linux-stable/arch/arm64/include/asm/pgalloc.h
Pingfan Liu d3eb70ead6 arm64: mm: Fix VM_BUG_ON(mm != &init_mm) for trans_pgd
trans_pgd_create_copy() can hit "VM_BUG_ON(mm != &init_mm)" in the
function pmd_populate_kernel().

This is the combined consequence of commit 5de59884ac ("arm64:
trans_pgd: pass NULL instead of init_mm to *_populate functions"), which
replaced &init_mm with NULL and commit 59511cfd08 ("arm64: mm: use XN
table mapping attributes for user/kernel mappings"), which introduced
the VM_BUG_ON.

Since the former sounds reasonable, it is better to work on the later.
From the perspective of trans_pgd, two groups of functions are
considered in the later one:

  pmd_populate_kernel()
    mm == NULL should be fixed, else it hits VM_BUG_ON()
  p?d_populate()
    mm == NULL means PXN, that is OK, since trans_pgd only copies a
    linear map, no execution will happen on the map.

So it is good enough to just relax VM_BUG_ON() to disregard mm == NULL

Fixes: 59511cfd08 ("arm64: mm: use XN table mapping attributes for user/kernel mappings")
Signed-off-by: Pingfan Liu <kernelfans@gmail.com>
Cc: <stable@vger.kernel.org> # 5.13.x
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: James Morse <james.morse@arm.com>
Cc: Matthias Brugger <mbrugger@suse.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Link: https://lore.kernel.org/r/20211112052214.9086-1-kernelfans@gmail.com
Signed-off-by: Will Deacon <will@kernel.org>
2021-11-16 10:12:57 +00:00

90 lines
2.2 KiB
C

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Based on arch/arm/include/asm/pgalloc.h
*
* Copyright (C) 2000-2001 Russell King
* Copyright (C) 2012 ARM Ltd.
*/
#ifndef __ASM_PGALLOC_H
#define __ASM_PGALLOC_H
#include <asm/pgtable-hwdef.h>
#include <asm/processor.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
#define __HAVE_ARCH_PGD_FREE
#include <asm-generic/pgalloc.h>
#define PGD_SIZE (PTRS_PER_PGD * sizeof(pgd_t))
#if CONFIG_PGTABLE_LEVELS > 2
static inline void __pud_populate(pud_t *pudp, phys_addr_t pmdp, pudval_t prot)
{
set_pud(pudp, __pud(__phys_to_pud_val(pmdp) | prot));
}
static inline void pud_populate(struct mm_struct *mm, pud_t *pudp, pmd_t *pmdp)
{
pudval_t pudval = PUD_TYPE_TABLE;
pudval |= (mm == &init_mm) ? PUD_TABLE_UXN : PUD_TABLE_PXN;
__pud_populate(pudp, __pa(pmdp), pudval);
}
#else
static inline void __pud_populate(pud_t *pudp, phys_addr_t pmdp, pudval_t prot)
{
BUILD_BUG();
}
#endif /* CONFIG_PGTABLE_LEVELS > 2 */
#if CONFIG_PGTABLE_LEVELS > 3
static inline void __p4d_populate(p4d_t *p4dp, phys_addr_t pudp, p4dval_t prot)
{
set_p4d(p4dp, __p4d(__phys_to_p4d_val(pudp) | prot));
}
static inline void p4d_populate(struct mm_struct *mm, p4d_t *p4dp, pud_t *pudp)
{
p4dval_t p4dval = P4D_TYPE_TABLE;
p4dval |= (mm == &init_mm) ? P4D_TABLE_UXN : P4D_TABLE_PXN;
__p4d_populate(p4dp, __pa(pudp), p4dval);
}
#else
static inline void __p4d_populate(p4d_t *p4dp, phys_addr_t pudp, p4dval_t prot)
{
BUILD_BUG();
}
#endif /* CONFIG_PGTABLE_LEVELS > 3 */
extern pgd_t *pgd_alloc(struct mm_struct *mm);
extern void pgd_free(struct mm_struct *mm, pgd_t *pgdp);
static inline void __pmd_populate(pmd_t *pmdp, phys_addr_t ptep,
pmdval_t prot)
{
set_pmd(pmdp, __pmd(__phys_to_pmd_val(ptep) | prot));
}
/*
* Populate the pmdp entry with a pointer to the pte. This pmd is part
* of the mm address space.
*/
static inline void
pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmdp, pte_t *ptep)
{
VM_BUG_ON(mm && mm != &init_mm);
__pmd_populate(pmdp, __pa(ptep), PMD_TYPE_TABLE | PMD_TABLE_UXN);
}
static inline void
pmd_populate(struct mm_struct *mm, pmd_t *pmdp, pgtable_t ptep)
{
VM_BUG_ON(mm == &init_mm);
__pmd_populate(pmdp, page_to_phys(ptep), PMD_TYPE_TABLE | PMD_TABLE_PXN);
}
#endif