On Wed, 2025-07-09 at 11:04 +0100, Matt Coster wrote: > It makes little to no sense to use SIZE_CHECK() on flexible structures, so > let's validate something that actually matters instead. > > Signed-off-by: Matt Coster <matt.cos...@imgtec.com>
Reviewed-by: Alessio Belle <alessio.be...@imgtec.com> Thanks, Alessio > --- > drivers/gpu/drm/imagination/pvr_rogue_fwif_check.h | 19 ++++++++++++++++++- > 1 file changed, 18 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/imagination/pvr_rogue_fwif_check.h > b/drivers/gpu/drm/imagination/pvr_rogue_fwif_check.h > index > 51dc37e78f41d7bdf45d1f434dd1aa5b9eca700a..e72f4064af187e2be3e26722e1ee1ac632087d3d > 100644 > --- a/drivers/gpu/drm/imagination/pvr_rogue_fwif_check.h > +++ b/drivers/gpu/drm/imagination/pvr_rogue_fwif_check.h > @@ -5,6 +5,8 @@ > #define PVR_ROGUE_FWIF_CHECK_H > > #include <linux/build_bug.h> > +#include <linux/overflow.h> > +#include <linux/stddef.h> > > #define OFFSET_CHECK(type, member, offset) \ > static_assert(offsetof(type, member) == (offset), \ > @@ -13,6 +15,21 @@ > #define SIZE_CHECK(type, size) \ > static_assert(sizeof(type) == (size), #type " is incorrect size") > > +/* > + * Where the last member of a struct is a flexible array member, using > + * SIZE_CHECK() is pointless. If the structure is not already padded to > + * alignment without the flexible array member, sizeof() will not match the > + * offset of the flexible array member and the "correct" sizeof() value is > + * completely meaningless. > + * > + * In those instances, use FLEX_ARRAY_CHECK() instead to assert that the > final > + * field is a flexible array member and that it behaves as expected. > + */ > +#define FLEX_ARRAY_CHECK(type, member) \ > + static_assert(flex_array_size((type *)NULL, member, 1) == \ > + sizeof_field(type, member[0]), \ > + #type "->" #member " is incorrect size") > + > OFFSET_CHECK(struct rogue_fwif_file_info_buf, path, 0); > OFFSET_CHECK(struct rogue_fwif_file_info_buf, info, 200); > OFFSET_CHECK(struct rogue_fwif_file_info_buf, line_num, 400); > @@ -157,7 +174,7 @@ OFFSET_CHECK(struct rogue_fwif_frag_ctx_state, > frag_reg_pm_deallocated_mask_stat > OFFSET_CHECK(struct rogue_fwif_frag_ctx_state, > frag_reg_dm_pds_mtilefree_status, 4); > OFFSET_CHECK(struct rogue_fwif_frag_ctx_state, ctx_state_flags, 8); > OFFSET_CHECK(struct rogue_fwif_frag_ctx_state, frag_reg_isp_store, 12); > -SIZE_CHECK(struct rogue_fwif_frag_ctx_state, 16); > +FLEX_ARRAY_CHECK(struct rogue_fwif_frag_ctx_state, frag_reg_isp_store); > > OFFSET_CHECK(struct rogue_fwif_compute_ctx_state, ctx_state_flags, 0); > SIZE_CHECK(struct rogue_fwif_compute_ctx_state, 4); >
