Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1190020

Re: [PATCH] regmap: Add function check before called format_val

Show all headers | View raw

On Tue, 2015-07-21 at 18:25 +0100, Mark Brown wrote:
> On Tue, Jul 21, 2015 at 02:07:25PM +0800, Henry Chen wrote:
> 
> > Then in driver rtc-mt6397.c, it used regmap_bulk_read() to get the time
> > of PMIC, and hit the null function of format_val(), because the
> > regmap_bus was null.
> 
> > It skipped the initialization of format_val() because bus == null, but
> > called the format_val() at regmap_bulk_read() if bus == null.
> 
> OK, so the issue here is that when we fall back to regmap_read() we may
> do so because we have reg_read() and reg_write() functions which in turn
> imply no formatting.  The expectation here is that val must be an array
> of int.  The code doesn't completely take that into account though and
> the user you're pointing at is assuming it's an array of 16 bit values
> which isn't totally unreasonable if it did specify val_bits (we don't
> check for that).
So, could I call regmap_bulk_read() on rtc-mt6307.c, should I need to
change it ?
> 
> > Maybe it was not the good fix for this, but should be a problem need to
> > be reported, or should I need to give the regmap_bus on mtk_pmic_wrap.c?
> 
> That file isn't in mainline...

oh...it's mtk-pmic-wrap.c, sorry about that.
> 
> memcpy() is definitely not a safe way to move from an unsigned int to a
> u16 which is what your specific use case is trying to do.  I'll need to
> do an audit of existing users (or someone else will!) to figure out what
> people are doing with .val_bits in drivers using reg_read() and
> reg_write() but I think what we should be doing here is probably
> providing appropriate conversion functions based on val_bits on init.

Ok, got it, memcpy() should not be used here anymore.

Thanks,
Henry

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH] regmap: Add function check before called format_val Henry Chen <henryc.chen@mediatek.com> - 2015-07-20 14:50 +0200
  Re: [PATCH] regmap: Add function check before called format_val Henry Chen <HenryC.Chen@mediatek.com> - 2015-07-21 08:10 +0200
    Re: [PATCH] regmap: Add function check before called format_val Henry Chen <HenryC.Chen@mediatek.com> - 2015-07-22 16:40 +0200
      Re: [PATCH] regmap: Add function check before called format_val Mark Brown <broonie@kernel.org> - 2015-07-22 19:10 +0200

csiph-web