1 files changed, 4 insertions, 44 deletions

diff --git a/arch/arm64/include/asm/mmu.h b/arch/arm64/include/asm/mmu.h
index f217e3292919..e4d862420bb4 100644
--- a/arch/arm64/include/asm/mmu.h
+++ b/arch/arm64/include/asm/mmu.h
@@ -29,52 +29,11 @@ typedef struct {
  */
 #define ASID(mm)	((mm)->context.id.counter & 0xffff)
 
-static inline bool arm64_kernel_unmapped_at_el0(void)
-{
-	return IS_ENABLED(CONFIG_UNMAP_KERNEL_AT_EL0) &&
-	       cpus_have_const_cap(ARM64_UNMAP_KERNEL_AT_EL0);
-}
+extern bool arm64_use_ng_mappings;
 
-static inline bool arm64_kernel_use_ng_mappings(void)
+static inline bool arm64_kernel_unmapped_at_el0(void)
 {
-	bool tx1_bug;
-
-	/* What's a kpti? Use global mappings if we don't know. */
-	if (!IS_ENABLED(CONFIG_UNMAP_KERNEL_AT_EL0))
-		return false;
-
-	/*
-	 * Note: this function is called before the CPU capabilities have
-	 * been configured, so our early mappings will be global. If we
-	 * later determine that kpti is required, then
-	 * kpti_install_ng_mappings() will make them non-global.
-	 */
-	if (arm64_kernel_unmapped_at_el0())
-		return true;
-
-	if (!IS_ENABLED(CONFIG_RANDOMIZE_BASE))
-		return false;
-
-	/*
-	 * KASLR is enabled so we're going to be enabling kpti on non-broken
-	 * CPUs regardless of their susceptibility to Meltdown. Rather
-	 * than force everybody to go through the G -> nG dance later on,
-	 * just put down non-global mappings from the beginning.
-	 */
-	if (!IS_ENABLED(CONFIG_CAVIUM_ERRATUM_27456)) {
-		tx1_bug = false;
-#ifndef MODULE
-	} else if (!static_branch_likely(&arm64_const_caps_ready)) {
-		extern const struct midr_range cavium_erratum_27456_cpus[];
-
-		tx1_bug = is_midr_in_range_list(read_cpuid_id(),
-						cavium_erratum_27456_cpus);
-#endif
-	} else {
-		tx1_bug = __cpus_have_const_cap(ARM64_WORKAROUND_CAVIUM_27456);
-	}
-
-	return !tx1_bug && kaslr_offset() > 0;
+	return arm64_use_ng_mappings;
 }
 
 typedef void (*bp_hardening_cb_t)(void);
@@ -128,6 +87,7 @@ extern void create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,
 			       pgprot_t prot, bool page_mappings_only);
 extern void *fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot);
 extern void mark_linear_text_alias_ro(void);
+extern bool kaslr_requires_kpti(void);
 
 #define INIT_MM_CONTEXT(name)	\
 	.pgd = init_pg_dir,