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Date: Mon, 10 Nov 2014 16:06:00 -0600
From: Aravind Gopalakrishnan <aravind.gopalakrishnan@....com>
To: Chen Yucong <slaoub@...il.com>, <bp@...en8.de>,
<tony.luck@...el.com>
CC: <ak@...ux.intel.com>, <linux-edac@...r.kernel.org>,
<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3 1/2] x86, mce, severity: extend the the mce_severity
mechanism to handle UCNA/DEFERRED error
On 11/7/2014 7:40 PM, Chen Yucong wrote:
> Until now, the mce_severity mechanism can only identify the severity
> of UCNA error as MCE_KEEP_SEVERITY. Meanwhile, it is not able to filter
> out DEFERRED error for ADM platform.
>
> This patch aims to extend the mce_severity mechanism for handling
> UCNA/DEFERRED error. In order to do this, the patch introduces a new
> severity level - MCE_UCNA/DEFERRED_SEVERITY.
>
> In addition, mce_severity is specific to machine check exception,
> and it will check MCIP/EIPV/RIPV bits. In order to use mce_severity
> mechanism in non-exception context, the patch also introduces a new
> argument (is_excp) for mce_severity. `is_excp' is used to explicitly
> specify the calling context of mce_severity.
>
> Signed-off-by: Chen Yucong <slaoub@...il.com>
> ---
> arch/x86/include/asm/mce.h | 4 ++++
> arch/x86/kernel/cpu/mcheck/mce-internal.h | 4 +++-
> arch/x86/kernel/cpu/mcheck/mce-severity.c | 21 ++++++++++++++++-----
> arch/x86/kernel/cpu/mcheck/mce.c | 14 ++++++++------
> drivers/edac/mce_amd.h | 3 ---
> 5 files changed, 31 insertions(+), 15 deletions(-)
>
> diff --git a/arch/x86/include/asm/mce.h b/arch/x86/include/asm/mce.h
> index 276392f..51b26e89 100644
> --- a/arch/x86/include/asm/mce.h
> +++ b/arch/x86/include/asm/mce.h
> @@ -34,6 +34,10 @@
> #define MCI_STATUS_S (1ULL<<56) /* Signaled machine check */
> #define MCI_STATUS_AR (1ULL<<55) /* Action required */
>
> +/* AMD-specific bits */
> +#define MCI_STATUS_DEFERRED (1ULL<<44) /* declare an uncorrected error */
> +#define MCI_STATUS_POISON (1ULL<<43) /* access poisonous data */
> +
> /*
> * Note that the full MCACOD field of IA32_MCi_STATUS MSR is
> * bits 15:0. But bit 12 is the 'F' bit, defined for corrected
> diff --git a/arch/x86/kernel/cpu/mcheck/mce-internal.h b/arch/x86/kernel/cpu/mcheck/mce-internal.h
> index 09edd0b..10b4690 100644
> --- a/arch/x86/kernel/cpu/mcheck/mce-internal.h
> +++ b/arch/x86/kernel/cpu/mcheck/mce-internal.h
> @@ -3,6 +3,8 @@
>
> enum severity_level {
> MCE_NO_SEVERITY,
> + MCE_DEFERRED_SEVERITY,
> + MCE_UCNA_SEVERITY = MCE_DEFERRED_SEVERITY,
> MCE_KEEP_SEVERITY,
> MCE_SOME_SEVERITY,
> MCE_AO_SEVERITY,
> @@ -21,7 +23,7 @@ struct mce_bank {
> char attrname[ATTR_LEN]; /* attribute name */
> };
>
> -int mce_severity(struct mce *a, int tolerant, char **msg);
> +int mce_severity(struct mce *a, int tolerant, char **msg, bool is_excp);
> struct dentry *mce_get_debugfs_dir(void);
>
> extern struct mce_bank *mce_banks;
> diff --git a/arch/x86/kernel/cpu/mcheck/mce-severity.c b/arch/x86/kernel/cpu/mcheck/mce-severity.c
> index c370e1c..c61feb3 100644
> --- a/arch/x86/kernel/cpu/mcheck/mce-severity.c
> +++ b/arch/x86/kernel/cpu/mcheck/mce-severity.c
> @@ -31,6 +31,7 @@
>
> enum context { IN_KERNEL = 1, IN_USER = 2 };
> enum ser { SER_REQUIRED = 1, NO_SER = 2 };
> +enum exception { EXCP_CONTEXT = 1, NO_EXCP = 2 };
>
> static struct severity {
> u64 mask;
> @@ -40,6 +41,7 @@ static struct severity {
> unsigned char mcgres;
> unsigned char ser;
> unsigned char context;
> + unsigned char excp;
> unsigned char covered;
> char *msg;
> } severities[] = {
> @@ -48,6 +50,8 @@ static struct severity {
> #define USER .context = IN_USER
> #define SER .ser = SER_REQUIRED
> #define NOSER .ser = NO_SER
> +#define EXCP .excp = EXCP_CONTEXT
> +#define NOEXCP .excp = NO_EXCP
> #define BITCLR(x) .mask = x, .result = 0
> #define BITSET(x) .mask = x, .result = x
> #define MCGMASK(x, y) .mcgmask = x, .mcgres = y
> @@ -71,16 +75,20 @@ static struct severity {
> /* When MCIP is not set something is very confused */
> MCESEV(
> PANIC, "MCIP not set in MCA handler",
> - MCGMASK(MCG_STATUS_MCIP, 0)
> + EXCP, MCGMASK(MCG_STATUS_MCIP, 0)
> ),
> /* Neither return not error IP -- no chance to recover -> PANIC */
> MCESEV(
> PANIC, "Neither restart nor error IP",
> - MCGMASK(MCG_STATUS_RIPV|MCG_STATUS_EIPV, 0)
> + EXCP, MCGMASK(MCG_STATUS_RIPV|MCG_STATUS_EIPV, 0)
> ),
> MCESEV(
> PANIC, "In kernel and no restart IP",
> - KERNEL, MCGMASK(MCG_STATUS_RIPV, 0)
> + EXCP, KERNEL, MCGMASK(MCG_STATUS_RIPV, 0)
> + ),
> + MCESEV(
> + DEFERRED, "Deferred error",
> + NOSER, MASK(MCI_STATUS_UC|MCI_STATUS_DEFERRED|MCI_STATUS_POISON, MCI_STATUS_DEFERRED)
> ),
We don't need to have MCI_STATUS_POISON in the MASK() here as a deferred
error is indicated by a {UC=0, Deferred = 1}
(Older docs might be unclear on that..)
And it still says ADM on the commit message :)
- Aravind.
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