linux-kernel - Re: [PATCH 09/13] kdb: Use 'unsigned int' in kdb

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Message-ID: <20240618152617.GF11330@aspen.lan>
Date: Tue, 18 Jun 2024 16:26:17 +0100
From: Daniel Thompson <daniel.thompson@...aro.org>
To: Douglas Anderson <dianders@...omium.org>
Cc: kgdb-bugreport@...ts.sourceforge.net,
	Christophe JAILLET <christophe.jaillet@...adoo.fr>,
	Jason Wessel <jason.wessel@...driver.com>,
	Thorsten Blum <thorsten.blum@...lux.com>,
	Yuran Pereira <yuran.pereira@...mail.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 09/13] kdb: Use 'unsigned int' in kdb_md() where
 appropriate

On Mon, Jun 17, 2024 at 05:34:43PM -0700, Douglas Anderson wrote:
> Several of the integers in kdb_md() should be marked unsigned. Mark
> them as such. When doing this, we need to add an explicit cast to the
> address masking or it ends up getting truncated down to "int" size.
>
> Signed-off-by: Douglas Anderson <dianders@...omium.org>
> ---
>
>  kernel/debug/kdb/kdb_main.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c
> index fcd5292351a7..c064ff093670 100644
> --- a/kernel/debug/kdb/kdb_main.c
> +++ b/kernel/debug/kdb/kdb_main.c
> @@ -1594,8 +1594,8 @@ static void kdb_md_line(const char *fmtstr, unsigned long addr,
>  static int kdb_md(int argc, const char **argv)
>  {
>  	static unsigned long last_addr;
> -	static int last_radix, last_bytesperword, last_repeat;
> -	int radix = 16, mdcount = 8, bytesperword = KDB_WORD_SIZE, repeat = 0;
> +	static unsigned int last_radix, last_bytesperword, last_repeat;
> +	unsigned int radix = 16, mdcount = 8, bytesperword = KDB_WORD_SIZE, repeat = 0;
>  	char fmtchar, fmtstr[64];
>  	unsigned long addr;
>  	unsigned long word;
> @@ -1722,11 +1722,11 @@ static int kdb_md(int argc, const char **argv)
>
>  	/* Round address down modulo BYTESPERWORD */
>
> -	addr &= ~(bytesperword-1);
> +	addr &= ~((unsigned long)bytesperword - 1);

I think the round_down() macro will take care of the cast for you (and
probably render the comment pointless too).

Other than that it looks like a good change.


Daniel.