linux/Documentation/arch
Palmer Dabbelt 52420e483d
RISC-V: Provide the frequency of time CSR via hwprobe
The RISC-V architecture makes a real time counter CSR (via RDTIME
instruction) available for applications in U-mode but there is no
architected mechanism for an application to discover the frequency
the counter is running at. Some applications (e.g., DPDK) use the
time counter for basic performance analysis as well as fine grained
time-keeping.

Add support to the hwprobe system call to export the time CSR
frequency to code running in U-mode.

Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
Reviewed-by: Evan Green <evan@rivosinc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Acked-by: Punit Agrawal <punit.agrawal@bytedance.com>
Link: https://lore.kernel.org/r/20240702033731.71955-2-cuiyunhui@bytedance.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-07-26 05:50:51 -07:00
..
arc docs: kernel_feat.py: fix potential command injection 2024-01-11 09:21:01 -07:00
arm docs: kernel_feat.py: fix potential command injection 2024-01-11 09:21:01 -07:00
arm64 Merge branch 'for-next/vcpu-hotplug' into for-next/core 2024-07-11 19:10:02 +01:00
loongarch A handful of late-arriving documentation fixes. 2024-01-17 11:49:11 -08:00
m68k Docs: typos/spelling 2024-05-02 10:02:29 -06:00
mips docs: kernel_feat.py: fix potential command injection 2024-01-11 09:21:01 -07:00
nios2 docs: kernel_feat.py: fix potential command injection 2024-01-11 09:21:01 -07:00
openrisc docs: kernel_feat.py: fix potential command injection 2024-01-11 09:21:01 -07:00
parisc docs: kernel_feat.py: fix potential command injection 2024-01-11 09:21:01 -07:00
powerpc Merge branch 'topic/ppc-kvm' into next 2024-07-18 14:32:46 +10:00
riscv RISC-V: Provide the frequency of time CSR via hwprobe 2024-07-26 05:50:51 -07:00
s390 docs: Update s390 vfio-ap doc for ap_config sysfs attribute 2024-04-22 12:49:18 +02:00
sh docs: kernel_feat.py: fix potential command injection 2024-01-11 09:21:01 -07:00
sparc Docs: typos/spelling 2024-05-02 10:02:29 -06:00
x86 Nothing hugely exciting happening in the documentation tree this time 2024-07-18 15:54:16 -07:00
xtensa docs: kernel_feat.py: fix potential command injection 2024-01-11 09:21:01 -07:00
index.rst The number of commits for documentation is not huge this time around, but 2023-11-01 17:11:41 -10:00