linux-kernel - Re: [PATCH v2] mtd: rawnand: meson: check buffer length

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Message-ID: <3a9470ed-d7ad-6cae-0d58-732399590272@sberdevices.ru>
Date:   Thu, 8 Jun 2023 00:17:35 +0300
From:   Arseniy Krasnov <avkrasnov@...rdevices.ru>
To:     Liang Yang <liang.yang@...ogic.com>,
        Miquel Raynal <miquel.raynal@...tlin.com>,
        Richard Weinberger <richard@....at>,
        Vignesh Raghavendra <vigneshr@...com>,
        Neil Armstrong <neil.armstrong@...aro.org>,
        Kevin Hilman <khilman@...libre.com>,
        Jerome Brunet <jbrunet@...libre.com>,
        Martin Blumenstingl <martin.blumenstingl@...glemail.com>
CC:     <oxffffaa@...il.com>, <kernel@...rdevices.ru>,
        <linux-mtd@...ts.infradead.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-amlogic@...ts.infradead.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] mtd: rawnand: meson: check buffer length

Hi again Miquel, Liang!

What do You think about this patch?

Thanks, Arseniy

On 06.06.2023 19:29, Arseniy Krasnov wrote:
> Sorry, here is changelog:
> v1 -> v2:
> * Move checks from 'switch/case' which executes commands in 'meson_nfc_exec_op()' to a special
>   separated function 'meson_nfc_check_op()' which is called before commands processing.
> 
> On 06.06.2023 13:16, Arseniy Krasnov wrote:
>> Meson NAND controller has limited buffer length, so check it before
>> command execution to avoid length trim. Also check MTD write size on
>> chip attach.
>>
>> Signed-off-by: Arseniy Krasnov <AVKrasnov@...rdevices.ru>
>> ---
>>  drivers/mtd/nand/raw/meson_nand.c | 47 +++++++++++++++++++++++++++----
>>  1 file changed, 42 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/mtd/nand/raw/meson_nand.c b/drivers/mtd/nand/raw/meson_nand.c
>> index 23a73268421b..db6b18753071 100644
>> --- a/drivers/mtd/nand/raw/meson_nand.c
>> +++ b/drivers/mtd/nand/raw/meson_nand.c
>> @@ -111,6 +111,8 @@
>>  
>>  #define PER_INFO_BYTE		8
>>  
>> +#define NFC_CMD_RAW_LEN	GENMASK(13, 0)
>> +
>>  struct meson_nfc_nand_chip {
>>  	struct list_head node;
>>  	struct nand_chip nand;
>> @@ -284,7 +286,7 @@ static void meson_nfc_cmd_access(struct nand_chip *nand, int raw, bool dir,
>>  
>>  	if (raw) {
>>  		len = mtd->writesize + mtd->oobsize;
>> -		cmd = (len & GENMASK(13, 0)) | scrambler | DMA_DIR(dir);
>> +		cmd = len | scrambler | DMA_DIR(dir);
>>  		writel(cmd, nfc->reg_base + NFC_REG_CMD);
>>  		return;
>>  	}
>> @@ -573,7 +575,7 @@ static int meson_nfc_read_buf(struct nand_chip *nand, u8 *buf, int len)
>>  	if (ret)
>>  		goto out;
>>  
>> -	cmd = NFC_CMD_N2M | (len & GENMASK(13, 0));
>> +	cmd = NFC_CMD_N2M | len;
>>  	writel(cmd, nfc->reg_base + NFC_REG_CMD);
>>  
>>  	meson_nfc_drain_cmd(nfc);
>> @@ -597,7 +599,7 @@ static int meson_nfc_write_buf(struct nand_chip *nand, u8 *buf, int len)
>>  	if (ret)
>>  		return ret;
>>  
>> -	cmd = NFC_CMD_M2N | (len & GENMASK(13, 0));
>> +	cmd = NFC_CMD_M2N | len;
>>  	writel(cmd, nfc->reg_base + NFC_REG_CMD);
>>  
>>  	meson_nfc_drain_cmd(nfc);
>> @@ -1007,6 +1009,31 @@ meson_nand_op_put_dma_safe_output_buf(const struct nand_op_instr *instr,
>>  		kfree(buf);
>>  }
>>  
>> +static int meson_nfc_check_op(struct nand_chip *chip,
>> +			      const struct nand_operation *op)
>> +{
>> +	int op_id;
>> +
>> +	for (op_id = 0; op_id < op->ninstrs; op_id++) {
>> +		const struct nand_op_instr *instr;
>> +
>> +		instr = &op->instrs[op_id];
>> +
>> +		switch (instr->type) {
>> +		case NAND_OP_DATA_IN_INSTR:
>> +		case NAND_OP_DATA_OUT_INSTR:
>> +			if (instr->ctx.data.len > NFC_CMD_RAW_LEN)
>> +				return -ENOTSUPP;
>> +
>> +			break;
>> +		default:
>> +			break;
>> +		}
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>>  static int meson_nfc_exec_op(struct nand_chip *nand,
>>  			     const struct nand_operation *op, bool check_only)
>>  {
>> @@ -1015,10 +1042,12 @@ static int meson_nfc_exec_op(struct nand_chip *nand,
>>  	const struct nand_op_instr *instr = NULL;
>>  	void *buf;
>>  	u32 op_id, delay_idle, cmd;
>> +	int err;
>>  	int i;
>>  
>> -	if (check_only)
>> -		return 0;
>> +	err = meson_nfc_check_op(nand, op);
>> +	if (err || check_only)
>> +		return err;
>>  
>>  	meson_nfc_select_chip(nand, op->cs);
>>  	for (op_id = 0; op_id < op->ninstrs; op_id++) {
>> @@ -1293,6 +1322,7 @@ static int meson_nand_attach_chip(struct nand_chip *nand)
>>  	struct meson_nfc_nand_chip *meson_chip = to_meson_nand(nand);
>>  	struct mtd_info *mtd = nand_to_mtd(nand);
>>  	int nsectors = mtd->writesize / 1024;
>> +	int raw_writesize;
>>  	int ret;
>>  
>>  	if (!mtd->name) {
>> @@ -1304,6 +1334,13 @@ static int meson_nand_attach_chip(struct nand_chip *nand)
>>  			return -ENOMEM;
>>  	}
>>  
>> +	raw_writesize = mtd->writesize + mtd->oobsize;
>> +	if (raw_writesize > NFC_CMD_RAW_LEN) {
>> +		dev_err(nfc->dev, "too big write size in raw mode: %d > %ld\n",
>> +			raw_writesize, NFC_CMD_RAW_LEN);
>> +		return -EINVAL;
>> +	}
>> +
>>  	if (nand->bbt_options & NAND_BBT_USE_FLASH)
>>  		nand->bbt_options |= NAND_BBT_NO_OOB;
>>