[PATCH 0/2] Disable 32-bit EL0 for Apple A10(X), T2

[PATCH 0/2] Disable 32-bit EL0 for Apple A10(X), T2

[Nick Chan]

Hi,

Apple's A10(X), T2 SoCs consists of pairs of performance and efficiency
cores. However, only one of the core types may be active at a given time,
and to software, it appears as logical cores that could switch between
P-mode and E-mode, depending on the p-state.

Unforunately, only the performance cores can execute 32-bit EL0. To
software, this results in logical cores that lose ability to execute
32-bit EL0 when the p-state is below a certain value.

Since these CPU cores only supported 16K pages, many AArch32
executables will not run anyways. This series disables 32-bit EL0 for
these SoCs.

Nick Chan

---

Nick Chan (2):
  arm64: cputype: Add CPU types for A7-A11, T2 SoCs
  arm64: cpufeature: Pretend that Apple A10(X), T2 does not support
    32-bit EL0

 arch/arm64/include/asm/cputype.h | 42 +++++++++++++++++++++++---------
 arch/arm64/kernel/cpufeature.c   | 25 +++++++++++++++++++
 2 files changed, 55 insertions(+), 12 deletions(-)


base-commit: 9aaeb87ce1e966169a57f53a02ba05b30880ffb8
-- 
2.46.0

[PATCH 1/2] arm64: cputype: Add CPU types for A7-A11, T2 SoCs

[Nick Chan]

A10(X), T2 types will be used soon, and the rest are added for
documentation purposes.

The A9 is made in two different fabs and those have different part
numbers, and the TSMC cores are also used in A9X, so it cannot use
the usual naming scheme.

The A10(X), T2 performance/efficiency core pairs appears as single
logical cores to software, so both the performance and efficiency
core codenames needs to be included.

Signed-off-by: Nick Chan <towinchenmi@gmail.com>
---
 arch/arm64/include/asm/cputype.h | 42 +++++++++++++++++++++++---------
 1 file changed, 30 insertions(+), 12 deletions(-)

diff --git a/arch/arm64/include/asm/cputype.h b/arch/arm64/include/asm/cputype.h
index 5a7dfeb8e8eb..f1720158a54f 100644
--- a/arch/arm64/include/asm/cputype.h
+++ b/arch/arm64/include/asm/cputype.h
@@ -129,18 +129,27 @@
 
 #define HISI_CPU_PART_TSV110		0xD01
 
-#define APPLE_CPU_PART_M1_ICESTORM	0x022
-#define APPLE_CPU_PART_M1_FIRESTORM	0x023
-#define APPLE_CPU_PART_M1_ICESTORM_PRO	0x024
-#define APPLE_CPU_PART_M1_FIRESTORM_PRO	0x025
-#define APPLE_CPU_PART_M1_ICESTORM_MAX	0x028
-#define APPLE_CPU_PART_M1_FIRESTORM_MAX	0x029
-#define APPLE_CPU_PART_M2_BLIZZARD	0x032
-#define APPLE_CPU_PART_M2_AVALANCHE	0x033
-#define APPLE_CPU_PART_M2_BLIZZARD_PRO	0x034
-#define APPLE_CPU_PART_M2_AVALANCHE_PRO	0x035
-#define APPLE_CPU_PART_M2_BLIZZARD_MAX	0x038
-#define APPLE_CPU_PART_M2_AVALANCHE_MAX	0x039
+#define APPLE_CPU_PART_A7_CYCLONE		0x1
+#define APPLE_CPU_PART_A8_TYPHOON		0x2
+#define APPLE_CPU_PART_A8X_TYPHOON		0x3
+#define APPLE_CPU_PART_SAMSUNG_TWISTER		0x4 /* Used in Samsung A9 */
+#define APPLE_CPU_PART_TSMC_TWISTER		0x5 /* Used in TSMC A9 and A9X */
+#define APPLE_CPU_PART_A10_T2_HURRICANE_ZEPHYR	0x6
+#define APPLE_CPU_PART_A10X_HURRICANE_ZEPHYR	0x7
+#define APPLE_CPU_PART_A11_MONSOON		0x8
+#define APPLE_CPU_PART_A11_MISTRAL		0x9
+#define APPLE_CPU_PART_M1_ICESTORM		0x022
+#define APPLE_CPU_PART_M1_FIRESTORM		0x023
+#define APPLE_CPU_PART_M1_ICESTORM_PRO		0x024
+#define APPLE_CPU_PART_M1_FIRESTORM_PRO		0x025
+#define APPLE_CPU_PART_M1_ICESTORM_MAX		0x028
+#define APPLE_CPU_PART_M1_FIRESTORM_MAX		0x029
+#define APPLE_CPU_PART_M2_BLIZZARD		0x032
+#define APPLE_CPU_PART_M2_AVALANCHE		0x033
+#define APPLE_CPU_PART_M2_BLIZZARD_PRO		0x034
+#define APPLE_CPU_PART_M2_AVALANCHE_PRO		0x035
+#define APPLE_CPU_PART_M2_BLIZZARD_MAX		0x038
+#define APPLE_CPU_PART_M2_AVALANCHE_MAX		0x039
 
 #define AMPERE_CPU_PART_AMPERE1		0xAC3
 #define AMPERE_CPU_PART_AMPERE1A	0xAC4
@@ -200,6 +209,15 @@
 #define MIDR_NVIDIA_CARMEL MIDR_CPU_MODEL(ARM_CPU_IMP_NVIDIA, NVIDIA_CPU_PART_CARMEL)
 #define MIDR_FUJITSU_A64FX MIDR_CPU_MODEL(ARM_CPU_IMP_FUJITSU, FUJITSU_CPU_PART_A64FX)
 #define MIDR_HISI_TSV110 MIDR_CPU_MODEL(ARM_CPU_IMP_HISI, HISI_CPU_PART_TSV110)
+#define MIDR_APPLE_A7_CYCLONE MIDR_CPU_MODEL(ARM_CPU_IMP_APPLE, APPLE_CPU_PART_A7_CYCLONE)
+#define MIDR_APPLE_A8_TYPHOON MIDR_CPU_MODEL(ARM_CPU_IMP_APPLE, APPLE_CPU_PART_A8_TYPHOON)
+#define MIDR_APPLE_A8X_TYPHOON MIDR_CPU_MODEL(ARM_CPU_IMP_APPLE, APPLE_CPU_PART_A8X_TYPHOON)
+#define MIDR_APPLE_SAMSUNG_TWISTER MIDR_CPU_MODEL(ARM_CPU_IMP_APPLE, APPLE_CPU_PART_SAMSUNG_TWISTER)
+#define MIDR_APPLE_TSMC_TWISTER MIDR_CPU_MODEL(ARM_CPU_IMP_APPLE, APPLE_CPU_PART_TSMC_TWISTER)
+#define MIDR_APPLE_A10_T2_HURRICANE_ZEPHYR MIDR_CPU_MODEL(ARM_CPU_IMP_APPLE, APPLE_CPU_PART_A10_T2_HURRICANE_ZEPHYR)
+#define MIDR_APPLE_A10X_HURRICANE_ZEPHYR MIDR_CPU_MODEL(ARM_CPU_IMP_APPLE, APPLE_CPU_PART_A10X_HURRICANE_ZEPHYR)
+#define MIDR_APPLE_A11_MONSOON MIDR_CPU_MODEL(ARM_CPU_IMP_APPLE, APPLE_CPU_PART_A11_MONSOON)
+#define MIDR_APPLE_A11_MISTRAL MIDR_CPU_MODEL(ARM_CPU_IMP_APPLE, APPLE_CPU_PART_A11_MISTRAL)
 #define MIDR_APPLE_M1_ICESTORM MIDR_CPU_MODEL(ARM_CPU_IMP_APPLE, APPLE_CPU_PART_M1_ICESTORM)
 #define MIDR_APPLE_M1_FIRESTORM MIDR_CPU_MODEL(ARM_CPU_IMP_APPLE, APPLE_CPU_PART_M1_FIRESTORM)
 #define MIDR_APPLE_M1_ICESTORM_PRO MIDR_CPU_MODEL(ARM_CPU_IMP_APPLE, APPLE_CPU_PART_M1_ICESTORM_PRO)
-- 
2.46.0

[PATCH 2/2] arm64: cpufeature: Pretend that Apple A10(X), T2 does not support 32-bit EL0

[Nick Chan]

The Apple A10(X), T2 consists of logical cores that can switch
between P-mode and E-mode based on the frequency. However, only
P-mode supported 32-bit EL0.

Trying to support 32-bit EL0 on a CPU that can only execute it in certain
states is a bad idea. The A10(X), T2 only supports 16KB page size anyway so
many AArch32 executables won't run anyways. Pretend that it does not
support 32-bit EL0 at all.

Signed-off-by: Nick Chan <towinchenmi@gmail.com>
---
 arch/arm64/kernel/cpufeature.c | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 718728a85430..458bcbc4f328 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -3529,6 +3529,29 @@ void __init setup_boot_cpu_features(void)
 	setup_boot_cpu_capabilities();
 }
 
+static void __init bad_aarch32_el0_fixup(void)
+{
+#ifdef CONFIG_ARCH_APPLE
+	static const struct midr_range bad_aarch32_el0[] = {
+		MIDR_ALL_VERSIONS(MIDR_APPLE_A10_T2_HURRICANE_ZEPHYR),
+		MIDR_ALL_VERSIONS(MIDR_APPLE_A10X_HURRICANE_ZEPHYR),
+		{}
+	};
+
+	if (is_midr_in_range_list(read_cpuid_id(), bad_aarch32_el0)) {
+		struct arm64_ftr_reg *regp;
+
+		regp = get_arm64_ftr_reg(SYS_ID_AA64PFR0_EL1);
+		if (!regp)
+			return;
+		u64 val = (regp->sys_val & ~ID_AA64PFR0_EL1_EL0_MASK)
+		  | ID_AA64PFR0_EL1_EL0_IMP;
+
+		update_cpu_ftr_reg(regp, val);
+	}
+#endif
+}
+
 static void __init setup_system_capabilities(void)
 {
 	/*
@@ -3562,6 +3585,8 @@ static void __init setup_system_capabilities(void)
 
 void __init setup_system_features(void)
 {
+	bad_aarch32_el0_fixup();
+
 	setup_system_capabilities();
 
 	kpti_install_ng_mappings();
-- 
2.46.0