On Sun, 23 Mar 2025, Damian Tometzki <dam...@riscv-rocks.de> wrote:
> On Mon, 10. Mar 15:23, Kees Cook wrote:
>> When a character array without a terminating NUL character has a static
>> initializer, GCC 15's -Wunterminated-string-initialization will only
>> warn if the array lacks the "nonstring" attribute[1]. Mark the arrays
>> with __nonstring to and correctly identify the char array as "not a C
>> string" and thereby eliminate the warning.
>>
>> Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117178 [1]
>> Cc: Zhenyu Wang <zhen...@linux.intel.com>
>> Cc: Zhi Wang <zhi.wang.li...@gmail.com>
>> Cc: Jani Nikula <jani.nik...@linux.intel.com>
>> Cc: Joonas Lahtinen <joonas.lahti...@linux.intel.com>
>> Cc: Rodrigo Vivi <rodrigo.v...@intel.com>
>> Cc: Tvrtko Ursulin <tursu...@ursulin.net>
>> Cc: David Airlie <airl...@gmail.com>
>> Cc: Simona Vetter <sim...@ffwll.ch>
>> Cc: intel-gvt-...@lists.freedesktop.org
>> Cc: intel-...@lists.freedesktop.org
>> Cc: dri-devel@lists.freedesktop.org
>> Signed-off-by: Kees Cook <k...@kernel.org>
>> ---
>> drivers/gpu/drm/i915/gvt/opregion.c | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/gvt/opregion.c
>> b/drivers/gpu/drm/i915/gvt/opregion.c
>> index 509f9ccae3a9..f701638d3145 100644
>> --- a/drivers/gpu/drm/i915/gvt/opregion.c
>> +++ b/drivers/gpu/drm/i915/gvt/opregion.c
>> @@ -43,7 +43,7 @@
>> #define DEVICE_TYPE_EFP4 0x10
>>
>> struct opregion_header {
>> - u8 signature[16];
>> + u8 signature[16] __nonstring;
Why would this annotation be needed? It's not treated as a string
anywhere, and it's u8 not char.
>> u32 size;
>> u32 opregion_ver;
>> u8 bios_ver[32];
>> @@ -222,7 +222,7 @@ int intel_vgpu_init_opregion(struct intel_vgpu *vgpu)
>> u8 *buf;
>> struct opregion_header *header;
>> struct vbt v;
>> - const char opregion_signature[16] = OPREGION_SIGNATURE;
>> + const char opregion_signature[16] __nonstring = OPREGION_SIGNATURE;
>>
>> gvt_dbg_core("init vgpu%d opregion\n", vgpu->id);
>> vgpu_opregion(vgpu)->va = (void *)__get_free_pages(GFP_KERNEL |
>> --
>> 2.34.1
>>
> Hello together,
>
> it doesnt resolve the build issue with gcc15 gcc (GCC) 15.0.1 20250228
>
> CC [M] drivers/gpu/drm/i915/gvt/scheduler.o
> /home/damian/kernel/linux/drivers/gpu/drm/i915/gvt/opregion.c: In function
> ‘intel_vgpu_init_opregion’:
> /home/damian/kernel/linux/drivers/gpu/drm/i915/gvt/opregion.c:35:28: error:
> initializer-string for array of ‘char’ is too long
> [-Werror=unterminated-string-initialization]
> 35 | #define OPREGION_SIGNATURE "IntelGraphicsMem"
> | ^~~~~~~~~~~~~~~~~~
> /home/damian/kernel/linux/drivers/gpu/drm/i915/gvt/opregion.c:225:57: note:
> in expansion of macro ‘OPREGION_SIGNATURE’
> 225 | const char opregion_signature[16] __nonstring =
> OPREGION_SIGNATURE;
> |
> ^~~~~~~~~~~~~~~~~~
> CC [M] drivers/gpu/drm/i915/gvt/trace_points.o
> cc1: all warnings being treated as errors
> make[7]: *** [/home/damian/kernel/linux/scripts/Makefile.build:207:
> drivers/gpu/drm/i915/gvt/opregion.o] Error 1
> make[7]: *** Waiting for unfinished jobs....
> CC [M] drivers/gpu/drm/i915/gvt/vgpu.o
> make[6]: *** [/home/damian/kernel/linux/scripts/Makefile.build:465:
> drivers/gpu/drm/i915] Error 2
> make[5]: *** [/home/damian/kernel/linux/s
What about this?
IMO it's anyway good practice to use sizeof(dest) rather than
sizeof(src) for memcpy.
diff --git a/drivers/gpu/drm/i915/gvt/opregion.c
b/drivers/gpu/drm/i915/gvt/opregion.c
index 509f9ccae3a9..dbad4d853d3a 100644
--- a/drivers/gpu/drm/i915/gvt/opregion.c
+++ b/drivers/gpu/drm/i915/gvt/opregion.c
@@ -222,7 +222,6 @@ int intel_vgpu_init_opregion(struct intel_vgpu *vgpu)
u8 *buf;
struct opregion_header *header;
struct vbt v;
- const char opregion_signature[16] = OPREGION_SIGNATURE;
gvt_dbg_core("init vgpu%d opregion\n", vgpu->id);
vgpu_opregion(vgpu)->va = (void *)__get_free_pages(GFP_KERNEL |
@@ -236,8 +235,10 @@ int intel_vgpu_init_opregion(struct intel_vgpu *vgpu)
/* emulated opregion with VBT mailbox only */
buf = (u8 *)vgpu_opregion(vgpu)->va;
header = (struct opregion_header *)buf;
- memcpy(header->signature, opregion_signature,
- sizeof(opregion_signature));
+
+ static_assert(sizeof(header->signature) == sizeof(OPREGION_SIGNATURE) -
1);
+ memcpy(header->signature, OPREGION_SIGNATURE,
sizeof(header->signature));
+
header->size = 0x8;
header->opregion_ver = 0x02000000;
header->mboxes = MBOX_VBT;
--
Jani Nikula, Intel
