linux-yocto/arch/x86/include/asm/smp.h
Thomas Gleixner 0af4750eaa x86/smp: Cure kexec() vs. mwait_play_dead() breakage
commit d7893093a7 upstream.

TLDR: It's a mess.

When kexec() is executed on a system with offline CPUs, which are parked in
mwait_play_dead() it can end up in a triple fault during the bootup of the
kexec kernel or cause hard to diagnose data corruption.

The reason is that kexec() eventually overwrites the previous kernel's text,
page tables, data and stack. If it writes to the cache line which is
monitored by a previously offlined CPU, MWAIT resumes execution and ends
up executing the wrong text, dereferencing overwritten page tables or
corrupting the kexec kernels data.

Cure this by bringing the offlined CPUs out of MWAIT into HLT.

Write to the monitored cache line of each offline CPU, which makes MWAIT
resume execution. The written control word tells the offlined CPUs to issue
HLT, which does not have the MWAIT problem.

That does not help, if a stray NMI, MCE or SMI hits the offlined CPUs as
those make it come out of HLT.

A follow up change will put them into INIT, which protects at least against
NMI and SMI.

Fixes: ea53069231 ("x86, hotplug: Use mwait to offline a processor, fix the legacy case")
Reported-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Ashok Raj <ashok.raj@intel.com>
Reviewed-by: Ashok Raj <ashok.raj@intel.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20230615193330.492257119@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-01 13:16:23 +02:00

208 lines
5.3 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_X86_SMP_H
#define _ASM_X86_SMP_H
#ifndef __ASSEMBLY__
#include <linux/cpumask.h>
#include <asm/percpu.h>
#include <asm/thread_info.h>
#include <asm/cpumask.h>
extern int smp_num_siblings;
extern unsigned int num_processors;
DECLARE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_sibling_map);
DECLARE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_core_map);
DECLARE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_die_map);
/* cpus sharing the last level cache: */
DECLARE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_llc_shared_map);
DECLARE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_l2c_shared_map);
DECLARE_PER_CPU_READ_MOSTLY(u16, cpu_llc_id);
DECLARE_PER_CPU_READ_MOSTLY(u16, cpu_l2c_id);
DECLARE_PER_CPU_READ_MOSTLY(int, cpu_number);
DECLARE_EARLY_PER_CPU_READ_MOSTLY(u16, x86_cpu_to_apicid);
DECLARE_EARLY_PER_CPU_READ_MOSTLY(u32, x86_cpu_to_acpiid);
DECLARE_EARLY_PER_CPU_READ_MOSTLY(u16, x86_bios_cpu_apicid);
#if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86_32)
DECLARE_EARLY_PER_CPU_READ_MOSTLY(int, x86_cpu_to_logical_apicid);
#endif
struct task_struct;
struct smp_ops {
void (*smp_prepare_boot_cpu)(void);
void (*smp_prepare_cpus)(unsigned max_cpus);
void (*smp_cpus_done)(unsigned max_cpus);
void (*stop_other_cpus)(int wait);
void (*crash_stop_other_cpus)(void);
void (*smp_send_reschedule)(int cpu);
int (*cpu_up)(unsigned cpu, struct task_struct *tidle);
int (*cpu_disable)(void);
void (*cpu_die)(unsigned int cpu);
void (*play_dead)(void);
void (*send_call_func_ipi)(const struct cpumask *mask);
void (*send_call_func_single_ipi)(int cpu);
};
/* Globals due to paravirt */
extern void set_cpu_sibling_map(int cpu);
#ifdef CONFIG_SMP
extern struct smp_ops smp_ops;
static inline void smp_send_stop(void)
{
smp_ops.stop_other_cpus(0);
}
static inline void stop_other_cpus(void)
{
smp_ops.stop_other_cpus(1);
}
static inline void smp_prepare_boot_cpu(void)
{
smp_ops.smp_prepare_boot_cpu();
}
static inline void smp_prepare_cpus(unsigned int max_cpus)
{
smp_ops.smp_prepare_cpus(max_cpus);
}
static inline void smp_cpus_done(unsigned int max_cpus)
{
smp_ops.smp_cpus_done(max_cpus);
}
static inline int __cpu_up(unsigned int cpu, struct task_struct *tidle)
{
return smp_ops.cpu_up(cpu, tidle);
}
static inline int __cpu_disable(void)
{
return smp_ops.cpu_disable();
}
static inline void __cpu_die(unsigned int cpu)
{
smp_ops.cpu_die(cpu);
}
static inline void play_dead(void)
{
smp_ops.play_dead();
}
static inline void smp_send_reschedule(int cpu)
{
smp_ops.smp_send_reschedule(cpu);
}
static inline void arch_send_call_function_single_ipi(int cpu)
{
smp_ops.send_call_func_single_ipi(cpu);
}
static inline void arch_send_call_function_ipi_mask(const struct cpumask *mask)
{
smp_ops.send_call_func_ipi(mask);
}
void cpu_disable_common(void);
void native_smp_prepare_boot_cpu(void);
void smp_prepare_cpus_common(void);
void native_smp_prepare_cpus(unsigned int max_cpus);
void calculate_max_logical_packages(void);
void native_smp_cpus_done(unsigned int max_cpus);
int common_cpu_up(unsigned int cpunum, struct task_struct *tidle);
int native_cpu_up(unsigned int cpunum, struct task_struct *tidle);
int native_cpu_disable(void);
int common_cpu_die(unsigned int cpu);
void native_cpu_die(unsigned int cpu);
void hlt_play_dead(void);
void native_play_dead(void);
void play_dead_common(void);
void wbinvd_on_cpu(int cpu);
int wbinvd_on_all_cpus(void);
void cond_wakeup_cpu0(void);
void smp_kick_mwait_play_dead(void);
void native_smp_send_reschedule(int cpu);
void native_send_call_func_ipi(const struct cpumask *mask);
void native_send_call_func_single_ipi(int cpu);
void x86_idle_thread_init(unsigned int cpu, struct task_struct *idle);
void smp_store_boot_cpu_info(void);
void smp_store_cpu_info(int id);
asmlinkage __visible void smp_reboot_interrupt(void);
__visible void smp_reschedule_interrupt(struct pt_regs *regs);
__visible void smp_call_function_interrupt(struct pt_regs *regs);
__visible void smp_call_function_single_interrupt(struct pt_regs *r);
#define cpu_physical_id(cpu) per_cpu(x86_cpu_to_apicid, cpu)
#define cpu_acpi_id(cpu) per_cpu(x86_cpu_to_acpiid, cpu)
/*
* This function is needed by all SMP systems. It must _always_ be valid
* from the initial startup. We map APIC_BASE very early in page_setup(),
* so this is correct in the x86 case.
*/
#define raw_smp_processor_id() this_cpu_read(cpu_number)
#define __smp_processor_id() __this_cpu_read(cpu_number)
#ifdef CONFIG_X86_32
extern int safe_smp_processor_id(void);
#else
# define safe_smp_processor_id() smp_processor_id()
#endif
static inline struct cpumask *cpu_llc_shared_mask(int cpu)
{
return per_cpu(cpu_llc_shared_map, cpu);
}
static inline struct cpumask *cpu_l2c_shared_mask(int cpu)
{
return per_cpu(cpu_l2c_shared_map, cpu);
}
#else /* !CONFIG_SMP */
#define wbinvd_on_cpu(cpu) wbinvd()
static inline int wbinvd_on_all_cpus(void)
{
wbinvd();
return 0;
}
static inline struct cpumask *cpu_llc_shared_mask(int cpu)
{
return (struct cpumask *)cpumask_of(0);
}
#endif /* CONFIG_SMP */
extern unsigned disabled_cpus;
#ifdef CONFIG_X86_LOCAL_APIC
extern int hard_smp_processor_id(void);
#else /* CONFIG_X86_LOCAL_APIC */
#define hard_smp_processor_id() 0
#endif /* CONFIG_X86_LOCAL_APIC */
#ifdef CONFIG_DEBUG_NMI_SELFTEST
extern void nmi_selftest(void);
#else
#define nmi_selftest() do { } while (0)
#endif
#endif /* __ASSEMBLY__ */
#endif /* _ASM_X86_SMP_H */