From: Ard Biesheuvel <ardb@kernel.org>
Date: Fri, 16 Feb 2024 23:59:44 +0000 (+0100)
Subject: arm64: mm: Make PUD folding check in set_pud() a runtime check
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=90e636f60b76c590aded72964543945084d97c2f;p=users%2Fjedix%2Flinux-maple.git
arm64: mm: Make PUD folding check in set_pud() a runtime check
When set_pud() is called on a 4-level paging build config that runs with
3 levels at runtime (which happens with 16k page size builds with
support for LPA2), the updated entry is in fact a PGD in
swapper_pg_dir[], and this is mapped read-only after boot.
So in this case, the existing check needs to be performed as well, even
though __PAGETABLE_PUD_FOLDED is not #define'd. So replace the #ifdef
with a call to pgtable_l4_enabled().
Cc: Will Deacon <will@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20240216235944.3677178-2-ardb+git@google.com
Reviewed-by: Itaru Kitayama <itaru.kitayama@fujitsu.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
---
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index b3c716fa8121..8bec85350865 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -699,14 +699,14 @@ static inline unsigned long pmd_page_vaddr(pmd_t pmd)
#define pud_user(pud) pte_user(pud_pte(pud))
#define pud_user_exec(pud) pte_user_exec(pud_pte(pud))
+static inline bool pgtable_l4_enabled(void);
+
static inline void set_pud(pud_t *pudp, pud_t pud)
{
-#ifdef __PAGETABLE_PUD_FOLDED
- if (in_swapper_pgdir(pudp)) {
+ if (!pgtable_l4_enabled() && in_swapper_pgdir(pudp)) {
set_swapper_pgd((pgd_t *)pudp, __pgd(pud_val(pud)));
return;
}
-#endif /* __PAGETABLE_PUD_FOLDED */
WRITE_ONCE(*pudp, pud);