Merge tag 'v4.9.93' into linux-linaro-lsk-v4.9

This is the 4.9.93 stable release

1 files changed, 31 insertions, 0 deletions

diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index c6ae09f01e23..5b1184c369d5 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -422,6 +422,37 @@ static void __init map_kernel_segment(pgd_t *pgd, void *va_start, void *va_end,
 	vm_area_add_early(vma);
 }
 
+#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
+static int __init map_entry_trampoline(void)
+{
+	extern char __entry_tramp_text_start[];
+
+	pgprot_t prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC;
+	phys_addr_t pa_start = __pa_symbol(__entry_tramp_text_start);
+
+	/* The trampoline is always mapped and can therefore be global */
+	pgprot_val(prot) &= ~PTE_NG;
+
+	/* Map only the text into the trampoline page table */
+	memset(tramp_pg_dir, 0, PGD_SIZE);
+	__create_pgd_mapping(tramp_pg_dir, pa_start, TRAMP_VALIAS, PAGE_SIZE,
+			     prot, pgd_pgtable_alloc, 0);
+
+	/* Map both the text and data into the kernel page table */
+	__set_fixmap(FIX_ENTRY_TRAMP_TEXT, pa_start, prot);
+	if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {
+		extern char __entry_tramp_data_start[];
+
+		__set_fixmap(FIX_ENTRY_TRAMP_DATA,
+			     __pa_symbol(__entry_tramp_data_start),
+			     PAGE_KERNEL_RO);
+	}
+
+	return 0;
+}
+core_initcall(map_entry_trampoline);
+#endif
+
 /*
  * Create fine-grained mappings for the kernel.
  */