[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>

5 files changed, 133 insertions, 6 deletions

diff --git a/include/asm-blackfin/cplb-mpu.h b/include/asm-blackfin/cplb-mpu.h
new file mode 100644
index 00000000000..75c67b99d60
--- /dev/null
+++ b/include/asm-blackfin/cplb-mpu.h
@@ -0,0 +1,61 @@
+/*
+ * File:         include/asm-blackfin/cplbinit.h
+ * Based on:
+ * Author:
+ *
+ * Created:
+ * Description:
+ *
+ * Modified:
+ *               Copyright 2004-2006 Analog Devices Inc.
+ *
+ * Bugs:         Enter bugs at http://blackfin.uclinux.org/
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see the file COPYING, or write
+ * to the Free Software Foundation, Inc.,
+ * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+#ifndef __ASM_BFIN_CPLB_MPU_H
+#define __ASM_BFIN_CPLB_MPU_H
+
+struct cplb_entry {
+	unsigned long data, addr;
+};
+
+struct mem_region {
+	unsigned long start, end;
+	unsigned long dcplb_data;
+	unsigned long icplb_data;
+};
+
+extern struct cplb_entry dcplb_tbl[MAX_CPLBS];
+extern struct cplb_entry icplb_tbl[MAX_CPLBS];
+extern int first_switched_icplb;
+extern int first_mask_dcplb;
+extern int first_switched_dcplb;
+
+extern int nr_dcplb_miss, nr_icplb_miss, nr_icplb_supv_miss, nr_dcplb_prot;
+extern int nr_cplb_flush;
+
+extern int page_mask_order;
+extern int page_mask_nelts;
+
+extern unsigned long *current_rwx_mask;
+
+extern void flush_switched_cplbs(void);
+extern void set_mask_dcplbs(unsigned long *);
+
+extern void __noreturn panic_cplb_error(int seqstat, struct pt_regs *);
+
+#endif /* __ASM_BFIN_CPLB_MPU_H */
diff --git a/include/asm-blackfin/cplb.h b/include/asm-blackfin/cplb.h
index 06828d77a58..654375c2b74 100644
--- a/include/asm-blackfin/cplb.h
+++ b/include/asm-blackfin/cplb.h
@@ -65,7 +65,11 @@
 #define SIZE_1M 0x00100000      /* 1M */
 #define SIZE_4M 0x00400000      /* 4M */
 
+#ifdef CONFIG_MPU
+#define MAX_CPLBS 16
+#else
 #define MAX_CPLBS (16 * 2)
+#endif
 
 #define ASYNC_MEMORY_CPLB_COVERAGE	((ASYNC_BANK0_SIZE + ASYNC_BANK1_SIZE + \
 				 ASYNC_BANK2_SIZE + ASYNC_BANK3_SIZE) / SIZE_4M)
diff --git a/include/asm-blackfin/cplbinit.h b/include/asm-blackfin/cplbinit.h
index c4d0596e8e9..0eb1c1b685a 100644
--- a/include/asm-blackfin/cplbinit.h
+++ b/include/asm-blackfin/cplbinit.h
@@ -33,6 +33,12 @@
 #include <asm/blackfin.h>
 #include <asm/cplb.h>
 
+#ifdef CONFIG_MPU
+
+#include <asm/cplb-mpu.h>
+
+#else
+
 #define INITIAL_T 0x1
 #define SWITCH_T  0x2
 #define I_CPLB    0x4
@@ -79,6 +85,8 @@ extern u_long ipdt_swapcount_table[];
 extern u_long dpdt_swapcount_table[];
 #endif
 
+#endif /* CONFIG_MPU */
+
 extern unsigned long reserved_mem_dcache_on;
 extern unsigned long reserved_mem_icache_on;
 
diff --git a/include/asm-blackfin/mmu.h b/include/asm-blackfin/mmu.h
index 11d52f1167d..757e43906ed 100644
--- a/include/asm-blackfin/mmu.h
+++ b/include/asm-blackfin/mmu.h
@@ -24,7 +24,9 @@ typedef struct {
 	unsigned long	exec_fdpic_loadmap;
 	unsigned long	interp_fdpic_loadmap;
 #endif
-
+#ifdef CONFIG_MPU
+	unsigned long *page_rwx_mask;
+#endif
 } mm_context_t;
 
 #endif
diff --git a/include/asm-blackfin/mmu_context.h b/include/asm-blackfin/mmu_context.h
index c5c71a6aaf1..b5eb67596ad 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 void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
 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 @@ static inline void destroy_context(struct mm_struct *mm)
 		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 @@ activate_l1stack(struct mm_struct *mm, unsigned long sp_base)
 
 #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 @@ static inline void activate_mm(struct mm_struct *prev_mm,
 	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)
+{
+	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)
 {
-	activate_mm(prev, next);
+	flush_switched_cplbs();
+	set_mask_dcplbs(mm->context.page_rwx_mask);
 }
+#endif
 
 #endif