The patch titled
Allow boot-time disable of SMP altinstructions
has been added to the -mm tree. Its filename is
allow-boot-time-disable-of-smp-altinstructions.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: Allow boot-time disable of SMP altinstructions
From: Jeremy Fitzhardinge <jeremy@xxxxxxxx>
Add "noreplace-smp" to disable SMP instruction replacement.
Signed-off-by: Jeremy Fitzhardinge <jeremy@xxxxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/kernel-parameters.txt | 6 ++++++
arch/i386/kernel/alternative.c | 23 +++++++++++++++++++----
2 files changed, 25 insertions(+), 4 deletions(-)
diff -puN Documentation/kernel-parameters.txt~allow-boot-time-disable-of-smp-altinstructions Documentation/kernel-parameters.txt
--- a/Documentation/kernel-parameters.txt~allow-boot-time-disable-of-smp-altinstructions
+++ a/Documentation/kernel-parameters.txt
@@ -1135,6 +1135,9 @@ and is between 256 and 4096 characters.
nomce [IA-32] Machine Check Exception
+ noreplace-smp [IA-32,SMP] Don't replace SMP instructions
+ with UP alternatives
+
noresidual [PPC] Don't use residual data on PReP machines.
noresume [SWSUSP] Disables resume and restores original swap
@@ -1540,6 +1543,9 @@ and is between 256 and 4096 characters.
smart2= [HW]
Format: <io1>[,<io2>[,...,<io8>]]
+ smp-alt-once [IA-32,SMP] On a hotplug CPU system, only
+ attempt to substitute SMP alternatives once at boot.
+
snd-ad1816a= [HW,ALSA]
snd-ad1848= [HW,ALSA]
diff -puN arch/i386/kernel/alternative.c~allow-boot-time-disable-of-smp-altinstructions arch/i386/kernel/alternative.c
--- a/arch/i386/kernel/alternative.c~allow-boot-time-disable-of-smp-altinstructions
+++ a/arch/i386/kernel/alternative.c
@@ -5,6 +5,7 @@
#include <asm/alternative.h>
#include <asm/sections.h>
+static int noreplace_smp = 0;
static int smp_alt_once = 0;
static int debug_alternative = 0;
@@ -13,15 +14,23 @@ static int __init bootonly(char *str)
smp_alt_once = 1;
return 1;
}
+__setup("smp-alt-boot", bootonly);
+
static int __init debug_alt(char *str)
{
debug_alternative = 1;
return 1;
}
-
-__setup("smp-alt-boot", bootonly);
__setup("debug-alternative", debug_alt);
+static int __init setup_noreplace_smp(char *str)
+{
+ noreplace_smp = 1;
+ return 1;
+}
+__setup("noreplace-smp", setup_noreplace_smp);
+
+
#define DPRINTK(fmt, args...) if (debug_alternative) \
printk(KERN_DEBUG fmt, args)
@@ -185,6 +194,9 @@ static void alternatives_smp_unlock(u8 *
{
u8 **ptr;
+ if (noreplace_smp)
+ return;
+
for (ptr = start; ptr < end; ptr++) {
if (*ptr < text)
continue;
@@ -219,6 +231,9 @@ void alternatives_smp_module_add(struct
struct smp_alt_module *smp;
unsigned long flags;
+ if (noreplace_smp)
+ return;
+
if (smp_alt_once) {
if (boot_cpu_has(X86_FEATURE_UP))
alternatives_smp_unlock(locks, locks_end,
@@ -253,7 +268,7 @@ void alternatives_smp_module_del(struct
struct smp_alt_module *item;
unsigned long flags;
- if (smp_alt_once)
+ if (smp_alt_once || noreplace_smp)
return;
spin_lock_irqsave(&smp_alt, flags);
@@ -284,7 +299,7 @@ void alternatives_smp_switch(int smp)
return;
#endif
- if (smp_alt_once)
+ if (noreplace_smp || smp_alt_once)
return;
BUG_ON(!smp && (num_online_cpus() > 1));
_
Patches currently in -mm which might be from jeremy@xxxxxxxx are
re-enable-vdso-by-default-with-paravirt.patch
remove-noreplacement-option.patch
remove-smp_alt_instructions.patch
rename-the-parainstructions-symbols-to-be-consistent-with-the-others.patch
allow-boot-time-disable-of-smp-altinstructions.patch
allow-boot-time-disable-of-paravirt_ops-patching.patch
fixes-and-cleanups-for-earlyprintk-aka-boot-console.patch
ignore-stolen-time-in-the-softlockup-watchdog.patch
add-touch_all_softlockup_watchdogs.patch
clean-up-elf-note-generation.patch
-
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