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Date:   Thu, 20 Aug 2020 13:44:56 -0700 (PDT)
Subject:     Re: [PATCH 1/3] riscv: Set more data to cacheinfo
In-Reply-To: <3ca47cfde607516e51f78f1645357ca739e775d0.1593766028.git.zong.li@sifive.com>
CC:     Paul Walmsley <paul.walmsley@sifive.com>,
        linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
        zong.li@sifive.com
From:   Palmer Dabbelt <palmer@dabbelt.com>
To:     zong.li@sifive.com
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On Fri, 03 Jul 2020 01:57:53 PDT (-0700), zong.li@sifive.com wrote:
> Set cacheinfo.{size,sets,line_size} for each cache node, then we can
> get these information from userland through auxiliary vector.
>
> Signed-off-by: Zong Li <zong.li@sifive.com>
> ---
>  arch/riscv/kernel/cacheinfo.c | 59 ++++++++++++++++++++++++++---------
>  1 file changed, 44 insertions(+), 15 deletions(-)
>
> diff --git a/arch/riscv/kernel/cacheinfo.c b/arch/riscv/kernel/cacheinfo.c
> index 4c90c07d8c39..cdd35e53fd98 100644
> --- a/arch/riscv/kernel/cacheinfo.c
> +++ b/arch/riscv/kernel/cacheinfo.c
> @@ -8,12 +8,46 @@
>  #include <linux/of.h>
>  #include <linux/of_device.h>
>
> -static void ci_leaf_init(struct cacheinfo *this_leaf,
> -			 struct device_node *node,
> -			 enum cache_type type, unsigned int level)
> +static void ci_leaf_init(struct cacheinfo *this_leaf, enum cache_type type,
> +			 unsigned int level, unsigned int size,
> +			 unsigned int sets, unsigned int line_size)
>  {
>  	this_leaf->level = level;
>  	this_leaf->type = type;
> +	this_leaf->size = size;
> +	this_leaf->number_of_sets = sets;
> +	this_leaf->coherency_line_size = line_size;
> +
> +	/*
> +	 * If the cache is fully associative, there is no need to
> +	 * check the other properties.
> +	 */
> +	if (!(sets == 1) && (sets > 0 && size > 0 && line_size > 0))
> +		this_leaf->ways_of_associativity = (size / sets) / line_size;
> +}
> +
> +static void fill_cacheinfo(struct cacheinfo **this_leaf,
> +			   struct device_node *node, unsigned int level)
> +{
> +	unsigned int size, sets, line_size;
> +
> +	if (!of_property_read_u32(node, "cache-size", &size)) {
> +		of_property_read_u32(node, "cache-block-size", &line_size);
> +		of_property_read_u32(node, "cache-sets", &sets);

Presumably we should be checking for errors here as well, rather than just
passing arbitrary values to userspace?

> +		ci_leaf_init((*this_leaf)++, CACHE_TYPE_UNIFIED, level, size, sets, line_size);
> +	}
> +
> +	if (!of_property_read_u32(node, "i-cache-size", &size)) {
> +		of_property_read_u32(node, "i-cache-sets", &sets);
> +		of_property_read_u32(node, "i-cache-block-size", &line_size);
> +		ci_leaf_init((*this_leaf)++, CACHE_TYPE_INST, level, size, sets, line_size);
> +	}
> +
> +	if (!of_property_read_u32(node, "d-cache-size", &size)) {
> +		of_property_read_u32(node, "d-cache-sets", &sets);
> +		of_property_read_u32(node, "d-cache-block-size", &line_size);
> +		ci_leaf_init((*this_leaf)++, CACHE_TYPE_DATA, level, size, sets, line_size);
> +	}
>  }
>
>  static int __init_cache_level(unsigned int cpu)
> @@ -66,29 +100,24 @@ static int __populate_cache_leaves(unsigned int cpu)
>  	struct device_node *prev = NULL;
>  	int levels = 1, level = 1;
>
> -	if (of_property_read_bool(np, "cache-size"))
> -		ci_leaf_init(this_leaf++, np, CACHE_TYPE_UNIFIED, level);
> -	if (of_property_read_bool(np, "i-cache-size"))
> -		ci_leaf_init(this_leaf++, np, CACHE_TYPE_INST, level);
> -	if (of_property_read_bool(np, "d-cache-size"))
> -		ci_leaf_init(this_leaf++, np, CACHE_TYPE_DATA, level);
> +	/* Level 1 caches in cpu node */
> +	fill_cacheinfo(&this_leaf, np, level);
>
> +	/* Next level caches in cache nodes */
>  	prev = np;
>  	while ((np = of_find_next_cache_node(np))) {
>  		of_node_put(prev);
>  		prev = np;
> +
>  		if (!of_device_is_compatible(np, "cache"))
>  			break;
>  		if (of_property_read_u32(np, "cache-level", &level))
>  			break;
>  		if (level <= levels)
>  			break;
> -		if (of_property_read_bool(np, "cache-size"))
> -			ci_leaf_init(this_leaf++, np, CACHE_TYPE_UNIFIED, level);
> -		if (of_property_read_bool(np, "i-cache-size"))
> -			ci_leaf_init(this_leaf++, np, CACHE_TYPE_INST, level);
> -		if (of_property_read_bool(np, "d-cache-size"))
> -			ci_leaf_init(this_leaf++, np, CACHE_TYPE_DATA, level);
> +
> +		fill_cacheinfo(&this_leaf, np, level);
> +
>  		levels = level;
>  	}
>  	of_node_put(np);