x86: correct/clarify comment in nops.h

<asm-x86/nops.h> describes certain multibyte instructions as "generic" nops when in fact they aren't nops at all in 64-bit mode (missing REX.W causing truncation of a register). Update the comment to state that K8 or P6 style nops should be used in 64-bit mode. This matches what the alternatives code does. Signed-off-by: Mikael Pettersson <mikpe@it.uu.se> Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: correct/clarify comment in nops.h
<asm-x86/nops.h> describes certain multibyte instructions as "generic" nops when in fact they aren't nops at all in 64-bit mode (missing REX.W causing truncation of a register). Update the comment to state that K8 or P6 style nops should be used in 64-bit mode. This matches what the alternatives code does. Signed-off-by: Mikael Pettersson <mikpe@it.uu.se> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Mikael Pettersson · Ingo Molnar
1 parent 1415d160c7
Showing 1 changed file with 2 additions and 0 deletions Side-by-side Diff
include/asm-x86/nops.h
@@ -5,6 +5,8 @@
  
 /* 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
...	...	@@ -5,6 +5,8 @@
5	5
6	6	/* generic versions from gas
7	7	1: nop
	8	+ the following instructions are NOT nops in 64-bit mode,
	9	+ for 64-bit mode use K8 or P6 nops instead
8	10	2: movl %esi,%esi
9	11	3: leal 0x00(%esi),%esi
10	12	4: leal 0x00(,%esi,1),%esi