diff mbox series

[v2,4/4] EDAC/mce_amd: Add support for FRU Text in MCA

Message ID 20240625195624.2565741-5-avadhut.naik@amd.com (mailing list archive)
State Superseded
Headers show
Series MCE wrapper and support for new SMCA syndrome MSRs | expand

Commit Message

Avadhut Naik June 25, 2024, 7:56 p.m. UTC 
From: Yazen Ghannam <yazen.ghannam@amd.com>

A new "FRU Text in MCA" feature is defined where the Field Replaceable
Unit (FRU) Text for a device is represented by a string in the new
MCA_SYND1 and MCA_SYND2 registers. This feature is supported per MCA
bank, and it is advertised by the McaFruTextInMca bit (MCA_CONFIG[9]).

The FRU Text is populated dynamically for each individual error state
(MCA_STATUS, MCA_ADDR, et al.). This handles the case where an MCA bank
covers multiple devices, for example, a Unified Memory Controller (UMC)
bank that manages two DIMMs.

Print the FRU Text string, if available, when decoding an MCA error.

Also, add field for MCA_CONFIG MSR in struct mce_hw_err as vendor specific
error information and save the value of the MSR. The very value can then be
exported through tracepoint for userspace tools like rasdaemon to print FRU
Text, if available.

 Note: Checkpatch checks/warnings are ignored to maintain coding style.

[Yazen: Add Avadhut as co-developer for wrapper changes. ]

Co-developed-by: Avadhut Naik <avadhut.naik@amd.com>
Signed-off-by: Avadhut Naik <avadhut.naik@amd.com>
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
---
 arch/x86/include/asm/mce.h     |  2 ++
 arch/x86/kernel/cpu/mce/amd.c  |  1 +
 arch/x86/kernel/cpu/mce/apei.c |  2 ++
 arch/x86/kernel/cpu/mce/core.c |  3 +++
 drivers/edac/mce_amd.c         | 21 ++++++++++++++-------
 5 files changed, 22 insertions(+), 7 deletions(-)

Comments

Borislav Petkov June 26, 2024, 12:04 p.m. UTC | #1 
On Tue, Jun 25, 2024 at 02:56:24PM -0500, Avadhut Naik wrote:
> From: Yazen Ghannam <yazen.ghannam@amd.com>
> 
> A new "FRU Text in MCA" feature is defined where the Field Replaceable
> Unit (FRU) Text for a device is represented by a string in the new
> MCA_SYND1 and MCA_SYND2 registers. This feature is supported per MCA
> bank, and it is advertised by the McaFruTextInMca bit (MCA_CONFIG[9]).
> 
> The FRU Text is populated dynamically for each individual error state
> (MCA_STATUS, MCA_ADDR, et al.). This handles the case where an MCA bank
> covers multiple devices, for example, a Unified Memory Controller (UMC)
> bank that manages two DIMMs.
> 

From here...

> Print the FRU Text string, if available, when decoding an MCA error.
> 
> Also, add field for MCA_CONFIG MSR in struct mce_hw_err as vendor specific
> error information and save the value of the MSR. The very value can then be
> exported through tracepoint for userspace tools like rasdaemon to print FRU
> Text, if available.
> 
>  Note: Checkpatch checks/warnings are ignored to maintain coding style.

... to here goes into the trash can except what MCA_CONFIG is for being logged
as part of the error.

> [Yazen: Add Avadhut as co-developer for wrapper changes. ]
> 
> Co-developed-by: Avadhut Naik <avadhut.naik@amd.com>
> Signed-off-by: Avadhut Naik <avadhut.naik@amd.com>
> Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>

Ditto as for patch 3.

> ---

> @@ -853,8 +850,18 @@ amd_decode_mce(struct notifier_block *nb, unsigned long val, void *data)
>  
>  		if (m->status & MCI_STATUS_SYNDV) {
>  			pr_cont(", Syndrome: 0x%016llx\n", m->synd);
> -			pr_emerg(HW_ERR "Syndrome1: 0x%016llx, Syndrome2: 0x%016llx",
> -				 err->vi.amd.synd1, err->vi.amd.synd2);
> +			if (mca_config & MCI_CONFIG_FRUTEXT) {
> +				char frutext[17];
> +
> +				memset(frutext, 0, sizeof(frutext));

Why are you clearing it if you're overwriting it immediately?

> +				memcpy(&frutext[0], &err->vi.amd.synd1, 8);
> +				memcpy(&frutext[8], &err->vi.amd.synd2, 8);
> +
> +				pr_emerg(HW_ERR "FRU Text: %s", frutext);
> +			} else {
> +				pr_emerg(HW_ERR "Syndrome1: 0x%016llx, Syndrome2: 0x%016llx",
> +					 err->vi.amd.synd1, err->vi.amd.synd2);
> +			}
>  		}
>  
>  		pr_cont("\n");
> -- 
> 2.34.1
>
Naik, Avadhut June 26, 2024, 6 p.m. UTC | #2 
On 6/26/2024 07:04, Borislav Petkov wrote:
> On Tue, Jun 25, 2024 at 02:56:24PM -0500, Avadhut Naik wrote:
>> From: Yazen Ghannam <yazen.ghannam@amd.com>
>>
>> A new "FRU Text in MCA" feature is defined where the Field Replaceable
>> Unit (FRU) Text for a device is represented by a string in the new
>> MCA_SYND1 and MCA_SYND2 registers. This feature is supported per MCA
>> bank, and it is advertised by the McaFruTextInMca bit (MCA_CONFIG[9]).
>>
>> The FRU Text is populated dynamically for each individual error state
>> (MCA_STATUS, MCA_ADDR, et al.). This handles the case where an MCA bank
>> covers multiple devices, for example, a Unified Memory Controller (UMC)
>> bank that manages two DIMMs.
>>
> 
> From here...
> 
>> Print the FRU Text string, if available, when decoding an MCA error.
>>
>> Also, add field for MCA_CONFIG MSR in struct mce_hw_err as vendor specific
>> error information and save the value of the MSR. The very value can then be
>> exported through tracepoint for userspace tools like rasdaemon to print FRU
>> Text, if available.
>>
>>  Note: Checkpatch checks/warnings are ignored to maintain coding style.
> 
> ... to here goes into the trash can except what MCA_CONFIG is for being logged
> as part of the error.
> 
Will do.

>> [Yazen: Add Avadhut as co-developer for wrapper changes. ]
>>
>> Co-developed-by: Avadhut Naik <avadhut.naik@amd.com>
>> Signed-off-by: Avadhut Naik <avadhut.naik@amd.com>
>> Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
> 
> Ditto as for patch 3.
> 
Will do.
>> ---
> 
>> @@ -853,8 +850,18 @@ amd_decode_mce(struct notifier_block *nb, unsigned long val, void *data)
>>  
>>  		if (m->status & MCI_STATUS_SYNDV) {
>>  			pr_cont(", Syndrome: 0x%016llx\n", m->synd);
>> -			pr_emerg(HW_ERR "Syndrome1: 0x%016llx, Syndrome2: 0x%016llx",
>> -				 err->vi.amd.synd1, err->vi.amd.synd2);
>> +			if (mca_config & MCI_CONFIG_FRUTEXT) {
>> +				char frutext[17];
>> +
>> +				memset(frutext, 0, sizeof(frutext));
> 
> Why are you clearing it if you're overwriting it immediately?
> 
Since its a local variable, wanted to ensure that the memory is zeroed out to prevent
any issues with the %s specifier, used later on.
Would you recommend removing that and using initializer instead for the string?

>> +				memcpy(&frutext[0], &err->vi.amd.synd1, 8);
>> +				memcpy(&frutext[8], &err->vi.amd.synd2, 8);
>> +
>> +				pr_emerg(HW_ERR "FRU Text: %s", frutext);
>> +			} else {
>> +				pr_emerg(HW_ERR "Syndrome1: 0x%016llx, Syndrome2: 0x%016llx",
>> +					 err->vi.amd.synd1, err->vi.amd.synd2);
>> +			}
>>  		}
>>  
>>  		pr_cont("\n");
>> -- 
>> 2.34.1
>>
>
Borislav Petkov June 26, 2024, 6:20 p.m. UTC | #3 
On Wed, Jun 26, 2024 at 01:00:30PM -0500, Naik, Avadhut wrote:
> > 
> > Why are you clearing it if you're overwriting it immediately?
> > 
> Since its a local variable, wanted to ensure that the memory is zeroed out to prevent
> any issues with the %s specifier, used later on.

What issues?

> Would you recommend removing that and using initializer instead for the string?

I'd recommend looking at what the code does and then really thinking whether
that makes any sense.
Yazen Ghannam June 27, 2024, 4:20 p.m. UTC | #4 
On Wed, Jun 26, 2024 at 08:20:13PM +0200, Borislav Petkov wrote:
> On Wed, Jun 26, 2024 at 01:00:30PM -0500, Naik, Avadhut wrote:
> > > 
> > > Why are you clearing it if you're overwriting it immediately?
> > > 
> > Since its a local variable, wanted to ensure that the memory is zeroed out to prevent
> > any issues with the %s specifier, used later on.
> 
> What issues?
> 
> > Would you recommend removing that and using initializer instead for the string?
> 
> I'd recommend looking at what the code does and then really thinking whether
> that makes any sense.
>

We need to make sure the string is NULL-terminated. So the memset()
could be replaced with this:

	frutext[16] = '\0';

Or better yet, maybe we can use scnprintf() or similar.

Thanks,
Yazen
Naik, Avadhut July 9, 2024, 6:29 a.m. UTC | #5 
On 6/26/2024 13:20, Borislav Petkov wrote:
> On Wed, Jun 26, 2024 at 01:00:30PM -0500, Naik, Avadhut wrote:
>>>
>>> Why are you clearing it if you're overwriting it immediately?
>>>
>> Since its a local variable, wanted to ensure that the memory is zeroed out to prevent
>> any issues with the %s specifier, used later on.
> 
> What issues?
> 
Its a locally defined string of 17 bytes. We are doing memcpy() into the first 16 bytes.
Don't we need to ensure that it is NULL-terminated to prevent undefined behavior when its
given to pr_emerg()? Am I missing something here?

>> Would you recommend removing that and using initializer instead for the string?
> 
> I'd recommend looking at what the code does and then really thinking whether
> that makes any sense.
>
diff mbox series

Patch

diff --git a/arch/x86/include/asm/mce.h b/arch/x86/include/asm/mce.h
index 2b43ba37bbda..c6dea9c12498 100644
--- a/arch/x86/include/asm/mce.h
+++ b/arch/x86/include/asm/mce.h
@@ -61,6 +61,7 @@ 
  *  - TCC bit is present in MCx_STATUS.
  */
 #define MCI_CONFIG_MCAX		0x1
+#define MCI_CONFIG_FRUTEXT	BIT_ULL(9)
 #define MCI_IPID_MCATYPE	0xFFFF0000
 #define MCI_IPID_HWID		0xFFF
 
@@ -199,6 +200,7 @@  struct mce_hw_err {
 		struct {
 			u64 synd1;
 			u64 synd2;
+			u64 config;
 		} amd;
 	} vi;
 };
diff --git a/arch/x86/kernel/cpu/mce/amd.c b/arch/x86/kernel/cpu/mce/amd.c
index fc69d244ca7f..f690905aa04f 100644
--- a/arch/x86/kernel/cpu/mce/amd.c
+++ b/arch/x86/kernel/cpu/mce/amd.c
@@ -798,6 +798,7 @@  static void __log_error(unsigned int bank, u64 status, u64 addr, u64 misc)
 
 	if (mce_flags.smca) {
 		rdmsrl(MSR_AMD64_SMCA_MCx_IPID(bank), m->ipid);
+		rdmsrl(MSR_AMD64_SMCA_MCx_CONFIG(bank), err.vi.amd.config);
 
 		if (m->status & MCI_STATUS_SYNDV) {
 			rdmsrl(MSR_AMD64_SMCA_MCx_SYND(bank), m->synd);
diff --git a/arch/x86/kernel/cpu/mce/apei.c b/arch/x86/kernel/cpu/mce/apei.c
index 7a15f0ca1bd1..ba8947983dc7 100644
--- a/arch/x86/kernel/cpu/mce/apei.c
+++ b/arch/x86/kernel/cpu/mce/apei.c
@@ -157,6 +157,8 @@  int apei_smca_report_x86_error(struct cper_ia_proc_ctx *ctx_info, u64 lapic_id)
 		fallthrough;
 	/* MCA_CONFIG */
 	case 4:
+		err.vi.amd.config = *(i_mce + 3);
+		fallthrough;
 	/* MCA_MISC0 */
 	case 3:
 		m->misc = *(i_mce + 2);
diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index 3bb0f8b39f97..cbd10e499a28 100644
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -195,6 +195,8 @@  static void __print_mce(struct mce_hw_err *err)
 			pr_cont("SYND2 %llx ", err->vi.amd.synd2);
 		if (m->ipid)
 			pr_cont("IPID %llx ", m->ipid);
+		if (err->vi.amd.config)
+			pr_cont("CONFIG %llx ", err->vi.amd.config);
 	}
 
 	pr_cont("\n");
@@ -667,6 +669,7 @@  static noinstr void mce_read_aux(struct mce_hw_err *err, int i)
 
 	if (mce_flags.smca) {
 		m->ipid = mce_rdmsrl(MSR_AMD64_SMCA_MCx_IPID(i));
+		err->vi.amd.config = mce_rdmsrl(MSR_AMD64_SMCA_MCx_CONFIG(i));
 
 		if (m->status & MCI_STATUS_SYNDV) {
 			m->synd = mce_rdmsrl(MSR_AMD64_SMCA_MCx_SYND(i));
diff --git a/drivers/edac/mce_amd.c b/drivers/edac/mce_amd.c
index 69e12cb2f0de..6ae6b89b1a1e 100644
--- a/drivers/edac/mce_amd.c
+++ b/drivers/edac/mce_amd.c
@@ -795,6 +795,7 @@  amd_decode_mce(struct notifier_block *nb, unsigned long val, void *data)
 	struct mce_hw_err *err = (struct mce_hw_err *)data;
 	struct mce *m = &err->m;
 	unsigned int fam = x86_family(m->cpuid);
+	u64 mca_config = err->vi.amd.config;
 	int ecc;
 
 	if (m->kflags & MCE_HANDLED_CEC)
@@ -814,11 +815,7 @@  amd_decode_mce(struct notifier_block *nb, unsigned long val, void *data)
 		((m->status & MCI_STATUS_PCC)	? "PCC"	  : "-"));
 
 	if (boot_cpu_has(X86_FEATURE_SMCA)) {
-		u32 low, high;
-		u32 addr = MSR_AMD64_SMCA_MCx_CONFIG(m->bank);
-
-		if (!rdmsr_safe(addr, &low, &high) &&
-		    (low & MCI_CONFIG_MCAX))
+		if (mca_config & MCI_CONFIG_MCAX)
 			pr_cont("|%s", ((m->status & MCI_STATUS_TCC) ? "TCC" : "-"));
 
 		pr_cont("|%s", ((m->status & MCI_STATUS_SYNDV) ? "SyndV" : "-"));
@@ -853,8 +850,18 @@  amd_decode_mce(struct notifier_block *nb, unsigned long val, void *data)
 
 		if (m->status & MCI_STATUS_SYNDV) {
 			pr_cont(", Syndrome: 0x%016llx\n", m->synd);
-			pr_emerg(HW_ERR "Syndrome1: 0x%016llx, Syndrome2: 0x%016llx",
-				 err->vi.amd.synd1, err->vi.amd.synd2);
+			if (mca_config & MCI_CONFIG_FRUTEXT) {
+				char frutext[17];
+
+				memset(frutext, 0, sizeof(frutext));
+				memcpy(&frutext[0], &err->vi.amd.synd1, 8);
+				memcpy(&frutext[8], &err->vi.amd.synd2, 8);
+
+				pr_emerg(HW_ERR "FRU Text: %s", frutext);
+			} else {
+				pr_emerg(HW_ERR "Syndrome1: 0x%016llx, Syndrome2: 0x%016llx",
+					 err->vi.amd.synd1, err->vi.amd.synd2);
+			}
 		}
 
 		pr_cont("\n");