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powerpc/nohash: Fix __ptep_set_access_flags() and ptep_set_wrprotect() 

Commit 26973fa5ac ("powerpc/mm: use pte helpers in generic code")
changed those two functions to use pte helpers to determine which
bits to clear and which bits to set.

This change was based on the assumption that bits to be set/cleared
are always the same and can be determined by applying the pte
manipulation helpers on __pte(0).

But on platforms like book3e, the bits depend on whether the page
is a user page or not.

For the time being it more or less works because of _PAGE_EXEC being
used for user pages only and exec right being set at all time on
kernel page. But following patch will clean that and output of
pte_mkexec() will depend on the page being a user or kernel page.

Instead of trying to make an even more complicated helper where bits
would become dependent on the final pte value, come back to a more
static situation like before commit 26973fa5ac ("powerpc/mm: use
pte helpers in generic code"), by introducing an 8xx specific
version of __ptep_set_access_flags() and ptep_set_wrprotect().

Fixes: 26973fa5ac ("powerpc/mm: use pte helpers in generic code")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/922bdab3a220781bae2360ff3dd5adb7fe4d34f1.1635226743.git.christophe.leroy@csgroup.eu
This commit is contained in:
Christophe Leroy 2021-10-26 07:39:24 +02:00 committed by Michael Ellerman
parent 44a8214de9
commit b1b93cb7e7
2 changed files with 30 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
arch/powerpc/include/asm/nohash/32/pgtable.h
View File

@ -306,30 +306,29 @@ static inline pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
}
#define __HAVE_ARCH_PTEP_SET_WRPROTECT
#ifndef ptep_set_wrprotect
static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr,
pte_t *ptep)
{
unsigned long clr = ~pte_val(pte_wrprotect(__pte(~0)));
unsigned long set = pte_val(pte_wrprotect(__pte(0)));
pte_update(mm, addr, ptep, clr, set, 0);
pte_update(mm, addr, ptep, _PAGE_RW, 0, 0);
}
#endif
#ifndef __ptep_set_access_flags
static inline void __ptep_set_access_flags(struct vm_area_struct *vma,
pte_t *ptep, pte_t entry,
unsigned long address,
int psize)
{
pte_t pte_set = pte_mkyoung(pte_mkdirty(pte_mkwrite(pte_mkexec(__pte(0)))));
pte_t pte_clr = pte_mkyoung(pte_mkdirty(pte_mkwrite(pte_mkexec(__pte(~0)))));
unsigned long set = pte_val(entry) & pte_val(pte_set);
unsigned long clr = ~pte_val(entry) & ~pte_val(pte_clr);
unsigned long set = pte_val(entry) &
(_PAGE_DIRTY | _PAGE_ACCESSED | _PAGE_RW | _PAGE_EXEC);
int huge = psize > mmu_virtual_psize ? 1 : 0;
pte_update(vma->vm_mm, address, ptep, clr, set, huge);
pte_update(vma->vm_mm, address, ptep, 0, set, huge);
flush_tlb_page(vma, address);
}
#endif
static inline int pte_young(pte_t pte)
{

22
arch/powerpc/include/asm/nohash/32/pte-8xx.h
View File

@ -136,6 +136,28 @@ static inline pte_t pte_mkhuge(pte_t pte)
#define pte_mkhuge pte_mkhuge
static inline pte_basic_t pte_update(struct mm_struct *mm, unsigned long addr, pte_t *p,
unsigned long clr, unsigned long set, int huge);
static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
{
pte_update(mm, addr, ptep, 0, _PAGE_RO, 0);
}
#define ptep_set_wrprotect ptep_set_wrprotect
static inline void __ptep_set_access_flags(struct vm_area_struct *vma, pte_t *ptep,
pte_t entry, unsigned long address, int psize)
{
unsigned long set = pte_val(entry) & (_PAGE_DIRTY | _PAGE_ACCESSED | _PAGE_EXEC);
unsigned long clr = ~pte_val(entry) & _PAGE_RO;
int huge = psize > mmu_virtual_psize ? 1 : 0;
pte_update(vma->vm_mm, address, ptep, clr, set, huge);
flush_tlb_page(vma, address);
}
#define __ptep_set_access_flags __ptep_set_access_flags
static inline unsigned long pgd_leaf_size(pgd_t pgd)
{
if (pgd_val(pgd) & _PMD_PAGE_8M)