Re: [PATCH v1] clk: microchip: mpfs-ccc: fix peripheral driver registration failures after oob fix

[Brian Masney <bmasney@redhat.com>]

On Thu, Apr 30, 2026 at 07:30:28PM +0100, Conor Dooley wrote:
> From: Conor Dooley <conor.dooley@microchip.com>
> 
> Commit 2f7ae8ab6aa73 ("clk: microchip: mpfs-ccc: fix out of bounds
> access during output registration") fixed the out of bounds access, but
> it did so by packing sparse indices into a linear space. When
> peripheral drivers request clocks, they obviously don't care for this
> compression and use the sparse indices, and therefore try to request the
> wrong clocks or clocks that don't exist.
> 
> The most straightforward fix here seems to stop being clever with the
> packing and just overallocate the array.
> 
> Fixes: 2f7ae8ab6aa73 ("clk: microchip: mpfs-ccc: fix out of bounds access during output registration")
> Fixes: d39fb172760e ("clk: microchip: add PolarFire SoC fabric clock support")
> Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
> ---
> CC: Daire McNamara <daire.mcnamara@microchip.com>
> CC: Michael Turquette <mturquette@baylibre.com>
> CC: Stephen Boyd <sboyd@kernel.org>
> CC: Brian Masney <bmasney@redhat.com>
> CC: Claudiu Beznea <claudiu.beznea@tuxon.dev>
> CC: linux-riscv@lists.infradead.org
> CC: linux-clk@vger.kernel.org
> CC: linux-kernel@vger.kernel.org
> ---
>  drivers/clk/microchip/clk-mpfs-ccc.c | 15 ++++-----------
>  1 file changed, 4 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/clk/microchip/clk-mpfs-ccc.c b/drivers/clk/microchip/clk-mpfs-ccc.c
> index 0a76a1aaa50f7..40c17593e5941 100644
> --- a/drivers/clk/microchip/clk-mpfs-ccc.c
> +++ b/drivers/clk/microchip/clk-mpfs-ccc.c
> @@ -32,6 +32,7 @@
>  #define MPFS_CCC_FIXED_DIV		4
>  #define MPFS_CCC_OUTPUTS_PER_PLL	4
>  #define MPFS_CCC_REFS_PER_PLL		2
> +#define MPFS_CCC_NUM_CLKS		16
>  
>  struct mpfs_ccc_data {
>  	void __iomem **pll_base;
> @@ -178,7 +179,7 @@ static int mpfs_ccc_register_outputs(struct device *dev, struct mpfs_ccc_out_hw_
>  			return dev_err_probe(dev, ret, "failed to register clock id: %d\n",
>  					     out_hw->id);
>  
> -		data->hw_data.hws[out_hw->id - 2] = &out_hw->divider.hw;
> +		data->hw_data.hws[out_hw->id] = &out_hw->divider.hw;
>  	}
>  
>  	return 0;
> @@ -231,17 +232,9 @@ static int mpfs_ccc_probe(struct platform_device *pdev)
>  {
>  	struct mpfs_ccc_data *clk_data;
>  	void __iomem *pll_base[ARRAY_SIZE(mpfs_ccc_pll_clks)];
> -	unsigned int num_clks;
>  	int ret;
>  
> -	/*
> -	 * If DLLs get added here, mpfs_ccc_register_outputs() currently packs
> -	 * sparse clock IDs in the hws array
> -	 */
> -	num_clks = ARRAY_SIZE(mpfs_ccc_pll_clks) + ARRAY_SIZE(mpfs_ccc_pll0out_clks) +
> -		   ARRAY_SIZE(mpfs_ccc_pll1out_clks);
> -
> -	clk_data = devm_kzalloc(&pdev->dev, struct_size(clk_data, hw_data.hws, num_clks),
> +	clk_data = devm_kzalloc(&pdev->dev, struct_size(clk_data, hw_data.hws, MPFS_CCC_NUM_CLKS),
>  				GFP_KERNEL);
>  	if (!clk_data)
>  		return -ENOMEM;
> @@ -255,7 +248,7 @@ static int mpfs_ccc_probe(struct platform_device *pdev)
>  		return PTR_ERR(pll_base[1]);
>  
>  	clk_data->pll_base = pll_base;
> -	clk_data->hw_data.num = num_clks;
> +	clk_data->hw_data.num = MPFS_CCC_NUM_CLKS;
>  	clk_data->dev = &pdev->dev;
>  
>  	ret = mpfs_ccc_register_plls(clk_data->dev, mpfs_ccc_pll_clks,

Reviewed-by: Brian Masney <bmasney@redhat.com>

I confirmed that there are 16 clock IDs defined at the bottom of
include/dt-bindings/clock/microchip,mpfs-clock.h.

Brian