powerpc: cleanup AMR, IAMR when a key is allocated or freed

Cleanup the bits corresponding to a key in the AMR, and IAMR
register, when the key is newly allocated/activated or is freed.
We dont want some residual bits cause the hardware enforce
unintended behavior when the key is activated or freed.

Reviewed-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h
index 79b105d1ff7369f121511d487b34e976fa3ef8ed..5ed52ac39bab20951c214fc61efabd8bfcdb63a6 100644 (file)
--- a/arch/powerpc/include/asm/pkeys.h
+++ b/arch/powerpc/include/asm/pkeys.h
@@ -58,6 +58,8 @@ static inline bool mm_pkey_is_allocated(struct mm_struct *mm, int pkey)
                __mm_pkey_is_allocated(mm, pkey));
 }
 
+extern void __arch_activate_pkey(int pkey);
+extern void __arch_deactivate_pkey(int pkey);
 /*
  * Returns a positive, 5-bit key on success, or -1 on failure.
  * Relies on the mmap_sem to protect against concurrency in mm_pkey_alloc() and
@@ -85,6 +87,12 @@ static inline int mm_pkey_alloc(struct mm_struct *mm)
 
        ret = ffz((u32)mm_pkey_allocation_map(mm));
        __mm_pkey_allocated(mm, ret);
+
+       /*
+        * Enable the key in the hardware
+        */
+       if (ret > 0)
+               __arch_activate_pkey(ret);
        return ret;
 }
 
@@ -96,6 +104,10 @@ static inline int mm_pkey_free(struct mm_struct *mm, int pkey)
        if (!mm_pkey_is_allocated(mm, pkey))
                return -EINVAL;
 
+       /*
+        * Disable the key in the hardware
+        */
+       __arch_deactivate_pkey(pkey);
        __mm_pkey_free(mm, pkey);
 
        return 0;