Commit cd05c865 authored by Felix Kuehling's avatar Felix Kuehling Committed by Alex Deucher
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drm/amdgpu: Disable page faults while reading user wptrs 



These wptrs must be pinned and GPU accessible when this is called
from hqd_load functions. So they should never fault. This resolves
a circular lock dependency issue involving four locks including the
DQM lock and mmap_sem.

Signed-off-by: default avatarFelix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: default avatarOak Zeng <Oak.Zeng@amd.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
parent 811bc15b

drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h

+8 −0
Original line number Diff line number Diff line
@@ -179,10 +179,17 @@ uint64_t amdgpu_amdkfd_get_mmio_remap_phys_addr(struct kgd_dev *kgd); 
uint32_t amdgpu_amdkfd_get_num_gws(struct kgd_dev *kgd);

uint8_t amdgpu_amdkfd_get_xgmi_hops_count(struct kgd_dev *dst, struct kgd_dev *src);



/* Read user wptr from a specified user address space with page fault

 * disabled. The memory must be pinned and mapped to the hardware when

 * this is called in hqd_load functions, so it should never fault in

 * the first place. This resolves a circular lock dependency involving

 * four locks, including the DQM lock and mmap_sem.

 */

#define read_user_wptr(mmptr, wptr, dst)				\

	({								\

		bool valid = false;					\

		if ((mmptr) && (wptr)) {				\

			pagefault_disable();				\

			if ((mmptr) == current->mm) {			\

				valid = !get_user((dst), (wptr));	\

			} else if (current->mm == NULL) {		\
@@ -190,6 +197,7 @@ uint8_t amdgpu_amdkfd_get_xgmi_hops_count(struct kgd_dev *dst, struct kgd_dev *s 
				valid = !get_user((dst), (wptr));	\

				unuse_mm(mmptr);			\

			}						\

			pagefault_enable();				\

		}							\

		valid;							\

	})