x86, cpu: Clean up and unify the NOP selection infrastructure

Clean up and unify the NOP selection infrastructure:

- Make the atomic 5-byte NOP a part of the selection system.
- Pick NOPs once during early boot and then be done with it.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jason Baron <jbaron@redhat.com>
Link: http://lkml.kernel.org/r/1303166160-10315-3-git-send-email-hpa@linux.intel.com

1 files changed, 84 insertions, 62 deletions

diff --git a/arch/x86/include/asm/nops.h b/arch/x86/include/asm/nops.h
index af788496020b..405b4032a60b 100644
--- a/arch/x86/include/asm/nops.h
+++ b/arch/x86/include/asm/nops.h
@@ -1,7 +1,13 @@
 #ifndef _ASM_X86_NOPS_H
 #define _ASM_X86_NOPS_H
 
-/* Define nops for use with alternative() */
+/*
+ * Define nops for use with alternative() and for tracing.
+ *
+ * *_NOP5_ATOMIC must be a single instruction.
+ */
+
+#define NOP_DS_PREFIX 0x3e
 
 /* generic versions from gas
    1: nop
@@ -13,14 +19,15 @@
    6: leal 0x00000000(%esi),%esi
    7: leal 0x00000000(,%esi,1),%esi
 */
-#define GENERIC_NOP1 ".byte 0x90\n"
-#define GENERIC_NOP2 ".byte 0x89,0xf6\n"
-#define GENERIC_NOP3 ".byte 0x8d,0x76,0x00\n"
-#define GENERIC_NOP4 ".byte 0x8d,0x74,0x26,0x00\n"
-#define GENERIC_NOP5 GENERIC_NOP1 GENERIC_NOP4
-#define GENERIC_NOP6 ".byte 0x8d,0xb6,0x00,0x00,0x00,0x00\n"
-#define GENERIC_NOP7 ".byte 0x8d,0xb4,0x26,0x00,0x00,0x00,0x00\n"
-#define GENERIC_NOP8 GENERIC_NOP1 GENERIC_NOP7
+#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
 
 /* Opteron 64bit nops
    1: nop
@@ -29,13 +36,14 @@
    4: osp osp osp nop
 */
 #define K8_NOP1 GENERIC_NOP1
-#define K8_NOP2	".byte 0x66,0x90\n"
-#define K8_NOP3	".byte 0x66,0x66,0x90\n"
-#define K8_NOP4	".byte 0x66,0x66,0x66,0x90\n"
-#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_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
 
 /* K7 nops
    uses eax dependencies (arbitrary choice)
@@ -47,13 +55,14 @@
    7: leal 0x00000000(,%eax,1),%eax
 */
 #define K7_NOP1	GENERIC_NOP1
-#define K7_NOP2	".byte 0x8b,0xc0\n"
-#define K7_NOP3	".byte 0x8d,0x04,0x20\n"
-#define K7_NOP4	".byte 0x8d,0x44,0x20,0x00\n"
-#define K7_NOP5	K7_NOP4 ASM_NOP1
-#define K7_NOP6	".byte 0x8d,0x80,0,0,0,0\n"
-#define K7_NOP7	".byte 0x8D,0x04,0x05,0,0,0,0\n"
-#define K7_NOP8	K7_NOP7 ASM_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
 
 /* P6 nops
    uses eax dependencies (Intel-recommended choice)
@@ -69,52 +78,65 @@
 	There is kernel code that depends on this.
 */
 #define P6_NOP1	GENERIC_NOP1
-#define P6_NOP2	".byte 0x66,0x90\n"
-#define P6_NOP3	".byte 0x0f,0x1f,0x00\n"
-#define P6_NOP4	".byte 0x0f,0x1f,0x40,0\n"
-#define P6_NOP5	".byte 0x0f,0x1f,0x44,0x00,0\n"
-#define P6_NOP6	".byte 0x66,0x0f,0x1f,0x44,0x00,0\n"
-#define P6_NOP7	".byte 0x0f,0x1f,0x80,0,0,0,0\n"
-#define P6_NOP8	".byte 0x0f,0x1f,0x84,0x00,0,0,0,0\n"
+#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
+
+#define _ASM_MK_NOP(x) ".byte " __stringify(x) "\n"
 
 #if defined(CONFIG_MK7)
-#define ASM_NOP1 K7_NOP1
-#define ASM_NOP2 K7_NOP2
-#define ASM_NOP3 K7_NOP3
-#define ASM_NOP4 K7_NOP4
-#define ASM_NOP5 K7_NOP5
-#define ASM_NOP6 K7_NOP6
-#define ASM_NOP7 K7_NOP7
-#define ASM_NOP8 K7_NOP8
+#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 P6_NOP1
-#define ASM_NOP2 P6_NOP2
-#define ASM_NOP3 P6_NOP3
-#define ASM_NOP4 P6_NOP4
-#define ASM_NOP5 P6_NOP5
-#define ASM_NOP6 P6_NOP6
-#define ASM_NOP7 P6_NOP7
-#define ASM_NOP8 P6_NOP8
+#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 K8_NOP1
-#define ASM_NOP2 K8_NOP2
-#define ASM_NOP3 K8_NOP3
-#define ASM_NOP4 K8_NOP4
-#define ASM_NOP5 K8_NOP5
-#define ASM_NOP6 K8_NOP6
-#define ASM_NOP7 K8_NOP7
-#define ASM_NOP8 K8_NOP8
+#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 GENERIC_NOP1
-#define ASM_NOP2 GENERIC_NOP2
-#define ASM_NOP3 GENERIC_NOP3
-#define ASM_NOP4 GENERIC_NOP4
-#define ASM_NOP5 GENERIC_NOP5
-#define ASM_NOP6 GENERIC_NOP6
-#define ASM_NOP7 GENERIC_NOP7
-#define ASM_NOP8 GENERIC_NOP8
+#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_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);
+#endif
 
 #endif /* _ASM_X86_NOPS_H */