diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 03b6bb5394a0..bc6abb7bc7ee 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -45,10 +45,9 @@
 struct alt_instr {
 	u8 *instr;		/* original instruction */
 	u8 *replacement;
-	u8  cpuid;		/* cpuid bit set for replacement */
+	u16 cpuid;		/* cpuid bit set for replacement */
 	u8  instrlen;		/* length of original instruction */
 	u8  replacementlen;	/* length of new instruction, <= instrlen */
-	u8  pad1;
 #ifdef CONFIG_X86_64
 	u32 pad2;
 #endif
@@ -86,9 +85,11 @@ static inline int alternatives_text_reserved(void *start, void *end)
       _ASM_ALIGN "\n"							\
       _ASM_PTR "661b\n"				/* label           */	\
       _ASM_PTR "663f\n"				/* new instruction */	\
-      "	 .byte " __stringify(feature) "\n"	/* feature bit     */	\
+      "	 .word " __stringify(feature) "\n"	/* feature bit     */	\
       "	 .byte 662b-661b\n"			/* sourcelen       */	\
       "	 .byte 664f-663f\n"			/* replacementlen  */	\
+      ".previous\n"							\
+      ".section .discard,\"aw\",@progbits\n"				\
       "	 .byte 0xff + (664f-663f) - (662b-661b)\n" /* rlen <= slen */	\
       ".previous\n"							\
       ".section .altinstr_replacement, \"ax\"\n"			\
diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index 0b205b8a4308..781a50b29a49 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -302,7 +302,7 @@ extern const char * const x86_power_flags[32];
  * patch the target code for additional performance.
  *
  */
-static __always_inline __pure bool __static_cpu_has(u8 bit)
+static __always_inline __pure bool __static_cpu_has(u16 bit)
 {
 #if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 5)
 		asm goto("1: jmp %l[t_no]\n"
@@ -311,11 +311,11 @@ static __always_inline __pure bool __static_cpu_has(u8 bit)
 			 _ASM_ALIGN "\n"
 			 _ASM_PTR "1b\n"
 			 _ASM_PTR "0\n" 	/* no replacement */
-			 " .byte %P0\n"		/* feature bit */
+			 " .word %P0\n"		/* feature bit */
 			 " .byte 2b - 1b\n"	/* source len */
 			 " .byte 0\n"		/* replacement len */
-			 " .byte 0xff + 0 - (2b-1b)\n"	/* padding */
 			 ".previous\n"
+			 /* skipping size check since replacement size = 0 */
 			 : : "i" (bit) : : t_no);
 		return true;
 	t_no:
@@ -329,10 +329,12 @@ static __always_inline __pure bool __static_cpu_has(u8 bit)
 			     _ASM_ALIGN "\n"
 			     _ASM_PTR "1b\n"
 			     _ASM_PTR "3f\n"
-			     " .byte %P1\n"		/* feature bit */
+			     " .word %P1\n"		/* feature bit */
 			     " .byte 2b - 1b\n"		/* source len */
 			     " .byte 4f - 3f\n"		/* replacement len */
-			     " .byte 0xff + (4f-3f) - (2b-1b)\n" /* padding */
+			     ".previous\n"
+			     ".section .discard,\"aw\",@progbits\n"
+			     " .byte 0xff + (4f-3f) - (2b-1b)\n" /* size check */
 			     ".previous\n"
 			     ".section .altinstr_replacement,\"ax\"\n"
 			     "3: movb $1,%0\n"
@@ -348,7 +350,7 @@ static __always_inline __pure bool __static_cpu_has(u8 bit)
 (								\
 	__builtin_constant_p(boot_cpu_has(bit)) ?		\
 		boot_cpu_has(bit) :				\
-	(__builtin_constant_p(bit) && !((bit) & ~0xff)) ?	\
+	__builtin_constant_p(bit) ?				\
 		__static_cpu_has(bit) :				\
 		boot_cpu_has(bit)				\
 )
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 70237732a6c7..f65ab8b014c4 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -214,6 +214,7 @@ void __init_or_module apply_alternatives(struct alt_instr *start,
 		u8 *instr = a->instr;
 		BUG_ON(a->replacementlen > a->instrlen);
 		BUG_ON(a->instrlen > sizeof(insnbuf));
+		BUG_ON(a->cpuid >= NCAPINTS*32);
 		if (!boot_cpu_has(a->cpuid))
 			continue;
 #ifdef CONFIG_X86_64
diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S
index 258e93fa2630..227d00920d2f 100644
--- a/arch/x86/kernel/entry_32.S
+++ b/arch/x86/kernel/entry_32.S
@@ -913,7 +913,7 @@ ENTRY(simd_coprocessor_error)
 	.balign 4
 	.long 661b
 	.long 663f
-	.byte X86_FEATURE_XMM
+	.word X86_FEATURE_XMM
 	.byte 662b-661b
 	.byte 664f-663f
 .previous
diff --git a/arch/x86/lib/clear_page_64.S b/arch/x86/lib/clear_page_64.S
index ebeafcce04a9..aa4326bfb24a 100644
--- a/arch/x86/lib/clear_page_64.S
+++ b/arch/x86/lib/clear_page_64.S
@@ -52,7 +52,7 @@ ENDPROC(clear_page)
 	.align 8
 	.quad clear_page
 	.quad 1b
-	.byte X86_FEATURE_REP_GOOD
+	.word X86_FEATURE_REP_GOOD
 	.byte .Lclear_page_end - clear_page
 	.byte 2b - 1b
 	.previous
diff --git a/arch/x86/lib/copy_page_64.S b/arch/x86/lib/copy_page_64.S
index 727a5d46d2fc..6fec2d1cebe1 100644
--- a/arch/x86/lib/copy_page_64.S
+++ b/arch/x86/lib/copy_page_64.S
@@ -113,7 +113,7 @@ ENDPROC(copy_page)
 	.align 8
 	.quad copy_page
 	.quad 1b
-	.byte X86_FEATURE_REP_GOOD
+	.word X86_FEATURE_REP_GOOD
 	.byte .Lcopy_page_end - copy_page
 	.byte 2b - 1b
 	.previous
diff --git a/arch/x86/lib/copy_user_64.S b/arch/x86/lib/copy_user_64.S
index 71100c98e337..a460158b5ac5 100644
--- a/arch/x86/lib/copy_user_64.S
+++ b/arch/x86/lib/copy_user_64.S
@@ -29,7 +29,7 @@
 	.align 8
 	.quad  0b
 	.quad  2b
-	.byte  \feature			/* when feature is set */
+	.word  \feature			/* when feature is set */
 	.byte  5
 	.byte  5
 	.previous
diff --git a/arch/x86/lib/memcpy_64.S b/arch/x86/lib/memcpy_64.S
index f82e884928af..bcbcd1e0f7d5 100644
--- a/arch/x86/lib/memcpy_64.S
+++ b/arch/x86/lib/memcpy_64.S
@@ -131,7 +131,7 @@ ENDPROC(__memcpy)
 	.align 8
 	.quad memcpy
 	.quad .Lmemcpy_c
-	.byte X86_FEATURE_REP_GOOD
+	.word X86_FEATURE_REP_GOOD
 
 	/*
 	 * Replace only beginning, memcpy is used to apply alternatives,
diff --git a/arch/x86/lib/memset_64.S b/arch/x86/lib/memset_64.S
index e88d3b81644a..09d344269652 100644
--- a/arch/x86/lib/memset_64.S
+++ b/arch/x86/lib/memset_64.S
@@ -121,7 +121,7 @@ ENDPROC(__memset)
 	.align 8
 	.quad memset
 	.quad .Lmemset_c
-	.byte X86_FEATURE_REP_GOOD
+	.word X86_FEATURE_REP_GOOD
 	.byte .Lfinal - memset
 	.byte .Lmemset_e - .Lmemset_c
 	.previous