[PATCH v2] arm64: cpufeature: Export matrix and other features to userspace

From: Steven Price
Date: Mon Dec 16 2019 - 06:33:47 EST

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Export the features introduced as part of ARMv8.6 exposed in the
ID_AA64ISAR1_EL1 and ID_AA64ZFR0_EL1 registers. This introduces the
Matrix features (ARMv8.2-I8MM, ARMv8.2-F64MM and ARMv8.2-F32MM) along
with BFloat16 (Armv8.2-BF16), speculation invalidation (SPECRES) and
Data Gathering Hint (ARMv8.0-DGH).

Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
[Added other features in those registers]
Signed-off-by: Steven Price <steven.price@xxxxxxx>
---
This is a v2 of Julien's patch[1] extended to export all the new
features contained within the ID_AA64ISAR1_EL1 and ID_AA64ZFR0_EL1
registers.

[1] https://lore.kernel.org/linux-arm-kernel/20191025171056.30641-1-julien.grall@xxxxxxx/

Documentation/arm64/cpu-feature-registers.rst | 16 ++++++++++
Documentation/arm64/elf_hwcaps.rst | 31 +++++++++++++++++++
arch/arm64/include/asm/hwcap.h | 8 +++++
arch/arm64/include/asm/sysreg.h | 12 +++++++
arch/arm64/include/uapi/asm/hwcap.h | 8 +++++
arch/arm64/kernel/cpufeature.c | 20 ++++++++++++
arch/arm64/kernel/cpuinfo.c | 8 +++++
7 files changed, 103 insertions(+)

diff --git a/Documentation/arm64/cpu-feature-registers.rst b/Documentation/arm64/cpu-feature-registers.rst
index b6e44884e3ad..5382981533f8 100644
--- a/Documentation/arm64/cpu-feature-registers.rst
+++ b/Documentation/arm64/cpu-feature-registers.rst
@@ -200,6 +200,14 @@ infrastructure:
+------------------------------+---------+---------+
| Name | bits | visible |
+------------------------------+---------+---------+
+ | I8MM | [55-52] | y |
+ +------------------------------+---------+---------+
+ | DGH | [51-48] | y |
+ +------------------------------+---------+---------+
+ | BF16 | [47-44] | y |
+ +------------------------------+---------+---------+
+ | SPECRES | [43-40] | y |
+ +------------------------------+---------+---------+
| SB | [39-36] | y |
+------------------------------+---------+---------+
| FRINTTS | [35-32] | y |
@@ -234,10 +242,18 @@ infrastructure:
+------------------------------+---------+---------+
| Name | bits | visible |
+------------------------------+---------+---------+
+ | F64MM | [59-56] | y |
+ +------------------------------+---------+---------+
+ | F32MM | [55-52] | y |
+ +------------------------------+---------+---------+
+ | I8MM | [47-44] | y |
+ +------------------------------+---------+---------+
| SM4 | [43-40] | y |
+------------------------------+---------+---------+
| SHA3 | [35-32] | y |
+------------------------------+---------+---------+
+ | BF16 | [23-20] | y |
+ +------------------------------+---------+---------+
| BitPerm | [19-16] | y |
+------------------------------+---------+---------+
| AES | [7-4] | y |
diff --git a/Documentation/arm64/elf_hwcaps.rst b/Documentation/arm64/elf_hwcaps.rst
index 7fa3d215ae6a..183ba86ad46e 100644
--- a/Documentation/arm64/elf_hwcaps.rst
+++ b/Documentation/arm64/elf_hwcaps.rst
@@ -204,6 +204,37 @@ HWCAP2_FRINT

Functionality implied by ID_AA64ISAR1_EL1.FRINTTS == 0b0001.

+HWCAP2_SVEI8MM
+
+ Functionality implied by ID_AA64ZFR0_EL1.I8MM == 0b0001.
+
+HWCAP2_SVEF32MM
+
+ Functionality implied by ID_AA64ZFR0_EL1.F32MM == 0b0001.
+
+HWCAP2_SVEF64MM
+
+ Functionality implied by ID_AA64ZFR0_EL1.F64MM == 0b0001.
+
+HWCAP2_SVEBF16
+
+ Functionality implied by ID_AA64ZFR0_EL1.BF16 == 0b0001.
+
+HWCAP2_I8MM
+
+ Functionality implied by ID_AA64ISAR1_EL1.I8MM == 0b0001.
+
+HWCAP2_BF16
+
+ Functionality implied by ID_AA64ISAR1_EL1.BF16 == 0b0001.
+
+HWCAP2_DGH
+
+ Functionality implied by ID_AA64ISAR1_EL1.DGH == 0b0001.
+
+HWCAP2_SPECRES
+
+ Functionality implied by ID_AA64ISAR1_EL1.SPECRES == 0b0001.

4. Unused AT_HWCAP bits
-----------------------
diff --git a/arch/arm64/include/asm/hwcap.h b/arch/arm64/include/asm/hwcap.h
index 3d2f2472a36c..ac7180b2c20b 100644
--- a/arch/arm64/include/asm/hwcap.h
+++ b/arch/arm64/include/asm/hwcap.h
@@ -86,6 +86,14 @@
#define KERNEL_HWCAP_SVESM4 __khwcap2_feature(SVESM4)
#define KERNEL_HWCAP_FLAGM2 __khwcap2_feature(FLAGM2)
#define KERNEL_HWCAP_FRINT __khwcap2_feature(FRINT)
+#define KERNEL_HWCAP_SVEI8MM __khwcap2_feature(SVEI8MM)
+#define KERNEL_HWCAP_SVEF32MM __khwcap2_feature(SVEF32MM)
+#define KERNEL_HWCAP_SVEF64MM __khwcap2_feature(SVEF64MM)
+#define KERNEL_HWCAP_SVEBF16 __khwcap2_feature(SVEBF16)
+#define KERNEL_HWCAP_I8MM __khwcap2_feature(I8MM)
+#define KERNEL_HWCAP_DGH __khwcap2_feature(DGH)
+#define KERNEL_HWCAP_BF16 __khwcap2_feature(BF16)
+#define KERNEL_HWCAP_SPECRES __khwcap2_feature(SPECRES)

/*
* This yields a mask that user programs can use to figure out what
diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index 6e919fafb43d..f56c4a02a127 100644
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -553,6 +553,10 @@
#define ID_AA64ISAR0_AES_SHIFT 4

/* id_aa64isar1 */
+#define ID_AA64ISAR1_I8MM_SHIFT 52
+#define ID_AA64ISAR1_DGH_SHIFT 48
+#define ID_AA64ISAR1_BF16_SHIFT 44
+#define ID_AA64ISAR1_SPECRES_SHIFT 40
#define ID_AA64ISAR1_SB_SHIFT 36
#define ID_AA64ISAR1_FRINTTS_SHIFT 32
#define ID_AA64ISAR1_GPI_SHIFT 28
@@ -605,12 +609,20 @@
#define ID_AA64PFR1_SSBS_PSTATE_INSNS 2

/* id_aa64zfr0 */
+#define ID_AA64ZFR0_F64MM_SHIFT 56
+#define ID_AA64ZFR0_F32MM_SHIFT 52
+#define ID_AA64ZFR0_I8MM_SHIFT 44
#define ID_AA64ZFR0_SM4_SHIFT 40
#define ID_AA64ZFR0_SHA3_SHIFT 32
+#define ID_AA64ZFR0_BF16_SHIFT 20
#define ID_AA64ZFR0_BITPERM_SHIFT 16
#define ID_AA64ZFR0_AES_SHIFT 4
#define ID_AA64ZFR0_SVEVER_SHIFT 0

+#define ID_AA64ZFR0_F64MM 0x1
+#define ID_AA64ZFR0_F32MM 0x1
+#define ID_AA64ZFR0_I8MM 0x1
+#define ID_AA64ZFR0_BF16 0x1
#define ID_AA64ZFR0_SM4 0x1
#define ID_AA64ZFR0_SHA3 0x1
#define ID_AA64ZFR0_BITPERM 0x1
diff --git a/arch/arm64/include/uapi/asm/hwcap.h b/arch/arm64/include/uapi/asm/hwcap.h
index a1e72886b30c..8f3f1b66f7b2 100644
--- a/arch/arm64/include/uapi/asm/hwcap.h
+++ b/arch/arm64/include/uapi/asm/hwcap.h
@@ -65,5 +65,13 @@
#define HWCAP2_SVESM4 (1 << 6)
#define HWCAP2_FLAGM2 (1 << 7)
#define HWCAP2_FRINT (1 << 8)
+#define HWCAP2_SVEI8MM (1 << 9)
+#define HWCAP2_SVEF32MM (1 << 10)
+#define HWCAP2_SVEF64MM (1 << 11)
+#define HWCAP2_SVEBF16 (1 << 12)
+#define HWCAP2_I8MM (1 << 13)
+#define HWCAP2_BF16 (1 << 14)
+#define HWCAP2_DGH (1 << 15)
+#define HWCAP2_SPECRES (1 << 16)

#endif /* _UAPI__ASM_HWCAP_H */
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 04cf64e9f0c9..bf9e9e09da0d 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -135,6 +135,10 @@ static const struct arm64_ftr_bits ftr_id_aa64isar0[] = {
};

static const struct arm64_ftr_bits ftr_id_aa64isar1[] = {
+ ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_I8MM_SHIFT, 4, 0),
+ ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_DGH_SHIFT, 4, 0),
+ ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_BF16_SHIFT, 4, 0),
+ ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_SPECRES_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_SB_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_FRINTTS_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_PTR_AUTH),
@@ -176,10 +180,18 @@ static const struct arm64_ftr_bits ftr_id_aa64pfr1[] = {
};

static const struct arm64_ftr_bits ftr_id_aa64zfr0[] = {
+ ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SVE),
+ FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ZFR0_F64MM_SHIFT, 4, 0),
+ ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SVE),
+ FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ZFR0_F32MM_SHIFT, 4, 0),
+ ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SVE),
+ FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ZFR0_I8MM_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SVE),
FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ZFR0_SM4_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SVE),
FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ZFR0_SHA3_SHIFT, 4, 0),
+ ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SVE),
+ FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ZFR0_BF16_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SVE),
FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ZFR0_BITPERM_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SVE),
@@ -1651,6 +1663,10 @@ static const struct arm64_cpu_capabilities arm64_elf_hwcaps[] = {
HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_LRCPC_SHIFT, FTR_UNSIGNED, 2, CAP_HWCAP, KERNEL_HWCAP_ILRCPC),
HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_FRINTTS_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_FRINT),
HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_SB_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_SB),
+ HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_SPECRES_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_SPECRES),
+ HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_BF16_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_BF16),
+ HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_DGH_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_DGH),
+ HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_I8MM_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_I8MM),
HWCAP_CAP(SYS_ID_AA64MMFR2_EL1, ID_AA64MMFR2_AT_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_USCAT),
#ifdef CONFIG_ARM64_SVE
HWCAP_CAP(SYS_ID_AA64PFR0_EL1, ID_AA64PFR0_SVE_SHIFT, FTR_UNSIGNED, ID_AA64PFR0_SVE, CAP_HWCAP, KERNEL_HWCAP_SVE),
@@ -1658,8 +1674,12 @@ static const struct arm64_cpu_capabilities arm64_elf_hwcaps[] = {
HWCAP_CAP(SYS_ID_AA64ZFR0_EL1, ID_AA64ZFR0_AES_SHIFT, FTR_UNSIGNED, ID_AA64ZFR0_AES, CAP_HWCAP, KERNEL_HWCAP_SVEAES),
HWCAP_CAP(SYS_ID_AA64ZFR0_EL1, ID_AA64ZFR0_AES_SHIFT, FTR_UNSIGNED, ID_AA64ZFR0_AES_PMULL, CAP_HWCAP, KERNEL_HWCAP_SVEPMULL),
HWCAP_CAP(SYS_ID_AA64ZFR0_EL1, ID_AA64ZFR0_BITPERM_SHIFT, FTR_UNSIGNED, ID_AA64ZFR0_BITPERM, CAP_HWCAP, KERNEL_HWCAP_SVEBITPERM),
+ HWCAP_CAP(SYS_ID_AA64ZFR0_EL1, ID_AA64ZFR0_BF16_SHIFT, FTR_UNSIGNED, ID_AA64ZFR0_BF16, CAP_HWCAP, KERNEL_HWCAP_SVEBF16),
HWCAP_CAP(SYS_ID_AA64ZFR0_EL1, ID_AA64ZFR0_SHA3_SHIFT, FTR_UNSIGNED, ID_AA64ZFR0_SHA3, CAP_HWCAP, KERNEL_HWCAP_SVESHA3),
HWCAP_CAP(SYS_ID_AA64ZFR0_EL1, ID_AA64ZFR0_SM4_SHIFT, FTR_UNSIGNED, ID_AA64ZFR0_SM4, CAP_HWCAP, KERNEL_HWCAP_SVESM4),
+ HWCAP_CAP(SYS_ID_AA64ZFR0_EL1, ID_AA64ZFR0_I8MM_SHIFT, FTR_UNSIGNED, ID_AA64ZFR0_I8MM, CAP_HWCAP, KERNEL_HWCAP_SVEI8MM),
+ HWCAP_CAP(SYS_ID_AA64ZFR0_EL1, ID_AA64ZFR0_F32MM_SHIFT, FTR_UNSIGNED, ID_AA64ZFR0_F32MM, CAP_HWCAP, KERNEL_HWCAP_SVEF32MM),
+ HWCAP_CAP(SYS_ID_AA64ZFR0_EL1, ID_AA64ZFR0_F64MM_SHIFT, FTR_UNSIGNED, ID_AA64ZFR0_F64MM, CAP_HWCAP, KERNEL_HWCAP_SVEF64MM),
#endif
HWCAP_CAP(SYS_ID_AA64PFR1_EL1, ID_AA64PFR1_SSBS_SHIFT, FTR_UNSIGNED, ID_AA64PFR1_SSBS_PSTATE_INSNS, CAP_HWCAP, KERNEL_HWCAP_SSBS),
#ifdef CONFIG_ARM64_PTR_AUTH
diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
index 56bba746da1c..1eaf4dc0c5a0 100644
--- a/arch/arm64/kernel/cpuinfo.c
+++ b/arch/arm64/kernel/cpuinfo.c
@@ -84,6 +84,14 @@ static const char *const hwcap_str[] = {
"svesm4",
"flagm2",
"frint",
+ "svei8mm",
+ "svef32mm",
+ "svef64mm",
+ "svebf16",
+ "i8mm",
+ "bf16",
+ "dgh",
+ "specres",
NULL
};

--
2.20.1

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