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arm64: Subscribe Microsoft Azure Cobalt 100 to ARM Neoverse N2 errata

PATCH Superseded Easwar Hariharan 3 participants 5 messages Feb 12, 2024 – Feb 15, 2024

Subsystems (3)
Stable branch Documentation arm64

v1 of 2 Superseded Latest is v2 →

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Easwar Hariharan

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#0 lore raw

PATCH 1/1 arm64: Subscribe Microsoft Azure Cobalt 100 to ARM Neoverse N2 errata

Add the MIDR value of Microsoft Azure Cobalt 100, which is a Microsoft implemented CPU based on r0p0 of the ARM Neoverse N2 CPU, and therefore suffers from all the same errata.

CC Mark Rutland <[email protected]>
CC Marc Zyngier <[email protected]>
CC Anshuman Khandual <[email protected]>
CC [email protected] # 5.15+
Signed-off-by Easwar Hariharan <[email protected]>
---
 Documentation/arch/arm64/silicon-errata.rst | 7 +++++++
 arch/arm64/include/asm/cputype.h            | 4 ++++
 arch/arm64/kernel/cpu_errata.c              | 3 +++
 3 files changed, 14 insertions(+)
Documentation/arch/arm64/silicon-errata.rst +7 -0
index e8c2ce1f9df6..45a7f4932fe0 100644
@@ -243,3 +243,10 @@ stable kernels.
 +----------------+-----------------+-----------------+-----------------------------+
 | ASR            | ASR8601         | #8601001        | N/A                         |
 +----------------+-----------------+-----------------+-----------------------------+
++----------------+-----------------+-----------------+-----------------------------+
+| Microsoft      | Azure Cobalt 100| #2139208        | ARM64_ERRATUM_2139208       |
++----------------+-----------------+-----------------+-----------------------------+
+| Microsoft      | Azure Cobalt 100| #2067961        | ARM64_ERRATUM_2067961       |
++----------------+-----------------+-----------------+-----------------------------+
+| Microsoft      | Azure Cobalt 100| #2253138        | ARM64_ERRATUM_2253138       |
++----------------+-----------------+-----------------+-----------------------------+
arch/arm64/include/asm/cputype.h +4 -0
index 7c7493cb571f..a632a7514e55 100644
@@ -61,6 +61,7 @@
 #define ARM_CPU_IMP_HISI		0x48
 #define ARM_CPU_IMP_APPLE		0x61
 #define ARM_CPU_IMP_AMPERE		0xC0
+#define ARM_CPU_IMP_MICROSOFT		0x6D
 
 #define ARM_CPU_PART_AEM_V8		0xD0F
 #define ARM_CPU_PART_FOUNDATION		0xD00

@@ -135,6 +136,8 @@
 
 #define AMPERE_CPU_PART_AMPERE1		0xAC3
 
+#define MSFT_CPU_PART_AZURE_COBALT_100	0xD49 /* Based on r0p0 of ARM Neoverse N2 */
+
 #define MIDR_CORTEX_A53 MIDR_CPU_MODEL(ARM_CPU_IMP_ARM, ARM_CPU_PART_CORTEX_A53)
 #define MIDR_CORTEX_A57 MIDR_CPU_MODEL(ARM_CPU_IMP_ARM, ARM_CPU_PART_CORTEX_A57)
 #define MIDR_CORTEX_A72 MIDR_CPU_MODEL(ARM_CPU_IMP_ARM, ARM_CPU_PART_CORTEX_A72)

@@ -193,6 +196,7 @@
 #define MIDR_APPLE_M2_BLIZZARD_MAX MIDR_CPU_MODEL(ARM_CPU_IMP_APPLE, APPLE_CPU_PART_M2_BLIZZARD_MAX)
 #define MIDR_APPLE_M2_AVALANCHE_MAX MIDR_CPU_MODEL(ARM_CPU_IMP_APPLE, APPLE_CPU_PART_M2_AVALANCHE_MAX)
 #define MIDR_AMPERE1 MIDR_CPU_MODEL(ARM_CPU_IMP_AMPERE, AMPERE_CPU_PART_AMPERE1)
+#define MIDR_MICROSOFT_AZURE_COBALT_100 MIDR_CPU_MODEL(ARM_CPU_IMP_MICROSOFT, MSFT_CPU_PART_AZURE_COBALT_100)
 
 /* Fujitsu Erratum 010001 affects A64FX 1.0 and 1.1, (v0r0 and v1r0) */
 #define MIDR_FUJITSU_ERRATUM_010001		MIDR_FUJITSU_A64FX
arch/arm64/kernel/cpu_errata.c +3 -0
index 967c7c7a4e7d..76b8dd37092a 100644
@@ -374,6 +374,7 @@ static const struct midr_range erratum_1463225[] = {
 static const struct midr_range trbe_overwrite_fill_mode_cpus[] = {
 #ifdef CONFIG_ARM64_ERRATUM_2139208
 	MIDR_ALL_VERSIONS(MIDR_NEOVERSE_N2),
+	MIDR_ALL_VERSIONS(MIDR_MICROSOFT_AZURE_COBALT_100),
 #endif
 #ifdef CONFIG_ARM64_ERRATUM_2119858
 	MIDR_ALL_VERSIONS(MIDR_CORTEX_A710),

@@ -387,6 +388,7 @@ static const struct midr_range trbe_overwrite_fill_mode_cpus[] = {
 static const struct midr_range tsb_flush_fail_cpus[] = {
 #ifdef CONFIG_ARM64_ERRATUM_2067961
 	MIDR_ALL_VERSIONS(MIDR_NEOVERSE_N2),
+	MIDR_ALL_VERSIONS(MIDR_MICROSOFT_AZURE_COBALT_100),
 #endif
 #ifdef CONFIG_ARM64_ERRATUM_2054223
 	MIDR_ALL_VERSIONS(MIDR_CORTEX_A710),

@@ -399,6 +401,7 @@ static const struct midr_range tsb_flush_fail_cpus[] = {
 static struct midr_range trbe_write_out_of_range_cpus[] = {
 #ifdef CONFIG_ARM64_ERRATUM_2253138
 	MIDR_ALL_VERSIONS(MIDR_NEOVERSE_N2),
+	MIDR_ALL_VERSIONS(MIDR_MICROSOFT_AZURE_COBALT_100),
 #endif
 #ifdef CONFIG_ARM64_ERRATUM_2224489
 	MIDR_ALL_VERSIONS(MIDR_CORTEX_A710),
Signature · 1 line
2.34.1
#1 lore raw

Hi Easwar,

Quoted 3 lines · Easwar Hariharan

Add the MIDR value of Microsoft Azure Cobalt 100, which is a Microsoft implemented CPU based on r0p0 of the ARM Neoverse N2 CPU, and therefore suffers from all the same errata.

Can you comment at all on where one might find this MIDR? That is, does your hypervisor report the native MIDR of the implementation or does it repaint it as an Arm Neoverse N2 (0x410FD490)?

Quoted 22 lines
arch/arm64/include/asm/cputype.h +3 -0
index 7c7493cb571f..a632a7514e55 100644
@@ -61,6 +61,7 @@
 #define ARM_CPU_IMP_HISI		0x48
 #define ARM_CPU_IMP_APPLE		0x61
 #define ARM_CPU_IMP_AMPERE		0xC0
+#define ARM_CPU_IMP_MICROSOFT		0x6D
 
 #define ARM_CPU_PART_AEM_V8		0xD0F
 #define ARM_CPU_PART_FOUNDATION		0xD00

@@ -135,6 +136,8 @@
 
 #define AMPERE_CPU_PART_AMPERE1		0xAC3
 
+#define MSFT_CPU_PART_AZURE_COBALT_100	0xD49 /* Based on r0p0 of ARM Neoverse N2 */
+
 #define MIDR_CORTEX_A53 MIDR_CPU_MODEL(ARM_CPU_IMP_ARM, ARM_CPU_PART_CORTEX_A53)
 #define MIDR_CORTEX_A57 MIDR_CPU_MODEL(ARM_CPU_IMP_ARM, ARM_CPU_PART_CORTEX_A57)
 #define MIDR_CORTEX_A72 MIDR_CPU_MODEL(ARM_CPU_IMP_ARM, ARM_CPU_PART_CORTEX_A72)

arch/arm64/include/asm/cputype.h line 199

Quoted 4 lines
arch/arm64/include/asm/cputype.h +1 -0
@@ -193,6 +196,7 @@
 #define MIDR_APPLE_M2_BLIZZARD_MAX MIDR_CPU_MODEL(ARM_CPU_IMP_APPLE, APPLE_CPU_PART_M2_BLIZZARD_MAX)
 #define MIDR_APPLE_M2_AVALANCHE_MAX MIDR_CPU_MODEL(ARM_CPU_IMP_APPLE, APPLE_CPU_PART_M2_AVALANCHE_MAX)
 #define MIDR_AMPERE1 MIDR_CPU_MODEL(ARM_CPU_IMP_AMPERE, AMPERE_CPU_PART_AMPERE1)
+#define MIDR_MICROSOFT_AZURE_COBALT_100 MIDR_CPU_MODEL(ARM_CPU_IMP_MICROSOFT, MSFT_CPU_PART_AZURE_COBALT_100)

nitpick: consistently use the abbreviated 'MSFT' for all the definitions you're adding.

Signature · 2 lines
Thanks,
Oliver
author
#2 lore raw
Quoted 10 lines · Oliver Upton

Hi Easwar,

Quoted 3 lines · Easwar Hariharan

Add the MIDR value of Microsoft Azure Cobalt 100, which is a Microsoft implemented CPU based on r0p0 of the ARM Neoverse N2 CPU, and therefore suffers from all the same errata.

Can you comment at all on where one might find this MIDR? That is, does your hypervisor report the native MIDR of the implementation or does it repaint it as an Arm Neoverse N2 (0x410FD490)?

We will check on the Microsoft hypervisor's plans, and get back to you.

Notwithstanding that, we do have baremetal use cases for Microsoft Azure Cobalt 100 as well where this MIDR value will show through.

Quoted 17 lines
Quoted 17 lines
arch/arm64/include/asm/cputype.h +1 -0
index 7c7493cb571f..a632a7514e55 100644
@@ -61,6 +61,7 @@
 #define ARM_CPU_IMP_HISI		0x48
 #define ARM_CPU_IMP_APPLE		0x61
 #define ARM_CPU_IMP_AMPERE		0xC0
+#define ARM_CPU_IMP_MICROSOFT		0x6D
 
 #define ARM_CPU_PART_AEM_V8		0xD0F
 #define ARM_CPU_PART_FOUNDATION		0xD00

@@ -135,6 +136,8 @@
 
 #define AMPERE_CPU_PART_AMPERE1		0xAC3
Quoted 14 lines

arch/arm64/include/asm/cputype.h line 199

Quoted 10 lines
arch/arm64/include/asm/cputype.h +3 -0
+#define MSFT_CPU_PART_AZURE_COBALT_100	0xD49 /* Based on r0p0 of ARM Neoverse N2 */
+
 #define MIDR_CORTEX_A53 MIDR_CPU_MODEL(ARM_CPU_IMP_ARM, ARM_CPU_PART_CORTEX_A53)
 #define MIDR_CORTEX_A57 MIDR_CPU_MODEL(ARM_CPU_IMP_ARM, ARM_CPU_PART_CORTEX_A57)
 #define MIDR_CORTEX_A72 MIDR_CPU_MODEL(ARM_CPU_IMP_ARM, ARM_CPU_PART_CORTEX_A72)

@@ -193,6 +196,7 @@
 #define MIDR_APPLE_M2_BLIZZARD_MAX MIDR_CPU_MODEL(ARM_CPU_IMP_APPLE, APPLE_CPU_PART_M2_BLIZZARD_MAX)
 #define MIDR_APPLE_M2_AVALANCHE_MAX MIDR_CPU_MODEL(ARM_CPU_IMP_APPLE, APPLE_CPU_PART_M2_AVALANCHE_MAX)
 #define MIDR_AMPERE1 MIDR_CPU_MODEL(ARM_CPU_IMP_AMPERE, AMPERE_CPU_PART_AMPERE1)
+#define MIDR_MICROSOFT_AZURE_COBALT_100 MIDR_CPU_MODEL(ARM_CPU_IMP_MICROSOFT, MSFT_CPU_PART_AZURE_COBALT_100)

nitpick: consistently use the abbreviated 'MSFT' for all the definitions you're adding.

I was rather hoping to use Microsoft throughout, but I chose MSFT for the CPU_PART* to align columns with the other defines. :) If consistency is of a higher priority than column alignment, I can change it to MICROSOFT rather than MSFT throughout.

Thanks,
Easwar

reviewer
#3 lore raw
Quoted 30 lines · Easwar Hariharan
Quoted 16 lines
Quoted 16 lines
arch/arm64/include/asm/cputype.h +1 -0
index 7c7493cb571f..a632a7514e55 100644
@@ -61,6 +61,7 @@
 #define ARM_CPU_IMP_HISI		0x48
 #define ARM_CPU_IMP_APPLE		0x61
 #define ARM_CPU_IMP_AMPERE		0xC0
+#define ARM_CPU_IMP_MICROSOFT		0x6D
 
 #define ARM_CPU_PART_AEM_V8		0xD0F
 #define ARM_CPU_PART_FOUNDATION		0xD00

@@ -135,6 +136,8 @@
 
 #define AMPERE_CPU_PART_AMPERE1		0xAC3
Quoted 13 lines

arch/arm64/include/asm/cputype.h line 199

Quoted 10 lines
arch/arm64/include/asm/cputype.h +3 -0
+#define MSFT_CPU_PART_AZURE_COBALT_100	0xD49 /* Based on r0p0 of ARM Neoverse N2 */
+
 #define MIDR_CORTEX_A53 MIDR_CPU_MODEL(ARM_CPU_IMP_ARM, ARM_CPU_PART_CORTEX_A53)
 #define MIDR_CORTEX_A57 MIDR_CPU_MODEL(ARM_CPU_IMP_ARM, ARM_CPU_PART_CORTEX_A57)
 #define MIDR_CORTEX_A72 MIDR_CPU_MODEL(ARM_CPU_IMP_ARM, ARM_CPU_PART_CORTEX_A72)

@@ -193,6 +196,7 @@
 #define MIDR_APPLE_M2_BLIZZARD_MAX MIDR_CPU_MODEL(ARM_CPU_IMP_APPLE, APPLE_CPU_PART_M2_BLIZZARD_MAX)
 #define MIDR_APPLE_M2_AVALANCHE_MAX MIDR_CPU_MODEL(ARM_CPU_IMP_APPLE, APPLE_CPU_PART_M2_AVALANCHE_MAX)
 #define MIDR_AMPERE1 MIDR_CPU_MODEL(ARM_CPU_IMP_AMPERE, AMPERE_CPU_PART_AMPERE1)
+#define MIDR_MICROSOFT_AZURE_COBALT_100 MIDR_CPU_MODEL(ARM_CPU_IMP_MICROSOFT, MSFT_CPU_PART_AZURE_COBALT_100)

nitpick: consistently use the abbreviated 'MSFT' for all the definitions you're adding.

Quoted 3 lines

I was rather hoping to use Microsoft throughout, but I chose MSFT for the CPU_PART* to align columns with the other defines. :) If consistency is of a higher priority than column alignment, I can change it to MICROSOFT rather than MSFT throughout.

Consistency across the definitions is more important than alignmen; please choose either "MSFT" or "MICROSOFT" and use that consistently.

Mark.

author
#4 lore raw
In reply to Easwar Hariharan
Quoted 8 lines · Easwar Hariharan
Quoted 7 lines · Oliver Upton

Hi Easwar,

Quoted 3 lines · Easwar Hariharan

Add the MIDR value of Microsoft Azure Cobalt 100, which is a Microsoft implemented CPU based on r0p0 of the ARM Neoverse N2 CPU, and therefore suffers from all the same errata.

Quoted 9 lines
Quoted 3 lines

Can you comment at all on where one might find this MIDR? That is, does your hypervisor report the native MIDR of the implementation or does it repaint it as an Arm Neoverse N2 (0x410FD490)?

We will check on the Microsoft hypervisor's plans, and get back to you.

Notwithstanding that, we do have baremetal use cases for Microsoft Azure Cobalt 100 as well where this MIDR value will show through.

<snip>

We checked in with our Microsoft hypervisor colleagues, and they do repaint the Azure Cobalt 100 as an Arm Neoverse N2, but again, we do have baremetal use cases.

Thanks,
Easwar