From 62ea0d873af3ef0a7e8387b67241ad43e3d377e1 Mon Sep 17 00:00:00 2001
From: Amit Daniel Kachhap <amit.kachhap@arm.com>
Date: Thu, 17 Nov 2022 06:32:56 +0100
Subject: [PATCH] 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>
---
arch/arm/include/uapi/asm/hwcap.h | 1 +
arch/arm/kernel/setup.c | 1 +
arch/arm/vfp/vfpmodule.c | 10 ++++++++++
3 files changed, 12 insertions(+)
diff --git a/arch/arm/include/uapi/asm/hwcap.h b/arch/arm/include/uapi/asm/hwcap.h
index 8b6f690f0ac49..64f3608e6f1bf 100644
--- 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 870e5d5c5b5bf..9841b897d476c 100644
--- 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 55dcd96c7e3b5..70f1e0f4eece8 100644
--- 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) {
--
2.30.2