| Message ID | 20200107212747.4182515-1-arnd@arndb.de |
|---|---|
| State | New |
| Headers | show |
| Series | drm: panel: fix excessive stack usage in td028ttec1_prepare | expand |
On Tue, Jan 7, 2020 at 11:00 PM Laurent Pinchart <laurent.pinchart@ideasonboard.com> wrote: > > Hi Arnd, > > Thank you for the patch. > > On Tue, Jan 07, 2020 at 10:27:33PM +0100, Arnd Bergmann wrote: > > With gcc -O3, the compiler can inline very aggressively, > > leading to rather large stack usage: > > > > drivers/gpu/drm/panel/panel-tpo-td028ttec1.c: In function 'td028ttec1_prepare': > > drivers/gpu/drm/panel/panel-tpo-td028ttec1.c:233:1: error: the frame size of 2768 bytes is larger than 2048 bytes [-Werror=frame-larger-than=] > > } > > > > Marking jbt_reg_write_1() as noinline avoids the case where > > multiple instances of this function get inlined into the same > > stack frame and each one adds a copy of 'tx_buf'. > > > > Fixes: mmtom ("init/Kconfig: enable -O3 for all arches") > > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > > Isn't this something that should be fixed at the compiler level ? I suspect but have not verified that structleak gcc plugin is partly at fault here as well, it has caused similar problems elsewhere. If you like I can try to dig deeper before that patch gets merged, and explain more in the changelog or open a gcc bug if necessary. Arnd _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
diff --git a/drivers/gpu/drm/panel/panel-tpo-td028ttec1.c b/drivers/gpu/drm/panel/panel-tpo-td028ttec1.c index cf29405a2dbe..17ee5e87141f 100644 --- a/drivers/gpu/drm/panel/panel-tpo-td028ttec1.c +++ b/drivers/gpu/drm/panel/panel-tpo-td028ttec1.c @@ -105,7 +105,7 @@ static int jbt_ret_write_0(struct td028ttec1_panel *lcd, u8 reg, int *err) return ret; } -static int jbt_reg_write_1(struct td028ttec1_panel *lcd, +static int noinline_for_stack jbt_reg_write_1(struct td028ttec1_panel *lcd, u8 reg, u8 data, int *err) { struct spi_device *spi = lcd->spi;
With gcc -O3, the compiler can inline very aggressively, leading to rather large stack usage: drivers/gpu/drm/panel/panel-tpo-td028ttec1.c: In function 'td028ttec1_prepare': drivers/gpu/drm/panel/panel-tpo-td028ttec1.c:233:1: error: the frame size of 2768 bytes is larger than 2048 bytes [-Werror=frame-larger-than=] } Marking jbt_reg_write_1() as noinline avoids the case where multiple instances of this function get inlined into the same stack frame and each one adds a copy of 'tx_buf'. Fixes: mmtom ("init/Kconfig: enable -O3 for all arches") Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- drivers/gpu/drm/panel/panel-tpo-td028ttec1.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) -- 2.20.0 _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel