When Firmware First is enabled, BIOS handles errors first and then it
makes them available to the kernel via the Common Platform Error Record
(CPER) sections (UEFI 2.10 Appendix N). Linux parses the CPER sections
via one of two similar paths, either ELOG or GHES.
Currently, ELOG and GHES show some inconsistencies in how they report to
userspace via trace events.
Therfore make the two mentioned paths act similarly by tracing the CPER
CXL Protocol Error Section (UEFI v2.10, Appendix N.2.13) signaled by the
I/O Machine Check Architecture and reported by BIOS in FW-First.
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Fabio M. De Francesco <fabio.m.de.francesco@linux.intel.com>
---
drivers/acpi/acpi_extlog.c | 60 ++++++++++++++++++++++++++++++++++++++
drivers/cxl/core/ras.c | 6 ++++
include/cxl/event.h | 2 ++
3 files changed, 68 insertions(+)
diff --git a/drivers/acpi/acpi_extlog.c b/drivers/acpi/acpi_extlog.c
index 7d7a813169f1..8f2ff3505d47 100644
--- a/drivers/acpi/acpi_extlog.c
+++ b/drivers/acpi/acpi_extlog.c
@@ -12,6 +12,7 @@
#include <linux/ratelimit.h>
#include <linux/edac.h>
#include <linux/ras.h>
+#include <cxl/event.h>
#include <acpi/ghes.h>
#include <asm/cpu.h>
#include <asm/mce.h>
@@ -157,6 +158,60 @@ static void extlog_print_pcie(struct cper_sec_pcie *pcie_err,
}
}
+static void
+extlog_cxl_cper_handle_prot_err(struct cxl_cper_sec_prot_err *prot_err,
+ int severity)
+{
+#ifdef CONFIG_ACPI_APEI_PCIEAER
+ struct cxl_cper_prot_err_work_data wd;
+ u8 *dvsec_start, *cap_start;
+
+ if (!(prot_err->valid_bits & PROT_ERR_VALID_AGENT_ADDRESS)) {
+ pr_err_ratelimited("CXL CPER invalid agent type\n");
+ return;
+ }
+
+ if (!(prot_err->valid_bits & PROT_ERR_VALID_ERROR_LOG)) {
+ pr_err_ratelimited("CXL CPER invalid protocol error log\n");
+ return;
+ }
+
+ if (prot_err->err_len != sizeof(struct cxl_ras_capability_regs)) {
+ pr_err_ratelimited("CXL CPER invalid RAS Cap size (%u)\n",
+ prot_err->err_len);
+ return;
+ }
+
+ if (!(prot_err->valid_bits & PROT_ERR_VALID_SERIAL_NUMBER))
+ pr_warn(FW_WARN "CXL CPER no device serial number\n");
+
+ switch (prot_err->agent_type) {
+ case RCD:
+ case DEVICE:
+ case LD:
+ case FMLD:
+ case RP:
+ case DSP:
+ case USP:
+ memcpy(&wd.prot_err, prot_err, sizeof(wd.prot_err));
+
+ dvsec_start = (u8 *)(prot_err + 1);
+ cap_start = dvsec_start + prot_err->dvsec_len;
+
+ memcpy(&wd.ras_cap, cap_start, sizeof(wd.ras_cap));
+ wd.severity = cper_severity_to_aer(severity);
+ break;
+ default:
+ pr_err_ratelimited("CXL CPER invalid agent type: %d\n",
+ prot_err->agent_type);
+ return;
+ }
+
+ cxl_cper_ras_handle_prot_err(&wd);
+
+#endif
+}
+
static int extlog_print(struct notifier_block *nb, unsigned long val,
void *data)
{
@@ -208,6 +263,10 @@ static int extlog_print(struct notifier_block *nb, unsigned long val,
if (gdata->error_data_length >= sizeof(*mem))
trace_extlog_mem_event(mem, err_seq, fru_id, fru_text,
(u8)gdata->error_severity);
+ } else if (guid_equal(sec_type, &CPER_SEC_CXL_PROT_ERR)) {
+ struct cxl_cper_sec_prot_err *prot_err = acpi_hest_get_payload(gdata);
+
+ extlog_cxl_cper_handle_prot_err(prot_err, gdata->error_severity);
} else if (guid_equal(sec_type, &CPER_SEC_PCIE)) {
struct cper_sec_pcie *pcie_err = acpi_hest_get_payload(gdata);
@@ -375,3 +434,4 @@ module_exit(extlog_exit);
MODULE_AUTHOR("Chen, Gong <gong.chen@intel.com>");
MODULE_DESCRIPTION("Extended MCA Error Log Driver");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS("CXL");
diff --git a/drivers/cxl/core/ras.c b/drivers/cxl/core/ras.c
index 485a831695c7..56db290c88d3 100644
--- a/drivers/cxl/core/ras.c
+++ b/drivers/cxl/core/ras.c
@@ -98,6 +98,12 @@ static void cxl_cper_handle_prot_err(struct cxl_cper_prot_err_work_data *data)
cxl_cper_trace_uncorr_prot_err(pdev, data->ras_cap);
}
+void cxl_cper_ras_handle_prot_err(struct cxl_cper_prot_err_work_data *wd)
+{
+ cxl_cper_handle_prot_err(wd);
+}
+EXPORT_SYMBOL_NS_GPL(cxl_cper_ras_handle_prot_err, "CXL");
+
static void cxl_cper_prot_err_work_fn(struct work_struct *work)
{
struct cxl_cper_prot_err_work_data wd;
diff --git a/include/cxl/event.h b/include/cxl/event.h
index f9ae1796da85..aef906e26033 100644
--- a/include/cxl/event.h
+++ b/include/cxl/event.h
@@ -285,4 +285,6 @@ static inline int cxl_cper_prot_err_kfifo_get(struct cxl_cper_prot_err_work_data
}
#endif
+void cxl_cper_ras_handle_prot_err(struct cxl_cper_prot_err_work_data *wd);
+
#endif /* _LINUX_CXL_EVENT_H */
--
2.48.1On Tue, Apr 29, 2025 at 07:21:09PM +0200, Fabio M. De Francesco wrote:
> When Firmware First is enabled, BIOS handles errors first and then it
> makes them available to the kernel via the Common Platform Error Record
> (CPER) sections (UEFI 2.10 Appendix N). Linux parses the CPER sections
> via one of two similar paths, either ELOG or GHES.
>
> Currently, ELOG and GHES show some inconsistencies in how they report to
> userspace via trace events.
>
> Therfore make the two mentioned paths act similarly by tracing the CPER
> CXL Protocol Error Section (UEFI v2.10, Appendix N.2.13) signaled by the
> I/O Machine Check Architecture and reported by BIOS in FW-First.
>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Signed-off-by: Fabio M. De Francesco <fabio.m.de.francesco@linux.intel.com>
> ---
> drivers/acpi/acpi_extlog.c | 60 ++++++++++++++++++++++++++++++++++++++
> drivers/cxl/core/ras.c | 6 ++++
> include/cxl/event.h | 2 ++
> 3 files changed, 68 insertions(+)
>
> diff --git a/drivers/acpi/acpi_extlog.c b/drivers/acpi/acpi_extlog.c
> index 7d7a813169f1..8f2ff3505d47 100644
> --- a/drivers/acpi/acpi_extlog.c
> +++ b/drivers/acpi/acpi_extlog.c
> @@ -12,6 +12,7 @@
> #include <linux/ratelimit.h>
> #include <linux/edac.h>
> #include <linux/ras.h>
> +#include <cxl/event.h>
> #include <acpi/ghes.h>
> #include <asm/cpu.h>
> #include <asm/mce.h>
> @@ -157,6 +158,60 @@ static void extlog_print_pcie(struct cper_sec_pcie *pcie_err,
> }
> }
>
> +static void
> +extlog_cxl_cper_handle_prot_err(struct cxl_cper_sec_prot_err *prot_err,
> + int severity)
> +{
> +#ifdef CONFIG_ACPI_APEI_PCIEAER
Why not apply this check on the function prototype?
Reference: Documentation/process/coding-style.rst
Section 21) Conditional Compilation
> + struct cxl_cper_prot_err_work_data wd;
> + u8 *dvsec_start, *cap_start;
> +
> + if (!(prot_err->valid_bits & PROT_ERR_VALID_AGENT_ADDRESS)) {
> + pr_err_ratelimited("CXL CPER invalid agent type\n");
> + return;
> + }
> +
> + if (!(prot_err->valid_bits & PROT_ERR_VALID_ERROR_LOG)) {
> + pr_err_ratelimited("CXL CPER invalid protocol error log\n");
> + return;
> + }
> +
> + if (prot_err->err_len != sizeof(struct cxl_ras_capability_regs)) {
> + pr_err_ratelimited("CXL CPER invalid RAS Cap size (%u)\n",
> + prot_err->err_len);
> + return;
> + }
> +
> + if (!(prot_err->valid_bits & PROT_ERR_VALID_SERIAL_NUMBER))
> + pr_warn(FW_WARN "CXL CPER no device serial number\n");
Is this a requirement (in the spec) that we should warn users about?
The UEFI spec says that serial number is only used if "CXL agent" is a
"CXL device".
"CXL ports" won't have serial numbers. So this will be a false warning
for port errors.
> +
> + switch (prot_err->agent_type) {
> + case RCD:
> + case DEVICE:
> + case LD:
> + case FMLD:
> + case RP:
> + case DSP:
> + case USP:
> + memcpy(&wd.prot_err, prot_err, sizeof(wd.prot_err));
> +
> + dvsec_start = (u8 *)(prot_err + 1);
> + cap_start = dvsec_start + prot_err->dvsec_len;
> +
> + memcpy(&wd.ras_cap, cap_start, sizeof(wd.ras_cap));
> + wd.severity = cper_severity_to_aer(severity);
> + break;
> + default:
> + pr_err_ratelimited("CXL CPER invalid agent type: %d\n",
"invalid" is too harsh given that the specs may be updated. Maybe say
"reserved" or "unknown" or "unrecognized" instead.
Hopefully things will settle down to where a user will be able to have a
system with newer CXL "agents" without *requiring* a kernel update. :)
Thanks,
Yazen
On Tuesday, April 29, 2025 8:20:55 PM Central European Summer Time Yazen Ghannam wrote:
> On Tue, Apr 29, 2025 at 07:21:09PM +0200, Fabio M. De Francesco wrote:
> > When Firmware First is enabled, BIOS handles errors first and then it
> > makes them available to the kernel via the Common Platform Error Record
> > (CPER) sections (UEFI 2.10 Appendix N). Linux parses the CPER sections
> > via one of two similar paths, either ELOG or GHES.
> >
> > Currently, ELOG and GHES show some inconsistencies in how they report to
> > userspace via trace events.
> >
> > Therfore make the two mentioned paths act similarly by tracing the CPER
> > CXL Protocol Error Section (UEFI v2.10, Appendix N.2.13) signaled by the
> > I/O Machine Check Architecture and reported by BIOS in FW-First.
> >
> > Cc: Dan Williams <dan.j.williams@intel.com>
> > Signed-off-by: Fabio M. De Francesco <fabio.m.de.francesco@linux.intel.com>
> > ---
> > drivers/acpi/acpi_extlog.c | 60 ++++++++++++++++++++++++++++++++++++++
> > drivers/cxl/core/ras.c | 6 ++++
> > include/cxl/event.h | 2 ++
> > 3 files changed, 68 insertions(+)
> >
> > diff --git a/drivers/acpi/acpi_extlog.c b/drivers/acpi/acpi_extlog.c
> > index 7d7a813169f1..8f2ff3505d47 100644
> > --- a/drivers/acpi/acpi_extlog.c
> > +++ b/drivers/acpi/acpi_extlog.c
> > @@ -12,6 +12,7 @@
> > #include <linux/ratelimit.h>
> > #include <linux/edac.h>
> > #include <linux/ras.h>
> > +#include <cxl/event.h>
> > #include <acpi/ghes.h>
> > #include <asm/cpu.h>
> > #include <asm/mce.h>
> > @@ -157,6 +158,60 @@ static void extlog_print_pcie(struct cper_sec_pcie *pcie_err,
> > }
> > }
> >
> > +static void
> > +extlog_cxl_cper_handle_prot_err(struct cxl_cper_sec_prot_err *prot_err,
> > + int severity)
> > +{
> > +#ifdef CONFIG_ACPI_APEI_PCIEAER
>
> Why not apply this check on the function prototype?
>
This function is static.
>
> Reference: Documentation/process/coding-style.rst
> Section 21) Conditional Compilation
>
> > + struct cxl_cper_prot_err_work_data wd;
> > + u8 *dvsec_start, *cap_start;
> > +
> > + if (!(prot_err->valid_bits & PROT_ERR_VALID_AGENT_ADDRESS)) {
> > + pr_err_ratelimited("CXL CPER invalid agent type\n");
> > + return;
> > + }
> > +
> > + if (!(prot_err->valid_bits & PROT_ERR_VALID_ERROR_LOG)) {
> > + pr_err_ratelimited("CXL CPER invalid protocol error log\n");
> > + return;
> > + }
> > +
> > + if (prot_err->err_len != sizeof(struct cxl_ras_capability_regs)) {
> > + pr_err_ratelimited("CXL CPER invalid RAS Cap size (%u)\n",
> > + prot_err->err_len);
> > + return;
> > + }
> > +
> > + if (!(prot_err->valid_bits & PROT_ERR_VALID_SERIAL_NUMBER))
> > + pr_warn(FW_WARN "CXL CPER no device serial number\n");
>
> Is this a requirement (in the spec) that we should warn users about?
>
> The UEFI spec says that serial number is only used if "CXL agent" is a
> "CXL device".
>
> "CXL ports" won't have serial numbers. So this will be a false warning
> for port errors.
>
I'll add a test and print that warning only if agent is a device (RCD,
DEVICE, LD, FMLD).
>
> > +
> > + switch (prot_err->agent_type) {
> > + case RCD:
> > + case DEVICE:
> > + case LD:
> > + case FMLD:
> > + case RP:
> > + case DSP:
> > + case USP:
> > + memcpy(&wd.prot_err, prot_err, sizeof(wd.prot_err));
> > +
> > + dvsec_start = (u8 *)(prot_err + 1);
> > + cap_start = dvsec_start + prot_err->dvsec_len;
> > +
> > + memcpy(&wd.ras_cap, cap_start, sizeof(wd.ras_cap));
> > + wd.severity = cper_severity_to_aer(severity);
> > + break;
> > + default:
> > + pr_err_ratelimited("CXL CPER invalid agent type: %d\n",
>
> "invalid" is too harsh given that the specs may be updated. Maybe say
> "reserved" or "unknown" or "unrecognized" instead.
>
> Hopefully things will settle down to where a user will be able to have a
> system with newer CXL "agents" without *requiring* a kernel update. :)
>
I'll replace "invalid" with "unknown".
>
> Thanks,
> Yazen
>
Thanks,
Fabio
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