[PATCH v6 21/24] x86/kprobes: Use vmalloc special flag

[nadav . amit]

From: Rick Edgecombe <rick.p.edgeco...@intel.com>

Use new flag VM_FLUSH_RESET_PERMS for handling freeing of special
permissioned memory in vmalloc and remove places where memory was set NX
and RW before freeing which is no longer needed.

Cc: Masami Hiramatsu <mhira...@kernel.org>
Signed-off-by: Rick Edgecombe <rick.p.edgeco...@intel.com>
---
 arch/x86/kernel/kprobes/core.c | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index 1591852d3ac4..136695e4434a 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -434,6 +434,7 @@ void *alloc_insn_page(void)
        if (!page)
                return NULL;
 
+       set_vm_flush_reset_perms(page);
        /*
         * First make the page read-only, and only then make it executable to
         * prevent it from being W+X in between.
@@ -452,12 +453,6 @@ void *alloc_insn_page(void)
 /* Recover page to RW mode before releasing it */
 void free_insn_page(void *page)
 {
-       /*
-        * First make the page non-executable, and only then make it writable to
-        * prevent it from being W+X in between.
-        */
-       set_memory_nx((unsigned long)page, 1);
-       set_memory_rw((unsigned long)page, 1);
        module_memfree(page);
 }
 
-- 
2.17.1