>So with that patch applied we can remove the boot_init_stack_canary()
>in process_32/64.c cpu_idle(), can't we ?
>
[[JPAN]] i agree, bsp stack canary will be initialized in start_kernel() and
ap stack canary will be covered in start_secondary().
arjan, do you have any comments? here is the new patch.
>From 1073c9f6e1e3b0012f85b5a9c7c83e35bcc16107 Mon Sep 17 00:00:00 2001
From: Jacob Pan <jacob.jun.pan@xxxxxxxxx>
Date: Mon, 22 Feb 2010 04:14:11 -0800
Subject: [PATCH] x86/boot: reduce redundant stack canary init
move secondary cpu boot stack canary initialization prior to cpu_idle()
then remove boot_init_stack_canary() calls from cpu_idle().
this change reduced redundent stack canary init for the bsp also avoid
fake stack check failure for secondary if early schedule needed before
cpu_idle.
Signed-off-by: Jacob Pan <jacob.jun.pan@xxxxxxxxx>
---
arch/x86/kernel/process_32.c | 9 ---------
arch/x86/kernel/process_64.c | 9 ---------
arch/x86/kernel/smpboot.c | 4 ++++
3 files changed, 4 insertions(+), 18 deletions(-)
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index f6c6266..d4c764a 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -85,15 +85,6 @@ void cpu_idle(void)
{
int cpu = smp_processor_id();
- /*
- * If we're the non-boot CPU, nothing set the stack canary up
- * for us. CPU0 already has it initialized but no harm in
- * doing it again. This is a good place for updating it, as
- * we wont ever return from this function (so the invalid
- * canaries already on the stack wont ever trigger).
- */
- boot_init_stack_canary();
-
current_thread_info()->status |= TS_POLLING;
/* endless idle loop with no priority at all */
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index fc6ad4b..1fd6713 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -110,15 +110,6 @@ void cpu_idle(void)
{
current_thread_info()->status |= TS_POLLING;
- /*
- * If we're the non-boot CPU, nothing set the stack canary up
- * for us. CPU0 already has it initialized but no harm in
- * doing it again. This is a good place for updating it, as
- * we wont ever return from this function (so the invalid
- * canaries already on the stack wont ever trigger).
- */
- boot_init_stack_canary();
-
/* endless idle loop with no priority at all */
while (1) {
tick_nohz_stop_sched_tick(1);
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index c08829a..820638d 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -48,6 +48,7 @@
#include <linux/err.h>
#include <linux/nmi.h>
#include <linux/tboot.h>
+#include <linux/stackprotector.h>
#include <asm/acpi.h>
#include <asm/desc.h>
@@ -328,6 +329,9 @@ notrace static void __cpuinit start_secondary(void *unused)
/* enable local interrupts */
local_irq_enable();
+ /* to prevent fake stack check failure in clock setup */
+ boot_init_stack_canary();
+
x86_cpuinit.setup_percpu_clockev();
wmb();
--
1.5.6.5
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