Merge "arm64: Make sure permission updates happen for pmd/pud" (e1cbdbc1) · Commits · e / devices / android_kernel_fairphone_FP3

arch/arm64/include/asm/pgtable.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -386,6 +386,7 @@ static inline int pmd_protnone(pmd_t pmd)

		#define pud_write(pud) pte_write(pud_pte(pud))
		#define pud_pfn(pud) (((pud_val(pud) & PUD_MASK) & PHYS_MASK) >> PAGE_SHIFT)
		#define pfn_pud(pfn,prot) (__pud(((phys_addr_t)(pfn) << PAGE_SHIFT) \| pgprot_val(prot)))

		#define set_pmd_at(mm, addr, pmdp, pmd) set_pte_at(mm, addr, (pte_t *)pmdp, pmd_pte(pmd))

arch/arm64/mm/mmu.c

+27 −6

Original line number	Diff line number	Diff line
		@@ -135,6 +135,17 @@ static phys_addr_t __init early_pgtable_alloc(void)
		return phys;
		}

		static bool pgattr_change_is_safe(u64 old, u64 new)
		{
		/*
		* The following mapping attributes may be updated in live
		* kernel mappings without the need for break-before-make.
		*/
		static const pteval_t mask = PTE_PXN \| PTE_RDONLY \| PTE_WRITE;

		return old == 0 \|\| new == 0 \|\| ((old ^ new) & ~mask) == 0;
		}

		static void alloc_init_pte(pmd_t *pmd, unsigned long addr,
		unsigned long end, unsigned long pfn,
		pgprot_t prot,
		@@ -826,23 +837,33 @@ int __init arch_ioremap_pmd_supported(void)

		int pud_set_huge(pud_t *pud, phys_addr_t phys, pgprot_t prot)
		{
		/* ioremap_page_range doesn't honour BBM */
		if (pud_present(READ_ONCE(*pud)))
		pgprot_t sect_prot = __pgprot(PUD_TYPE_SECT \|
		pgprot_val(mk_sect_prot(prot)));
		pud_t new_pud = pfn_pud(__phys_to_pfn(phys), sect_prot);

		/* Only allow permission changes for now */
		if (!pgattr_change_is_safe(READ_ONCE(pud_val(*pud)),
		pud_val(new_pud)))
		return 0;

		BUG_ON(phys & ~PUD_MASK);
		set_pud(pud, __pud(phys \| PUD_TYPE_SECT \| pgprot_val(mk_sect_prot(prot))));
		set_pud(pud, new_pud);
		return 1;
		}

		int pmd_set_huge(pmd_t *pmd, phys_addr_t phys, pgprot_t prot)
		{
		/* ioremap_page_range doesn't honour BBM */
		if (pmd_present(READ_ONCE(*pmd)))
		pgprot_t sect_prot = __pgprot(PMD_TYPE_SECT \|
		pgprot_val(mk_sect_prot(prot)));
		pmd_t new_pmd = pfn_pmd(__phys_to_pfn(phys), sect_prot);

		/* Only allow permission changes for now */
		if (!pgattr_change_is_safe(READ_ONCE(pmd_val(*pmd)),
		pmd_val(new_pmd)))
		return 0;

		BUG_ON(phys & ~PMD_MASK);
		set_pmd(pmd, __pmd(phys \| PMD_TYPE_SECT \| pgprot_val(mk_sect_prot(prot))));
		set_pmd(pmd, new_pmd);
		return 1;
		}