From f41ef8e3c65f1c424004493f7792ce06daa147df Mon Sep 17 00:00:00 2001 From: Matt Coster Date: Wed, 9 Jul 2025 11:04:09 +0100 Subject: [PATCH] drm/imagination: Add and use FLEX_ARRAY_CHECK() 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 Reviewed-by: Alessio Belle Link: https://patch.msgid.link/20250709-flex-array-check-v1-1-8adeb0bf0cde@imgtec.com Signed-off-by: Alessio Belle --- .../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 51dc37e78f41..e72f4064af18 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 +#include +#include #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);