[tip: x86/mm] x86/mm: Implement native set_memory_rox()

[tip-bot2 for Peter Zijlstra]

The following commit has been merged into the x86/mm branch of tip:

Commit-ID:     60463628c9e0a8060ac6bef0457b0505c7532c7c
Gitweb:        https://git.kernel.org/tip/60463628c9e0a8060ac6bef0457b0505c7532c7c
Author:        Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate:    Sat, 29 Oct 2022 13:19:31 +02:00
Committer:     Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
CommitterDate: Thu, 15 Dec 2022 10:37:27 -08:00

x86/mm: Implement native set_memory_rox()

Provide a native implementation of set_memory_rox(), avoiding the
double set_memory_ro();set_memory_x(); calls.

Suggested-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
---
 arch/x86/include/asm/set_memory.h |  3 +++
 arch/x86/mm/pat/set_memory.c      | 10 ++++++++++
 include/linux/set_memory.h        |  2 ++
 3 files changed, 15 insertions(+)

diff --git a/arch/x86/include/asm/set_memory.h b/arch/x86/include/asm/set_memory.h
index b45c4d2..a5e8964 100644
--- a/arch/x86/include/asm/set_memory.h
+++ b/arch/x86/include/asm/set_memory.h
@@ -6,6 +6,9 @@
 #include <asm/page.h>
 #include <asm-generic/set_memory.h>
 
+#define set_memory_rox set_memory_rox
+int set_memory_rox(unsigned long addr, int numpages);
+
 /*
  * The set_memory_* API can be used to change various attributes of a virtual
  * address range. The attributes include:
diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c
index 97342c4..f275605 100644
--- a/arch/x86/mm/pat/set_memory.c
+++ b/arch/x86/mm/pat/set_memory.c
@@ -2025,6 +2025,16 @@ int set_memory_ro(unsigned long addr, int numpages)
 	return change_page_attr_clear(&addr, numpages, __pgprot(_PAGE_RW), 0);
 }
 
+int set_memory_rox(unsigned long addr, int numpages)
+{
+	pgprot_t clr = __pgprot(_PAGE_RW);
+
+	if (__supported_pte_mask & _PAGE_NX)
+		clr.pgprot |= _PAGE_NX;
+
+	return change_page_attr_clear(&addr, numpages, clr, 0);
+}
+
 int set_memory_rw(unsigned long addr, int numpages)
 {
 	return change_page_attr_set(&addr, numpages, __pgprot(_PAGE_RW), 0);
diff --git a/include/linux/set_memory.h b/include/linux/set_memory.h
index 023ebc6..95ac839 100644
--- a/include/linux/set_memory.h
+++ b/include/linux/set_memory.h
@@ -14,6 +14,7 @@ static inline int set_memory_x(unsigned long addr,  int numpages) { return 0; }
 static inline int set_memory_nx(unsigned long addr, int numpages) { return 0; }
 #endif
 
+#ifndef set_memory_rox
 static inline int set_memory_rox(unsigned long addr, int numpages)
 {
 	int ret = set_memory_ro(addr, numpages);
@@ -21,6 +22,7 @@ static inline int set_memory_rox(unsigned long addr, int numpages)
 		return ret;
 	return set_memory_x(addr, numpages);
 }
+#endif
 
 #ifndef CONFIG_ARCH_HAS_SET_DIRECT_MAP
 static inline int set_direct_map_invalid_noflush(struct page *page)