[PATCH v11 09/11] poweprc: mm: Implement *_user_accessible_page() for ptes
From: Rohan McLure <hidden>
Date: 2024-03-28 04:58:40
Also in:
linux-arm-kernel, linux-riscv
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
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 preliminary 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 of
pte_user_accessible_page() are specialised.
Signed-off-by: Rohan McLure <redacted>
---
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
v11: Conditionally define p{m,u}d_user_accessible_page(), as not all
platforms have p{m,u}d_leaf(), p{m,u}d_pte() stubs.
---
arch/powerpc/include/asm/book3s/32/pgtable.h | 5 +++++
arch/powerpc/include/asm/book3s/64/pgtable.h | 17 +++++++++++++++++
arch/powerpc/include/asm/nohash/pgtable.h | 5 +++++
arch/powerpc/include/asm/pgtable.h | 8 ++++++++
4 files changed, 35 insertions(+)
diff --git a/arch/powerpc/include/asm/book3s/32/pgtable.h b/arch/powerpc/include/asm/book3s/32/pgtable.h
index 52971ee30717..83f7b98ef49f 100644
--- a/arch/powerpc/include/asm/book3s/32/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/32/pgtable.h@@ -436,6 +436,11 @@ static inline bool pte_access_permitted(pte_t pte, bool write) return true; } +static inline bool pte_user_accessible_page(pte_t pte, unsigned long addr) +{ + return pte_present(pte) && !is_kernel_addr(addr); +} + /* Conversion functions: convert a page and protection to a page entry, * and a page entry and page directory to the page they refer to. *
diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index fac5615e6bc5..d8640ddbcad1 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h@@ -538,6 +538,11 @@ static inline bool pte_access_permitted(pte_t pte, bool write) return arch_pte_access_permitted(pte_val(pte), write, 0); } +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.
@@ -1441,5 +1446,17 @@ static inline bool pud_leaf(pud_t pud) return !!(pud_raw(pud) & cpu_to_be64(_PAGE_PTE)); } +#define pmd_user_accessible_page pmd_user_accessible_page +static inline bool pmd_user_accessible_page(pmd_t pmd, unsigned long addr) +{ + return pmd_leaf(pmd) && pte_user_accessible_page(pmd_pte(pmd), addr); +} + +#define pud_user_accessible_page pud_user_accessible_page +static inline bool pud_user_accessible_page(pud_t pud, unsigned long addr) +{ + return pud_leaf(pud) && pte_user_accessible_page(pud_pte(pud), addr); +} + #endif /* __ASSEMBLY__ */ #endif /* _ASM_POWERPC_BOOK3S_64_PGTABLE_H_ */
diff --git a/arch/powerpc/include/asm/nohash/pgtable.h b/arch/powerpc/include/asm/nohash/pgtable.h
index 427db14292c9..413d01a51e6f 100644
--- a/arch/powerpc/include/asm/nohash/pgtable.h
+++ b/arch/powerpc/include/asm/nohash/pgtable.h@@ -213,6 +213,11 @@ static inline bool pte_access_permitted(pte_t pte, bool write) return true; } +static inline bool pte_user_accessible_page(pte_t pte, unsigned long addr) +{ + return pte_present(pte) && !is_kernel_addr(addr); +} + /* Conversion functions: convert a page and protection to a page entry, * and a page entry and page directory to the page they refer to. *
diff --git a/arch/powerpc/include/asm/pgtable.h b/arch/powerpc/include/asm/pgtable.h
index ee8c82c0528f..f1ceae778cb1 100644
--- a/arch/powerpc/include/asm/pgtable.h
+++ b/arch/powerpc/include/asm/pgtable.h@@ -219,6 +219,14 @@ static inline int pud_pfn(pud_t pud) } #endif +#ifndef pmd_user_accessible_page +#define pmd_user_accessible_page(pmd, addr) false +#endif + +#ifndef pud_user_accessible_page +#define pud_user_accessible_page(pud, addr) false +#endif + #endif /* __ASSEMBLY__ */ #endif /* _ASM_POWERPC_PGTABLE_H */
--
2.44.0