This system call, associates the pkey with vma corresponding to
the given address range.

Signed-off-by: Ram Pai <linux...@us.ibm.com>
---
 arch/powerpc/include/asm/mman.h        |  8 ++-
 arch/powerpc/include/asm/pkeys.h       | 17 ++++++-
 arch/powerpc/include/asm/systbl.h      |  1 +
 arch/powerpc/include/asm/unistd.h      |  4 +-
 arch/powerpc/include/uapi/asm/unistd.h |  1 +
 arch/powerpc/mm/pkeys.c                | 93 +++++++++++++++++++++++++++++++++-
 6 files changed, 117 insertions(+), 7 deletions(-)

diff --git a/arch/powerpc/include/asm/mman.h b/arch/powerpc/include/asm/mman.h
index 30922f6..067eec2 100644
--- a/arch/powerpc/include/asm/mman.h
+++ b/arch/powerpc/include/asm/mman.h
@@ -13,6 +13,7 @@
 
 #include <asm/cputable.h>
 #include <linux/mm.h>
+#include <linux/pkeys.h>
 #include <asm/cpu_has_feature.h>
 
 /*
@@ -22,7 +23,12 @@
 static inline unsigned long arch_calc_vm_prot_bits(unsigned long prot,
                unsigned long pkey)
 {
-       return (prot & PROT_SAO) ? VM_SAO : 0;
+#ifdef CONFIG_PPC64_MEMORY_PROTECTION_KEYS
+       return (((prot & PROT_SAO) ? VM_SAO : 0) |
+                       pkey_to_vmflag_bits(pkey));
+#else
+       return ((prot & PROT_SAO) ? VM_SAO : 0);
+#endif
 }
 #define arch_calc_vm_prot_bits(prot, pkey) arch_calc_vm_prot_bits(prot, pkey)
 
diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h
index 7bc8746..41bf5d4 100644
--- a/arch/powerpc/include/asm/pkeys.h
+++ b/arch/powerpc/include/asm/pkeys.h
@@ -14,6 +14,15 @@
                        VM_PKEY_BIT3 | \
                        VM_PKEY_BIT4)
 
+static inline unsigned long  pkey_to_vmflag_bits(int pkey)
+{
+       return (((pkey & 0x1UL) ? VM_PKEY_BIT0 : 0x0UL) |
+               ((pkey & 0x2UL) ? VM_PKEY_BIT1 : 0x0UL) |
+               ((pkey & 0x4UL) ? VM_PKEY_BIT2 : 0x0UL) |
+               ((pkey & 0x8UL) ? VM_PKEY_BIT3 : 0x0UL) |
+               ((pkey & 0x10UL) ? VM_PKEY_BIT4 : 0x0UL));
+}
+
 /*
  * Bits are in BE format.
  * NOTE: key 31, 1, 0 are not used.
@@ -42,6 +51,12 @@
 #define mm_set_pkey_is_reserved(mm, pkey) (PKEY_INITIAL_ALLOCAION & \
                                        pkeybit_mask(pkey))
 
+
+static inline int vma_pkey(struct vm_area_struct *vma)
+{
+       return (vma->vm_flags & ARCH_VM_PKEY_FLAGS) >> VM_PKEY_SHIFT;
+}
+
 static inline bool mm_pkey_is_allocated(struct mm_struct *mm, int pkey)
 {
        /* a reserved key is never considered as 'explicitly allocated' */
@@ -114,7 +129,7 @@ static inline int arch_set_user_pkey_access(struct 
task_struct *tsk, int pkey,
        return __arch_set_user_pkey_access(tsk, pkey, init_val);
 }
 
-static inline pkey_mm_init(struct mm_struct *mm)
+static inline void pkey_mm_init(struct mm_struct *mm)
 {
        mm_pkey_allocation_map(mm) = PKEY_INITIAL_ALLOCAION;
        /* -1 means unallocated or invalid */
diff --git a/arch/powerpc/include/asm/systbl.h 
b/arch/powerpc/include/asm/systbl.h
index 22dd776..b33b551 100644
--- a/arch/powerpc/include/asm/systbl.h
+++ b/arch/powerpc/include/asm/systbl.h
@@ -390,3 +390,4 @@
 SYSCALL(statx)
 SYSCALL(pkey_alloc)
 SYSCALL(pkey_free)
+SYSCALL(pkey_mprotect)
diff --git a/arch/powerpc/include/asm/unistd.h 
b/arch/powerpc/include/asm/unistd.h
index e0273bc..daf1ba9 100644
--- a/arch/powerpc/include/asm/unistd.h
+++ b/arch/powerpc/include/asm/unistd.h
@@ -12,12 +12,10 @@
 #include <uapi/asm/unistd.h>
 
 
-#define NR_syscalls            386
+#define NR_syscalls            387
 
 #define __NR__exit __NR_exit
 
-#define __IGNORE_pkey_mprotect
-
 #ifndef __ASSEMBLY__
 
 #include <linux/types.h>
diff --git a/arch/powerpc/include/uapi/asm/unistd.h 
b/arch/powerpc/include/uapi/asm/unistd.h
index 7993a07..71ae45e 100644
--- a/arch/powerpc/include/uapi/asm/unistd.h
+++ b/arch/powerpc/include/uapi/asm/unistd.h
@@ -396,5 +396,6 @@
 #define __NR_statx             383
 #define __NR_pkey_alloc                384
 #define __NR_pkey_free         385
+#define __NR_pkey_mprotect     386
 
 #endif /* _UAPI_ASM_POWERPC_UNISTD_H_ */
diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c
index b97366e..11a32b3 100644
--- a/arch/powerpc/mm/pkeys.c
+++ b/arch/powerpc/mm/pkeys.c
@@ -15,6 +15,17 @@
 #include <linux/pkeys.h>                /* PKEY_*                       */
 #include <uapi/asm-generic/mman-common.h>
 
+#define pkeyshift(pkey) ((arch_max_pkey()-pkey-1) * AMR_BITS_PER_PKEY)
+
+static inline bool pkey_allows_readwrite(int pkey)
+{
+       int pkey_shift = pkeyshift(pkey);
+
+       if (!(read_uamor() & (0x3UL << pkey_shift)))
+               return true;
+
+       return !(read_amr() & ((AMR_AD_BIT|AMR_WD_BIT) << pkey_shift));
+}
 
 /*
  * set the access right in AMR IAMR and UAMOR register
@@ -68,7 +79,60 @@ int __arch_set_user_pkey_access(struct task_struct *tsk, int 
pkey,
 
 int __execute_only_pkey(struct mm_struct *mm)
 {
-       return -1;
+       bool need_to_set_mm_pkey = false;
+       int execute_only_pkey = mm->context.execute_only_pkey;
+       int ret;
+
+       /* Do we need to assign a pkey for mm's execute-only maps? */
+       if (execute_only_pkey == -1) {
+               /* Go allocate one to use, which might fail */
+               execute_only_pkey = mm_pkey_alloc(mm);
+               if (execute_only_pkey < 0)
+                       return -1;
+               need_to_set_mm_pkey = true;
+       }
+
+       /*
+        * We do not want to go through the relatively costly
+        * dance to set AMR if we do not need to.  Check it
+        * first and assume that if the execute-only pkey is
+        * readwrite-disabled than we do not have to set it
+        * ourselves.
+        */
+       if (!need_to_set_mm_pkey &&
+           !pkey_allows_readwrite(execute_only_pkey))
+               return execute_only_pkey;
+
+       /*
+        * Set up AMR so that it denies access for everything
+        * other than execution.
+        */
+       ret = __arch_set_user_pkey_access(current, execute_only_pkey,
+                       (PKEY_DISABLE_ACCESS | PKEY_DISABLE_WRITE));
+       /*
+        * If the AMR-set operation failed somehow, just return
+        * 0 and effectively disable execute-only support.
+        */
+       if (ret) {
+               mm_set_pkey_free(mm, execute_only_pkey);
+               return -1;
+       }
+
+       /* We got one, store it and use it from here on out */
+       if (need_to_set_mm_pkey)
+               mm->context.execute_only_pkey = execute_only_pkey;
+       return execute_only_pkey;
+}
+
+static inline bool vma_is_pkey_exec_only(struct vm_area_struct *vma)
+{
+       /* Do this check first since the vm_flags should be hot */
+       if ((vma->vm_flags & (VM_READ | VM_WRITE | VM_EXEC)) != VM_EXEC)
+               return false;
+       if (vma_pkey(vma) != vma->vm_mm->context.execute_only_pkey)
+               return false;
+
+       return true;
 }
 
 /*
@@ -84,5 +148,30 @@ int __arch_override_mprotect_pkey(struct vm_area_struct 
*vma, int prot,
        if (pkey != -1)
                return pkey;
 
-       return 0;
+       /*
+        * Look for a protection-key-drive execute-only mapping
+        * which is now being given permissions that are not
+        * execute-only.  Move it back to the default pkey.
+        */
+       if (vma_is_pkey_exec_only(vma) &&
+           (prot & (PROT_READ|PROT_WRITE))) {
+               return 0;
+       }
+       /*
+        * The mapping is execute-only.  Go try to get the
+        * execute-only protection key.  If we fail to do that,
+        * fall through as if we do not have execute-only
+        * support.
+        */
+       if (prot == PROT_EXEC) {
+               pkey = execute_only_pkey(vma->vm_mm);
+               if (pkey > 0)
+                       return pkey;
+       }
+       /*
+        * This is a vanilla, non-pkey mprotect (or we failed to
+        * setup execute-only), inherit the pkey from the VMA we
+        * are working on.
+        */
+       return vma_pkey(vma);
 }
-- 
1.8.3.1

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