Page table checking depends on architectures providing an
implementation of p{te,md,ud}_user_accessible_page. With
refactorisations made on powerpc/mm, the pte_access_permitted() and
similar methods verify whether a userland page is accessible with the
required permissions.
Since page table checking is the only user of
p{te,md,ud}_user_accessible_page(), implement these for all platforms,
using some of the same preliminay checks taken by pte_access_permitted()
on that platform.
Since Commit 8e9bd41e4ce1 ("powerpc/nohash: Replace pte_user() by pte_read()")
pte_user() is no longer required to be present on all platforms as it
may be equivalent to or implied by pte_read(). Hence implementations are
specialised.
Signed-off-by: Rohan McLure <rmcl...@linux.ibm.com>
---
v9: New implementation
v10: Let book3s/64 use pte_user(), but otherwise default other platforms
to using the address provided with the call to infer whether it is a
user page or not. pmd/pud variants will warn on all other platforms, as
they should not be used for user page mappings
---
arch/powerpc/include/asm/book3s/64/pgtable.h | 19 ++++++++++++++
arch/powerpc/include/asm/pgtable.h | 26 ++++++++++++++++++++
2 files changed, 45 insertions(+)
diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h
b/arch/powerpc/include/asm/book3s/64/pgtable.h
index 382724c5e872..ca765331e21d 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -538,6 +538,12 @@ static inline bool pte_access_permitted(pte_t pte, bool
write)
return arch_pte_access_permitted(pte_val(pte), write, 0);
}
+#define pte_user_accessible_page pte_user_accessible_page
+static inline bool pte_user_accessible_page(pte_t pte, unsigned long addr)
+{
+ return pte_present(pte) && pte_user(pte);
+}
+
/*
* Conversion functions: convert a page and protection to a page entry,
* and a page entry and page directory to the page they refer to.
@@ -881,6 +887,7 @@ static inline int pud_present(pud_t pud)
extern struct page *pud_page(pud_t pud);
extern struct page *pmd_page(pmd_t pmd);
+
static inline pte_t pud_pte(pud_t pud)
{
return __pte_raw(pud_raw(pud));
@@ -926,6 +933,12 @@ static inline bool pud_access_permitted(pud_t pud, bool
write)
return pte_access_permitted(pud_pte(pud), write);
}
+#define pud_user_accessible_page pud_user_accessible_page
+static inline bool pud_user_accessible_page(pud_t pud, unsigned long addr)
+{
+ return pte_user_accessible_page(pud_pte(pud), addr);
+}
+
#define __p4d_raw(x) ((p4d_t) { __pgd_raw(x) })
static inline __be64 p4d_raw(p4d_t x)
{
@@ -1091,6 +1104,12 @@ static inline bool pmd_access_permitted(pmd_t pmd, bool
write)
return pte_access_permitted(pmd_pte(pmd), write);
}
+#define pmd_user_accessible_page pmd_user_accessible_page
+static inline bool pmd_user_accessible_page(pmd_t pmd, unsigned long addr)
+{
+ return pte_user_accessible_page(pmd_pte(pmd), addr);
+}
+
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
extern pmd_t pfn_pmd(unsigned long pfn, pgprot_t pgprot);
extern pud_t pfn_pud(unsigned long pfn, pgprot_t pgprot);
diff --git a/arch/powerpc/include/asm/pgtable.h
b/arch/powerpc/include/asm/pgtable.h
index 13f661831333..3741a63fb82e 100644
--- a/arch/powerpc/include/asm/pgtable.h
+++ b/arch/powerpc/include/asm/pgtable.h
@@ -227,6 +227,32 @@ static inline int pud_pfn(pud_t pud)
}
#endif
+#ifndef pte_user_accessible_page
+#define pte_user_accessible_page pte_user_accessible_page
+static inline bool pte_user_accessible_page(pte_t pte, unsigned long addr)
+{
+ return pte_present(pte) && !is_kernel_addr(addr);
+}
+#endif
+
+#ifndef pmd_user_accessible_page
+#define pmd_user_accessible_page pmd_user_accessible_page
+static inline bool pmd_user_accessible_page(pmd_t pmd, unsigned long addr)
+{
+ WARN_ONCE(1, "pmd: platform does not use pmd entries directly");
+ return false;
+}
+#endif
+
+#ifndef pud_user_accessible_page
+#define pud_user_accessible_page pud_user_accessible_page
+static inline bool pud_user_accessible_page(pud_t pud, unsigned long addr)
+{
+ WARN_ONCE(1, "pud: platform does not use pud entries directly");
+ return false;
+}
+#endif
+
#endif /* __ASSEMBLY__ */
#endif /* _ASM_POWERPC_PGTABLE_H */
--
2.44.0
