Merge "mmu: arm64: fix ability to write to protected memory" (9071c08e) · Commits · e / devices / android_kernel_sony_msm8994

arch/arm64/mm/mmu.c

+15 −6

Original line number	Diff line number	Diff line
		@@ -75,7 +75,9 @@ static struct cachepolicy cache_policies[] __initdata = {
		#ifdef CONFIG_STRICT_MEMORY_RWX
		static struct {
		pmd_t *pmd;
		pte_t *pte;
		pmd_t saved_pmd;
		pte_t saved_pte;
		bool made_writeable;
		} mem_unprotect;

		@@ -126,11 +128,15 @@ void mem_text_address_writeable(u64 addr)
		mem_unprotect.pmd = pmd_offset(pud, addr);
		addr_aligned = addr & PAGE_MASK;
		mem_unprotect.saved_pmd = *mem_unprotect.pmd;
		if ((mem_unprotect.saved_pmd & PMD_TYPE_MASK) != PMD_TYPE_SECT)
		return;

		if ((mem_unprotect.saved_pmd & PMD_TYPE_MASK) == PMD_TYPE_SECT) {
		set_pmd(mem_unprotect.pmd,
		__pmd(__pa(addr_aligned) \| prot_sect_kernel));
		} else {
		mem_unprotect.pte = pte_offset_kernel(mem_unprotect.pmd, addr);
		mem_unprotect.saved_pte = *mem_unprotect.pte;
		set_pte(mem_unprotect.pte, pfn_pte(__pa(addr) >> PAGE_SHIFT,
		PAGE_KERNEL_EXEC));
		}
		flush_tlb_kernel_range(addr, addr + PAGE_SIZE);

		mem_unprotect.made_writeable = 1;
		@@ -140,7 +146,10 @@ void mem_text_address_writeable(u64 addr)
		void mem_text_address_restore(u64 addr)
		{
		if (mem_unprotect.made_writeable) {
		if ((mem_unprotect.saved_pmd & PMD_TYPE_MASK) == PMD_TYPE_SECT)
		*mem_unprotect.pmd = mem_unprotect.saved_pmd;
		else
		*mem_unprotect.pte = mem_unprotect.saved_pte;
		flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
		}
		}