[Blackfin] arch: Initial checkin of the memory protection support.
Enable it with CONFIG_MPU.
Signed-off-by: Bernd Schmidt <bernd.schmidt@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>
diff --git a/include/asm-blackfin/mmu_context.h b/include/asm-blackfin/mmu_context.h
index c5c71a6..b5eb675 100644
--- a/include/asm-blackfin/mmu_context.h
+++ b/include/asm-blackfin/mmu_context.h
@@ -30,9 +30,12 @@
#ifndef __BLACKFIN_MMU_CONTEXT_H__
#define __BLACKFIN_MMU_CONTEXT_H__
+#include <linux/gfp.h>
+#include <linux/sched.h>
#include <asm/setup.h>
#include <asm/page.h>
#include <asm/pgalloc.h>
+#include <asm/cplbinit.h>
extern void *current_l1_stack_save;
extern int nr_l1stack_tasks;
@@ -50,6 +53,12 @@
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;
}
@@ -73,6 +82,11 @@
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
@@ -106,9 +120,21 @@
#define deactivate_mm(tsk,mm) do { } while (0)
-static inline void activate_mm(struct mm_struct *prev_mm,
- struct mm_struct *next_mm)
+#define activate_mm(prev, next) switch_mm(prev, next, NULL)
+
+static inline void switch_mm(struct mm_struct *prev_mm, struct mm_struct *next_mm,
+ struct task_struct *tsk)
{
+ if (prev_mm == next_mm)
+ return;
+#ifdef CONFIG_MPU
+ if (prev_mm->context.page_rwx_mask == current_rwx_mask) {
+ flush_switched_cplbs();
+ set_mask_dcplbs(next_mm->context.page_rwx_mask);
+ }
+#endif
+
+ /* L1 stack switching. */
if (!next_mm->context.l1_stack_save)
return;
if (next_mm->context.l1_stack_save == current_l1_stack_save)
@@ -120,10 +146,36 @@
memcpy(l1_stack_base, current_l1_stack_save, l1_stack_len);
}
-static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
- struct task_struct *tsk)
+#ifdef CONFIG_MPU
+static inline void protect_page(struct mm_struct *mm, unsigned long addr,
+ unsigned long flags)
{
- activate_mm(prev, next);
+ unsigned long *mask = mm->context.page_rwx_mask;
+ unsigned long page = addr >> 12;
+ unsigned long idx = page >> 5;
+ unsigned long bit = 1 << (page & 31);
+
+ if (flags & VM_MAYREAD)
+ mask[idx] |= bit;
+ else
+ mask[idx] &= ~bit;
+ mask += page_mask_nelts;
+ if (flags & VM_MAYWRITE)
+ mask[idx] |= bit;
+ else
+ mask[idx] &= ~bit;
+ mask += page_mask_nelts;
+ if (flags & VM_MAYEXEC)
+ mask[idx] |= bit;
+ else
+ mask[idx] &= ~bit;
}
+static inline void update_protections(struct mm_struct *mm)
+{
+ flush_switched_cplbs();
+ set_mask_dcplbs(mm->context.page_rwx_mask);
+}
+#endif
+
#endif