linux-kernel - Re: [PATCH] Revert "riscv: Set more data to cacheinfo"

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Date:   Wed, 8 Mar 2023 11:03:35 +0000
From:   Conor Dooley <conor@...nel.org>
To:     Song Shuai <suagrfillet@...il.com>
Cc:     paul.walmsley@...ive.com, palmer@...belt.com,
        aou@...s.berkeley.edu, sudeep.holla@....com,
        pierre.gondois@....com, conor.dooley@...rochip.com,
        linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Revert "riscv: Set more data to cacheinfo"

On Wed, Mar 08, 2023 at 02:47:34PM +0800, Song Shuai wrote:
> This reverts commit baf7cbd94b5688f167443a2cc3dcea3300132099.
> 
> There are some duplicate cache attributes populations executed
> in both ci_leaf_init() and later cache_setup_properties().
> 
> Revert the commit baf7cbd94b56 ("riscv: Set more data to cacheinfo")
> to setup only the level and type attributes at this early place.
>

I've attempted to do a little bit of history diving to figure out what
commit to "blame" in a fixes tag for this.
My initial thought was to blame 03f11f03dbfe ("RISC-V: Parse cpu topology
during boot."), but baf7cbd94b56 ("riscv: Set more data to cacheinfo")
looks like it came along some months later.
I assume you double checked that the stuff in the aux vector is the same
before/after this revert? Looking on lore, that seems to be why Zong did
it this way in the first place:
https://lore.kernel.org/linux-riscv/b6fed9b4c2a3eacb2a9c353c2570d9dc1d0c1c88.1598859038.git.zong.li@sifive.com/

Cheers,
Conor.

> Signed-off-by: Song Shuai <suagrfillet@...il.com>
> ---
>  arch/riscv/kernel/cacheinfo.c | 66 ++++++++---------------------------
>  1 file changed, 15 insertions(+), 51 deletions(-)
> 
> diff --git a/arch/riscv/kernel/cacheinfo.c b/arch/riscv/kernel/cacheinfo.c
> index 3a13113f1b29..305ebbdc780d 100644
> --- a/arch/riscv/kernel/cacheinfo.c
> +++ b/arch/riscv/kernel/cacheinfo.c
> @@ -64,53 +64,12 @@ uintptr_t get_cache_geometry(u32 level, enum cache_type type)
>  			   0;
>  }
>  
> -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)
> +static void ci_leaf_init(struct cacheinfo *this_leaf,
> +			 struct device_node *node,
> +			 enum cache_type type, unsigned int level)
>  {
>  	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)
> -		return;
> -
> -	/*
> -	 * Set the ways number for n-ways associative, make sure
> -	 * all properties are big than zero.
> -	 */
> -	if (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)) {
> -		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);
> -	}
>  }
>  
>  int populate_cache_leaves(unsigned int cpu)
> @@ -121,24 +80,29 @@ int populate_cache_leaves(unsigned int cpu)
>  	struct device_node *prev = NULL;
>  	int levels = 1, level = 1;
>  
> -	/* Level 1 caches in cpu node */
> -	fill_cacheinfo(&this_leaf, np, level);
> +	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);
>  
> -	/* 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;
> -
> -		fill_cacheinfo(&this_leaf, np, level);
> -
> +		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);
>  		levels = level;
>  	}
>  	of_node_put(np);
> -- 
> 2.20.1
> 

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