Commit 5463bafa authored by Michael Ellerman's avatar Michael Ellerman Committed by Andrew Morton
Browse files

powerpc/mm: handle VDSO unmapping via close() rather than arch_unmap() 

Add a close() callback to the VDSO special mapping to handle unmapping of
the VDSO.  That will make it possible to remove the arch_unmap() hook
entirely in a subsequent patch.

Link: https://lkml.kernel.org/r/20240812082605.743814-2-mpe@ellerman.id.au


Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Suggested-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
Reviewed-by: default avatarLiam R. Howlett <Liam.Howlett@oracle.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Jeff Xu <jeffxu@google.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Pedro Falcato <pedro.falcato@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 223febc6

arch/powerpc/include/asm/mmu_context.h

+0 −4
Original line number Diff line number Diff line
@@ -263,10 +263,6 @@ extern void arch_exit_mmap(struct mm_struct *mm); 
static inline void arch_unmap(struct mm_struct *mm,

			      unsigned long start, unsigned long end)

{

	unsigned long vdso_base = (unsigned long)mm->context.vdso;



	if (start <= vdso_base && vdso_base < end)

		mm->context.vdso = NULL;

}



#ifdef CONFIG_PPC_MEM_KEYS

arch/powerpc/kernel/vdso.c

+17 −0
Original line number Diff line number Diff line
@@ -81,6 +81,21 @@ static int vdso64_mremap(const struct vm_special_mapping *sm, struct vm_area_str 
	return vdso_mremap(sm, new_vma, &vdso64_end - &vdso64_start);

}



static void vdso_close(const struct vm_special_mapping *sm, struct vm_area_struct *vma)

{

	struct mm_struct *mm = vma->vm_mm;



	/*

	 * close() is called for munmap() but also for mremap(). In the mremap()

	 * case the vdso pointer has already been updated by the mremap() hook

	 * above, so it must not be set to NULL here.

	 */

	if (vma->vm_start != (unsigned long)mm->context.vdso)

		return;



	mm->context.vdso = NULL;

}



static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,

			     struct vm_area_struct *vma, struct vm_fault *vmf);
@@ -92,11 +107,13 @@ static struct vm_special_mapping vvar_spec __ro_after_init = { 
static struct vm_special_mapping vdso32_spec __ro_after_init = {

	.name = "[vdso]",

	.mremap = vdso32_mremap,

	.close = vdso_close,

};



static struct vm_special_mapping vdso64_spec __ro_after_init = {

	.name = "[vdso]",

	.mremap = vdso64_mremap,

	.close = vdso_close,

};



#ifdef CONFIG_TIME_NS