On Fri, Feb 26, 2016 at 1:43 PM, Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
> We have an arch specific callback here already.
>
> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> ---
> arch/x86/kernel/process.c | 12 ++++++++++++
> kernel/sched/idle.c | 15 ---------------
> 2 files changed, 12 insertions(+), 15 deletions(-)
>
> Index: b/arch/x86/kernel/process.c
> ===================================================================
> --- a/arch/x86/kernel/process.c
> +++ b/arch/x86/kernel/process.c
> @@ -271,6 +271,18 @@ 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. 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();
> +}
> +
> void arch_cpu_idle_enter(void)
> {
> local_touch_nmi();
> Index: b/kernel/sched/idle.c
> ===================================================================
> --- a/kernel/sched/idle.c
> +++ b/kernel/sched/idle.c
> @@ -275,21 +275,6 @@ 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
> arch_cpu_idle_prepare();
> cpu_idle_loop();
> }
Does this actually work with stack protector enabled?
boot_init_stack_canary() is inlined while arch_cpu_idle_prepare() is
not.
--
Brian Gerst
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