Using the uapi-safe __GENMASK_ULL(), we can stably define the layout of
64-bit packed BVNCs. These defs replace the replicated doc comment that
appears all over the place.
Signed-off-by: Matt Coster <matt.coster@imgtec.com>
---
Changes in v2:
- Add _CONST variant of PVR_PACKED_BVNC() for use in case statements.
This fixes the build issue reported by the test bot[1][2]
- Link to v1: https://patch.msgid.link/20260206-bvnc-cleanup-v1-1-f3c818541fbe@imgtec.com
[1]: https://lore.kernel.org/r/202602070204.PjaKNSpZ-lkp@intel.com/
[2]: https://lore.kernel.org/r/202602070500.zo0DrH6U-lkp@intel.com/
---
drivers/gpu/drm/imagination/pvr_device.c | 6 ++---
drivers/gpu/drm/imagination/pvr_device.h | 43 +++++++++++++-------------------
include/uapi/drm/pvr_drm.h | 14 +++++------
3 files changed, 27 insertions(+), 36 deletions(-)
diff --git a/drivers/gpu/drm/imagination/pvr_device.c b/drivers/gpu/drm/imagination/pvr_device.c
index f58bb66a6327..9b26585a42bf 100644
--- a/drivers/gpu/drm/imagination/pvr_device.c
+++ b/drivers/gpu/drm/imagination/pvr_device.c
@@ -547,11 +547,11 @@ static enum pvr_gpu_support_level
pvr_gpu_support_level(const struct pvr_gpu_id *gpu_id)
{
switch (pvr_gpu_id_to_packed_bvnc(gpu_id)) {
- case PVR_PACKED_BVNC(33, 15, 11, 3):
- case PVR_PACKED_BVNC(36, 53, 104, 796):
+ case PVR_PACKED_BVNC_CONST(33, 15, 11, 3):
+ case PVR_PACKED_BVNC_CONST(36, 53, 104, 796):
return PVR_GPU_SUPPORTED;
- case PVR_PACKED_BVNC(36, 52, 104, 182):
+ case PVR_PACKED_BVNC_CONST(36, 52, 104, 182):
return PVR_GPU_EXPERIMENTAL;
default:
diff --git a/drivers/gpu/drm/imagination/pvr_device.h b/drivers/gpu/drm/imagination/pvr_device.h
index d51c57cf9332..55d8ff11d507 100644
--- a/drivers/gpu/drm/imagination/pvr_device.h
+++ b/drivers/gpu/drm/imagination/pvr_device.h
@@ -14,7 +14,7 @@
#include <drm/drm_file.h>
#include <drm/drm_mm.h>
-#include <linux/bits.h>
+#include <linux/bitfield.h>
#include <linux/compiler_attributes.h>
#include <linux/compiler_types.h>
#include <linux/device.h>
@@ -470,6 +470,12 @@ struct pvr_file {
#define to_pvr_file(file) ((file)->driver_priv)
+#define __PVR_PACKED_BVNC(prep, b, v, n, c) \
+ (prep(DRM_PVR_BVNC_B, b) | \
+ prep(DRM_PVR_BVNC_V, v) | \
+ prep(DRM_PVR_BVNC_N, n) | \
+ prep(DRM_PVR_BVNC_C, c))
+
/**
* PVR_PACKED_BVNC() - Packs B, V, N and C values into a 64-bit unsigned integer
* @b: Branch ID.
@@ -477,39 +483,24 @@ struct pvr_file {
* @n: Number of scalable units.
* @c: Config ID.
*
- * The packed layout is as follows:
- *
- * +--------+--------+--------+-------+
- * | 63..48 | 47..32 | 31..16 | 15..0 |
- * +========+========+========+=======+
- * | B | V | N | C |
- * +--------+--------+--------+-------+
+ * The packed layout follows the bitfield defined by the DRM_PVR_BVNC_* macros.
*
* pvr_gpu_id_to_packed_bvnc() should be used instead of this macro when a
* &struct pvr_gpu_id is available in order to ensure proper type checking.
*
* Return: Packed BVNC.
*/
-/* clang-format off */
-#define PVR_PACKED_BVNC(b, v, n, c) \
- ((((u64)(b) & GENMASK_ULL(15, 0)) << 48) | \
- (((u64)(v) & GENMASK_ULL(15, 0)) << 32) | \
- (((u64)(n) & GENMASK_ULL(15, 0)) << 16) | \
- (((u64)(c) & GENMASK_ULL(15, 0)) << 0))
-/* clang-format on */
+#define PVR_PACKED_BVNC(b, v, n, c) __PVR_PACKED_BVNC(FIELD_PREP, b, v, n, c)
+
+/** PVR_PACKED_BVNC_CONST() - Compile-time equivalent of PVR_PACKED_BVNC(). */
+#define PVR_PACKED_BVNC_CONST(b, v, n, c) __PVR_PACKED_BVNC(FIELD_PREP_CONST, b, v, n, c)
/**
* pvr_gpu_id_to_packed_bvnc() - Packs B, V, N and C values into a 64-bit
* unsigned integer
* @gpu_id: GPU ID.
*
- * The packed layout is as follows:
- *
- * +--------+--------+--------+-------+
- * | 63..48 | 47..32 | 31..16 | 15..0 |
- * +========+========+========+=======+
- * | B | V | N | C |
- * +--------+--------+--------+-------+
+ * The packed layout follows the bitfield defined by the DRM_PVR_BVNC_* macros.
*
* This should be used in preference to PVR_PACKED_BVNC() when a &struct
* pvr_gpu_id is available in order to ensure proper type checking.
@@ -525,10 +516,10 @@ pvr_gpu_id_to_packed_bvnc(const struct pvr_gpu_id *gpu_id)
static __always_inline void
packed_bvnc_to_pvr_gpu_id(u64 bvnc, struct pvr_gpu_id *gpu_id)
{
- gpu_id->b = (bvnc & GENMASK_ULL(63, 48)) >> 48;
- gpu_id->v = (bvnc & GENMASK_ULL(47, 32)) >> 32;
- gpu_id->n = (bvnc & GENMASK_ULL(31, 16)) >> 16;
- gpu_id->c = bvnc & GENMASK_ULL(15, 0);
+ gpu_id->b = FIELD_GET(DRM_PVR_BVNC_B, bvnc);
+ gpu_id->v = FIELD_GET(DRM_PVR_BVNC_V, bvnc);
+ gpu_id->n = FIELD_GET(DRM_PVR_BVNC_N, bvnc);
+ gpu_id->c = FIELD_GET(DRM_PVR_BVNC_C, bvnc);
}
int pvr_device_init(struct pvr_device *pvr_dev);
diff --git a/include/uapi/drm/pvr_drm.h b/include/uapi/drm/pvr_drm.h
index ccf6c2112468..72f3f90560cf 100644
--- a/include/uapi/drm/pvr_drm.h
+++ b/include/uapi/drm/pvr_drm.h
@@ -6,6 +6,7 @@
#include "drm.h"
+#include <linux/bits.h>
#include <linux/const.h>
#include <linux/types.h>
@@ -113,6 +114,11 @@ struct drm_pvr_obj_array {
* DOC: PowerVR IOCTL DEV_QUERY interface
*/
+#define DRM_PVR_BVNC_B __GENMASK_ULL(63, 48)
+#define DRM_PVR_BVNC_V __GENMASK_ULL(47, 32)
+#define DRM_PVR_BVNC_N __GENMASK_ULL(31, 16)
+#define DRM_PVR_BVNC_C __GENMASK_ULL(15, 0)
+
/**
* struct drm_pvr_dev_query_gpu_info - Container used to fetch information about
* the graphics processor.
@@ -125,13 +131,7 @@ struct drm_pvr_dev_query_gpu_info {
* @gpu_id: GPU identifier.
*
* For all currently supported GPUs this is the BVNC encoded as a 64-bit
- * value as follows:
- *
- * +--------+--------+--------+-------+
- * | 63..48 | 47..32 | 31..16 | 15..0 |
- * +========+========+========+=======+
- * | B | V | N | C |
- * +--------+--------+--------+-------+
+ * value using the DRM_PVR_BVNC_* bitmasks.
*/
__u64 gpu_id;
--
2.53.0Hi Matt,
kernel test robot noticed the following build errors:
[auto build test ERROR on fbef867cf6614178bc6afd15ee15f85cddf19eab]
url: https://github.com/intel-lab-lkp/linux/commits/Matt-Coster/drm-imagination-Define-packed-BVNCs-in-the-uapi/20260322-112647
base: fbef867cf6614178bc6afd15ee15f85cddf19eab
patch link: https://lore.kernel.org/r/20260320-bvnc-cleanup-v2-1-49c3c1453289%40imgtec.com
patch subject: [PATCH v2 1/2] drm/imagination: Define packed BVNCs in the uapi
config: arm64-randconfig-002-20260322 (https://download.01.org/0day-ci/archive/20260322/202603222211.A2XiR1YU-lkp@intel.com/config)
compiler: aarch64-linux-gcc (GCC) 11.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260322/202603222211.A2XiR1YU-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202603222211.A2XiR1YU-lkp@intel.com/
All errors (new ones prefixed by >>):
In file included from include/linux/build_bug.h:5,
from include/linux/bits.h:30,
from drivers/gpu/drm/imagination/pvr_rogue_fwif.h:7,
from drivers/gpu/drm/imagination/pvr_ccb.h:7,
from drivers/gpu/drm/imagination/pvr_device.h:7,
from drivers/gpu/drm/imagination/pvr_device.c:4:
drivers/gpu/drm/imagination/pvr_device.c: In function 'pvr_gpu_support_level':
>> include/linux/compiler.h:203:82: error: expression in static assertion is not constant
203 | #define __BUILD_BUG_ON_ZERO_MSG(e, msg, ...) ((int)sizeof(struct {_Static_assert(!(e), msg);}))
| ^~~~
include/linux/build_bug.h:17:9: note: in expansion of macro '__BUILD_BUG_ON_ZERO_MSG'
17 | __BUILD_BUG_ON_ZERO_MSG(e, ##__VA_ARGS__, #e " is true")
| ^~~~~~~~~~~~~~~~~~~~~~~
include/linux/bitfield.h:160:17: note: in expansion of macro 'BUILD_BUG_ON_ZERO'
160 | BUILD_BUG_ON_ZERO(~((_mask) >> __bf_shf(_mask)) & (_val)) + \
| ^~~~~~~~~~~~~~~~~
drivers/gpu/drm/imagination/pvr_device.h:474:10: note: in expansion of macro 'FIELD_PREP_CONST'
474 | (prep(DRM_PVR_BVNC_B, b) | \
| ^~~~
drivers/gpu/drm/imagination/pvr_device.h:496:43: note: in expansion of macro '__PVR_PACKED_BVNC'
496 | #define PVR_PACKED_BVNC_CONST(b, v, n, c) __PVR_PACKED_BVNC(FIELD_PREP_CONST, b, v, n, c)
| ^~~~~~~~~~~~~~~~~
drivers/gpu/drm/imagination/pvr_device.c:550:14: note: in expansion of macro 'PVR_PACKED_BVNC_CONST'
550 | case PVR_PACKED_BVNC_CONST(33, 15, 11, 3):
| ^~~~~~~~~~~~~~~~~~~~~
>> include/linux/compiler.h:203:82: error: expression in static assertion is not constant
203 | #define __BUILD_BUG_ON_ZERO_MSG(e, msg, ...) ((int)sizeof(struct {_Static_assert(!(e), msg);}))
| ^~~~
include/linux/build_bug.h:17:9: note: in expansion of macro '__BUILD_BUG_ON_ZERO_MSG'
17 | __BUILD_BUG_ON_ZERO_MSG(e, ##__VA_ARGS__, #e " is true")
| ^~~~~~~~~~~~~~~~~~~~~~~
include/linux/bitfield.h:141:33: note: in expansion of macro 'BUILD_BUG_ON_ZERO'
141 | #define __BF_CHECK_POW2(n) BUILD_BUG_ON_ZERO(((n) & ((n) - 1)) != 0)
| ^~~~~~~~~~~~~~~~~
include/linux/bitfield.h:162:17: note: in expansion of macro '__BF_CHECK_POW2'
162 | __BF_CHECK_POW2((_mask) + (1ULL << __bf_shf(_mask))) + \
| ^~~~~~~~~~~~~~~
drivers/gpu/drm/imagination/pvr_device.h:474:10: note: in expansion of macro 'FIELD_PREP_CONST'
474 | (prep(DRM_PVR_BVNC_B, b) | \
| ^~~~
drivers/gpu/drm/imagination/pvr_device.h:496:43: note: in expansion of macro '__PVR_PACKED_BVNC'
496 | #define PVR_PACKED_BVNC_CONST(b, v, n, c) __PVR_PACKED_BVNC(FIELD_PREP_CONST, b, v, n, c)
| ^~~~~~~~~~~~~~~~~
drivers/gpu/drm/imagination/pvr_device.c:550:14: note: in expansion of macro 'PVR_PACKED_BVNC_CONST'
550 | case PVR_PACKED_BVNC_CONST(33, 15, 11, 3):
| ^~~~~~~~~~~~~~~~~~~~~
>> include/linux/compiler.h:203:82: error: expression in static assertion is not constant
203 | #define __BUILD_BUG_ON_ZERO_MSG(e, msg, ...) ((int)sizeof(struct {_Static_assert(!(e), msg);}))
| ^~~~
include/linux/build_bug.h:17:9: note: in expansion of macro '__BUILD_BUG_ON_ZERO_MSG'
17 | __BUILD_BUG_ON_ZERO_MSG(e, ##__VA_ARGS__, #e " is true")
| ^~~~~~~~~~~~~~~~~~~~~~~
include/linux/bitfield.h:160:17: note: in expansion of macro 'BUILD_BUG_ON_ZERO'
160 | BUILD_BUG_ON_ZERO(~((_mask) >> __bf_shf(_mask)) & (_val)) + \
| ^~~~~~~~~~~~~~~~~
drivers/gpu/drm/imagination/pvr_device.h:474:10: note: in expansion of macro 'FIELD_PREP_CONST'
474 | (prep(DRM_PVR_BVNC_B, b) | \
| ^~~~
drivers/gpu/drm/imagination/pvr_device.h:496:43: note: in expansion of macro '__PVR_PACKED_BVNC'
496 | #define PVR_PACKED_BVNC_CONST(b, v, n, c) __PVR_PACKED_BVNC(FIELD_PREP_CONST, b, v, n, c)
| ^~~~~~~~~~~~~~~~~
drivers/gpu/drm/imagination/pvr_device.c:551:14: note: in expansion of macro 'PVR_PACKED_BVNC_CONST'
551 | case PVR_PACKED_BVNC_CONST(36, 53, 104, 796):
| ^~~~~~~~~~~~~~~~~~~~~
>> include/linux/compiler.h:203:82: error: expression in static assertion is not constant
203 | #define __BUILD_BUG_ON_ZERO_MSG(e, msg, ...) ((int)sizeof(struct {_Static_assert(!(e), msg);}))
| ^~~~
include/linux/build_bug.h:17:9: note: in expansion of macro '__BUILD_BUG_ON_ZERO_MSG'
17 | __BUILD_BUG_ON_ZERO_MSG(e, ##__VA_ARGS__, #e " is true")
| ^~~~~~~~~~~~~~~~~~~~~~~
include/linux/bitfield.h:141:33: note: in expansion of macro 'BUILD_BUG_ON_ZERO'
141 | #define __BF_CHECK_POW2(n) BUILD_BUG_ON_ZERO(((n) & ((n) - 1)) != 0)
| ^~~~~~~~~~~~~~~~~
include/linux/bitfield.h:162:17: note: in expansion of macro '__BF_CHECK_POW2'
162 | __BF_CHECK_POW2((_mask) + (1ULL << __bf_shf(_mask))) + \
| ^~~~~~~~~~~~~~~
drivers/gpu/drm/imagination/pvr_device.h:474:10: note: in expansion of macro 'FIELD_PREP_CONST'
474 | (prep(DRM_PVR_BVNC_B, b) | \
| ^~~~
drivers/gpu/drm/imagination/pvr_device.h:496:43: note: in expansion of macro '__PVR_PACKED_BVNC'
496 | #define PVR_PACKED_BVNC_CONST(b, v, n, c) __PVR_PACKED_BVNC(FIELD_PREP_CONST, b, v, n, c)
| ^~~~~~~~~~~~~~~~~
drivers/gpu/drm/imagination/pvr_device.c:551:14: note: in expansion of macro 'PVR_PACKED_BVNC_CONST'
551 | case PVR_PACKED_BVNC_CONST(36, 53, 104, 796):
| ^~~~~~~~~~~~~~~~~~~~~
>> include/linux/compiler.h:203:82: error: expression in static assertion is not constant
203 | #define __BUILD_BUG_ON_ZERO_MSG(e, msg, ...) ((int)sizeof(struct {_Static_assert(!(e), msg);}))
| ^~~~
include/linux/build_bug.h:17:9: note: in expansion of macro '__BUILD_BUG_ON_ZERO_MSG'
17 | __BUILD_BUG_ON_ZERO_MSG(e, ##__VA_ARGS__, #e " is true")
| ^~~~~~~~~~~~~~~~~~~~~~~
include/linux/bitfield.h:160:17: note: in expansion of macro 'BUILD_BUG_ON_ZERO'
160 | BUILD_BUG_ON_ZERO(~((_mask) >> __bf_shf(_mask)) & (_val)) + \
| ^~~~~~~~~~~~~~~~~
drivers/gpu/drm/imagination/pvr_device.h:474:10: note: in expansion of macro 'FIELD_PREP_CONST'
474 | (prep(DRM_PVR_BVNC_B, b) | \
| ^~~~
drivers/gpu/drm/imagination/pvr_device.h:496:43: note: in expansion of macro '__PVR_PACKED_BVNC'
496 | #define PVR_PACKED_BVNC_CONST(b, v, n, c) __PVR_PACKED_BVNC(FIELD_PREP_CONST, b, v, n, c)
| ^~~~~~~~~~~~~~~~~
drivers/gpu/drm/imagination/pvr_device.c:554:14: note: in expansion of macro 'PVR_PACKED_BVNC_CONST'
554 | case PVR_PACKED_BVNC_CONST(36, 52, 104, 182):
| ^~~~~~~~~~~~~~~~~~~~~
>> include/linux/compiler.h:203:82: error: expression in static assertion is not constant
203 | #define __BUILD_BUG_ON_ZERO_MSG(e, msg, ...) ((int)sizeof(struct {_Static_assert(!(e), msg);}))
| ^~~~
include/linux/build_bug.h:17:9: note: in expansion of macro '__BUILD_BUG_ON_ZERO_MSG'
17 | __BUILD_BUG_ON_ZERO_MSG(e, ##__VA_ARGS__, #e " is true")
| ^~~~~~~~~~~~~~~~~~~~~~~
include/linux/bitfield.h:141:33: note: in expansion of macro 'BUILD_BUG_ON_ZERO'
141 | #define __BF_CHECK_POW2(n) BUILD_BUG_ON_ZERO(((n) & ((n) - 1)) != 0)
| ^~~~~~~~~~~~~~~~~
include/linux/bitfield.h:162:17: note: in expansion of macro '__BF_CHECK_POW2'
162 | __BF_CHECK_POW2((_mask) + (1ULL << __bf_shf(_mask))) + \
| ^~~~~~~~~~~~~~~
drivers/gpu/drm/imagination/pvr_device.h:474:10: note: in expansion of macro 'FIELD_PREP_CONST'
474 | (prep(DRM_PVR_BVNC_B, b) | \
| ^~~~
drivers/gpu/drm/imagination/pvr_device.h:496:43: note: in expansion of macro '__PVR_PACKED_BVNC'
496 | #define PVR_PACKED_BVNC_CONST(b, v, n, c) __PVR_PACKED_BVNC(FIELD_PREP_CONST, b, v, n, c)
| ^~~~~~~~~~~~~~~~~
drivers/gpu/drm/imagination/pvr_device.c:554:14: note: in expansion of macro 'PVR_PACKED_BVNC_CONST'
554 | case PVR_PACKED_BVNC_CONST(36, 52, 104, 182):
| ^~~~~~~~~~~~~~~~~~~~~
vim +203 include/linux/compiler.h
230fa253df6352 Christian Borntraeger 2014-11-25 199
cb7380de9e4cbc Kees Cook 2025-02-05 200 #ifdef __CHECKER__
243c90e917f5cf Vincent Mailhol 2025-03-29 201 #define __BUILD_BUG_ON_ZERO_MSG(e, msg, ...) (0)
cb7380de9e4cbc Kees Cook 2025-02-05 202 #else /* __CHECKER__ */
243c90e917f5cf Vincent Mailhol 2025-03-29 @203 #define __BUILD_BUG_ON_ZERO_MSG(e, msg, ...) ((int)sizeof(struct {_Static_assert(!(e), msg);}))
cb7380de9e4cbc Kees Cook 2025-02-05 204 #endif /* __CHECKER__ */
cb7380de9e4cbc Kees Cook 2025-02-05 205
--
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