x86: multi-byte single instruction NOPs
Add support for and use the multi-byte NOPs recently documented to be
available on all PentiumPro and later processors.
This patch only applies cleanly on top of the "x86: misc.
constifications" patch sent earlier.
[ tglx: arch/x86 adaptation ]
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
arch/x86/kernel/alternative.c | 23 ++++++++++++++++++++++-
include/asm-x86/processor_32.h | 22 ++++++++++++++++++++++
include/asm-x86/processor_64.h | 22 ++++++++++++++++++++++
3 files changed, 66 insertions(+), 1 deletion(-)
diff --git a/include/asm-x86/processor_64.h b/include/asm-x86/processor_64.h
index 2f12eb6..f422bec 100644
--- a/include/asm-x86/processor_64.h
+++ b/include/asm-x86/processor_64.h
@@ -334,6 +334,16 @@
};
+#if defined(CONFIG_MPSC) || defined(CONFIG_MCORE2)
+#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
+#else
#define ASM_NOP1 K8_NOP1
#define ASM_NOP2 K8_NOP2
#define ASM_NOP3 K8_NOP3
@@ -342,6 +352,7 @@
#define ASM_NOP6 K8_NOP6
#define ASM_NOP7 K8_NOP7
#define ASM_NOP8 K8_NOP8
+#endif
/* Opteron nops */
#define K8_NOP1 ".byte 0x90\n"
@@ -353,6 +364,17 @@
#define K8_NOP7 K8_NOP4 K8_NOP3
#define K8_NOP8 K8_NOP4 K8_NOP4
+/* P6 nops */
+/* uses eax dependencies (Intel-recommended choice) */
+#define P6_NOP1 ".byte 0x90\n"
+#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 ASM_NOP_MAX 8
/* REP NOP (PAUSE) is a good thing to insert into busy-wait loops. */