4 files changed, 75 insertions, 4 deletions
diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
index b5a28336c077..b6a20b767af6 100644
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -462,3 +462,67 @@ void __init enable_errata_workarounds(void)
 {
 	enable_cpu_capabilities(arm64_errata);
 }
+
+static inline bool retp_compiler(void)
+{
+	return __is_defined(RETPOLINE);
+}
+
+/* The Spectre V2 mitigation variants */
+enum spectre_v2_mitigation {
+	SPECTRE_V2_NONE,
+	SPECTRE_V2_RETPOLINE_MINIMAL,
+	SPECTRE_V2_RETPOLINE_GENERIC,
+};
+
+static const char *spectre_v2_strings[] = {
+	[SPECTRE_V2_NONE]			= "Vulnerable",
+	[SPECTRE_V2_RETPOLINE_MINIMAL]		= "Vulnerable: Minimal generic ASM retpoline",
+	[SPECTRE_V2_RETPOLINE_GENERIC]		= "Mitigation: Full generic retpoline",
+};
+
+enum spectre_v2_mitigation get_spectre_v2_mitigation(void)
+{
+	enum spectre_v2_mitigation mode;
+
+#ifndef RETPOLINE
+	return SPECTRE_V2_NONE;
+#endif
+
+	mode = retp_compiler() ? SPECTRE_V2_RETPOLINE_GENERIC :
+				 SPECTRE_V2_RETPOLINE_MINIMAL;
+
+	return mode;
+}
+
+#ifdef RETPOLINE
+static bool spectre_v2_bad_module;
+
+bool retpoline_module_ok(bool has_retpoline)
+{
+	if (has_retpoline)
+		return true;
+
+	pr_err("System may be vulnerable to spectre v2\n");
+	spectre_v2_bad_module = true;
+	return false;
+}
+
+static inline const char *spectre_v2_module_string(void)
+{
+	return spectre_v2_bad_module ? " - vulnerable module loaded" : "";
+}
+#else
+static inline const char *spectre_v2_module_string(void) { return ""; }
+#endif
+
+#ifdef CONFIG_SYSFS
+ssize_t cpu_show_spectre_v2(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	enum spectre_v2_mitigation mode;
+
+	mode = get_spectre_v2_mitigation();
+	return sprintf(buf, "%s%s\n", spectre_v2_strings[mode],
+		       spectre_v2_module_string());
+}
+#endif
diff --git a/arch/arm64/kernel/entry-ftrace.S b/arch/arm64/kernel/entry-ftrace.S
index 1175f5827ae1..27bb502aa5e6 100644
--- a/arch/arm64/kernel/entry-ftrace.S
+++ b/arch/arm64/kernel/entry-ftrace.S
@@ -106,7 +106,7 @@ ENTRY(_mcount)
 
 	mcount_get_pc	x0		//       function's pc
 	mcount_get_lr	x1		//       function's lr (= parent's pc)
-	blr	x2			//   (*ftrace_trace_function)(pc, lr);
+	blr_nospec	x2		//   (*ftrace_trace_function)(pc, lr);
 
 skip_ftrace_call:			// }
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index f409b7750114..7475dbdb816f 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -395,7 +395,7 @@ tsk	.req	x28		// current thread_info
 	ldr_l	x1, handle_arch_irq
 	mov	x0, sp
 	irq_stack_entry
-	blr	x1
+	blr_nospec	x1
 	irq_stack_exit
 	.endm
 
@@ -976,7 +976,7 @@ el0_svc_naked:					// compat entry point
 	b.hs	ni_sys
 	mask_nospec64 xscno, xsc_nr, x19	// enforce bounds for syscall number
 	ldr	x16, [stbl, xscno, lsl #3]	// address in the syscall table
-	blr	x16				// call sys_* routine
+	blr_nospec	x16			// call sys_* routine
 	b	ret_fast_syscall
 ni_sys:
 	mov	x0, sp
@@ -1006,7 +1006,7 @@ __sys_trace:
 	ldp	x4, x5, [sp, #S_X4]
 	ldp	x6, x7, [sp, #S_X6]
 	ldr	x16, [stbl, xscno, lsl #3]	// address in the syscall table
-	blr	x16				// call sys_* routine
+	blr_nospec	x16			// call sys_* routine
 
 __sys_trace_return:
 	str	x0, [sp, #S_X0]			// save returned x0
diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S
index 0221aca6493d..7d534afe66b7 100644
--- a/arch/arm64/kernel/vmlinux.lds.S
+++ b/arch/arm64/kernel/vmlinux.lds.S
@@ -127,6 +127,13 @@ SECTIONS
 			TRAMP_TEXT
 			*(.fixup)
 			*(.gnu.warning)
+
+#ifdef CONFIG_RETPOLINE
+		__indirect_thunk_start = .;
+		*(.text.__aarch64.indirect_thunk)
+		__indirect_thunk_end = .;
+#endif /* CONFIG_RETPOLINE */
+
 		. = ALIGN(16);
 		*(.got)			/* Global offset table		*/
 	}