Blackfin arch: add CONFIG_APP_STACKS_L1 to enable or disable putting kernel stacks in L1

use CONFIG_APP_STACKS_L1 to enable or disable putting kernel stacks in L1,
default is enabled, SMP kernel need turn it off

Signed-off-by: Graf Yang <graf.yang@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>

2 files changed, 51 insertions, 37 deletions

diff --git a/arch/blackfin/Kconfig b/arch/blackfin/Kconfig
index c507a92cb289..9d936a3986c8 100644
--- a/arch/blackfin/Kconfig
+++ b/arch/blackfin/Kconfig
@@ -629,6 +629,15 @@ config CPLB_SWITCH_TAB_L1
           If enabled, the CPLB Switch Tables are linked
           into L1 data memory. (less latency)
 
+config APP_STACK_L1
+        bool "Support locating application stack in L1 Scratch Memory"
+        default y
+        help
+          If enabled the application stack can be located in L1
+          scratch memory (less latency).
+
+          Currently only works with FLAT binaries.
+
 comment "Speed Optimizations"
 config BFIN_INS_LOWOVERHEAD
         bool "ins[bwl] low overhead, higher interrupt latency"
diff --git a/arch/blackfin/include/asm/mmu_context.h b/arch/blackfin/include/asm/mmu_context.h
index 8529552a981f..35593dda2a4d 100644
--- a/arch/blackfin/include/asm/mmu_context.h
+++ b/arch/blackfin/include/asm/mmu_context.h
@@ -45,49 +45,12 @@ extern unsigned long l1_stack_len;
 extern int l1sram_free(const void*);
 extern void *l1sram_alloc_max(void*);
 
-static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
-{
-}
-
-/* Called when creating a new context during fork() or execve().  */
-static inline int
-init_new_context(struct task_struct *tsk, struct mm_struct *mm)
-{
-#ifdef CONFIG_MPU
-        unsigned long p = __get_free_pages(GFP_KERNEL, page_mask_order);
-        mm->context.page_rwx_mask = (unsigned long *)p;
-        memset(mm->context.page_rwx_mask, 0,
-               page_mask_nelts * 3 * sizeof(long));
-#endif
-        return 0;
-}
-
 static inline void free_l1stack(void)
 {
         nr_l1stack_tasks--;
         if (nr_l1stack_tasks == 0)
                 l1sram_free(l1_stack_base);
 }
-static inline void destroy_context(struct mm_struct *mm)
-{
-        struct sram_list_struct *tmp;
-
-        if (current_l1_stack_save == mm->context.l1_stack_save)
-                current_l1_stack_save = NULL;
-        if (mm->context.l1_stack_save)
-                free_l1stack();
-
-        while ((tmp = mm->context.sram_list)) {
-                mm->context.sram_list = tmp->next;
-                sram_free(tmp->addr);
-                kfree(tmp);
-        }
-#ifdef CONFIG_MPU
-        if (current_rwx_mask == mm->context.page_rwx_mask)
-                current_rwx_mask = NULL;
-        free_pages((unsigned long)mm->context.page_rwx_mask, page_mask_order);
-#endif
-}
 
 static inline unsigned long
 alloc_l1stack(unsigned long length, unsigned long *stack_base)
@@ -134,6 +97,7 @@ static inline void switch_mm(struct mm_struct *prev_mm, struct mm_struct *next_m
         }
 #endif
 
+#ifdef CONFIG_APP_STACK_L1
         /* L1 stack switching.  */
         if (!next_mm->context.l1_stack_save)
                 return;
@@ -144,6 +108,7 @@ static inline void switch_mm(struct mm_struct *prev_mm, struct mm_struct *next_m
         }
         current_l1_stack_save = next_mm->context.l1_stack_save;
         memcpy(l1_stack_base, current_l1_stack_save, l1_stack_len);
+#endif
 }
 
 #ifdef CONFIG_MPU
@@ -180,4 +145,44 @@ static inline void update_protections(struct mm_struct *mm)
 }
 #endif
 
+static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
+{
+}
+
+/* Called when creating a new context during fork() or execve().  */
+static inline int
+init_new_context(struct task_struct *tsk, struct mm_struct *mm)
+{
+#ifdef CONFIG_MPU
+        unsigned long p = __get_free_pages(GFP_KERNEL, page_mask_order);
+        mm->context.page_rwx_mask = (unsigned long *)p;
+        memset(mm->context.page_rwx_mask, 0,
+               page_mask_nelts * 3 * sizeof(long));
+#endif
+        return 0;
+}
+
+static inline void destroy_context(struct mm_struct *mm)
+{
+        struct sram_list_struct *tmp;
+
+#ifdef CONFIG_APP_STACK_L1
+        if (current_l1_stack_save == mm->context.l1_stack_save)
+                current_l1_stack_save = 0;
+        if (mm->context.l1_stack_save)
+                free_l1stack();
+#endif
+
+        while ((tmp = mm->context.sram_list)) {
+                mm->context.sram_list = tmp->next;
+                sram_free(tmp->addr);
+                kfree(tmp);
+        }
+#ifdef CONFIG_MPU
+        if (current_rwx_mask == mm->context.page_rwx_mask)
+                current_rwx_mask = NULL;
+        free_pages((unsigned long)mm->context.page_rwx_mask, page_mask_order);
+#endif
+}
+
 #endif