Re: [PATCH V5 03/10] efi: parse ARMv8 processor error

From: Baicar, Tyler
Date: Tue Nov 29 2016 - 10:38:05 EST

Hello James,

On 11/25/2016 11:23 AM, James Morse wrote:
Hi Tyler,

On 21/11/16 22:35, Tyler Baicar wrote:
Add support for ARMv8 Common Platform Error Record (CPER).
UEFI 2.6 specification adds support for ARMv8 specific
processor error information to be reported as part of the
CPER records. This provides more detail on for processor error logs.
I think I'm missing a big part of the puzzle here, I will come back to this next
week. I can't quite line up some of the masks and shifts with the table
descriptions in the UEFI spec[0].

It looks like there was some misunderstanding when the context info parsing was added here
(probably because the spec has some issues that I describe below).
I'll need to clean quite a bit of the context info parsing up. I didn't catch this earlier because
we aren't reporting context info in firmware right now for the errors I have been testing.

diff --git a/include/linux/cper.h b/include/linux/cper.h
index 13ea41c..2a9d553 100644
--- a/include/linux/cper.h
+++ b/include/linux/cper.h
@@ -180,6 +185,10 @@ enum {
UUID_LE(0xE429FAF1, 0x3CB7, 0x11D4, 0x0B, 0xCA, 0x07, 0x00, \
0x80, 0xC7, 0x3C, 0x88, 0x81)
+/* Processor Specific: ARMv8 */
+#define CPER_SEC_PROC_ARMV8 \
+ UUID_LE(0xE19E3D16, 0xBC11, 0x11E4, 0x9C, 0xAA, 0xC2, 0x05, \
+ 0x1D, 0x5D, 0x46, 0xB0)
Nit: UEFI v2.6 N.2.2 (table 249) describes this as 'ARM' not 'ARMV8' (which is
an architectural version).

I'll change it in the next set.

/* Platform Memory */
UUID_LE(0xA5BC1114, 0x6F64, 0x4EDE, 0xB8, 0x63, 0x3E, 0x83, \
@@ -255,6 +264,34 @@ enum {
+#define CPER_ARMV8_ERR_INFO_NUM_MASK 0x00000000000000FF
+#define CPER_ARMV8_CTX_INFO_NUM_MASK 0x0000000000FFFF00
Table 260 describes both ERR_INFO_NUM and CONTEXT_INFO_NUM for as both being
2bytes long, as does your struct cper_sec_proc_armv8 below. Are these for
something else? Do these correspond with one of the four bitfield formats
described in Table 262->265?

I can't see where they are used, and they look like they are reaching across
multiple fields in a struct.

I will remove these as they aren't needed.

+#define CPER_ARMV8_VALID_MPIDR 0x00000001
+#define CPER_ARMV8_VALID_RUNNING_STATE 0x00000004
+#define CPER_ARMV8_VALID_VENDOR_INFO 0x00000008
+#define CPER_ARMV8_INFO_FLAGS_LAST 0x0002
+#define CPER_AARCH64_CTX_LEN 368
+#define CPER_AARCH32_CTX_LEN 256
Are these the worst case sizes for combinations of the structures in N2.4.4.2?
(Tables 266 to 273)

If so is there any chance they could be sizeof(<some union of structs>), even if
the structs are things like:
/* ARMv8 AArch64 GPRs (Type 4) - defined in UEFI Spec N2.4.4.2 */
struct cper_armv8_aarch64_gprs {
u64 regs[32];
This way its easier to check the number is correct, and if a new type is added
this won't get forgotten.

These were representing the sizes of table 266 and table 267, but looking at this more it seems
like some of the spec doesn't make sense:

Table 260 has the Processor Context field which only mentions tables 266 and 267.
I think that should really be tables 266 - 274 representing all 9 context types.

Table 265 then has the Register Array field which mentions the contents of the array
are described in tables 267 - 271. I think this also should be tables 266 - 274 to cover
all 9 context types.

And then the text before table 274 is clearly wrong calling it table 275...seems like there
are several mistakes in the table numbering mentioned in this section.

I'm going to need to update the context info parsing code and add the other register array
sizes based on all of the context tables. Looks like the code will need to be restructured
some because otherwise there will be quite a bit of duplication.

+#define CPER_ARMV8_CTX_TYPE_MASK 0x000000000000000F
+#define CPER_ARMV8_CTX_EL_MASK 0x0000000000000070
+#define CPER_ARMV8_CTX_NS_MASK 0x0000000000000080
Again, I can't work out what these correspond to. I can't see a secure bit or EL
field in any of those UEFI tables.

Is this one of the 'ARM Vendor Specific Micro-Architecture Error Structure's? If
so we should have some infrastructure for picking the correct (or unknown)
decode function based on a range of MIDRs.

These will be removed. The exception level and secure context information will be covered by
which register context type is being reported.

0 – AArch32 GPRs (General Purpose Registers).
1 -- AArch32 EL1 context registers
2 -- AArch32 EL2 context registers
3 -- Aarch32 secure context registers
4 – AArch64 GPRs
5 -- AArch64 EL1 context registers
6 – Aarch64 EL2 context registers
7 -- AArch64 EL3 context registers
8 – Misc. System Register Structure

#define acpi_hest_generic_data_error_length(gdata) \
(((struct acpi_hest_generic_data *)(gdata))->error_data_length)
#define acpi_hest_generic_data_size(gdata) \
@@ -352,6 +389,41 @@ struct cper_ia_proc_ctx {
__u64 mm_reg_addr;
+/* ARMv8 Processor Error Section */
+struct cper_sec_proc_armv8 {
+ __u32 validation_bits;
+ __u16 err_info_num; /* Number of Processor Error Info */
+ __u16 context_info_num; /* Number of Processor Context Info Records*/
+ __u32 section_length;
+ __u8 affinity_level;
+ __u8 reserved[3]; /* must be zero */
+ __u64 mpidr;
+ __u64 midr;
+ __u32 running_state; /* Bit 0 set - Processor running. PSCI = 0 */
+ __u32 psci_state;
+/* ARMv8 Processor Error Information Structure */
+struct cper_armv8_err_info {
+ __u8 version;
+ __u8 length;
+ __u16 validation_bits;
+ __u8 type;
+ __u16 multiple_error;
+ __u8 flags;
+ __u64 error_info;
+ __u64 virt_fault_addr;
+ __u64 physical_fault_addr;

+/* ARMv8 AARCH64 Processor Context Information Structure */
+struct cper_armv8_aarch64_ctx {
+ __u8 type_el_ns;
+ __u8 reserved[7]; /* must be zero */
+ __u8 gpr[288];
+ __u8 spr[68];
Is this:
"Table 265. ARM Processor Error Context Information Header Structure"?

This structure should be removed, it doesn't get used in code now.


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