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powerpc/vdso: Provide vdso_remap()

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Provide vdso_remap() through _install_special_mapping() and
drop arch_remap().

This adds a test of the size and returns -EINVAL if the size
is not correct.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/373c66f768fa9cc8890f3b55462209a98c522326.1601197618.git.christophe.leroy@csgroup.eu
This commit is contained in:
Christophe Leroy 2020-09-27 09:16:28 +00:00 committed by Michael Ellerman
parent c1bab64360
commit 526a9c4a72
2 changed files with 24 additions and 25 deletions
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25
arch/powerpc/include/asm/mm-arch-hooks.h
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@ -1,25 +0,0 @@
/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Architecture specific mm hooks
*
* Copyright (C) 2015, IBM Corporation
* Author: Laurent Dufour <ldufour@linux.vnet.ibm.com>
*/
#ifndef _ASM_POWERPC_MM_ARCH_HOOKS_H
#define _ASM_POWERPC_MM_ARCH_HOOKS_H
static inline void arch_remap(struct mm_struct *mm,
unsigned long old_start, unsigned long old_end,
unsigned long new_start, unsigned long new_end)
{
/*
* mremap() doesn't allow moving multiple vmas so we can limit the
* check to old_start == vdso_base.
*/
if (old_start == mm->context.vdso_base)
mm->context.vdso_base = new_start;
}
#define arch_remap arch_remap
#endif /* _ASM_POWERPC_MM_ARCH_HOOKS_H */

24
arch/powerpc/kernel/vdso.c
View File

@ -115,13 +115,37 @@ struct lib64_elfinfo
unsigned long text;
};
static int vdso_mremap(const struct vm_special_mapping *sm, struct vm_area_struct *new_vma,
unsigned long text_size)
{
unsigned long new_size = new_vma->vm_end - new_vma->vm_start;
if (new_size != text_size + PAGE_SIZE)
return -EINVAL;
current->mm->context.vdso_base = new_vma->vm_start;
return 0;
}
static int vdso32_mremap(const struct vm_special_mapping *sm, struct vm_area_struct *new_vma)
{
return vdso_mremap(sm, new_vma, &vdso32_end - &vdso32_start);
}
static int vdso64_mremap(const struct vm_special_mapping *sm, struct vm_area_struct *new_vma)
{
return vdso_mremap(sm, new_vma, &vdso64_end - &vdso64_start);
}
static struct vm_special_mapping vdso32_spec __ro_after_init = {
.name = "[vdso]",
.mremap = vdso32_mremap,
};
static struct vm_special_mapping vdso64_spec __ro_after_init = {
.name = "[vdso]",
.mremap = vdso64_mremap,
};
/*