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

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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: Michael Ellerman <mpe@ellerman.id.au>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Liam 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: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Michael Ellerman 2024-08-12 18:26:03 +10:00 committed by Andrew Morton
parent 223febc6e5
commit 5463bafab4
2 changed files with 17 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
arch/powerpc/include/asm/mmu_context.h
View File

@ -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

17
arch/powerpc/kernel/vdso.c
View File

@ -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