linux-kernel - [PATCH v2 2/2] mm: provide a fallback for PAGE_KERNEL

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Date:   Wed,  9 May 2018 18:44:47 -0700
From:   "Luis R. Rodriguez" <mcgrof@...nel.org>
To:     arnd@...db.de
Cc:     gregkh@...uxfoundation.org, willy@...radead.org,
        geert@...ux-m68k.org, linux-m68k@...ts.linux-m68k.org,
        linux-arch@...r.kernel.org, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org,
        "Luis R. Rodriguez" <mcgrof@...nel.org>
Subject: [PATCH v2 2/2] mm: provide a fallback for PAGE_KERNEL_EXEC for architectures

Some architectures just don't have PAGE_KERNEL_EXEC. The mm/nommu.c
and mm/vmalloc.c code have been using PAGE_KERNEL as a fallback for years.
Move this fallback to asm-generic.

Architectures which do not define PAGE_KERNEL_EXEC yet:

  o alpha
  o mips
  o openrisc
  o sparc64

Suggested-by: Matthew Wilcox <willy@...radead.org>
Signed-off-by: Luis R. Rodriguez <mcgrof@...nel.org>
---
 include/asm-generic/pgtable.h | 12 ++++++++++++
 mm/nommu.c                    |  4 ----
 mm/vmalloc.c                  |  4 ----
 3 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index 890fc54f4713..39e9bd66c786 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -1107,6 +1107,18 @@ static inline void init_espfix_bsp(void) { }
 # define PAGE_KERNEL_RO PAGE_KERNEL
 #endif
 
+/*
+ * Current architectures known to not define PAGE_KERNEL_EXEC:
+ *
+ *  o alpha
+ *  o mips
+ *  o openrisc
+ *  o sparc64
+ */
+#ifndef PAGE_KERNEL_EXEC
+# define PAGE_KERNEL_EXEC PAGE_KERNEL
+#endif
+
 #endif /* !__ASSEMBLY__ */
 
 #ifndef io_remap_pfn_range
diff --git a/mm/nommu.c b/mm/nommu.c
index 13723736d38f..08ad4dcd281d 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -364,10 +364,6 @@ void *vzalloc_node(unsigned long size, int node)
 }
 EXPORT_SYMBOL(vzalloc_node);
 
-#ifndef PAGE_KERNEL_EXEC
-# define PAGE_KERNEL_EXEC PAGE_KERNEL
-#endif
-
 /**
  *	vmalloc_exec  -  allocate virtually contiguous, executable memory
  *	@size:		allocation size
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index ebff729cc956..89543d13e32a 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1920,10 +1920,6 @@ void *vzalloc_node(unsigned long size, int node)
 }
 EXPORT_SYMBOL(vzalloc_node);
 
-#ifndef PAGE_KERNEL_EXEC
-# define PAGE_KERNEL_EXEC PAGE_KERNEL
-#endif
-
 /**
  *	vmalloc_exec  -  allocate virtually contiguous, executable memory
  *	@size:		allocation size
-- 
2.17.0