> Subject: [PATCH 2/2] drm/i915/gt: Fix parameter in gmch_ggtt_insert_{entries,page}()
>
> When building with clang's -Wincompatible-function-pointer-types-strict,
> the following warnings occur:
>
> drivers/gpu/drm/i915/gt/intel_ggtt_gmch.c:102:23: error: incompatible function pointer types assigning to 'void (*)(struct i915_address_space *, dma_addr_t, u64, unsigned int, u32)' (aka 'void (*)(struct i915_address_space *, unsigned int, unsigned long long, unsigned int, unsigned int)') from 'void (struct i915_address_space *, dma_addr_t, u64, enum i915_cache_level, u32)' (aka 'void (struct i915_address_space *, unsigned int, unsigned long long, enum i915_cache_level, unsigned int)') [-Werror,-Wincompatible-function-pointer-types-strict]
> ggtt->vm.insert_page = gmch_ggtt_insert_page;
> ^ ~~~~~~~~~~~~~~~~~~~~~
> drivers/gpu/drm/i915/gt/intel_ggtt_gmch.c:103:26: error: incompatible function pointer types assigning to 'void (*)(struct i915_address_space *, struct i915_vma_resource *, unsigned int, u32)' (aka 'void (*)(struct i915_address_space *, struct i915_vma_resource *, unsigned int, unsigned int)') from 'void (struct i915_address_space *, struct i915_vma_resource *, enum i915_cache_level, u32)' (aka 'void (struct i915_address_space *, struct i915_vma_resource *, enum i915_cache_level, unsigned int)') [-Werror, -Wincompatible-function-pointer-types-strict]
> ggtt->vm.insert_entries = gmch_ggtt_insert_entries;
> ^ ~~~~~~~~~~~~~~~~~~~~~~~~
> 2 errors generated.
>
> The warning is pointing out that while 'enum i915_cache_level' and 'unsigned int' are ABI compatible, these indirect calls will fail clang's kernel Control Flow Integrity (kCFI) checks, as the callback's signature does not exactly match the prototype's signature.
>
> To fix this, replace the cache_level parameter with pat_index, as was done in other places within i915 where there is no difference between cache_level and pat_index on certain generations.
>
> Fixes: 9275277d5324 ("drm/i915: use pat_index instead of cache_level")
> Signed-off-by: Nathan Chancellor <nathan@xxxxxxxxxx>
Reviewed-by: Fei Yang <fei.yang@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/gt/intel_ggtt_gmch.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/intel_ggtt_gmch.c b/drivers/gpu/drm/i915/gt/intel_ggtt_gmch.c
> index d6a74ae2527b..866c416afb73 100644
> --- a/drivers/gpu/drm/i915/gt/intel_ggtt_gmch.c
> +++ b/drivers/gpu/drm/i915/gt/intel_ggtt_gmch.c
> @@ -18,10 +18,10 @@
> static void gmch_ggtt_insert_page(struct i915_address_space *vm,
> dma_addr_t addr,
> u64 offset,
> - enum i915_cache_level cache_level,
> + unsigned int pat_index,
> u32 unused)
> {
> - unsigned int flags = (cache_level == I915_CACHE_NONE) ?
> + unsigned int flags = (pat_index == I915_CACHE_NONE) ?
> AGP_USER_MEMORY : AGP_USER_CACHED_MEMORY;
>
> intel_gmch_gtt_insert_page(addr, offset >> PAGE_SHIFT, flags); @@ -29,10 +29,10 @@ static void gmch_ggtt_insert_page(struct i915_address_space *vm,
>
> static void gmch_ggtt_insert_entries(struct i915_address_space *vm,
> struct i915_vma_resource *vma_res,
> - enum i915_cache_level cache_level,
> + unsigned int pat_index,
> u32 unused)
> {
> - unsigned int flags = (cache_level == I915_CACHE_NONE) ?
> + unsigned int flags = (pat_index == I915_CACHE_NONE) ?
> AGP_USER_MEMORY : AGP_USER_CACHED_MEMORY;
>
> intel_gmch_gtt_insert_sg_entries(vma_res->bi.pages, vma_res->start >> PAGE_SHIFT,
>
> --
> 2.40.1
