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Subject[PATCH v3 1/2] x86, mce, severity: extend the the mce_severity mechanism to handle UCNA/DEFERRED error
Date
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@gmail.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)
),
MCESEV(
KEEP, "Corrected error",
@@ -89,7 +97,7 @@ static struct severity {

/* ignore OVER for UCNA */
MCESEV(
- KEEP, "Uncorrected no action required",
+ UCNA, "Uncorrected no action required",
SER, MASK(MCI_UC_SAR, MCI_STATUS_UC)
),
MCESEV(
@@ -178,8 +186,9 @@ static int error_context(struct mce *m)
return ((m->cs & 3) == 3) ? IN_USER : IN_KERNEL;
}

-int mce_severity(struct mce *m, int tolerant, char **msg)
+int mce_severity(struct mce *m, int tolerant, char **msg, bool is_excp)
{
+ enum exception excp = (is_excp ? EXCP_CONTEXT : NO_EXCP);
enum context ctx = error_context(m);
struct severity *s;

@@ -194,6 +203,8 @@ int mce_severity(struct mce *m, int tolerant, char **msg)
continue;
if (s->context && ctx != s->context)
continue;
+ if (s->excp && excp != s->excp)
+ continue;
if (msg)
*msg = s->msg;
s->covered = 1;
diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index 61a9668ce..453e9bf 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -668,7 +668,8 @@ static int mce_no_way_out(struct mce *m, char **msg, unsigned long *validp,
if (quirk_no_way_out)
quirk_no_way_out(i, m, regs);
}
- if (mce_severity(m, mca_cfg.tolerant, msg) >= MCE_PANIC_SEVERITY)
+ if (mce_severity(m, mca_cfg.tolerant, msg, true) >=
+ MCE_PANIC_SEVERITY)
ret = 1;
}
return ret;
@@ -754,7 +755,7 @@ static void mce_reign(void)
for_each_possible_cpu(cpu) {
int severity = mce_severity(&per_cpu(mces_seen, cpu),
mca_cfg.tolerant,
- &nmsg);
+ &nmsg, true);
if (severity > global_worst) {
msg = nmsg;
global_worst = severity;
@@ -1095,13 +1096,14 @@ void do_machine_check(struct pt_regs *regs, long error_code)
*/
add_taint(TAINT_MACHINE_CHECK, LOCKDEP_NOW_UNRELIABLE);

- severity = mce_severity(&m, cfg->tolerant, NULL);
+ severity = mce_severity(&m, cfg->tolerant, NULL, true);

/*
- * When machine check was for corrected handler don't touch,
- * unless we're panicing.
+ * When machine check was for corrected/deferred handler don't
+ * touch, unless we're panicing.
*/
- if (severity == MCE_KEEP_SEVERITY && !no_way_out)
+ if ((severity == MCE_KEEP_SEVERITY ||
+ severity == MCE_UCNA_SEVERITY) && !no_way_out)
continue;
__set_bit(i, toclear);
if (severity == MCE_NO_SEVERITY) {
diff --git a/drivers/edac/mce_amd.h b/drivers/edac/mce_amd.h
index 51b7e3a..c2359a1 100644
--- a/drivers/edac/mce_amd.h
+++ b/drivers/edac/mce_amd.h
@@ -32,9 +32,6 @@
#define R4(x) (((x) >> 4) & 0xf)
#define R4_MSG(x) ((R4(x) < 9) ? rrrr_msgs[R4(x)] : "Wrong R4!")

-#define MCI_STATUS_DEFERRED BIT_64(44)
-#define MCI_STATUS_POISON BIT_64(43)
-
extern const char * const pp_msgs[];

enum tt_ids {
--
1.7.10.4


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