From: Vineet Gupta <vgupta@kernel.org>
Date: Thu, 14 May 2020 23:26:45 +0000 (-0700)
Subject: ARC: kernel stack: INIT_THREAD need not setup @init_stack in @ksp
X-Git-Tag: v6.6-rc1~56^2~12
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=d1d1569e89e9cc5c07a389ac859bd045b906923c;p=thirdparty%2Fkernel%2Flinux.git

ARC: kernel stack: INIT_THREAD need not setup @init_stack in @ksp

There are 2 pointers to kernel mode stack of a task
 - task_struct.stack: base address of stack page (max possible stack top)
 - thread_info.ksp  : runtime stack top in __switch_to

INIT_THREAD was setting up ksp to stack base which was not really needed
 - it would get overwritten with dynamic value on first call to
   __switch_to when init is switched out for the very first time.
 - generic code already does
      init_task.stack = init_stack
   and ARC code uses that to retrieve task's stack base.

Signed-off-by: Vineet Gupta <vgupta@kernel.org>
---

diff --git a/arch/arc/include/asm/processor.h b/arch/arc/include/asm/processor.h
index fb844fce1ab67..82ddc929d6e73 100644
--- a/arch/arc/include/asm/processor.h
+++ b/arch/arc/include/asm/processor.h
@@ -33,9 +33,7 @@ struct thread_struct {
 #endif
 };
 
-#define INIT_THREAD  {                          \
-	.ksp = sizeof(init_stack) + (unsigned long) init_stack, \
-}
+#define INIT_THREAD  { }
 
 /* Forward declaration, a strange C thing */
 struct task_struct;