From 63f93a3ca891fd90353cf81f5d2fc4cbc3508f1a Mon Sep 17 00:00:00 2001 From: =?utf8?q?Cl=C3=A9ment=20L=C3=A9ger?= Date: Wed, 21 Feb 2024 09:31:06 +0100 Subject: [PATCH] riscv: hwprobe: export Zihintpause ISA extension MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Export the Zihintpause ISA extension through hwprobe which allows using "pause" instructions. Some userspace applications (OpenJDK for instance) uses this to handle some locking back-off. Signed-off-by: Clément Léger Reviewed-by: Atish Patra Link: https://lore.kernel.org/r/20240221083108.1235311-1-cleger@rivosinc.com Signed-off-by: Palmer Dabbelt --- Documentation/arch/riscv/hwprobe.rst | 4 ++++ arch/riscv/include/uapi/asm/hwprobe.h | 1 + arch/riscv/kernel/sys_hwprobe.c | 1 + 3 files changed, 6 insertions(+) diff --git a/Documentation/arch/riscv/hwprobe.rst b/Documentation/arch/riscv/hwprobe.rst index b2bcc9eed9aa9..204cd4433af5b 100644 --- a/Documentation/arch/riscv/hwprobe.rst +++ b/Documentation/arch/riscv/hwprobe.rst @@ -188,6 +188,10 @@ The following keys are defined: manual starting from commit 95cf1f9 ("Add changes requested by Ved during signoff") + * :c:macro:`RISCV_HWPROBE_EXT_ZIHINTPAUSE`: The Zihintpause extension is + supported as defined in the RISC-V ISA manual starting from commit + d8ab5c78c207 ("Zihintpause is ratified"). + * :c:macro:`RISCV_HWPROBE_KEY_CPUPERF_0`: A bitmask that contains performance information about the selected set of processors. diff --git a/arch/riscv/include/uapi/asm/hwprobe.h b/arch/riscv/include/uapi/asm/hwprobe.h index 9f2a8e3ff2048..31c570cbd1c58 100644 --- a/arch/riscv/include/uapi/asm/hwprobe.h +++ b/arch/riscv/include/uapi/asm/hwprobe.h @@ -59,6 +59,7 @@ struct riscv_hwprobe { #define RISCV_HWPROBE_EXT_ZTSO (1ULL << 33) #define RISCV_HWPROBE_EXT_ZACAS (1ULL << 34) #define RISCV_HWPROBE_EXT_ZICOND (1ULL << 35) +#define RISCV_HWPROBE_EXT_ZIHINTPAUSE (1ULL << 36) #define RISCV_HWPROBE_KEY_CPUPERF_0 5 #define RISCV_HWPROBE_MISALIGNED_UNKNOWN (0 << 0) #define RISCV_HWPROBE_MISALIGNED_EMULATED (1 << 0) diff --git a/arch/riscv/kernel/sys_hwprobe.c b/arch/riscv/kernel/sys_hwprobe.c index 8cae41a502dd4..969ef3d59dbe0 100644 --- a/arch/riscv/kernel/sys_hwprobe.c +++ b/arch/riscv/kernel/sys_hwprobe.c @@ -111,6 +111,7 @@ static void hwprobe_isa_ext0(struct riscv_hwprobe *pair, EXT_KEY(ZTSO); EXT_KEY(ZACAS); EXT_KEY(ZICOND); + EXT_KEY(ZIHINTPAUSE); if (has_vector()) { EXT_KEY(ZVBB); -- 2.30.2