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Subject[PATCH v10 07/27] powerpc: cleanup AMR, IAMR when a key is allocated or freed
Date
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>
---
arch/powerpc/include/asm/pkeys.h | 12 ++++++++++++
1 files changed, 12 insertions(+), 0 deletions(-)

diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h
index 1e8cef2..9964b46 100644
--- a/arch/powerpc/include/asm/pkeys.h
+++ b/arch/powerpc/include/asm/pkeys.h
@@ -69,6 +69,8 @@ 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
@@ -96,6 +98,12 @@ 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;
}

@@ -107,6 +115,10 @@ 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;
--
1.7.1
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