[PATCH v4 18/57] x86/smp: fix initial idle stack location on 32-bit

From: Josh Poimboeuf
Date: Thu Aug 18 2016 - 09:09:14 EST


On 32-bit, the initial idle stack calculation doesn't take into account
the TOP_OF_KERNEL_STACK_PADDING, making the stack end address
inconsistent with other tasks on 32-bit.

Reviewed-by: Andy Lutomirski <luto@xxxxxxxxxx>
Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
---
arch/x86/kernel/smpboot.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 3878725..3d919b8 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -964,9 +964,7 @@ static int do_boot_cpu(int apicid, int cpu, struct task_struct *idle)
int cpu0_nmi_registered = 0;
unsigned long timeout;

- idle->thread.sp = (unsigned long) (((struct pt_regs *)
- (THREAD_SIZE + task_stack_page(idle))) - 1);
-
+ idle->thread.sp = (unsigned long)task_pt_regs(idle);
early_gdt_descr.address = (unsigned long)get_cpu_gdt_table(cpu);
initial_code = (unsigned long)start_secondary;
initial_stack = idle->thread.sp;
--
2.7.4