Re: [PATCH v3 3/3] x86/mce: Add CMCI storm switching support for Zhaoxin

[Yazen Ghannam <yazen.ghannam@amd.com>]

On Wed, Sep 18, 2024 at 01:54:36PM +0800, Tony W Wang-oc wrote:
> From: Lyle Li <LyleLi@zhaoxin.com>
> 
> Zhaoxin CPUs support CMCI compatible with Intel, because
> Zhaoxin's UCR error is not reported through CMCI, and in
> order to be compatible with intel's CMCI code, so add Zhaoxin
> CMCI storm toggle to support the new CMCI storm switching
> in mce/intel.c, mce/zhaoxin.c, mce/threshold.c, and mce/internal.h.
> 
> Signed-off-by: Lyle Li <LyleLi@zhaoxin.com>
> Signed-off-by: Tony W Wang-oc <TonyWWang-oc@zhaoxin.com>
> ---
>  arch/x86/kernel/cpu/mce/intel.c     |  5 ++---
>  arch/x86/kernel/cpu/mce/internal.h  |  7 ++++++-
>  arch/x86/kernel/cpu/mce/threshold.c |  4 ++++
>  arch/x86/kernel/cpu/mce/zhaoxin.c   | 18 ++++++++++++++++++
>  4 files changed, 30 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/x86/kernel/cpu/mce/intel.c b/arch/x86/kernel/cpu/mce/intel.c
> index b7e67f4f7..aa75e2848 100644
> --- a/arch/x86/kernel/cpu/mce/intel.c
> +++ b/arch/x86/kernel/cpu/mce/intel.c
> @@ -45,7 +45,7 @@ static DEFINE_PER_CPU(mce_banks_t, mce_banks_owned);
>   * cmci_discover_lock protects against parallel discovery attempts
>   * which could race against each other.
>   */
> -static DEFINE_RAW_SPINLOCK(cmci_discover_lock);
> +DEFINE_RAW_SPINLOCK(cmci_discover_lock);
>  
>  /*
>   * On systems that do support CMCI but it's disabled, polling for MCEs can
> @@ -61,7 +61,7 @@ static DEFINE_SPINLOCK(cmci_poll_lock);
>   * MCi_CTL2 threshold for each bank when there is no storm.
>   * Default value for each bank may have been set by BIOS.
>   */
> -static u16 cmci_threshold[MAX_NR_BANKS];
> +u16 cmci_threshold[MAX_NR_BANKS];
>  
>  /*
>   * High threshold to limit CMCI rate during storms. Max supported is
> @@ -73,7 +73,6 @@ static u16 cmci_threshold[MAX_NR_BANKS];
>   * to corrected errors, so keeping CMCI enabled means that uncorrected
>   * errors will still be processed in a timely fashion.
>   */
> -#define CMCI_STORM_THRESHOLD	32749
>  
>  static int cmci_supported(int *banks)
>  {
> diff --git a/arch/x86/kernel/cpu/mce/internal.h b/arch/x86/kernel/cpu/mce/internal.h
> index 836e56027..086b833c5 100644
> --- a/arch/x86/kernel/cpu/mce/internal.h
> +++ b/arch/x86/kernel/cpu/mce/internal.h
> @@ -7,7 +7,7 @@
>  
>  #include <linux/device.h>
>  #include <asm/mce.h>
> -
> +#include <linux/spinlock.h>
>  enum severity_level {
>  	MCE_NO_SEVERITY,
>  	MCE_DEFERRED_SEVERITY,
> @@ -334,11 +334,16 @@ static __always_inline u32 mca_msr_reg(int bank, enum mca_msr reg)
>  }
>  
>  extern void (*mc_poll_banks)(void);
> +#define CMCI_STORM_THRESHOLD    32749
> +extern raw_spinlock_t cmci_discover_lock;
> +extern u16 cmci_threshold[MAX_NR_BANKS];
>  #ifdef CONFIG_X86_MCE_ZHAOXIN
>  void mce_zhaoxin_feature_init(struct cpuinfo_x86 *c);
>  void mce_zhaoxin_feature_clear(struct cpuinfo_x86 *c);
> +void mce_zhaoxin_handle_storm(int bank, bool on);
>  #else
>  static inline void mce_zhaoxin_feature_init(struct cpuinfo_x86 *c) { }
>  static inline void mce_zhaoxin_feature_clear(struct cpuinfo_x86 *c) { }
> +static inline void mce_zhaoxin_handle_storm(int bank, bool on) { }
>  #endif
>  #endif /* __X86_MCE_INTERNAL_H__ */
> diff --git a/arch/x86/kernel/cpu/mce/threshold.c b/arch/x86/kernel/cpu/mce/threshold.c
> index 89e31e1e5..200280387 100644
> --- a/arch/x86/kernel/cpu/mce/threshold.c
> +++ b/arch/x86/kernel/cpu/mce/threshold.c
> @@ -63,6 +63,10 @@ static void mce_handle_storm(unsigned int bank, bool on)
>  	case X86_VENDOR_INTEL:
>  		mce_intel_handle_storm(bank, on);
>  		break;
> +	case X86_VENDOR_ZHAOXIN:
> +	case X86_VENDOR_CENTAUR:
> +		mce_zhaoxin_handle_storm(bank, on);
> +		break;
>  	}
>  }
>  
> diff --git a/arch/x86/kernel/cpu/mce/zhaoxin.c b/arch/x86/kernel/cpu/mce/zhaoxin.c
> index de69c560f..994b8520a 100644
> --- a/arch/x86/kernel/cpu/mce/zhaoxin.c
> +++ b/arch/x86/kernel/cpu/mce/zhaoxin.c
> @@ -63,3 +63,21 @@ void mce_zhaoxin_feature_clear(struct cpuinfo_x86 *c)
>  {
>  	intel_clear_lmce();
>  }
> +
> +void mce_zhaoxin_handle_storm(int bank, bool on)
> +{
> +	unsigned long flags;
> +	u64 val;
> +
> +	raw_spin_lock_irqsave(&cmci_discover_lock, flags);
> +	rdmsrl(MSR_IA32_MCx_CTL2(bank), val);
> +	if (on) {
> +		val &= ~(MCI_CTL2_CMCI_EN | MCI_CTL2_CMCI_THRESHOLD_MASK);
> +		val |= CMCI_STORM_THRESHOLD;
> +	} else {
> +		val &= ~MCI_CTL2_CMCI_THRESHOLD_MASK;
> +		val |= (MCI_CTL2_CMCI_EN | cmci_threshold[bank]);
> +	}
> +	wrmsrl(MSR_IA32_MCx_CTL2(bank), val);
> +	raw_spin_unlock_irqrestore(&cmci_discover_lock, flags);
> +}

Why does this need to be different than mce_intel_handle_storm()?

Thanks,
Yazen