[PATCH v2 1/1] riscv: Get cache information through sysconf

[Zong Li]

On Fri, Oct 30, 2020 at 1:33 AM Zong Li <zong.li@sifive.com> wrote:
>
> Add support to query cache information on RISC-V through sysconf()
> function. The cache information had been added in AUX vector of RISC-V
> architecture in Linux kernel v.5.10-rc1.
> ---
>  sysdeps/unix/sysv/linux/riscv/sysconf.c | 100 ++++++++++++++++++++++++
>  1 file changed, 100 insertions(+)
>  create mode 100644 sysdeps/unix/sysv/linux/riscv/sysconf.c
>
> diff --git a/sysdeps/unix/sysv/linux/riscv/sysconf.c b/sysdeps/unix/sysv/linux/riscv/sysconf.c
> new file mode 100644
> index 0000000000..02b469cc65
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/riscv/sysconf.c
> @@ -0,0 +1,100 @@
> +/* Copyright (C) 2020 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library.  If not, see
> +   <https://www.gnu.org/licenses/>.  */
> +
> +#include <errno.h>
> +#include <unistd.h>
> +#include <sys/auxv.h>
> +
> +static long int linux_sysconf (int name);
> +
> +static inline bool
> +getauxval2_einval (unsigned long int type, unsigned long int *result)
> +{
> +  if (__getauxval2 (type, result))
> +    return true;
> +
> +  __set_errno (EINVAL);
> +
> +  return false;
> +}
> +
> +static inline long int
> +sysconf_get_cache_associativity (unsigned long type)
> +{
> +  unsigned long int result;
> +
> +  if (getauxval2_einval (type, &result))
> +    return (result & 0xffff0000) >> 16;
> +
> +  return -1;
> +}
> +
> +static inline long int
> +sysconf_get_cache_linesize (unsigned long type)
> +{
> +  unsigned long int result;
> +
> +  if (getauxval2_einval (type, &result))
> +    return result & 0xffff;
> +
> +  return -1;
> +}
> +
> +static inline long int
> +sysconf_get_cache_size (unsigned long type)
> +{
> +  unsigned long int result;
> +
> +  if (getauxval2_einval (type, &result))
> +    return result;
> +
> +  return -1;
> +}
> +
> +/* Get the value of the system variable NAME.  */
> +long int
> +__sysconf (int name)
> +{
> +  switch (name)
> +    {
> +      case _SC_LEVEL1_ICACHE_SIZE:
> +       return sysconf_get_cache_size (AT_L1I_CACHESIZE);
> +      case _SC_LEVEL1_ICACHE_ASSOC:
> +       return sysconf_get_cache_associativity (AT_L1I_CACHEGEOMETRY);
> +      case _SC_LEVEL1_ICACHE_LINESIZE:
> +       return sysconf_get_cache_linesize (AT_L1I_CACHEGEOMETRY);
> +      case _SC_LEVEL1_DCACHE_SIZE:
> +       return sysconf_get_cache_size (AT_L1D_CACHESIZE);
> +      case _SC_LEVEL1_DCACHE_ASSOC:
> +       return sysconf_get_cache_associativity (AT_L1D_CACHEGEOMETRY);
> +      case _SC_LEVEL1_DCACHE_LINESIZE:
> +       return sysconf_get_cache_linesize (AT_L1D_CACHEGEOMETRY);
> +      case _SC_LEVEL2_CACHE_SIZE:
> +       return sysconf_get_cache_size (AT_L2_CACHESIZE);
> +      case _SC_LEVEL2_CACHE_ASSOC:
> +       return sysconf_get_cache_associativity (AT_L2_CACHEGEOMETRY);
> +      case _SC_LEVEL2_CACHE_LINESIZE:
> +       return sysconf_get_cache_linesize (AT_L2_CACHEGEOMETRY);
> +      default:
> +       return linux_sysconf (name);
> +    }
> +}
> +
> +/* Now the generic Linux version.  */
> +#undef __sysconf
> +#define __sysconf static linux_sysconf
> +#include <sysdeps/unix/sysv/linux/sysconf.c>
> --
> 2.28.0
>

ping