Commit-ID: d7880812b3594d3c6dcbe3cfd71dabb17347d082
Gitweb: http://git.kernel.org/tip/d7880812b3594d3c6dcbe3cfd71dabb17347d082
Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Mon, 10 Jun 2013 16:52:03 +0200
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Tue, 11 Jun 2013 22:04:47 +0200
idle: Add the stack canary init to cpu_startup_entry()
Moving x86 to the generic idle implementation (commit 7d1a9417 "x86:
Use generic idle loop") wreckaged the stack protector.
I stupidly missed that boot_init_stack_canary() must be inlined from a
function which never returns, but I put that call into
arch_cpu_idle_prepare() which of course returns.
I pondered to play tricks with arch_cpu_idle_prepare() first, but then
I noticed, that the other archs which have implemented the
stackprotector (ARM and SH) do not initialize the canary for the
non-boot cpus.
So I decided to move the boot_init_stack_canary() call into
cpu_startup_entry() ifdeffed with an CONFIG_X86 for now. This #ifdef
is just a temporary measure as I don't want to inflict the
boot_init_stack_canary() call on ARM and SH that late in the cycle.
I'll queue a patch for 3.11 which removes the #ifdef if the ARM/SH
maintainers have no objection.
Reported-by: Wouter van Kesteren <woutershep@xxxxxxxxx>
Cc: x86@xxxxxxxxxx
Cc: Russell King <linux@xxxxxxxxxxxxxxxx>
Cc: Paul Mundt <lethal@xxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
arch/x86/kernel/process.c | 12 ------------
kernel/cpu/idle.c | 16 ++++++++++++++++
2 files changed, 16 insertions(+), 12 deletions(-)
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 4e7a37f..81a5f5e 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -277,18 +277,6 @@ void exit_idle(void)
}
#endif
-void arch_cpu_idle_prepare(void)
-{
- /*
- * 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();
-}
-
void arch_cpu_idle_enter(void)
{
local_touch_nmi();
diff --git a/kernel/cpu/idle.c b/kernel/cpu/idle.c
index d5585f5..bf2ee1a 100644
--- a/kernel/cpu/idle.c
+++ b/kernel/cpu/idle.c
@@ -5,6 +5,7 @@
#include <linux/cpu.h>
#include <linux/tick.h>
#include <linux/mm.h>
+#include <linux/stackprotector.h>
#include <asm/tlb.h>
@@ -112,6 +113,21 @@ static void cpu_idle_loop(void)
void cpu_startup_entry(enum cpuhp_state state)
{
+ /*
+ * This #ifdef needs to die, but it's too late in the cycle to
+ * make this generic (arm and sh have never invoked the canary
+ * init for the non boot cpus!). Will be fixed in 3.11
+ */
+#ifdef CONFIG_X86
+ /*
+ * If we're the non-boot CPU, nothing set the stack canary up
+ * for us. The boot CPU 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();
+#endif
current_set_polling();
arch_cpu_idle_prepare();
cpu_idle_loop();
--
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