| Message ID | 20230627130102.63665-1-dmantipov@yandex.ru (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Kalle Valo |
| Headers | show |
| Series | wifi: b43: fix cordic arithmetic | expand |
On 6/27/23 08:00, Dmitry Antipov wrote: > In 'lpphy_start_tx_tone()', 'CORDIC_FLOAT((sample.i * max) & 0xFF)' > is invalid because it is (<32-bit> & 0xff) shifted right by 15 bits > and so always evaluates to zero. Looking through brcmsmac's > 'wlc_lcnphy_start_tx_tone()', the result should be masked instead, > i. e. 'CORDIC_FLOAT(sample[i].max) & 0xFF'. > > Found by Linux Verification Center (linuxtesting.org) with SVACE. > > Suggested-by: Jonas Gorski <jonas.gorski@gmail.com> > Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru> > --- > drivers/net/wireless/broadcom/b43/phy_lp.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/net/wireless/broadcom/b43/phy_lp.c b/drivers/net/wireless/broadcom/b43/phy_lp.c > index 0e5c076e7544..e8ef04e509aa 100644 > --- a/drivers/net/wireless/broadcom/b43/phy_lp.c > +++ b/drivers/net/wireless/broadcom/b43/phy_lp.c > @@ -1788,8 +1788,8 @@ static void lpphy_start_tx_tone(struct b43_wldev *dev, s32 freq, u16 max) > for (i = 0; i < samples; i++) { > sample = cordic_calc_iq(CORDIC_FIXED(theta)); > theta += rotation; > - buf[i] = CORDIC_FLOAT((sample.i * max) & 0xFF) << 8; > - buf[i] |= CORDIC_FLOAT((sample.q * max) & 0xFF); > + buf[i] = (u16)((CORDIC_FLOAT(sample.i * max) & 0xFF) << 8); > + buf[i] |= (u16)(CORDIC_FLOAT(sample.q * max) & 0xFF); > } > > b43_lptab_write_bulk(dev, B43_LPTAB16(5, 0), samples, buf); This has not yet been tested, but it does need a "Fixes:" tag, and a Cc for stable. Larry
diff --git a/drivers/net/wireless/broadcom/b43/phy_lp.c b/drivers/net/wireless/broadcom/b43/phy_lp.c index 0e5c076e7544..e8ef04e509aa 100644 --- a/drivers/net/wireless/broadcom/b43/phy_lp.c +++ b/drivers/net/wireless/broadcom/b43/phy_lp.c @@ -1788,8 +1788,8 @@ static void lpphy_start_tx_tone(struct b43_wldev *dev, s32 freq, u16 max) for (i = 0; i < samples; i++) { sample = cordic_calc_iq(CORDIC_FIXED(theta)); theta += rotation; - buf[i] = CORDIC_FLOAT((sample.i * max) & 0xFF) << 8; - buf[i] |= CORDIC_FLOAT((sample.q * max) & 0xFF); + buf[i] = (u16)((CORDIC_FLOAT(sample.i * max) & 0xFF) << 8); + buf[i] |= (u16)(CORDIC_FLOAT(sample.q * max) & 0xFF); } b43_lptab_write_bulk(dev, B43_LPTAB16(5, 0), samples, buf);
In 'lpphy_start_tx_tone()', 'CORDIC_FLOAT((sample.i * max) & 0xFF)' is invalid because it is (<32-bit> & 0xff) shifted right by 15 bits and so always evaluates to zero. Looking through brcmsmac's 'wlc_lcnphy_start_tx_tone()', the result should be masked instead, i. e. 'CORDIC_FLOAT(sample[i].max) & 0xFF'. Found by Linux Verification Center (linuxtesting.org) with SVACE. Suggested-by: Jonas Gorski <jonas.gorski@gmail.com> Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru> --- drivers/net/wireless/broadcom/b43/phy_lp.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)