[PATCH v4 0/3] Get cache information from userland

[Zong Li]

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 v4:
  - Check null pointer before use.
  - Re-write the code for readability.
  - Rebase source to v5.9-rc3.

Changed in v3:
  - Fix sparse warning: Use NULL instead of integer 0.

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        | 98 +++++++++++++++++++++++-----
 4 files changed, 124 insertions(+), 16 deletions(-)

-- 
2.28.0