ARM: 9268/1: vfp: Add hwcap FPHP and ASIMDHP for FEAT_FP16

Floating point half-precision (FPHP) and Advanced SIMD half-precision
(ASIMDHP) are VFP features (FEAT_FP16) represented by MVFR1 identification register. These capabilities can optionally exist with VFPv3 and mandatory with VFPv4. Both these new features exist for Armv8 architecture in AArch32 state.

These hwcaps may be useful for the userspace to add conditional check
before trying to use FEAT_FP16 feature specific instructions.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>

diff --git a/arch/arm/include/asm/vfp.h b/arch/arm/include/asm/vfp.h
index 19928bf..157ea34 100644 (file)
--- a/arch/arm/include/asm/vfp.h
+++ b/arch/arm/include/asm/vfp.h
@@ -87,6 +87,12 @@
 #define MVFR0_DP_BIT           (8)
 #define MVFR0_DP_MASK          (0xf << MVFR0_DP_BIT)
 
+/* MVFR1 bits */
+#define MVFR1_ASIMDHP_BIT      (20)
+#define MVFR1_ASIMDHP_MASK     (0xf << MVFR1_ASIMDHP_BIT)
+#define MVFR1_FPHP_BIT         (24)
+#define MVFR1_FPHP_MASK                (0xf << MVFR1_FPHP_BIT)
+
 /* Bit patterns for decoding the packaged operation descriptors */
 #define VFPOPDESC_LENGTH_BIT   (9)
 #define VFPOPDESC_LENGTH_MASK  (0x07 << VFPOPDESC_LENGTH_BIT)

diff --git a/arch/arm/include/uapi/asm/hwcap.h b/arch/arm/include/uapi/asm/hwcap.h
index 990199d..8b6f690 100644 (file)
--- a/arch/arm/include/uapi/asm/hwcap.h
+++ b/arch/arm/include/uapi/asm/hwcap.h
@@ -28,6 +28,8 @@
 #define HWCAP_IDIV     (HWCAP_IDIVA | HWCAP_IDIVT)
 #define HWCAP_LPAE     (1 << 20)
 #define HWCAP_EVTSTRM  (1 << 21)
+#define HWCAP_FPHP     (1 << 22)
+#define HWCAP_ASIMDHP  (1 << 23)
 
 /*
  * HWCAP2 flags - for elf_hwcap2 (in kernel) and AT_HWCAP2

diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index 1e8a50a..870e5d5 100644 (file)
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -1249,6 +1249,8 @@ static const char *hwcap_str[] = {
        "vfpd32",
        "lpae",
        "evtstrm",
+       "fphp",
+       "asimdhp",
        NULL
 };
 

diff --git a/arch/arm/vfp/vfpmodule.c b/arch/arm/vfp/vfpmodule.c
index 2cb355c..55dcd96 100644 (file)
--- a/arch/arm/vfp/vfpmodule.c
+++ b/arch/arm/vfp/vfpmodule.c
@@ -831,6 +831,10 @@ static int __init vfp_init(void)
 
                        if ((fmrx(MVFR1) & 0xf0000000) == 0x10000000)
                                elf_hwcap |= HWCAP_VFPv4;
+                       if (((fmrx(MVFR1) & MVFR1_ASIMDHP_MASK) >> MVFR1_ASIMDHP_BIT) == 0x2)
+                               elf_hwcap |= HWCAP_ASIMDHP;
+                       if (((fmrx(MVFR1) & MVFR1_FPHP_MASK) >> MVFR1_FPHP_BIT) == 0x3)
+                               elf_hwcap |= HWCAP_FPHP;
                }
        /* Extract the architecture version on pre-cpuid scheme */
        } else {