On Wed, Mar 10, 2021 at 10:35:45AM +0100, Peter Zijlstra wrote:
> On Wed, Mar 10, 2021 at 10:14:35AM +0100, Peter Zijlstra wrote:
> > Sure, but we can have one set on 32bit and another set on 64bit.
> 
> > Although I would use DS prefix nops for 32bit nop5/nop8 to keep them
> > single instructions.
> > 
> > Then we can do away with runtime nop selection and special atomic nops
> > and simplify things.
> > 
> > All this runtime faffing about nops is tedious and causes complications
> > we can do without.
> 
> Something like so, except I think there's more cleanups possible.

This one builds and boots x86_64-defconfig. Still, more cleanups are
possible.

---
 arch/x86/include/asm/jump_label.h    |  12 +--
 arch/x86/include/asm/nops.h          | 176 ++++++++++---------------------
 arch/x86/include/asm/special_insns.h |   4 +-
 arch/x86/kernel/alternative.c        | 198 ++++-------------------------------
 arch/x86/kernel/ftrace.c             |   4 +-
 arch/x86/kernel/jump_label.c         |  23 +---
 arch/x86/kernel/kprobes/core.c       |   2 +-
 arch/x86/kernel/setup.c              |   1 -
 arch/x86/kernel/static_call.c        |   4 +-
 arch/x86/net/bpf_jit_comp.c          |   8 +-
 10 files changed, 93 insertions(+), 339 deletions(-)

diff --git a/arch/x86/include/asm/jump_label.h 
b/arch/x86/include/asm/jump_label.h
index 7f2006645d84..610a05374c02 100644
--- a/arch/x86/include/asm/jump_label.h
+++ b/arch/x86/include/asm/jump_label.h
@@ -6,12 +6,6 @@
 
 #define JUMP_LABEL_NOP_SIZE 5
 
-#ifdef CONFIG_X86_64
-# define STATIC_KEY_INIT_NOP P6_NOP5_ATOMIC
-#else
-# define STATIC_KEY_INIT_NOP GENERIC_NOP5_ATOMIC
-#endif
-
 #include <asm/asm.h>
 #include <asm/nops.h>
 
@@ -23,7 +17,7 @@
 static __always_inline bool arch_static_branch(struct static_key * const key, 
const bool branch)
 {
        asm_volatile_goto("1:"
-               ".byte " __stringify(STATIC_KEY_INIT_NOP) "\n\t"
+               ".byte " __stringify(BYTES_NOP5) "\n\t"
                ".pushsection __jump_table,  \"aw\" \n\t"
                _ASM_ALIGN "\n\t"
                ".long 1b - ., %l[l_yes] - . \n\t"
@@ -63,7 +57,7 @@ static __always_inline bool arch_static_branch_jump(struct 
static_key * const ke
        .long           \target - .Lstatic_jump_after_\@
 .Lstatic_jump_after_\@:
        .else
-       .byte           STATIC_KEY_INIT_NOP
+       .byte           BYTES_NOP5
        .endif
        .pushsection __jump_table, "aw"
        _ASM_ALIGN
@@ -75,7 +69,7 @@ static __always_inline bool arch_static_branch_jump(struct 
static_key * const ke
 .macro STATIC_JUMP_IF_FALSE target, key, def
 .Lstatic_jump_\@:
        .if \def
-       .byte           STATIC_KEY_INIT_NOP
+       .byte           BYTES_NOP5
        .else
        /* Equivalent to "jmp.d32 \target" */
        .byte           0xe9
diff --git a/arch/x86/include/asm/nops.h b/arch/x86/include/asm/nops.h
index 12f12b5cf2ca..c6bdf8d8e79d 100644
--- a/arch/x86/include/asm/nops.h
+++ b/arch/x86/include/asm/nops.h
@@ -4,89 +4,58 @@
 
 /*
  * Define nops for use with alternative() and for tracing.
- *
- * *_NOP5_ATOMIC must be a single instruction.
  */
 
-#define NOP_DS_PREFIX 0x3e
+#ifndef CONFIG_64BIT
 
-/* generic versions from gas
-   1: nop
-   the following instructions are NOT nops in 64-bit mode,
-   for 64-bit mode use K8 or P6 nops instead
-   2: movl %esi,%esi
-   3: leal 0x00(%esi),%esi
-   4: leal 0x00(,%esi,1),%esi
-   6: leal 0x00000000(%esi),%esi
-   7: leal 0x00000000(,%esi,1),%esi
-*/
-#define GENERIC_NOP1 0x90
-#define GENERIC_NOP2 0x89,0xf6
-#define GENERIC_NOP3 0x8d,0x76,0x00
-#define GENERIC_NOP4 0x8d,0x74,0x26,0x00
-#define GENERIC_NOP5 GENERIC_NOP1,GENERIC_NOP4
-#define GENERIC_NOP6 0x8d,0xb6,0x00,0x00,0x00,0x00
-#define GENERIC_NOP7 0x8d,0xb4,0x26,0x00,0x00,0x00,0x00
-#define GENERIC_NOP8 GENERIC_NOP1,GENERIC_NOP7
-#define GENERIC_NOP5_ATOMIC NOP_DS_PREFIX,GENERIC_NOP4
+/*
+ * Generic 32bit nops from GAS:
+ *
+ * 1: nop
+ * 2: movl %esi,%esi
+ * 3: leal 0x00(%esi),%esi
+ * 4: leal 0x00(,%esi,1),%esi
+ * 5: leal %ds:0x00(,%esi,1),%esi
+ * 6: leal 0x00000000(%esi),%esi
+ * 7: leal 0x00000000(,%esi,1),%esi
+ * 8: leal %ds:0x00000000(,%esi,1),%esi
+ *
+ * Except 5 and 8, which are DS prefixed 4 and 7 resp, where GAS would emit 2
+ * nop instructions.
+ */
+#define BYTES_NOP1     0x90
+#define BYTES_NOP2     0x89,0xf6
+#define BYTES_NOP3     0x8d,0x76,0x00
+#define BYTES_NOP4     0x8d,0x74,0x26,0x00
+#define BYTES_NOP5     0x3e,BYTES_NOP4
+#define BYTES_NOP6     0x8d,0xb6,0x00,0x00,0x00,0x00
+#define BYTES_NOP7     0x8d,0xb4,0x26,0x00,0x00,0x00,0x00
+#define BYTES_NOP8     0x3e,BYTES_NOP7
 
-/* Opteron 64bit nops
-   1: nop
-   2: osp nop
-   3: osp osp nop
-   4: osp osp osp nop
-*/
-#define K8_NOP1 GENERIC_NOP1
-#define K8_NOP2        0x66,K8_NOP1
-#define K8_NOP3        0x66,K8_NOP2
-#define K8_NOP4        0x66,K8_NOP3
-#define K8_NOP5        K8_NOP3,K8_NOP2
-#define K8_NOP6        K8_NOP3,K8_NOP3
-#define K8_NOP7        K8_NOP4,K8_NOP3
-#define K8_NOP8        K8_NOP4,K8_NOP4
-#define K8_NOP5_ATOMIC 0x66,K8_NOP4
+#else
 
-/* K7 nops
-   uses eax dependencies (arbitrary choice)
-   1: nop
-   2: movl %eax,%eax
-   3: leal (,%eax,1),%eax
-   4: leal 0x00(,%eax,1),%eax
-   6: leal 0x00000000(%eax),%eax
-   7: leal 0x00000000(,%eax,1),%eax
-*/
-#define K7_NOP1        GENERIC_NOP1
-#define K7_NOP2        0x8b,0xc0
-#define K7_NOP3        0x8d,0x04,0x20
-#define K7_NOP4        0x8d,0x44,0x20,0x00
-#define K7_NOP5        K7_NOP4,K7_NOP1
-#define K7_NOP6        0x8d,0x80,0,0,0,0
-#define K7_NOP7        0x8D,0x04,0x05,0,0,0,0
-#define K7_NOP8        K7_NOP7,K7_NOP1
-#define K7_NOP5_ATOMIC NOP_DS_PREFIX,K7_NOP4
+/*
+ * Generic 64bit nops from GAS:
+ *
+ * 1: nop
+ * 2: osp nop
+ * 3: nopl (%eax)
+ * 4: nopl 0x00(%eax)
+ * 5: nopl 0x00(%eax,%eax,1)
+ * 6: osp nopl 0x00(%eax,%eax,1)
+ * 7: nopl 0x00000000(%eax)
+ * 8: nopl 0x00000000(%eax,%eax,1)
+ */
+#define BYTES_NOP1     0x90
+#define BYTES_NOP2     0x66,0x90
+#define BYTES_NOP3     0x0f,0x1f,0x00
+#define BYTES_NOP4     0x0f,0x1f,0x40,0
+#define BYTES_NOP5     0x0f,0x1f,0x44,0x00,0
+#define BYTES_NOP6     0x66,0x0f,0x1f,0x44,0x00,0
+#define BYTES_NOP7     0x0f,0x1f,0x80,0,0,0,0
+#define BYTES_NOP8     0x0f,0x1f,0x84,0x00,0,0,0,0
 
-/* P6 nops
-   uses eax dependencies (Intel-recommended choice)
-   1: nop
-   2: osp nop
-   3: nopl (%eax)
-   4: nopl 0x00(%eax)
-   5: nopl 0x00(%eax,%eax,1)
-   6: osp nopl 0x00(%eax,%eax,1)
-   7: nopl 0x00000000(%eax)
-   8: nopl 0x00000000(%eax,%eax,1)
-   Note: All the above are assumed to be a single instruction.
-       There is kernel code that depends on this.
-*/
-#define P6_NOP1        GENERIC_NOP1
-#define P6_NOP2        0x66,0x90
-#define P6_NOP3        0x0f,0x1f,0x00
-#define P6_NOP4        0x0f,0x1f,0x40,0
-#define P6_NOP5        0x0f,0x1f,0x44,0x00,0
-#define P6_NOP6        0x66,0x0f,0x1f,0x44,0x00,0
-#define P6_NOP7        0x0f,0x1f,0x80,0,0,0,0
-#define P6_NOP8        0x0f,0x1f,0x84,0x00,0,0,0,0
-#define P6_NOP5_ATOMIC P6_NOP5
+#endif /* CONFIG_64BIT */
 
 #ifdef __ASSEMBLY__
 #define _ASM_MK_NOP(x) .byte x
@@ -94,54 +63,19 @@
 #define _ASM_MK_NOP(x) ".byte " __stringify(x) "\n"
 #endif
 
-#if defined(CONFIG_MK7)
-#define ASM_NOP1 _ASM_MK_NOP(K7_NOP1)
-#define ASM_NOP2 _ASM_MK_NOP(K7_NOP2)
-#define ASM_NOP3 _ASM_MK_NOP(K7_NOP3)
-#define ASM_NOP4 _ASM_MK_NOP(K7_NOP4)
-#define ASM_NOP5 _ASM_MK_NOP(K7_NOP5)
-#define ASM_NOP6 _ASM_MK_NOP(K7_NOP6)
-#define ASM_NOP7 _ASM_MK_NOP(K7_NOP7)
-#define ASM_NOP8 _ASM_MK_NOP(K7_NOP8)
-#define ASM_NOP5_ATOMIC _ASM_MK_NOP(K7_NOP5_ATOMIC)
-#elif defined(CONFIG_X86_P6_NOP)
-#define ASM_NOP1 _ASM_MK_NOP(P6_NOP1)
-#define ASM_NOP2 _ASM_MK_NOP(P6_NOP2)
-#define ASM_NOP3 _ASM_MK_NOP(P6_NOP3)
-#define ASM_NOP4 _ASM_MK_NOP(P6_NOP4)
-#define ASM_NOP5 _ASM_MK_NOP(P6_NOP5)
-#define ASM_NOP6 _ASM_MK_NOP(P6_NOP6)
-#define ASM_NOP7 _ASM_MK_NOP(P6_NOP7)
-#define ASM_NOP8 _ASM_MK_NOP(P6_NOP8)
-#define ASM_NOP5_ATOMIC _ASM_MK_NOP(P6_NOP5_ATOMIC)
-#elif defined(CONFIG_X86_64)
-#define ASM_NOP1 _ASM_MK_NOP(K8_NOP1)
-#define ASM_NOP2 _ASM_MK_NOP(K8_NOP2)
-#define ASM_NOP3 _ASM_MK_NOP(K8_NOP3)
-#define ASM_NOP4 _ASM_MK_NOP(K8_NOP4)
-#define ASM_NOP5 _ASM_MK_NOP(K8_NOP5)
-#define ASM_NOP6 _ASM_MK_NOP(K8_NOP6)
-#define ASM_NOP7 _ASM_MK_NOP(K8_NOP7)
-#define ASM_NOP8 _ASM_MK_NOP(K8_NOP8)
-#define ASM_NOP5_ATOMIC _ASM_MK_NOP(K8_NOP5_ATOMIC)
-#else
-#define ASM_NOP1 _ASM_MK_NOP(GENERIC_NOP1)
-#define ASM_NOP2 _ASM_MK_NOP(GENERIC_NOP2)
-#define ASM_NOP3 _ASM_MK_NOP(GENERIC_NOP3)
-#define ASM_NOP4 _ASM_MK_NOP(GENERIC_NOP4)
-#define ASM_NOP5 _ASM_MK_NOP(GENERIC_NOP5)
-#define ASM_NOP6 _ASM_MK_NOP(GENERIC_NOP6)
-#define ASM_NOP7 _ASM_MK_NOP(GENERIC_NOP7)
-#define ASM_NOP8 _ASM_MK_NOP(GENERIC_NOP8)
-#define ASM_NOP5_ATOMIC _ASM_MK_NOP(GENERIC_NOP5_ATOMIC)
-#endif
+#define ASM_NOP1 _ASM_MK_NOP(BYTES_NOP1)
+#define ASM_NOP2 _ASM_MK_NOP(BYTES_NOP2)
+#define ASM_NOP3 _ASM_MK_NOP(BYTES_NOP3)
+#define ASM_NOP4 _ASM_MK_NOP(BYTES_NOP4)
+#define ASM_NOP5 _ASM_MK_NOP(BYTES_NOP5)
+#define ASM_NOP6 _ASM_MK_NOP(BYTES_NOP6)
+#define ASM_NOP7 _ASM_MK_NOP(BYTES_NOP7)
+#define ASM_NOP8 _ASM_MK_NOP(BYTES_NOP8)
 
 #define ASM_NOP_MAX 8
-#define NOP_ATOMIC5 (ASM_NOP_MAX+1)    /* Entry for the 5-byte atomic NOP */
 
 #ifndef __ASSEMBLY__
-extern const unsigned char * const *ideal_nops;
-extern void arch_init_ideal_nops(void);
+extern const unsigned char * const x86_nops[];
 #endif
 
 #endif /* _ASM_X86_NOPS_H */
diff --git a/arch/x86/include/asm/special_insns.h 
b/arch/x86/include/asm/special_insns.h
index 1d3cbaef4bb7..2acd6cb62328 100644
--- a/arch/x86/include/asm/special_insns.h
+++ b/arch/x86/include/asm/special_insns.h
@@ -214,7 +214,7 @@ static inline void clflush(volatile void *__p)
 
 static inline void clflushopt(volatile void *__p)
 {
-       alternative_io(".byte " __stringify(NOP_DS_PREFIX) "; clflush %P0",
+       alternative_io(".byte 0x3e; clflush %P0",
                       ".byte 0x66; clflush %P0",
                       X86_FEATURE_CLFLUSHOPT,
                       "+m" (*(volatile char __force *)__p));
@@ -225,7 +225,7 @@ static inline void clwb(volatile void *__p)
        volatile struct { char x[64]; } *p = __p;
 
        asm volatile(ALTERNATIVE_2(
-               ".byte " __stringify(NOP_DS_PREFIX) "; clflush (%[pax])",
+               ".byte 0x3e; clflush (%[pax])",
                ".byte 0x66; clflush (%[pax])", /* clflushopt (%%rax) */
                X86_FEATURE_CLFLUSHOPT,
                ".byte 0x66, 0x0f, 0xae, 0x30",  /* clwb (%%rax) */
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 94649f86d653..98e621ceb7d0 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -74,186 +74,30 @@ do {                                                       
                \
        }                                                               \
 } while (0)
 
-/*
- * Each GENERIC_NOPX is of X bytes, and defined as an array of bytes
- * that correspond to that nop. Getting from one nop to the next, we
- * add to the array the offset that is equal to the sum of all sizes of
- * nops preceding the one we are after.
- *
- * Note: The GENERIC_NOP5_ATOMIC is at the end, as it breaks the
- * nice symmetry of sizes of the previous nops.
- */
-#if defined(GENERIC_NOP1) && !defined(CONFIG_X86_64)
-static const unsigned char intelnops[] =
+const unsigned char x86nops[] =
 {
-       GENERIC_NOP1,
-       GENERIC_NOP2,
-       GENERIC_NOP3,
-       GENERIC_NOP4,
-       GENERIC_NOP5,
-       GENERIC_NOP6,
-       GENERIC_NOP7,
-       GENERIC_NOP8,
-       GENERIC_NOP5_ATOMIC
-};
-static const unsigned char * const intel_nops[ASM_NOP_MAX+2] =
-{
-       NULL,
-       intelnops,
-       intelnops + 1,
-       intelnops + 1 + 2,
-       intelnops + 1 + 2 + 3,
-       intelnops + 1 + 2 + 3 + 4,
-       intelnops + 1 + 2 + 3 + 4 + 5,
-       intelnops + 1 + 2 + 3 + 4 + 5 + 6,
-       intelnops + 1 + 2 + 3 + 4 + 5 + 6 + 7,
-       intelnops + 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8,
+       BYTES_NOP1,
+       BYTES_NOP2,
+       BYTES_NOP3,
+       BYTES_NOP4,
+       BYTES_NOP5,
+       BYTES_NOP6,
+       BYTES_NOP7,
+       BYTES_NOP8,
 };
-#endif
 
-#ifdef K8_NOP1
-static const unsigned char k8nops[] =
-{
-       K8_NOP1,
-       K8_NOP2,
-       K8_NOP3,
-       K8_NOP4,
-       K8_NOP5,
-       K8_NOP6,
-       K8_NOP7,
-       K8_NOP8,
-       K8_NOP5_ATOMIC
-};
-static const unsigned char * const k8_nops[ASM_NOP_MAX+2] =
-{
-       NULL,
-       k8nops,
-       k8nops + 1,
-       k8nops + 1 + 2,
-       k8nops + 1 + 2 + 3,
-       k8nops + 1 + 2 + 3 + 4,
-       k8nops + 1 + 2 + 3 + 4 + 5,
-       k8nops + 1 + 2 + 3 + 4 + 5 + 6,
-       k8nops + 1 + 2 + 3 + 4 + 5 + 6 + 7,
-       k8nops + 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8,
-};
-#endif
-
-#if defined(K7_NOP1) && !defined(CONFIG_X86_64)
-static const unsigned char k7nops[] =
-{
-       K7_NOP1,
-       K7_NOP2,
-       K7_NOP3,
-       K7_NOP4,
-       K7_NOP5,
-       K7_NOP6,
-       K7_NOP7,
-       K7_NOP8,
-       K7_NOP5_ATOMIC
-};
-static const unsigned char * const k7_nops[ASM_NOP_MAX+2] =
-{
-       NULL,
-       k7nops,
-       k7nops + 1,
-       k7nops + 1 + 2,
-       k7nops + 1 + 2 + 3,
-       k7nops + 1 + 2 + 3 + 4,
-       k7nops + 1 + 2 + 3 + 4 + 5,
-       k7nops + 1 + 2 + 3 + 4 + 5 + 6,
-       k7nops + 1 + 2 + 3 + 4 + 5 + 6 + 7,
-       k7nops + 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8,
-};
-#endif
-
-#ifdef P6_NOP1
-static const unsigned char p6nops[] =
-{
-       P6_NOP1,
-       P6_NOP2,
-       P6_NOP3,
-       P6_NOP4,
-       P6_NOP5,
-       P6_NOP6,
-       P6_NOP7,
-       P6_NOP8,
-       P6_NOP5_ATOMIC
-};
-static const unsigned char * const p6_nops[ASM_NOP_MAX+2] =
+const unsigned char * const x86_nops[ASM_NOP_MAX+1] =
 {
        NULL,
-       p6nops,
-       p6nops + 1,
-       p6nops + 1 + 2,
-       p6nops + 1 + 2 + 3,
-       p6nops + 1 + 2 + 3 + 4,
-       p6nops + 1 + 2 + 3 + 4 + 5,
-       p6nops + 1 + 2 + 3 + 4 + 5 + 6,
-       p6nops + 1 + 2 + 3 + 4 + 5 + 6 + 7,
-       p6nops + 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8,
+       x86nops,
+       x86nops + 1,
+       x86nops + 1 + 2,
+       x86nops + 1 + 2 + 3,
+       x86nops + 1 + 2 + 3 + 4,
+       x86nops + 1 + 2 + 3 + 4 + 5,
+       x86nops + 1 + 2 + 3 + 4 + 5 + 6,
+       x86nops + 1 + 2 + 3 + 4 + 5 + 6 + 7,
 };
-#endif
-
-/* Initialize these to a safe default */
-#ifdef CONFIG_X86_64
-const unsigned char * const *ideal_nops = p6_nops;
-#else
-const unsigned char * const *ideal_nops = intel_nops;
-#endif
-
-void __init arch_init_ideal_nops(void)
-{
-       switch (boot_cpu_data.x86_vendor) {
-       case X86_VENDOR_INTEL:
-               /*
-                * Due to a decoder implementation quirk, some
-                * specific Intel CPUs actually perform better with
-                * the "k8_nops" than with the SDM-recommended NOPs.
-                */
-               if (boot_cpu_data.x86 == 6 &&
-                   boot_cpu_data.x86_model >= 0x0f &&
-                   boot_cpu_data.x86_model != 0x1c &&
-                   boot_cpu_data.x86_model != 0x26 &&
-                   boot_cpu_data.x86_model != 0x27 &&
-                   boot_cpu_data.x86_model < 0x30) {
-                       ideal_nops = k8_nops;
-               } else if (boot_cpu_has(X86_FEATURE_NOPL)) {
-                          ideal_nops = p6_nops;
-               } else {
-#ifdef CONFIG_X86_64
-                       ideal_nops = k8_nops;
-#else
-                       ideal_nops = intel_nops;
-#endif
-               }
-               break;
-
-       case X86_VENDOR_HYGON:
-               ideal_nops = p6_nops;
-               return;
-
-       case X86_VENDOR_AMD:
-               if (boot_cpu_data.x86 > 0xf) {
-                       ideal_nops = p6_nops;
-                       return;
-               }
-
-               fallthrough;
-
-       default:
-#ifdef CONFIG_X86_64
-               ideal_nops = k8_nops;
-#else
-               if (boot_cpu_has(X86_FEATURE_K8))
-                       ideal_nops = k8_nops;
-               else if (boot_cpu_has(X86_FEATURE_K7))
-                       ideal_nops = k7_nops;
-               else
-                       ideal_nops = intel_nops;
-#endif
-       }
-}
 
 /* Use this to add nops to a buffer, then text_poke the whole buffer. */
 static void __init_or_module add_nops(void *insns, unsigned int len)
@@ -262,7 +106,7 @@ static void __init_or_module add_nops(void *insns, unsigned 
int len)
                unsigned int noplen = len;
                if (noplen > ASM_NOP_MAX)
                        noplen = ASM_NOP_MAX;
-               memcpy(insns, ideal_nops[noplen], noplen);
+               memcpy(insns, x86_nops[noplen], noplen);
                insns += noplen;
                len -= noplen;
        }
@@ -1302,13 +1146,13 @@ static void text_poke_loc_init(struct text_poke_loc 
*tp, void *addr,
        default: /* assume NOP */
                switch (len) {
                case 2: /* NOP2 -- emulate as JMP8+0 */
-                       BUG_ON(memcmp(emulate, ideal_nops[len], len));
+                       BUG_ON(memcmp(emulate, x86_nops[len], len));
                        tp->opcode = JMP8_INSN_OPCODE;
                        tp->rel32 = 0;
                        break;
 
                case 5: /* NOP5 -- emulate as JMP32+0 */
-                       BUG_ON(memcmp(emulate, ideal_nops[NOP_ATOMIC5], len));
+                       BUG_ON(memcmp(emulate, x86_nops[len], len));
                        tp->opcode = JMP32_INSN_OPCODE;
                        tp->rel32 = 0;
                        break;
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 7edbd5ee5ed4..1b3ce3b4a2a2 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -66,7 +66,7 @@ int ftrace_arch_code_modify_post_process(void)
 
 static const char *ftrace_nop_replace(void)
 {
-       return ideal_nops[NOP_ATOMIC5];
+       return x86_nops[5];
 }
 
 static const char *ftrace_call_replace(unsigned long ip, unsigned long addr)
@@ -377,7 +377,7 @@ create_trampoline(struct ftrace_ops *ops, unsigned int 
*tramp_size)
                ip = trampoline + (jmp_offset - start_offset);
                if (WARN_ON(*(char *)ip != 0x75))
                        goto fail;
-               ret = copy_from_kernel_nofault(ip, ideal_nops[2], 2);
+               ret = copy_from_kernel_nofault(ip, x86_nops[2], 2);
                if (ret < 0)
                        goto fail;
        }
diff --git a/arch/x86/kernel/jump_label.c b/arch/x86/kernel/jump_label.c
index 5ba8477c2cb7..e2b549a9d62e 100644
--- a/arch/x86/kernel/jump_label.c
+++ b/arch/x86/kernel/jump_label.c
@@ -30,8 +30,7 @@ static void bug_at(const void *ip, int line)
 static const void *
 __jump_label_set_jump_code(struct jump_entry *entry, enum jump_label_type 
type, int init)
 {
-       const unsigned char default_nop[] = { STATIC_KEY_INIT_NOP };
-       const unsigned char *ideal_nop = ideal_nops[NOP_ATOMIC5];
+       const unsigned char default_nop[] = { BYTES_NOP5 };
        const void *expect, *code;
        const void *addr, *dest;
        int line;
@@ -44,7 +43,7 @@ __jump_label_set_jump_code(struct jump_entry *entry, enum 
jump_label_type type,
        if (init) {
                expect = default_nop; line = __LINE__;
        } else if (type == JUMP_LABEL_JMP) {
-               expect = ideal_nop; line = __LINE__;
+               expect = x86_nops[5]; line = __LINE__;
        } else {
                expect = code; line = __LINE__;
        }
@@ -53,7 +52,7 @@ __jump_label_set_jump_code(struct jump_entry *entry, enum 
jump_label_type type,
                bug_at(addr, line);
 
        if (type == JUMP_LABEL_NOP)
-               code = ideal_nop;
+               code = x86_nops[5];
 
        return code;
 }
@@ -136,22 +135,6 @@ static enum {
 __init_or_module void arch_jump_label_transform_static(struct jump_entry 
*entry,
                                      enum jump_label_type type)
 {
-       /*
-        * This function is called at boot up and when modules are
-        * first loaded. Check if the default nop, the one that is
-        * inserted at compile time, is the ideal nop. If it is, then
-        * we do not need to update the nop, and we can leave it as is.
-        * If it is not, then we need to update the nop to the ideal nop.
-        */
-       if (jlstate == JL_STATE_START) {
-               const unsigned char default_nop[] = { STATIC_KEY_INIT_NOP };
-               const unsigned char *ideal_nop = ideal_nops[NOP_ATOMIC5];
-
-               if (memcmp(ideal_nop, default_nop, 5) != 0)
-                       jlstate = JL_STATE_UPDATE;
-               else
-                       jlstate = JL_STATE_NO_UPDATE;
-       }
        if (jlstate == JL_STATE_UPDATE)
                jump_label_transform(entry, type, 1);
 }
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index df776cdca327..6356834928b9 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -229,7 +229,7 @@ __recover_probed_insn(kprobe_opcode_t *buf, unsigned long 
addr)
                return 0UL;
 
        if (faddr)
-               memcpy(buf, ideal_nops[NOP_ATOMIC5], 5);
+               memcpy(buf, x86_nops[5], 5);
        else
                buf[0] = kp->opcode;
        return (unsigned long)buf;
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index d883176ef2ce..3b4b9b281545 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -822,7 +822,6 @@ void __init setup_arch(char **cmdline_p)
 
        idt_setup_early_traps();
        early_cpu_init();
-       arch_init_ideal_nops();
        jump_label_init();
        static_call_init();
        early_ioremap_init();
diff --git a/arch/x86/kernel/static_call.c b/arch/x86/kernel/static_call.c
index 9442c4136c38..ea028e736831 100644
--- a/arch/x86/kernel/static_call.c
+++ b/arch/x86/kernel/static_call.c
@@ -34,7 +34,7 @@ static void __ref __static_call_transform(void *insn, enum 
insn_type type, void
                break;
 
        case NOP:
-               code = ideal_nops[NOP_ATOMIC5];
+               code = x86_nops[5];
                break;
 
        case JMP:
@@ -66,7 +66,7 @@ static void __static_call_validate(void *insn, bool tail)
                        return;
        } else {
                if (opcode == CALL_INSN_OPCODE ||
-                   !memcmp(insn, ideal_nops[NOP_ATOMIC5], 5) ||
+                   !memcmp(insn, x86_nops[5], 5) ||
                    !memcmp(insn, xor5rax, 5))
                        return;
        }
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index 79e7a0ec1da5..6aa29c45c3f9 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -282,7 +282,7 @@ static void emit_prologue(u8 **pprog, u32 stack_depth, bool 
ebpf_from_cbpf,
        /* BPF trampoline can be made to work without these nops,
         * but let's waste 5 bytes for now and optimize later
         */
-       memcpy(prog, ideal_nops[NOP_ATOMIC5], cnt);
+       memcpy(prog, x86_nops[5], cnt);
        prog += cnt;
        if (!ebpf_from_cbpf) {
                if (tail_call_reachable && !is_subprog)
@@ -330,7 +330,7 @@ static int __bpf_arch_text_poke(void *ip, enum 
bpf_text_poke_type t,
                                void *old_addr, void *new_addr,
                                const bool text_live)
 {
-       const u8 *nop_insn = ideal_nops[NOP_ATOMIC5];
+       const u8 *nop_insn = x86_nops[5];
        u8 old_insn[X86_PATCH_SIZE];
        u8 new_insn[X86_PATCH_SIZE];
        u8 *prog;
@@ -560,7 +560,7 @@ static void emit_bpf_tail_call_direct(struct 
bpf_jit_poke_descriptor *poke,
        if (stack_depth)
                EMIT3_off32(0x48, 0x81, 0xC4, round_up(stack_depth, 8));
 
-       memcpy(prog, ideal_nops[NOP_ATOMIC5], X86_PATCH_SIZE);
+       memcpy(prog, x86_nops[5], X86_PATCH_SIZE);
        prog += X86_PATCH_SIZE;
        /* out: */
 
@@ -881,7 +881,7 @@ static int emit_nops(u8 **pprog, int len)
                        noplen = ASM_NOP_MAX;
 
                for (i = 0; i < noplen; i++)
-                       EMIT1(ideal_nops[noplen][i]);
+                       EMIT1(x86_nops[noplen][i]);
                len -= noplen;
        }
 

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