ARM: 9269/1: vfp: Add hwcap for FEAT_DotProd

Advanced Dot product is a feature present in AArch32 state for Armv8 and
is represented by ISAR6 identification register.

This feature denotes the presence of UDOT and SDOT instructions and hence adding a hwcap will enable the userspace to check it before trying to use those 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/uapi/asm/hwcap.h b/arch/arm/include/uapi/asm/hwcap.h
index 8b6f690f0ac492cd5c5792029633274a97cae698..64f3608e6f1bf68294fb0520a2d55eb0aa1a1e23 100644 (file)
--- a/arch/arm/include/uapi/asm/hwcap.h
+++ b/arch/arm/include/uapi/asm/hwcap.h
@@ -30,6 +30,7 @@
 #define HWCAP_EVTSTRM  (1 << 21)
 #define HWCAP_FPHP     (1 << 22)
 #define HWCAP_ASIMDHP  (1 << 23)
+#define HWCAP_ASIMDDP  (1 << 24)
 
 /*
  * 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 870e5d5c5b5bf7a817f5c781402a5ca379352fc5..9841b897d476c78d3969689f805e4a54fc488cf0 100644 (file)
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -1251,6 +1251,7 @@ static const char *hwcap_str[] = {
        "evtstrm",
        "fphp",
        "asimdhp",
+       "asimddp",
        NULL
 };
 

diff --git a/arch/arm/vfp/vfpmodule.c b/arch/arm/vfp/vfpmodule.c
index 55dcd96c7e3b522b65b5cfe574dfc2cb6a1d3f2b..70f1e0f4eece8da01887a928a79b5bd954bd4d06 100644 (file)
--- a/arch/arm/vfp/vfpmodule.c
+++ b/arch/arm/vfp/vfpmodule.c
@@ -774,6 +774,7 @@ static int __init vfp_init(void)
 {
        unsigned int vfpsid;
        unsigned int cpu_arch = cpu_architecture();
+       unsigned int isar6;
 
        /*
         * Enable the access to the VFP on all online CPUs so the
@@ -836,6 +837,15 @@ static int __init vfp_init(void)
                        if (((fmrx(MVFR1) & MVFR1_FPHP_MASK) >> MVFR1_FPHP_BIT) == 0x3)
                                elf_hwcap |= HWCAP_FPHP;
                }
+
+               /*
+                * Check for the presence of Advanced SIMD Dot Product
+                * instructions.
+                */
+               isar6 = read_cpuid_ext(CPUID_EXT_ISAR6);
+               if (cpuid_feature_extract_field(isar6, 4) == 0x1)
+                       elf_hwcap |= HWCAP_ASIMDDP;
+
        /* Extract the architecture version on pre-cpuid scheme */
        } else {
                if (vfpsid & FPSID_NODOUBLE) {