_secondary_cpus(void) { }
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#endif /* !CONFIG_PM_SLEEP_SMP */
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void cpu_startup_entry(enum cpuhp_state state);
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void cpu_idle_poll_ctrl(bool enable);
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/* Attach to any functions which should be considered cpuidle. */
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#define __cpuidle __section(".cpuidle.text")
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bool cpu_in_idle(unsigned long pc);
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void arch_cpu_idle(void);
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void arch_cpu_idle_prepare(void);
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void arch_cpu_idle_enter(void);
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void arch_cpu_idle_exit(void);
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void arch_cpu_idle_dead(void);
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#ifdef CONFIG_ARCH_HAS_CPU_FINALIZE_INIT
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void arch_cpu_finalize_init(void);
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#else
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static inline void arch_cpu_finalize_init(void) { }
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#endif
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int cpu_report_state(int cpu);
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int cpu_check_up_prepare(int cpu);
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void cpu_set_state_online(int cpu);
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void play_idle_precise(u64 duration_ns, u64 latency_ns);
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static inline void play_idle(unsigned long duration_us)
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{
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play_idle_precise(duration_us * NSEC_PER_USEC, U64_MAX);
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}
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#ifdef CONFIG_HOTPLUG_CPU
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bool cpu_wait_death(unsigned int cpu, int seconds);
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bool cpu_report_death(void);
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void cpuhp_report_idle_dead(void);
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#else
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static inline void cpuhp_report_idle_dead(void) { }
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#endif /* #ifdef CONFIG_HOTPLUG_CPU */
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enum cpuhp_smt_control {
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CPU_SMT_ENABLED,
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CPU_SMT_DISABLED,
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CPU_SMT_FORCE_DISABLED,
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CPU_SMT_NOT_SUPPORTED,
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CPU_SMT_NOT_IMPLEMENTED,
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};
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#if defined(CONFIG_SMP) && defined(CONFIG_HOTPLUG_SMT)
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extern enum cpuhp_smt_control cpu_smt_control;
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extern void cpu_smt_disable(bool force);
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extern void cpu_smt_check_topology(void);
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extern bool cpu_smt_possible(void);
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extern int cpuhp_smt_enable(void);
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extern int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval);
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#else
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# define cpu_smt_control (CPU_SMT_NOT_IMPLEMENTED)
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static inline void cpu_smt_disable(bool force) { }
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static inline void cpu_smt_check_topology(void) { }
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static inline bool cpu_smt_possible(void) { return false; }
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static inline int cpuhp_smt_enable(void) { return 0; }
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static inline int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval) { return 0; }
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#endif
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extern bool cpu_mitigations_off(void);
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extern bool cpu_mitigations_auto_nosmt(void);
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#endif /* _LINUX_CPU_H_ */
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