Some applications (e.g., DPDK) use the time counter for basic performance analysis as well as fine grained time-keeping. So we need export the time CSR frequency to userspace by hwporbe syscall. Changes: v1->v2: Modify "mtime" to "time CSR". v2->v3: Rebase "RISCV_HWPROBE_MAX_KEY 7" to "RISCV_HWPROBE_MAX_KEY 8" from Jesse. v3->v4: 1. Update the commit log from Punit. 2. Because RISCV_HWPROBE_MAX_KEY in https://git.kernel.org/pub/scm/linux/kernel/git/palmer/linux.git/tree/arch/riscv/include/asm/hwprobe.h?h=for-next is 6, so keep RISCV_HWPROBE_MAX_KEY to 7 Palmer Dabbelt (1): RISC-V: Provide the frequency of time CSR via hwprobe Documentation/arch/riscv/hwprobe.rst | 2 ++ arch/riscv/include/asm/hwprobe.h | 2 +- arch/riscv/include/uapi/asm/hwprobe.h | 1 + arch/riscv/kernel/sys_hwprobe.c | 5 +++++ 4 files changed, 9 insertions(+), 1 deletion(-) -- 2.20.1
