[PATCH v6 0/5] Fix issues with ARM Processor CPER records

[PATCH v6 0/5] Fix issues with ARM Processor CPER records

[Daniel Ferguson]

This is needed for both kernelspace and userspace properly handle
ARM processor CPER events.

Patch 1 of this series fix the UEFI 2.6+ implementation of the ARM
trace event, as the original implementation was incomplete.
Changeset e9279e83ad1f ("trace, ras: add ARM processor error trace event")
added such event, but it reports only some fields of the CPER record
defined on UEFI 2.6+ appendix N, table N.16.  Those are not enough
actually parse such events on userspace, as not even the event type
is exported.

Patch 2 fixes a compilation breakage when W=1;

Patch 3 adds a new helper function to be used by cper and ghes drivers to
display CPER bitmaps;

Patch 4 fixes CPER logic according with UEFI 2.9A errata. Before it, there
was no description about how processor type field was encoded. The errata
defines it as a bitmask, and provides the information about how it should
be encoded.

Patch 5 adds CPER functions to Kernel-doc.

This series was validated with the help of an ARM EINJ code for QEMU:

	https://gitlab.com/mchehab_kernel/qemu/-/tree/qemu_submission

$ scripts/ghes_inject.py -d arm -p 0xdeadbeef -t cache,bus,micro-arch

[   11.094205] {1}[Hardware Error]: Hardware error from APEI Generic Hardware Error Source: 0
[   11.095009] {1}[Hardware Error]: event severity: recoverable
[   11.095486] {1}[Hardware Error]:  Error 0, type: recoverable
[   11.096090] {1}[Hardware Error]:   section_type: ARM processor error
[   11.096399] {1}[Hardware Error]:   MIDR: 0x00000000000f0510
[   11.097135] {1}[Hardware Error]:   Multiprocessor Affinity Register (MPIDR): 0x0000000080000000
[   11.097811] {1}[Hardware Error]:   running state: 0x0
[   11.098193] {1}[Hardware Error]:   Power State Coordination Interface state: 0
[   11.098699] {1}[Hardware Error]:   Error info structure 0:
[   11.099174] {1}[Hardware Error]:   num errors: 2
[   11.099682] {1}[Hardware Error]:    error_type: 0x1a: cache error|bus error|micro-architectural error
[   11.100150] {1}[Hardware Error]:    physical fault address: 0x00000000deadbeef
[   11.111214] Memory failure: 0xdeadb: recovery action for free buddy page: Recovered

- 

I also tested the ghes and cper reports both with and without this
change, using different versions of rasdaemon, with and without
support for the extended trace event. Those are a summary of the
test results:

- adding more fields to the trace events didn't break userspace API:
  both versions of rasdaemon handled it;

- the rasdaemon patches to handle the new trace report was missing
  a backward-compatibility logic. I fixed already. So, rasdaemon
  can now handle both old and new trace events.

Btw, rasdaemon has gained support for the extended trace since its
version 0.5.8 (released in 2021). I didn't saw any issues there
complain about troubles on it, so either distros used on ARM servers
are using an old version of rasdaemon, or they're carrying on the trace
event changes as well.

---
v6:
 - fix typo in Jonathans "reviewed-by" in patch 3
 - Link to v5: https://lore.kernel.org/linux-acpi/20250813-mauro_v3-v6-16-rev2-v5-0-954db8ccfbe6@os.amperecomputing.com

v5:
 - fix a few code formatting issues
 - remove "Co-developed-by: danielf" because his/my contribution was
   removed in v2.
 - adjust tag block
 - Link to v4: https://lore.kernel.org/linux-acpi/20250805-mauro_v3-v6-16-rev2-v4-0-ea538759841c@os.amperecomputing.com

v4:
 - rebase to kernel v6.16
 - modify commit message of patch 1, and adjust white spaces
   per Boris' suggestions.
 - Link to v3: https://lore.kernel.org/linux-acpi/cover.1725429659.git.mchehab+huawei@kernel.org

v3:
 - history of patch 1 improved with a chain of co-developed-by;
 - add a better description and an example on patch 3;
 - use BIT_ULL() on patch 3;
 - add a missing include on patch 4.

v2:
  - removed an uneeded patch adding #ifdef for CONFIG_ARM/ARM64;
  - cper_bits_to_str() now returns the number of chars filled at the buffer;
  - did a cosmetic (blank lines) improvement at include/linux/ras.h;
  - arm_event trace dynamic arrays renamed to pei_buf/ctx_buf/oem_buf.

    

---
Changes in v6:
- EDITME: describe what is new in this series revision.
- EDITME: use bulletpoints and terse descriptions.
- Link to v5: https://lore.kernel.org/r/20250813-mauro_v3-v6-16-rev2-v5-0-954db8ccfbe6@os.amperecomputing.com

Jason Tian (1):
      RAS: Report all ARM processor CPER information to userspace

Mauro Carvalho Chehab (4):
      efi/cper: Adjust infopfx size to accept an extra space
      efi/cper: Add a new helper function to print bitmasks
      efi/cper: align ARM CPER type with UEFI 2.9A/2.10 specs
      docs: efi: add CPER functions to driver-api

 Documentation/driver-api/firmware/efi/index.rst | 11 +++--
 drivers/acpi/apei/ghes.c                        | 27 +++++------
 drivers/firmware/efi/cper-arm.c                 | 52 ++++++++++-----------
 drivers/firmware/efi/cper.c                     | 62 ++++++++++++++++++++++++-
 drivers/ras/ras.c                               | 40 +++++++++++++++-
 include/linux/cper.h                            | 12 +++--
 include/linux/ras.h                             | 16 +++++--
 include/ras/ras_event.h                         | 49 +++++++++++++++++--
 8 files changed, 210 insertions(+), 59 deletions(-)

[PATCH v6 1/5] RAS: Report all ARM processor CPER information to userspace

[Daniel Ferguson]

From: Jason Tian <jason@os.amperecomputing.com>

The ARM processor CPER record was added in UEFI v2.6 and remained
unchanged up to v2.10.

Yet, the original arm_event trace code added by

  e9279e83ad1f ("trace, ras: add ARM processor error trace event")

is incomplete, as it only traces some fields of UAPI 2.6 table N.16, not
exporting any information from tables N.17 to N.29 of the record.

This is not enough for the user to be able to figure out what has
exactly happened or to take appropriate action.

According to the UEFI v2.9 specification chapter N2.4.4, the ARM
processor error section includes:

- several (ERR_INFO_NUM) ARM processor error information structures
  (Tables N.17 to N.20);
- several (CONTEXT_INFO_NUM) ARM processor context information
  structures (Tables N.21 to N.29);
- several vendor specific error information structures. The
  size is given by Section Length minus the size of the other
  fields.

In addition, it also exports two fields that are parsed by the GHES
driver when firmware reports it, e.g.:

- error severity
- CPU logical index

Report all of these information to userspace via a the ARM tracepoint so
that userspace can properly record the error and take decisions related
to CPU core isolation according to error severity and other info.

The updated ARM trace event now contains the following fields:

======================================  =============================
UEFI field on table N.16                ARM Processor trace fields
======================================  =============================
Validation                              handled when filling data for
                                        affinity MPIDR and running
                                        state.
ERR_INFO_NUM                            pei_len
CONTEXT_INFO_NUM                        ctx_len
Section Length                          indirectly reported by
                                        pei_len, ctx_len and oem_len
Error affinity level                    affinity
MPIDR_EL1                               mpidr
MIDR_EL1                                midr
Running State                           running_state
PSCI State                              psci_state
Processor Error Information Structure   pei_err - count at pei_len
Processor Context                       ctx_err- count at ctx_len
Vendor Specific Error Info              oem - count at oem_len
======================================  =============================

It should be noted that decoding of tables N.17 to N.29, if needed, will
be handled in userspace. That gives more flexibility, as there won't be
any need to flood the kernel with micro-architecture specific error
decoding.

Also, decoding the other fields require a complex logic, and should be
done for each of the several values inside the record field.  So, let
userspace daemons like rasdaemon decode them, parsing such tables and
having vendor-specific micro-architecture-specific decoders.

 [mchehab: modified description, solved merge conflicts and fixed coding style]

Signed-off-by: Jason Tian <jason@os.amperecomputing.com>
Co-developed-by: Shengwei Luo <luoshengwei@huawei.com>
Signed-off-by: Shengwei Luo <luoshengwei@huawei.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Daniel Ferguson <danielf@os.amperecomputing.com> # rebased
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Tested-by: Shiju Jose <shiju.jose@huawei.com>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
Fixes: e9279e83ad1f ("trace, ras: add ARM processor error trace event")
Link: https://uefi.org/specs/UEFI/2.10/Apx_N_Common_Platform_Error_Record.html#arm-processor-error-section
---
 drivers/acpi/apei/ghes.c | 11 ++++-------
 drivers/ras/ras.c        | 40 +++++++++++++++++++++++++++++++++++++--
 include/linux/ras.h      | 16 +++++++++++++---
 include/ras/ras_event.h  | 49 +++++++++++++++++++++++++++++++++++++++++++-----
 4 files changed, 99 insertions(+), 17 deletions(-)

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index f0584ccad451915a2679c17f2367461c141663c5..99e25553fc1320b2306efb751e12f2377c86878a 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -527,7 +527,7 @@ static bool ghes_handle_memory_failure(struct acpi_hest_generic_data *gdata,
 }
 
 static bool ghes_handle_arm_hw_error(struct acpi_hest_generic_data *gdata,
-				       int sev, bool sync)
+				     int sev, bool sync)
 {
 	struct cper_sec_proc_arm *err = acpi_hest_get_payload(gdata);
 	int flags = sync ? MF_ACTION_REQUIRED : 0;
@@ -535,9 +535,8 @@ static bool ghes_handle_arm_hw_error(struct acpi_hest_generic_data *gdata,
 	int sec_sev, i;
 	char *p;
 
-	log_arm_hw_error(err);
-
 	sec_sev = ghes_severity(gdata->error_severity);
+	log_arm_hw_error(err, sec_sev);
 	if (sev != GHES_SEV_RECOVERABLE || sec_sev != GHES_SEV_RECOVERABLE)
 		return false;
 
@@ -870,11 +869,9 @@ static bool ghes_do_proc(struct ghes *ghes,
 
 			arch_apei_report_mem_error(sev, mem_err);
 			queued = ghes_handle_memory_failure(gdata, sev, sync);
-		}
-		else if (guid_equal(sec_type, &CPER_SEC_PCIE)) {
+		} else if (guid_equal(sec_type, &CPER_SEC_PCIE)) {
 			ghes_handle_aer(gdata);
-		}
-		else if (guid_equal(sec_type, &CPER_SEC_PROC_ARM)) {
+		} else if (guid_equal(sec_type, &CPER_SEC_PROC_ARM)) {
 			queued = ghes_handle_arm_hw_error(gdata, sev, sync);
 		} else if (guid_equal(sec_type, &CPER_SEC_CXL_PROT_ERR)) {
 			struct cxl_cper_sec_prot_err *prot_err = acpi_hest_get_payload(gdata);
diff --git a/drivers/ras/ras.c b/drivers/ras/ras.c
index a6e4792a1b2e9239f44f29102a7cc058d64b93ef..c1b36a5601c4b12988089ad292ee5f1c5dc862d5 100644
--- a/drivers/ras/ras.c
+++ b/drivers/ras/ras.c
@@ -52,9 +52,45 @@ void log_non_standard_event(const guid_t *sec_type, const guid_t *fru_id,
 	trace_non_standard_event(sec_type, fru_id, fru_text, sev, err, len);
 }
 
-void log_arm_hw_error(struct cper_sec_proc_arm *err)
+void log_arm_hw_error(struct cper_sec_proc_arm *err, const u8 sev)
 {
-	trace_arm_event(err);
+	struct cper_arm_err_info *err_info;
+	struct cper_arm_ctx_info *ctx_info;
+	u8 *ven_err_data;
+	u32 ctx_len = 0;
+	int n, sz, cpu;
+	s32 vsei_len;
+	u32 pei_len;
+	u8 *pei_err, *ctx_err;
+
+	pei_len = sizeof(struct cper_arm_err_info) * err->err_info_num;
+	pei_err = (u8 *)(err + 1);
+
+	err_info = (struct cper_arm_err_info *)(err + 1);
+	ctx_info = (struct cper_arm_ctx_info *)(err_info + err->err_info_num);
+	ctx_err = (u8 *)ctx_info;
+
+	for (n = 0; n < err->context_info_num; n++) {
+		sz = sizeof(struct cper_arm_ctx_info) + ctx_info->size;
+		ctx_info = (struct cper_arm_ctx_info *)((long)ctx_info + sz);
+		ctx_len += sz;
+	}
+
+	vsei_len = err->section_length - (sizeof(struct cper_sec_proc_arm) + pei_len + ctx_len);
+	if (vsei_len < 0) {
+		pr_warn(FW_BUG "section length: %d\n", err->section_length);
+		pr_warn(FW_BUG "section length is too small\n");
+		pr_warn(FW_BUG "firmware-generated error record is incorrect\n");
+		vsei_len = 0;
+	}
+	ven_err_data = (u8 *)ctx_info;
+
+	cpu = GET_LOGICAL_INDEX(err->mpidr);
+	if (cpu < 0)
+		cpu = -1;
+
+	trace_arm_event(err, pei_err, pei_len, ctx_err, ctx_len,
+			ven_err_data, (u32)vsei_len, sev, cpu);
 }
 
 static int __init ras_init(void)
diff --git a/include/linux/ras.h b/include/linux/ras.h
index a64182bc72ad3f2b430c53c7a9e23e798a1c1fbe..468941bfe855f6a1e3471245d98df5ffb362385b 100644
--- a/include/linux/ras.h
+++ b/include/linux/ras.h
@@ -24,8 +24,7 @@ int __init parse_cec_param(char *str);
 void log_non_standard_event(const guid_t *sec_type,
 			    const guid_t *fru_id, const char *fru_text,
 			    const u8 sev, const u8 *err, const u32 len);
-void log_arm_hw_error(struct cper_sec_proc_arm *err);
-
+void log_arm_hw_error(struct cper_sec_proc_arm *err, const u8 sev);
 #else
 static inline void
 log_non_standard_event(const guid_t *sec_type,
@@ -33,7 +32,7 @@ log_non_standard_event(const guid_t *sec_type,
 		       const u8 sev, const u8 *err, const u32 len)
 { return; }
 static inline void
-log_arm_hw_error(struct cper_sec_proc_arm *err) { return; }
+log_arm_hw_error(struct cper_sec_proc_arm *err, const u8 sev) { return; }
 #endif
 
 struct atl_err {
@@ -53,4 +52,15 @@ static inline unsigned long
 amd_convert_umc_mca_addr_to_sys_addr(struct atl_err *err) { return -EINVAL; }
 #endif /* CONFIG_AMD_ATL */
 
+#if defined(CONFIG_ARM) || defined(CONFIG_ARM64)
+#include <asm/smp_plat.h>
+/*
+ * Include ARM-specific SMP header which provides a function mapping mpidr to
+ * CPU logical index.
+ */
+#define GET_LOGICAL_INDEX(mpidr) get_logical_index(mpidr & MPIDR_HWID_BITMASK)
+#else
+#define GET_LOGICAL_INDEX(mpidr) -EINVAL
+#endif /* CONFIG_ARM || CONFIG_ARM64 */
+
 #endif /* __RAS_H__ */
diff --git a/include/ras/ras_event.h b/include/ras/ras_event.h
index 14c9f943d53fb6cbadeef3f4b13e61470f0b5dee..ab217cc277c556b8847971c807ebbb587d5a29ce 100644
--- a/include/ras/ras_event.h
+++ b/include/ras/ras_event.h
@@ -168,11 +168,25 @@ TRACE_EVENT(mc_event,
  * This event is generated when hardware detects an ARM processor error
  * has occurred. UEFI 2.6 spec section N.2.4.4.
  */
+#define APEIL "ARM Processor Err Info data len"
+#define APEID "ARM Processor Err Info raw data"
+#define APECIL "ARM Processor Err Context Info data len"
+#define APECID "ARM Processor Err Context Info raw data"
+#define VSEIL "Vendor Specific Err Info data len"
+#define VSEID "Vendor Specific Err Info raw data"
 TRACE_EVENT(arm_event,
 
-	TP_PROTO(const struct cper_sec_proc_arm *proc),
+	TP_PROTO(const struct cper_sec_proc_arm *proc,
+		 const u8 *pei_err,
+		 const u32 pei_len,
+		 const u8 *ctx_err,
+		 const u32 ctx_len,
+		 const u8 *oem,
+		 const u32 oem_len,
+		 u8 sev,
+		 int cpu),
 
-	TP_ARGS(proc),
+	TP_ARGS(proc, pei_err, pei_len, ctx_err, ctx_len, oem, oem_len, sev, cpu),
 
 	TP_STRUCT__entry(
 		__field(u64, mpidr)
@@ -180,6 +194,14 @@ TRACE_EVENT(arm_event,
 		__field(u32, running_state)
 		__field(u32, psci_state)
 		__field(u8, affinity)
+		__field(u32, pei_len)
+		__dynamic_array(u8, pei_buf, pei_len)
+		__field(u32, ctx_len)
+		__dynamic_array(u8, ctx_buf, ctx_len)
+		__field(u32, oem_len)
+		__dynamic_array(u8, oem_buf, oem_len)
+		__field(u8, sev)
+		__field(int, cpu)
 	),
 
 	TP_fast_assign(
@@ -199,12 +221,29 @@ TRACE_EVENT(arm_event,
 			__entry->running_state = ~0;
 			__entry->psci_state = ~0;
 		}
+		__entry->pei_len = pei_len;
+		memcpy(__get_dynamic_array(pei_buf), pei_err, pei_len);
+		__entry->ctx_len = ctx_len;
+		memcpy(__get_dynamic_array(ctx_buf), ctx_err, ctx_len);
+		__entry->oem_len = oem_len;
+		memcpy(__get_dynamic_array(oem_buf), oem, oem_len);
+		__entry->sev = sev;
+		__entry->cpu = cpu;
 	),
 
-	TP_printk("affinity level: %d; MPIDR: %016llx; MIDR: %016llx; "
-		  "running state: %d; PSCI state: %d",
+	TP_printk("cpu: %d; error: %d; affinity level: %d; MPIDR: %016llx; MIDR: %016llx; "
+		  "running state: %d; PSCI state: %d; "
+		  "%s: %d; %s: %s; %s: %d; %s: %s; %s: %d; %s: %s",
+		  __entry->cpu,
+		  __entry->sev,
 		  __entry->affinity, __entry->mpidr, __entry->midr,
-		  __entry->running_state, __entry->psci_state)
+		  __entry->running_state, __entry->psci_state,
+		  APEIL, __entry->pei_len, APEID,
+		  __print_hex(__get_dynamic_array(pei_buf), __entry->pei_len),
+		  APECIL, __entry->ctx_len, APECID,
+		  __print_hex(__get_dynamic_array(ctx_buf), __entry->ctx_len),
+		  VSEIL, __entry->oem_len, VSEID,
+		  __print_hex(__get_dynamic_array(oem_buf), __entry->oem_len))
 );
 
 /*

-- 
2.50.0

[PATCH v6 2/5] efi/cper: Adjust infopfx size to accept an extra space

[Daniel Ferguson]

From: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

Compiling with W=1 with werror enabled produces an error:

drivers/firmware/efi/cper-arm.c: In function ‘cper_print_proc_arm’:
drivers/firmware/efi/cper-arm.c:298:64: error: ‘snprintf’ output may be truncated before the last format character [-Werror=format-truncation=]
  298 |                         snprintf(infopfx, sizeof(infopfx), "%s ", newpfx);
      |                                                                ^
drivers/firmware/efi/cper-arm.c:298:25: note: ‘snprintf’ output between 2 and 65 bytes into a destination of size 64
  298 |                         snprintf(infopfx, sizeof(infopfx), "%s ", newpfx);
      |                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

As the logic there adds an space at the end of infopx buffer.
Add an extra space to avoid such warning.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
---
 drivers/firmware/efi/cper-arm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/firmware/efi/cper-arm.c b/drivers/firmware/efi/cper-arm.c
index f0a63d09d3c499b2f1e51d5ef35b69deeb3cbdb3..6ff781e47147c05c784ca5aa57149d1435cb2467 100644
--- a/drivers/firmware/efi/cper-arm.c
+++ b/drivers/firmware/efi/cper-arm.c
@@ -240,7 +240,7 @@ void cper_print_proc_arm(const char *pfx,
 	int i, len, max_ctx_type;
 	struct cper_arm_err_info *err_info;
 	struct cper_arm_ctx_info *ctx_info;
-	char newpfx[64], infopfx[64];
+	char newpfx[64], infopfx[ARRAY_SIZE(newpfx) + 1];
 
 	printk("%sMIDR: 0x%016llx\n", pfx, proc->midr);
 

-- 
2.50.0

[PATCH v6 3/5] efi/cper: Add a new helper function to print bitmasks

[Daniel Ferguson]

From: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

Add a helper function to print a string with names associated
to each bit field.

A typical example is:

	const char * const bits[] = {
		"bit 3 name",
		"bit 4 name",
		"bit 5 name",
	};
	char str[120];
        unsigned int bitmask = BIT(3) | BIT(5);

	#define MASK  GENMASK(5,3)

	cper_bits_to_str(str, sizeof(str), FIELD_GET(MASK, bitmask),
			 bits, ARRAY_SIZE(bits));

The above code fills string "str" with "bit 3 name|bit 5 name".

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
---
 drivers/firmware/efi/cper.c | 60 +++++++++++++++++++++++++++++++++++++++++++++
 include/linux/cper.h        |  2 ++
 2 files changed, 62 insertions(+)

diff --git a/drivers/firmware/efi/cper.c b/drivers/firmware/efi/cper.c
index 928409199a1a4009b11cf3189fe036ad8861169c..79ba688a64f8da7af2dad097b9331c72afc73864 100644
--- a/drivers/firmware/efi/cper.c
+++ b/drivers/firmware/efi/cper.c
@@ -12,6 +12,7 @@
  * Specification version 2.4.
  */
 
+#include <linux/bitmap.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/time.h>
@@ -106,6 +107,65 @@ void cper_print_bits(const char *pfx, unsigned int bits,
 		printk("%s\n", buf);
 }
 
+/**
+ * cper_bits_to_str - return a string for set bits
+ * @buf: buffer to store the output string
+ * @buf_size: size of the output string buffer
+ * @bits: bit mask
+ * @strs: string array, indexed by bit position
+ * @strs_size: size of the string array: @strs
+ *
+ * Add to @buf the bitmask in hexadecimal. Then, for each set bit in @bits,
+ * add the corresponding string describing the bit in @strs to @buf.
+ *
+ * A typical example is::
+ *
+ *	const char * const bits[] = {
+ *		"bit 3 name",
+ *		"bit 4 name",
+ *		"bit 5 name",
+ *	};
+ *	char str[120];
+ *	unsigned int bitmask = BIT(3) | BIT(5);
+ *	#define MASK GENMASK(5,3)
+ *
+ *	cper_bits_to_str(str, sizeof(str), FIELD_GET(MASK, bitmask),
+ *			 bits, ARRAY_SIZE(bits));
+ *
+ * The above code fills the string ``str`` with ``bit 3 name|bit 5 name``.
+ *
+ * Return: number of bytes stored or an error code if lower than zero.
+ */
+int cper_bits_to_str(char *buf, int buf_size, unsigned long bits,
+		     const char * const strs[], unsigned int strs_size)
+{
+	int len = buf_size;
+	char *str = buf;
+	int i, size;
+
+	*buf = '\0';
+
+	for_each_set_bit(i, &bits, strs_size) {
+		if (!(bits & BIT_ULL(i)))
+			continue;
+
+		if (*buf && len > 0) {
+			*str = '|';
+			len--;
+			str++;
+		}
+
+		size = strscpy(str, strs[i], len);
+		if (size < 0)
+			return size;
+
+		len -= size;
+		str += size;
+	}
+	return len - buf_size;
+}
+EXPORT_SYMBOL_GPL(cper_bits_to_str);
+
 static const char * const proc_type_strs[] = {
 	"IA32/X64",
 	"IA64",
diff --git a/include/linux/cper.h b/include/linux/cper.h
index 0ed60a91eca9d6425c9a41947a927b59f7aa2c71..58f40477c824e61c7f798978947bf1f441ce45ad 100644
--- a/include/linux/cper.h
+++ b/include/linux/cper.h
@@ -588,6 +588,8 @@ const char *cper_mem_err_type_str(unsigned int);
 const char *cper_mem_err_status_str(u64 status);
 void cper_print_bits(const char *prefix, unsigned int bits,
 		     const char * const strs[], unsigned int strs_size);
+int cper_bits_to_str(char *buf, int buf_size, unsigned long bits,
+		     const char * const strs[], unsigned int strs_size);
 void cper_mem_err_pack(const struct cper_sec_mem_err *,
 		       struct cper_mem_err_compact *);
 const char *cper_mem_err_unpack(struct trace_seq *,

-- 
2.50.0

[PATCH v6 4/5] efi/cper: align ARM CPER type with UEFI 2.9A/2.10 specs

[Daniel Ferguson]

From: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

Up to UEFI spec 2.9, the type byte of CPER struct for ARM processor
was defined simply as:

Type at byte offset 4:

	- Cache error
	- TLB Error
	- Bus Error
	- Micro-architectural Error
	All other values are reserved

Yet, there was no information about how this would be encoded.

Spec 2.9A errata corrected it by defining:

	- Bit 1 - Cache Error
	- Bit 2 - TLB Error
	- Bit 3 - Bus Error
	- Bit 4 - Micro-architectural Error
	All other values are reserved

That actually aligns with the values already defined on older
versions at N.2.4.1. Generic Processor Error Section.

Spec 2.10 also preserve the same encoding as 2.9A.

Adjust CPER and GHES handling code for both generic and ARM
processors to properly handle UEFI 2.9A and 2.10 encoding.

Link: https://uefi.org/specs/UEFI/2.10/Apx_N_Common_Platform_Error_Record.html#arm-processor-error-information
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
---
 drivers/acpi/apei/ghes.c        | 16 ++++++++-----
 drivers/firmware/efi/cper-arm.c | 50 ++++++++++++++++++++---------------------
 include/linux/cper.h            | 10 ++++-----
 3 files changed, 39 insertions(+), 37 deletions(-)

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index 99e25553fc1320b2306efb751e12f2377c86878a..79a128cb04c351c1d01ee749904ee844963d0f10 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -22,6 +22,7 @@
 #include <linux/moduleparam.h>
 #include <linux/init.h>
 #include <linux/acpi.h>
+#include <linux/bitfield.h>
 #include <linux/io.h>
 #include <linux/interrupt.h>
 #include <linux/timer.h>
@@ -531,6 +532,7 @@ static bool ghes_handle_arm_hw_error(struct acpi_hest_generic_data *gdata,
 {
 	struct cper_sec_proc_arm *err = acpi_hest_get_payload(gdata);
 	int flags = sync ? MF_ACTION_REQUIRED : 0;
+	char error_type[120];
 	bool queued = false;
 	int sec_sev, i;
 	char *p;
@@ -543,9 +545,8 @@ static bool ghes_handle_arm_hw_error(struct acpi_hest_generic_data *gdata,
 	p = (char *)(err + 1);
 	for (i = 0; i < err->err_info_num; i++) {
 		struct cper_arm_err_info *err_info = (struct cper_arm_err_info *)p;
-		bool is_cache = (err_info->type == CPER_ARM_CACHE_ERROR);
+		bool is_cache = err_info->type & CPER_ARM_CACHE_ERROR;
 		bool has_pa = (err_info->validation_bits & CPER_ARM_INFO_VALID_PHYSICAL_ADDR);
-		const char *error_type = "unknown error";
 
 		/*
 		 * The field (err_info->error_info & BIT(26)) is fixed to set to
@@ -559,12 +560,15 @@ static bool ghes_handle_arm_hw_error(struct acpi_hest_generic_data *gdata,
 			continue;
 		}
 
-		if (err_info->type < ARRAY_SIZE(cper_proc_error_type_strs))
-			error_type = cper_proc_error_type_strs[err_info->type];
+		cper_bits_to_str(error_type, sizeof(error_type),
+				 FIELD_GET(CPER_ARM_ERR_TYPE_MASK, err_info->type),
+				 cper_proc_error_type_strs,
+				 ARRAY_SIZE(cper_proc_error_type_strs));
 
 		pr_warn_ratelimited(FW_WARN GHES_PFX
-				    "Unhandled processor error type: %s\n",
-				    error_type);
+				    "Unhandled processor error type 0x%02x: %s%s\n",
+				    err_info->type, error_type,
+				    (err_info->type & ~CPER_ARM_ERR_TYPE_MASK) ? " with reserved bit(s)" : "");
 		p += err_info->length;
 	}
 
diff --git a/drivers/firmware/efi/cper-arm.c b/drivers/firmware/efi/cper-arm.c
index 6ff781e47147c05c784ca5aa57149d1435cb2467..76542a53e20275cf0f059e9ce409fd898de16d4d 100644
--- a/drivers/firmware/efi/cper-arm.c
+++ b/drivers/firmware/efi/cper-arm.c
@@ -93,15 +93,11 @@ static void cper_print_arm_err_info(const char *pfx, u32 type,
 	bool proc_context_corrupt, corrected, precise_pc, restartable_pc;
 	bool time_out, access_mode;
 
-	/* If the type is unknown, bail. */
-	if (type > CPER_ARM_MAX_TYPE)
-		return;
-
 	/*
 	 * Vendor type errors have error information values that are vendor
 	 * specific.
 	 */
-	if (type == CPER_ARM_VENDOR_ERROR)
+	if (type & CPER_ARM_VENDOR_ERROR)
 		return;
 
 	if (error_info & CPER_ARM_ERR_VALID_TRANSACTION_TYPE) {
@@ -116,43 +112,38 @@ static void cper_print_arm_err_info(const char *pfx, u32 type,
 	if (error_info & CPER_ARM_ERR_VALID_OPERATION_TYPE) {
 		op_type = ((error_info >> CPER_ARM_ERR_OPERATION_SHIFT)
 			   & CPER_ARM_ERR_OPERATION_MASK);
-		switch (type) {
-		case CPER_ARM_CACHE_ERROR:
+		if (type & CPER_ARM_CACHE_ERROR) {
 			if (op_type < ARRAY_SIZE(arm_cache_err_op_strs)) {
-				printk("%soperation type: %s\n", pfx,
+				printk("%scache error, operation type: %s\n", pfx,
 				       arm_cache_err_op_strs[op_type]);
 			}
-			break;
-		case CPER_ARM_TLB_ERROR:
+		}
+		if (type & CPER_ARM_TLB_ERROR) {
 			if (op_type < ARRAY_SIZE(arm_tlb_err_op_strs)) {
-				printk("%soperation type: %s\n", pfx,
+				printk("%sTLB error, operation type: %s\n", pfx,
 				       arm_tlb_err_op_strs[op_type]);
 			}
-			break;
-		case CPER_ARM_BUS_ERROR:
+		}
+		if (type & CPER_ARM_BUS_ERROR) {
 			if (op_type < ARRAY_SIZE(arm_bus_err_op_strs)) {
-				printk("%soperation type: %s\n", pfx,
+				printk("%sbus error, operation type: %s\n", pfx,
 				       arm_bus_err_op_strs[op_type]);
 			}
-			break;
 		}
 	}
 
 	if (error_info & CPER_ARM_ERR_VALID_LEVEL) {
 		level = ((error_info >> CPER_ARM_ERR_LEVEL_SHIFT)
 			 & CPER_ARM_ERR_LEVEL_MASK);
-		switch (type) {
-		case CPER_ARM_CACHE_ERROR:
+		if (type & CPER_ARM_CACHE_ERROR)
 			printk("%scache level: %d\n", pfx, level);
-			break;
-		case CPER_ARM_TLB_ERROR:
+
+		if (type & CPER_ARM_TLB_ERROR)
 			printk("%sTLB level: %d\n", pfx, level);
-			break;
-		case CPER_ARM_BUS_ERROR:
+
+		if (type & CPER_ARM_BUS_ERROR)
 			printk("%saffinity level at which the bus error occurred: %d\n",
 			       pfx, level);
-			break;
-		}
 	}
 
 	if (error_info & CPER_ARM_ERR_VALID_PROC_CONTEXT_CORRUPT) {
@@ -241,6 +232,7 @@ void cper_print_proc_arm(const char *pfx,
 	struct cper_arm_err_info *err_info;
 	struct cper_arm_ctx_info *ctx_info;
 	char newpfx[64], infopfx[ARRAY_SIZE(newpfx) + 1];
+	char error_type[120];
 
 	printk("%sMIDR: 0x%016llx\n", pfx, proc->midr);
 
@@ -289,9 +281,15 @@ void cper_print_proc_arm(const char *pfx,
 				       newpfx);
 		}
 
-		printk("%serror_type: %d, %s\n", newpfx, err_info->type,
-			err_info->type < ARRAY_SIZE(cper_proc_error_type_strs) ?
-			cper_proc_error_type_strs[err_info->type] : "unknown");
+		cper_bits_to_str(error_type, sizeof(error_type),
+				 FIELD_GET(CPER_ARM_ERR_TYPE_MASK, err_info->type),
+				 cper_proc_error_type_strs,
+				 ARRAY_SIZE(cper_proc_error_type_strs));
+
+		printk("%serror_type: 0x%02x: %s%s\n", newpfx, err_info->type,
+		       error_type,
+		       (err_info->type & ~CPER_ARM_ERR_TYPE_MASK) ? " with reserved bit(s)" : "");
+
 		if (err_info->validation_bits & CPER_ARM_INFO_VALID_ERR_INFO) {
 			printk("%serror_info: 0x%016llx\n", newpfx,
 			       err_info->error_info);
diff --git a/include/linux/cper.h b/include/linux/cper.h
index 58f40477c824e61c7f798978947bf1f441ce45ad..5b1236d8c65bb7d285a327c457115a18fc9d7953 100644
--- a/include/linux/cper.h
+++ b/include/linux/cper.h
@@ -297,11 +297,11 @@ enum {
 #define CPER_ARM_INFO_FLAGS_PROPAGATED		BIT(2)
 #define CPER_ARM_INFO_FLAGS_OVERFLOW		BIT(3)
 
-#define CPER_ARM_CACHE_ERROR			0
-#define CPER_ARM_TLB_ERROR			1
-#define CPER_ARM_BUS_ERROR			2
-#define CPER_ARM_VENDOR_ERROR			3
-#define CPER_ARM_MAX_TYPE			CPER_ARM_VENDOR_ERROR
+#define CPER_ARM_ERR_TYPE_MASK			GENMASK(4,1)
+#define CPER_ARM_CACHE_ERROR			BIT(1)
+#define CPER_ARM_TLB_ERROR			BIT(2)
+#define CPER_ARM_BUS_ERROR			BIT(3)
+#define CPER_ARM_VENDOR_ERROR			BIT(4)
 
 #define CPER_ARM_ERR_VALID_TRANSACTION_TYPE	BIT(0)
 #define CPER_ARM_ERR_VALID_OPERATION_TYPE	BIT(1)

-- 
2.50.0

[PATCH v6 5/5] docs: efi: add CPER functions to driver-api

[Daniel Ferguson]

From: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

There are two kernel-doc like descriptions at cper, which is used
by other parts of cper and on ghes driver. They both have kernel-doc
like descriptions.

Change the tags for them to be actual kernel-doc tags and add them
to the driver-api documentaion at the UEFI section.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
---
 Documentation/driver-api/firmware/efi/index.rst | 11 ++++++++---
 drivers/firmware/efi/cper.c                     |  2 +-
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/Documentation/driver-api/firmware/efi/index.rst b/Documentation/driver-api/firmware/efi/index.rst
index 4fe8abba9fc6bf8ed53443e48e79285730871c32..5a6b6229592c9a9d1eb223966c582e0969ee9514 100644
--- a/Documentation/driver-api/firmware/efi/index.rst
+++ b/Documentation/driver-api/firmware/efi/index.rst
@@ -1,11 +1,16 @@
 .. SPDX-License-Identifier: GPL-2.0
 
-============
-UEFI Support
-============
+====================================================
+Unified Extensible Firmware Interface (UEFI) Support
+====================================================
 
 UEFI stub library functions
 ===========================
 
 .. kernel-doc:: drivers/firmware/efi/libstub/mem.c
    :internal:
+
+UEFI Common Platform Error Record (CPER) functions
+==================================================
+
+.. kernel-doc:: drivers/firmware/efi/cper.c
diff --git a/drivers/firmware/efi/cper.c b/drivers/firmware/efi/cper.c
index 79ba688a64f8da7af2dad097b9331c72afc73864..0232bd040f61c9b4521ae50ec4b6a1b0bfa5cc19 100644
--- a/drivers/firmware/efi/cper.c
+++ b/drivers/firmware/efi/cper.c
@@ -70,7 +70,7 @@ const char *cper_severity_str(unsigned int severity)
 }
 EXPORT_SYMBOL_GPL(cper_severity_str);
 
-/*
+/**
  * cper_print_bits - print strings for set bits
  * @pfx: prefix for each line, including log level and prefix string
  * @bits: bit mask

-- 
2.50.0