Commit 82e69a12 authored by Fenghua Yu's avatar Fenghua Yu Committed by Linus Torvalds
Browse files

mm/fork: clear PASID for new mm 

When a new mm is created, its PASID should be cleared, i.e.  the PASID is
initialized to its init state 0 on both ARM and X86.

This patch was part of the series introducing mm->pasid, but got lost
along the way [1].  It still makes sense to have it, because each address
space has a different PASID.  And the IOMMU code in
iommu_sva_alloc_pasid() expects the pasid field of a new mm struct to be
cleared.

[1] https://lore.kernel.org/linux-iommu/YDgh53AcQHT+T3L0@otcwcpicx3.sc.intel.com/

Link: https://lkml.kernel.org/r/20210302103837.2562625-1-jean-philippe@linaro.org


Signed-off-by: default avatarFenghua Yu <fenghua.yu@intel.com>
Signed-off-by: default avatarJean-Philippe Brucker <jean-philippe@linaro.org>
Reviewed-by: default avatarTony Luck <tony.luck@intel.com>
Cc: Jacob Pan <jacob.jun.pan@intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 0740a50b

include/linux/mm_types.h

+1 −0
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ 
#endif

#define AT_VECTOR_SIZE (2*(AT_VECTOR_SIZE_ARCH + AT_VECTOR_SIZE_BASE + 1))



#define INIT_PASID	0



struct address_space;

struct mem_cgroup;

kernel/fork.c

+8 −0
Original line number Diff line number Diff line
@@ -994,6 +994,13 @@ static void mm_init_owner(struct mm_struct *mm, struct task_struct *p) 
#endif

}



static void mm_init_pasid(struct mm_struct *mm)

{

#ifdef CONFIG_IOMMU_SUPPORT

	mm->pasid = INIT_PASID;

#endif

}



static void mm_init_uprobes_state(struct mm_struct *mm)

{

#ifdef CONFIG_UPROBES
@@ -1024,6 +1031,7 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p, 
	mm_init_cpumask(mm);

	mm_init_aio(mm);

	mm_init_owner(mm, p);

	mm_init_pasid(mm);

	RCU_INIT_POINTER(mm->exe_file, NULL);

	mmu_notifier_subscriptions_init(mm);

	init_tlb_flush_pending(mm);