[PATCH] [33/40] i386: Allow boot-time disable of paravirt_ops patching

From: Andi Kleen
Date: Mon Apr 30 2007 - 06:42:50 EST



From: Jeremy Fitzhardinge <jeremy@xxxxxxxx>

Add "noreplace-paravirt" to disable paravirt_ops patching.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xxxxxxxxxxxxx>
Signed-off-by: Andi Kleen <ak@xxxxxxx>
Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---

Documentation/kernel-parameters.txt | 3 +++
arch/i386/kernel/alternative.c | 13 +++++++++++++
2 files changed, 16 insertions(+)

Index: linux/Documentation/kernel-parameters.txt
===================================================================
--- linux.orig/Documentation/kernel-parameters.txt
+++ linux/Documentation/kernel-parameters.txt
@@ -64,6 +64,7 @@ parameter is applicable:
GENERIC_TIME The generic timeofday code is enabled.
NFS Appropriate NFS support is enabled.
OSS OSS sound support is enabled.
+ PV_OPS A paravirtualized kernel
PARIDE The ParIDE subsystem is enabled.
PARISC The PA-RISC architecture is enabled.
PCI PCI bus support is enabled.
@@ -1142,6 +1143,8 @@ and is between 256 and 4096 characters.

nomce [IA-32] Machine Check Exception

+ noreplace-paravirt [IA-32,PV_OPS] Don't patch paravirt_ops
+
noreplace-smp [IA-32,SMP] Don't replace SMP instructions
with UP alternatives

Index: linux/arch/i386/kernel/alternative.c
===================================================================
--- linux.orig/arch/i386/kernel/alternative.c
+++ linux/arch/i386/kernel/alternative.c
@@ -30,6 +30,16 @@ static int __init setup_noreplace_smp(ch
}
__setup("noreplace-smp", setup_noreplace_smp);

+#ifdef CONFIG_PARAVIRT
+static int noreplace_paravirt = 0;
+
+static int __init setup_noreplace_paravirt(char *str)
+{
+ noreplace_paravirt = 1;
+ return 1;
+}
+__setup("noreplace-paravirt", setup_noreplace_paravirt);
+#endif

#define DPRINTK(fmt, args...) if (debug_alternative) \
printk(KERN_DEBUG fmt, args)
@@ -330,6 +340,9 @@ void apply_paravirt(struct paravirt_patc
{
struct paravirt_patch_site *p;

+ if (noreplace_paravirt)
+ return;
+
for (p = start; p < end; p++) {
unsigned int used;

-
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