linux-kernel - Re: [PATCH 2/2] phy: qualcomm: eusb2-repeater: Drop the redundant zeroing

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <33b32e2b-fa35-448c-8b4c-c5c51a514922@linaro.org>
Date: Thu, 4 Jan 2024 23:50:48 +0100
From: Konrad Dybcio <konrad.dybcio@...aro.org>
To: Abel Vesa <abel.vesa@...aro.org>, Bjorn Andersson <andersson@...nel.org>,
 Vinod Koul <vkoul@...nel.org>, Kishon Vijay Abraham I <kishon@...nel.org>
Cc: linux-arm-msm@...r.kernel.org, linux-phy@...ts.infradead.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] phy: qualcomm: eusb2-repeater: Drop the redundant
 zeroing

On 4.01.2024 15:52, Abel Vesa wrote:
> The local init_tlb is already zero initialized, so the entire zeroing loop
> is useless in this case, since the initial values are copied over anyway,
> before being written.
> 
> Fixes: 99a517a582fc ("phy: qualcomm: phy-qcom-eusb2-repeater: Zero out untouched tuning regs")
> Signed-off-by: Abel Vesa <abel.vesa@...aro.org>
> ---

That's another good spot.. partial struct initialization of
pm8550b_init_tbl zeroes out the uninitialized fields.


>  drivers/phy/qualcomm/phy-qcom-eusb2-repeater.c | 10 ----------
>  1 file changed, 10 deletions(-)
> 
> diff --git a/drivers/phy/qualcomm/phy-qcom-eusb2-repeater.c b/drivers/phy/qualcomm/phy-qcom-eusb2-repeater.c
> index 5f5862a68b73..3060c0749797 100644
> --- a/drivers/phy/qualcomm/phy-qcom-eusb2-repeater.c
> +++ b/drivers/phy/qualcomm/phy-qcom-eusb2-repeater.c
> @@ -156,16 +156,6 @@ static int eusb2_repeater_init(struct phy *phy)
>  
>  	regmap_field_update_bits(rptr->regs[F_EN_CTL1], EUSB2_RPTR_EN, EUSB2_RPTR_EN);
>  
> -	for (i = 0; i < F_NUM_TUNE_FIELDS; i++) {
> -		if (init_tbl[i]) {
> -			regmap_field_update_bits(rptr->regs[i], init_tbl[i], init_tbl[i]);
> -		} else {
> -			/* Write 0 if there's no value set */
> -			u32 mask = GENMASK(regfields[i].msb, regfields[i].lsb);
> -
> -			regmap_field_update_bits(rptr->regs[i], mask, 0);
> -		}
> -	}
>  	memcpy(init_tbl, rptr->cfg->init_tbl, sizeof(init_tbl));

I think this patchset can be made even better, this memcpy is also
useless and we can simply initialize init_tbl=rptr->cfg->init_tbl.

Konrad