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arm64: mm: Make PUD folding check in set_pud() a runtime check

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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>
This commit is contained in:
Ard Biesheuvel 2024-02-17 00:59:44 +01:00 committed by Catalin Marinas
parent 50e3ed0f93
commit 90e636f60b
1 changed files with 3 additions and 3 deletions
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6
arch/arm64/include/asm/pgtable.h
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@ -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);