arm64: Expose FRINT capabilities to userspace

ARMv8.5 introduces the FRINT series of instructions for rounding floating
point numbers to integers. Provide a capability to userspace in order to
allow applications to determine if the system supports these instructions.

Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/Documentation/arm64/elf_hwcaps.txt b/Documentation/arm64/elf_hwcaps.txt
index ee8dbfe..5ae2ef2 100644 (file)
--- a/Documentation/arm64/elf_hwcaps.txt
+++ b/Documentation/arm64/elf_hwcaps.txt
@@ -227,6 +227,10 @@ HWCAP_PACG
     ID_AA64ISAR1_EL1.GPI == 0b0001, as described by
     Documentation/arm64/pointer-authentication.txt.
 
+HWCAP2_FRINT
+
+    Functionality implied by ID_AA64ISAR1_EL1.FRINTTS == 0b0001.
+
 
 4. Unused AT_HWCAP bits
 -----------------------

diff --git a/arch/arm64/include/asm/hwcap.h b/arch/arm64/include/asm/hwcap.h
index 838c47f..8371202 100644 (file)
--- a/arch/arm64/include/asm/hwcap.h
+++ b/arch/arm64/include/asm/hwcap.h
@@ -96,6 +96,7 @@
 #define KERNEL_HWCAP_SVESHA3           __khwcap2_feature(SVESHA3)
 #define KERNEL_HWCAP_SVESM4            __khwcap2_feature(SVESM4)
 #define KERNEL_HWCAP_FLAGM2            __khwcap2_feature(FLAGM2)
+#define KERNEL_HWCAP_FRINT             __khwcap2_feature(FRINT)
 
 /*
  * 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 902d75b..6019727 100644 (file)
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -560,6 +560,7 @@
 
 /* id_aa64isar1 */
 #define ID_AA64ISAR1_SB_SHIFT          36
+#define ID_AA64ISAR1_FRINTTS_SHIFT     32
 #define ID_AA64ISAR1_GPI_SHIFT         28
 #define ID_AA64ISAR1_GPA_SHIFT         24
 #define ID_AA64ISAR1_LRCPC_SHIFT       20

diff --git a/arch/arm64/include/uapi/asm/hwcap.h b/arch/arm64/include/uapi/asm/hwcap.h
index 7902ae4..a1e7288 100644 (file)
--- a/arch/arm64/include/uapi/asm/hwcap.h
+++ b/arch/arm64/include/uapi/asm/hwcap.h
@@ -64,5 +64,6 @@
 #define HWCAP2_SVESHA3         (1 << 5)
 #define HWCAP2_SVESM4          (1 << 6)
 #define HWCAP2_FLAGM2          (1 << 7)
+#define HWCAP2_FRINT           (1 << 8)
 
 #endif /* _UAPI__ASM_HWCAP_H */

diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 8350016..a0f0091 100644 (file)
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -1640,6 +1640,7 @@ static const struct arm64_cpu_capabilities arm64_elf_hwcaps[] = {
        HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_FCMA_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_FCMA),
        HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_LRCPC_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_LRCPC),
        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_AA64MMFR2_EL1, ID_AA64MMFR2_AT_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_USCAT),
 #ifdef CONFIG_ARM64_SVE

diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
index 62102f7..fda8ded 100644 (file)
--- a/arch/arm64/kernel/cpuinfo.c
+++ b/arch/arm64/kernel/cpuinfo.c
@@ -93,6 +93,7 @@ static const char *const hwcap_str[] = {
        "svesha3",
        "svesm4",
        "flagm2",
+       "frint",
        NULL
 };