3 files changed, 63 insertions, 2 deletions

diff --git a/arch/arm/include/asm/assembler.h b/arch/arm/include/asm/assembler.h
index a91177043467..3ae0eda5e64f 100644
--- a/arch/arm/include/asm/assembler.h
+++ b/arch/arm/include/asm/assembler.h
@@ -446,15 +446,45 @@ THUMB(	orr	\reg , \reg , #PSR_T_BIT	)
         .endm
 
         .macro  uaccess_disable, tmp, isb=1
+#ifdef CONFIG_CPU_SW_DOMAIN_PAN
+        /*
+         * Whenever we re-enter userspace, the domains should always be
+         * set appropriately.
+         */
+        mov     \tmp, #DACR_UACCESS_DISABLE
+        mcr     p15, 0, \tmp, c3, c0, 0         @ Set domain register
+        .if     \isb
+        instr_sync
+        .endif
+#endif
         .endm
 
         .macro  uaccess_enable, tmp, isb=1
+#ifdef CONFIG_CPU_SW_DOMAIN_PAN
+        /*
+         * Whenever we re-enter userspace, the domains should always be
+         * set appropriately.
+         */
+        mov     \tmp, #DACR_UACCESS_ENABLE
+        mcr     p15, 0, \tmp, c3, c0, 0
+        .if     \isb
+        instr_sync
+        .endif
+#endif
         .endm
 
         .macro  uaccess_save, tmp
+#ifdef CONFIG_CPU_SW_DOMAIN_PAN
+        mrc     p15, 0, \tmp, c3, c0, 0
+        str     \tmp, [sp, #S_FRAME_SIZE]
+#endif
         .endm
 
         .macro  uaccess_restore
+#ifdef CONFIG_CPU_SW_DOMAIN_PAN
+        ldr     r0, [sp, #S_FRAME_SIZE]
+        mcr     p15, 0, r0, c3, c0, 0
+#endif
         .endm
 
         .macro  uaccess_save_and_disable, tmp
diff --git a/arch/arm/include/asm/domain.h b/arch/arm/include/asm/domain.h
index 2be929549938..e878129f2fee 100644
--- a/arch/arm/include/asm/domain.h
+++ b/arch/arm/include/asm/domain.h
@@ -57,11 +57,29 @@
 #define domain_mask(dom)        ((3) << (2 * (dom)))
 #define domain_val(dom,type)    ((type) << (2 * (dom)))
 
+#ifdef CONFIG_CPU_SW_DOMAIN_PAN
+#define DACR_INIT \
+        (domain_val(DOMAIN_USER, DOMAIN_NOACCESS) | \
+         domain_val(DOMAIN_KERNEL, DOMAIN_MANAGER) | \
+         domain_val(DOMAIN_IO, DOMAIN_CLIENT) | \
+         domain_val(DOMAIN_VECTORS, DOMAIN_CLIENT))
+#else
 #define DACR_INIT \
         (domain_val(DOMAIN_USER, DOMAIN_CLIENT) | \
          domain_val(DOMAIN_KERNEL, DOMAIN_MANAGER) | \
          domain_val(DOMAIN_IO, DOMAIN_CLIENT) | \
          domain_val(DOMAIN_VECTORS, DOMAIN_CLIENT))
+#endif
+
+#define __DACR_DEFAULT \
+        domain_val(DOMAIN_KERNEL, DOMAIN_CLIENT) | \
+        domain_val(DOMAIN_IO, DOMAIN_CLIENT) | \
+        domain_val(DOMAIN_VECTORS, DOMAIN_CLIENT)
+
+#define DACR_UACCESS_DISABLE    \
+        (__DACR_DEFAULT | domain_val(DOMAIN_USER, DOMAIN_NOACCESS))
+#define DACR_UACCESS_ENABLE     \
+        (__DACR_DEFAULT | domain_val(DOMAIN_USER, DOMAIN_CLIENT))
 
 #ifndef __ASSEMBLY__
 
@@ -76,7 +94,6 @@ static inline unsigned int get_domain(void)
         return domain;
 }
 
-#ifdef CONFIG_CPU_USE_DOMAINS
 static inline void set_domain(unsigned val)
 {
         asm volatile(
@@ -85,6 +102,7 @@ static inline void set_domain(unsigned val)
         isb();
 }
 
+#ifdef CONFIG_CPU_USE_DOMAINS
 #define modify_domain(dom,type)                                 \
         do {                                                    \
                 unsigned int domain = get_domain();             \
@@ -94,7 +112,6 @@ static inline void set_domain(unsigned val)
         } while (0)
 
 #else
-static inline void set_domain(unsigned val) { }
 static inline void modify_domain(unsigned dom, unsigned type)   { }
 #endif
 
diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h
index 82880132f941..01bae13b2cea 100644
--- a/arch/arm/include/asm/uaccess.h
+++ b/arch/arm/include/asm/uaccess.h
@@ -57,11 +57,25 @@ extern int fixup_exception(struct pt_regs *regs);
  */
 static inline unsigned int uaccess_save_and_enable(void)
 {
+#ifdef CONFIG_CPU_SW_DOMAIN_PAN
+        unsigned int old_domain = get_domain();
+
+        /* Set the current domain access to permit user accesses */
+        set_domain((old_domain & ~domain_mask(DOMAIN_USER)) |
+                   domain_val(DOMAIN_USER, DOMAIN_CLIENT));
+
+        return old_domain;
+#else
         return 0;
+#endif
 }
 
 static inline void uaccess_restore(unsigned int flags)
 {
+#ifdef CONFIG_CPU_SW_DOMAIN_PAN
+        /* Restore the user access mask */
+        set_domain(flags);
+#endif
 }
 
 /*