Re: [PATCH v2 0/3] Get cache information from userland

[Palmer Dabbelt]

On Thu, 27 Aug 2020 01:22:25 PDT (-0700), zong.li@xxxxxxxxxx wrote:
> There are no standard CSR registers to provide cache information, the
> way for RISC-V is to get this information from DT. Currently, AT_L1I_X,
> AT_L1D_X and AT_L2_X are present in glibc header, and sysconf syscall
> could use them to get information of cache through AUX vector. We
> exploit 'struct cacheinfo' to obtain the information of cache, then we
> don't need additional variable or data structure to record it.
>
> We also need some works in glibc, but we have to support the function in
> kernel first by rule of glibc, then post the patch to glibc site.
>
> The result of 'getconf -a' as follows:
>
> LEVEL1_ICACHE_SIZE                 32768
> LEVEL1_ICACHE_ASSOC                8
> LEVEL1_ICACHE_LINESIZE             64
> LEVEL1_DCACHE_SIZE                 32768
> LEVEL1_DCACHE_ASSOC                8
> LEVEL1_DCACHE_LINESIZE             64
> LEVEL2_CACHE_SIZE                  2097152
> LEVEL2_CACHE_ASSOC                 32
> LEVEL2_CACHE_LINESIZE              64
>
> Changed in v2:
>   - Add error checking for parsing cache properties.
>
> Zong Li (3):
>   riscv: Set more data to cacheinfo
>   riscv: Define AT_VECTOR_SIZE_ARCH for ARCH_DLINFO
>   riscv: Add cache information in AUX vector
>
>  arch/riscv/include/asm/cacheinfo.h   |  5 ++
>  arch/riscv/include/asm/elf.h         | 13 ++++
>  arch/riscv/include/uapi/asm/auxvec.h | 24 ++++++++
>  arch/riscv/kernel/cacheinfo.c        | 91 +++++++++++++++++++++++-----
>  4 files changed, 117 insertions(+), 16 deletions(-)

Thanks, these are on for-next.