On Monday, May 14, 2018 8:52:17 PM CEST Fenghua Yu wrote: > During suspend or hibernation, system enters BIOS. To avoid potential > BIOS issue that may generate #AC exception for split locked accesses, > handle the #AC as fatal exception, and block suspend or hibernation, > the split lock setting is restored to BIOS setting. When resuming > from suspend or hibernation, the split lock setting is restored to > kernel setting. > > Signed-off-by: Fenghua Yu <[email protected]>
Acked-by: Rafael J. Wysocki <[email protected]> > --- > arch/x86/include/asm/cpu.h | 2 ++ > arch/x86/kernel/cpu/split_lock.c | 54 > ++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 56 insertions(+) > > diff --git a/arch/x86/include/asm/cpu.h b/arch/x86/include/asm/cpu.h > index 0b00033b6fa8..89d62d7051fa 100644 > --- a/arch/x86/include/asm/cpu.h > +++ b/arch/x86/include/asm/cpu.h > @@ -45,11 +45,13 @@ int __init enumerate_split_lock(void); > void setup_split_lock(void); > bool do_split_lock_exception(struct pt_regs *regs, unsigned long error_code); > bool restore_split_lock_ac_bios(int *enable); > +bool restore_split_lock_ac_kernel(int *enable); > #else /* CONFIG_SPLIT_LOCK_AC */ > static inline int enumerate_split_lock(void) { return 0; } > static inline void setup_split_lock(void) {} > static inline bool > do_split_lock_exception(struct pt_regs *regs, unsigned long error_code) {} > static inline bool restore_split_lock_ac_bios(int *enable) { return true; } > +static inline bool restore_split_lock_ac_kernel(int *enable) { return true; } > #endif /* CONFIG_SPLIT_LOCK_AC */ > #endif /* _ASM_X86_CPU_H */ > diff --git a/arch/x86/kernel/cpu/split_lock.c > b/arch/x86/kernel/cpu/split_lock.c > index d2735259800b..5187a9c6cea6 100644 > --- a/arch/x86/kernel/cpu/split_lock.c > +++ b/arch/x86/kernel/cpu/split_lock.c > @@ -14,6 +14,7 @@ > #include <linux/workqueue.h> > #include <linux/cpu.h> > #include <linux/reboot.h> > +#include <linux/syscore_ops.h> > #include <asm/msr.h> > > static bool split_lock_ac_supported; > @@ -143,6 +144,15 @@ bool restore_split_lock_ac_bios(int *enable) > return restore_split_lock_ac(split_lock_ac_bios); > } > > +/* Restore kernel setting for #AC enable bit for split lock. */ > +bool restore_split_lock_ac_kernel(int *enable) > +{ > + if (enable) > + *enable = split_lock_ac == ENABLE_SPLIT_LOCK_AC ? 1 : 0; > + > + return restore_split_lock_ac(split_lock_ac); > +} > + > static void split_lock_cpu_reboot(void *unused) > { > restore_split_lock_ac_bios(NULL); > @@ -223,11 +233,55 @@ bool do_split_lock_exception(struct pt_regs *regs, > unsigned long error_code) > return true; > } > > +static int split_lock_offline(unsigned int cpu) > +{ > + int enable; > + > + if (restore_split_lock_ac_bios(&enable)) > + pr_info("%s split lock on CPU%d\n", > + enable ? "enable" : "disable", smp_processor_id()); > + > + return 0; > +} > + > +static int split_lock_bsp_suspend(void) > +{ > + restore_split_lock_ac_bios(NULL); > + > + return 0; > +} > + > +static void split_lock_bsp_resume(void) > +{ > + restore_split_lock_ac_kernel(NULL); > +} > + > +static struct syscore_ops split_lock_syscore_ops = { > + .suspend = split_lock_bsp_suspend, > + .resume = split_lock_bsp_resume, > +}; > + > static int __init split_lock_init(void) > { > + int ret; > + > + if (!split_lock_ac_supported) > + return -ENODEV; > + > + ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, > + "x86/split_lock:online:", > + NULL, split_lock_offline); > + if (ret < 0) > + goto out_fail; > + > + register_syscore_ops(&split_lock_syscore_ops); > + > register_reboot_notifier(&split_lock_reboot_nb); > > return 0; > + > +out_fail: > + return ret; > } > > late_initcall(split_lock_init); >
