[PATCH] powerpc: Implement set_memory_rox()

[Christophe Leroy]

Same as x86 and s390, add set_memory_rox() to avoid doing
one pass with set_memory_ro() and a second pass with set_memory_x().

See commit 60463628c9e0 ("x86/mm: Implement native set_memory_rox()")
and commit 22e99fa56443 ("s390/mm: implement set_memory_rox()") for
more information.

Signed-off-by: Christophe Leroy <christophe.le...@csgroup.eu>
---
 arch/powerpc/include/asm/set_memory.h | 7 +++++++
 arch/powerpc/mm/pageattr.c            | 4 ++++
 2 files changed, 11 insertions(+)

diff --git a/arch/powerpc/include/asm/set_memory.h 
b/arch/powerpc/include/asm/set_memory.h
index 7ebc807aa8cc..9a025b776a4b 100644
--- a/arch/powerpc/include/asm/set_memory.h
+++ b/arch/powerpc/include/asm/set_memory.h
@@ -8,6 +8,7 @@
 #define SET_MEMORY_X   3
 #define SET_MEMORY_NP  4       /* Set memory non present */
 #define SET_MEMORY_P   5       /* Set memory present */
+#define SET_MEMORY_ROX 6
 
 int change_memory_attr(unsigned long addr, int numpages, long action);
 
@@ -41,4 +42,10 @@ static inline int set_memory_p(unsigned long addr, int 
numpages)
        return change_memory_attr(addr, numpages, SET_MEMORY_P);
 }
 
+static inline int set_memory_rox(unsigned long addr, int numpages)
+{
+       return change_memory_attr(addr, numpages, SET_MEMORY_ROX);
+}
+#define set_memory_rox set_memory_rox
+
 #endif
diff --git a/arch/powerpc/mm/pageattr.c b/arch/powerpc/mm/pageattr.c
index 6163e484bc6d..421db7c4f2a4 100644
--- a/arch/powerpc/mm/pageattr.c
+++ b/arch/powerpc/mm/pageattr.c
@@ -38,6 +38,10 @@ static int change_page_attr(pte_t *ptep, unsigned long addr, 
void *data)
                /* Don't clear DIRTY bit */
                pte_update_delta(ptep, addr, _PAGE_KERNEL_RW & ~_PAGE_DIRTY, 
_PAGE_KERNEL_RO);
                break;
+       case SET_MEMORY_ROX:
+               /* Don't clear DIRTY bit */
+               pte_update_delta(ptep, addr, _PAGE_KERNEL_RW & ~_PAGE_DIRTY, 
_PAGE_KERNEL_ROX);
+               break;
        case SET_MEMORY_RW:
                pte_update_delta(ptep, addr, _PAGE_KERNEL_RO, _PAGE_KERNEL_RW);
                break;
-- 
2.43.0