[v2,19/20] x86/kprobes: Use vmalloc special flag
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Message ID 20190129003422.9328-20-rick.p.edgecombe@intel.com
State New
Headers show
Series
  • Merge text_poke fixes and executable lockdowns
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Commit Message

Edgecombe, Rick P Jan. 29, 2019, 12:34 a.m. UTC
Use new flag VM_HAS_SPECIAL_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 <mhiramat@kernel.org>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
 arch/x86/kernel/kprobes/core.c | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

Patch
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diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index fac692e36833..f2fab35bcb82 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 == NULL)
 		return NULL;
 
+	set_vm_special(page);
 	/*
 	 * First make the page read-only, and then 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 then 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);
 }