--- a/arch/um/kernel/um_arch.c
+++ b/arch/um/kernel/um_arch.c
@@ -421,6 +421,10 @@ void __init check_bugs(void)
 	os_check_bugs();
 }
 
+void apply_retpolines(s32 *start, s32 *end)
+{
+}
+
 void apply_alternatives(struct alt_instr *start, struct alt_instr *end)
 {
 }
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -75,6 +75,7 @@ extern int alternatives_patched;
 
 extern void alternative_instructions(void);
 extern void apply_alternatives(struct alt_instr *start, struct alt_instr *end);
+extern void apply_retpolines(s32 *start, s32 *end);
 
 struct module;
 
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -29,6 +29,7 @@
 #include <asm/io.h>
 #include <asm/fixmap.h>
 #include <asm/paravirt.h>
+#include <asm/asm-prototypes.h>
 
 int __read_mostly alternatives_patched;
 
@@ -113,6 +114,7 @@ static void __init_or_module add_nops(vo
 	}
 }
 
+extern s32 __retpoline_sites[], __retpoline_sites_end[];
 extern struct alt_instr __alt_instructions[], __alt_instructions_end[];
 extern s32 __smp_locks[], __smp_locks_end[];
 void text_poke_early(void *addr, const void *opcode, size_t len);
@@ -221,7 +223,7 @@ static __always_inline int optimize_nops
  * "noinline" to cause control flow change and thus invalidate I$ and
  * cause refetch after modification.
  */
-static void __init_or_module noinline optimize_nops(struct alt_instr *a, u8 *instr)
+static void __init_or_module noinline optimize_nops(u8 *instr, size_t len)
 {
 	struct insn insn;
 	int i = 0;
@@ -239,11 +241,11 @@ static void __init_or_module noinline op
 		 * optimized.
 		 */
 		if (insn.length == 1 && insn.opcode.bytes[0] == 0x90)
-			i += optimize_nops_range(instr, a->instrlen, i);
+			i += optimize_nops_range(instr, len, i);
 		else
 			i += insn.length;
 
-		if (i >= a->instrlen)
+		if (i >= len)
 			return;
 	}
 }
@@ -331,10 +333,135 @@ void __init_or_module noinline apply_alt
 		text_poke_early(instr, insn_buff, insn_buff_sz);
 
 next:
-		optimize_nops(a, instr);
+		optimize_nops(instr, a->instrlen);
 	}
 }
 
+#if defined(CONFIG_RETPOLINE) && defined(CONFIG_STACK_VALIDATION)
+
+/*
+ * CALL/JMP *%\reg
+ */
+static int emit_indirect(int op, int reg, u8 *bytes)
+{
+	int i = 0;
+	u8 modrm;
+
+	switch (op) {
+	case CALL_INSN_OPCODE:
+		modrm = 0x10; /* Reg = 2; CALL r/m */
+		break;
+
+	case JMP32_INSN_OPCODE:
+		modrm = 0x20; /* Reg = 4; JMP r/m */
+		break;
+
+	default:
+		WARN_ON_ONCE(1);
+		return -1;
+	}
+
+	if (reg >= 8) {
+		bytes[i++] = 0x41; /* REX.B prefix */
+		reg -= 8;
+	}
+
+	modrm |= 0xc0; /* Mod = 3 */
+	modrm += reg;
+
+	bytes[i++] = 0xff; /* opcode */
+	bytes[i++] = modrm;
+
+	return i;
+}
+
+/*
+ * Rewrite the compiler generated retpoline thunk calls.
+ *
+ * For spectre_v2=off (!X86_FEATURE_RETPOLINE), rewrite them into immediate
+ * indirect instructions, avoiding the extra indirection.
+ *
+ * For example, convert:
+ *
+ *   CALL __x86_indirect_thunk_\reg
+ *
+ * into:
+ *
+ *   CALL *%\reg
+ *
+ */
+static int patch_retpoline(void *addr, struct insn *insn, u8 *bytes)
+{
+	retpoline_thunk_t *target;
+	int reg, i = 0;
+
+	target = addr + insn->length + insn->immediate.value;
+	reg = target - __x86_indirect_thunk_array;
+
+	if (WARN_ON_ONCE(reg & ~0xf))
+		return -1;
+
+	/* If anyone ever does: CALL/JMP *%rsp, we're in deep trouble. */
+	BUG_ON(reg == 4);
+
+	if (cpu_feature_enabled(X86_FEATURE_RETPOLINE))
+		return -1;
+
+	i = emit_indirect(insn->opcode.bytes[0], reg, bytes);
+	if (i < 0)
+		return i;
+
+	for (; i < insn->length;)
+		bytes[i++] = BYTES_NOP1;
+
+	return i;
+}
+
+/*
+ * Generated by 'objtool --retpoline'.
+ */
+void __init_or_module noinline apply_retpolines(s32 *start, s32 *end)
+{
+	s32 *s;
+
+	for (s = start; s < end; s++) {
+		void *addr = (void *)s + *s;
+		struct insn insn;
+		int len, ret;
+		u8 bytes[16];
+		u8 op1, op2;
+
+		ret = insn_decode_kernel(&insn, addr);
+		if (WARN_ON_ONCE(ret < 0))
+			continue;
+
+		op1 = insn.opcode.bytes[0];
+		op2 = insn.opcode.bytes[1];
+
+		switch (op1) {
+		case CALL_INSN_OPCODE:
+		case JMP32_INSN_OPCODE:
+			break;
+
+		default:
+			WARN_ON_ONCE(1);
+			continue;
+		}
+
+		len = patch_retpoline(addr, &insn, bytes);
+		if (len == insn.length) {
+			optimize_nops(bytes, len);
+			text_poke_early(addr, bytes, len);
+		}
+	}
+}
+
+#else /* !RETPOLINES || !CONFIG_STACK_VALIDATION */
+
+void __init_or_module noinline apply_retpolines(s32 *start, s32 *end) { }
+
+#endif /* CONFIG_RETPOLINE && CONFIG_STACK_VALIDATION */
+
 #ifdef CONFIG_SMP
 static void alternatives_smp_lock(const s32 *start, const s32 *end,
 				  u8 *text, u8 *text_end)
@@ -643,6 +770,12 @@ void __init alternative_instructions(voi
 	apply_paravirt(__parainstructions, __parainstructions_end);
 
 	/*
+	 * Rewrite the retpolines, must be done before alternatives since
+	 * those can rewrite the retpoline thunks.
+	 */
+	apply_retpolines(__retpoline_sites, __retpoline_sites_end);
+
+	/*
 	 * Then patch alternatives, such that those paravirt calls that are in
 	 * alternatives can be overwritten by their immediate fragments.
 	 */
--- a/arch/x86/kernel/module.c
+++ b/arch/x86/kernel/module.c
@@ -251,7 +251,8 @@ int module_finalize(const Elf_Ehdr *hdr,
 		    struct module *me)
 {
 	const Elf_Shdr *s, *text = NULL, *alt = NULL, *locks = NULL,
-		*para = NULL, *orc = NULL, *orc_ip = NULL;
+		*para = NULL, *orc = NULL, *orc_ip = NULL,
+		*retpolines = NULL;
 	char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
 
 	for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
@@ -267,8 +268,14 @@ int module_finalize(const Elf_Ehdr *hdr,
 			orc = s;
 		if (!strcmp(".orc_unwind_ip", secstrings + s->sh_name))
 			orc_ip = s;
+		if (!strcmp(".retpoline_sites", secstrings + s->sh_name))
+			retpolines = s;
 	}
 
+	if (retpolines) {
+		void *rseg = (void *)retpolines->sh_addr;
+		apply_retpolines(rseg, rseg + retpolines->sh_size);
+	}
 	if (alt) {
 		/* patch .altinstructions */
 		void *aseg = (void *)alt->sh_addr;
