UPSTREAM: arm64: cpufeature: add HWCAP for FEAT_AFP
commit 5c13f042e73200b50573ace63e1a6b94e2917616 upstream.
Add a new HWCAP to detect the Alternate Floating-point Behaviour
feature (FEAT_AFP), introduced in Armv8.7.
Also expose this to userspace in the ID_AA64MMFR1_EL1 feature register.
Bug: 215557547
Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Cc: Will Deacon <will@kernel.org>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211210165432.8106-2-joey.gouly@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: Ifb7685f6d97cb469262a3766daab71d09f293b1b
diff --git a/Documentation/arm64/cpu-feature-registers.rst b/Documentation/arm64/cpu-feature-registers.rst
index 9f9b8fd..1b19d20 100644
--- a/Documentation/arm64/cpu-feature-registers.rst
+++ b/Documentation/arm64/cpu-feature-registers.rst
@@ -275,6 +275,15 @@
| SVEVer | [3-0] | y |
+------------------------------+---------+---------+
+ 8) ID_AA64MMFR1_EL1 - Memory model feature register 1
+
+ +------------------------------+---------+---------+
+ | Name | bits | visible |
+ +------------------------------+---------+---------+
+ | AFP | [47-44] | y |
+ +------------------------------+---------+---------+
+
+
Appendix I: Example
-------------------
diff --git a/Documentation/arm64/elf_hwcaps.rst b/Documentation/arm64/elf_hwcaps.rst
index b8b5b89..0ec6539 100644
--- a/Documentation/arm64/elf_hwcaps.rst
+++ b/Documentation/arm64/elf_hwcaps.rst
@@ -249,6 +249,10 @@
Functionality implied by ID_AA64MMFR0_EL1.ECV == 0b0001.
+HWCAP2_AFP
+
+ Functionality implied by ID_AA64MFR1_EL1.AFP == 0b0001.
+
HWCAP2_MTE3
Functionality implied by ID_AA64PFR1_EL1.MTE == 0b0011, as described
diff --git a/arch/arm64/include/asm/hwcap.h b/arch/arm64/include/asm/hwcap.h
index 9273d1d..a3a8325 100644
--- a/arch/arm64/include/asm/hwcap.h
+++ b/arch/arm64/include/asm/hwcap.h
@@ -106,6 +106,7 @@
#define KERNEL_HWCAP_BTI __khwcap2_feature(BTI)
#define KERNEL_HWCAP_MTE __khwcap2_feature(MTE)
#define KERNEL_HWCAP_ECV __khwcap2_feature(ECV)
+#define KERNEL_HWCAP_AFP __khwcap2_feature(AFP)
#define KERNEL_HWCAP_MTE3 __khwcap2_feature(MTE3)
/*
diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index 25905ce..6c83060 100644
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -892,6 +892,7 @@
#endif
/* id_aa64mmfr1 */
+#define ID_AA64MMFR1_AFP_SHIFT 44
#define ID_AA64MMFR1_ETS_SHIFT 36
#define ID_AA64MMFR1_TWED_SHIFT 32
#define ID_AA64MMFR1_XNX_SHIFT 28
diff --git a/arch/arm64/include/uapi/asm/hwcap.h b/arch/arm64/include/uapi/asm/hwcap.h
index 79ecc90..03bf486 100644
--- a/arch/arm64/include/uapi/asm/hwcap.h
+++ b/arch/arm64/include/uapi/asm/hwcap.h
@@ -76,6 +76,7 @@
#define HWCAP2_BTI (1 << 17)
#define HWCAP2_MTE (1 << 18)
#define HWCAP2_ECV (1 << 19)
+#define HWCAP2_AFP (1 << 20)
#define HWCAP2_MTE3 (1 << 22)
#endif /* _UAPI__ASM_HWCAP_H */
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 211587e..9866cc9 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -330,6 +330,7 @@
};
static const struct arm64_ftr_bits ftr_id_aa64mmfr1[] = {
+ ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_AFP_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_ETS_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_TWED_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_XNX_SHIFT, 4, 0),
@@ -2443,6 +2444,7 @@
HWCAP_CAP(SYS_ID_AA64PFR1_EL1, ID_AA64PFR1_MTE_SHIFT, FTR_UNSIGNED, ID_AA64PFR1_MTE_ASYMM, CAP_HWCAP, KERNEL_HWCAP_MTE3),
#endif /* CONFIG_ARM64_MTE */
HWCAP_CAP(SYS_ID_AA64MMFR0_EL1, ID_AA64MMFR0_ECV_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_ECV),
+ HWCAP_CAP(SYS_ID_AA64MMFR1_EL1, ID_AA64MMFR1_AFP_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_AFP),
{},
};
diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
index 39e38cc..26624e7 100644
--- a/arch/arm64/kernel/cpuinfo.c
+++ b/arch/arm64/kernel/cpuinfo.c
@@ -95,6 +95,7 @@
[KERNEL_HWCAP_BTI] = "bti",
[KERNEL_HWCAP_MTE] = "mte",
[KERNEL_HWCAP_ECV] = "ecv",
+ [KERNEL_HWCAP_AFP] = "afp",
[KERNEL_HWCAP_MTE3] = "mte3",
};
