The patch titled
Subject: mm: provide a fallback for PAGE_KERNEL_RO for architectures
has been added to the -mm tree. Its filename is
mm-provide-a-fallback-for-page_kernel_ro-for-architectures.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-provide-a-fallback-for-page_kernel_ro-for-architectures.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-provide-a-fallback-for-page_kernel_ro-for-architectures.patch
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------------------------------------------------------
From: "Luis R. Rodriguez" <mcgrof@xxxxxxxxxx>
Subject: mm: provide a fallback for PAGE_KERNEL_RO for architectures
Some architectures do not define certain PAGE_KERNEL_* flags, this is
either because:
a) The way to implement some of these flags is *not yet ported*, or
b) The architecture *has no way* to describe them
Over time we have accumulated a few PAGE_KERNEL_* fallback workarounds for
architectures in the kernel which do not define them using *relatively
safe* equivalents. Move these scattered fallback hacks into asm-generic.
We start off with PAGE_KERNEL_RO using PAGE_KERNEL as a fallback. This
has been in place on the firmware loader for years. Move the fallback
into the respective asm-generic header.
Link: http://lkml.kernel.org/r/20180510185507.2439-2-mcgrof@xxxxxxxxxx
Signed-off-by: Luis R. Rodriguez <mcgrof@xxxxxxxxxx>
Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/base/firmware_loader/fallback.c | 5 -----
include/asm-generic/pgtable.h | 14 ++++++++++++++
2 files changed, 14 insertions(+), 5 deletions(-)
diff -puN drivers/base/firmware_loader/fallback.c~mm-provide-a-fallback-for-page_kernel_ro-for-architectures drivers/base/firmware_loader/fallback.c
--- a/drivers/base/firmware_loader/fallback.c~mm-provide-a-fallback-for-page_kernel_ro-for-architectures
+++ a/drivers/base/firmware_loader/fallback.c
@@ -219,11 +219,6 @@ static ssize_t firmware_loading_show(str
return sprintf(buf, "%d\n", loading);
}
-/* Some architectures don't have PAGE_KERNEL_RO */
-#ifndef PAGE_KERNEL_RO
-#define PAGE_KERNEL_RO PAGE_KERNEL
-#endif
-
/* one pages buffer should be mapped/unmapped only once */
static int map_fw_priv_pages(struct fw_priv *fw_priv)
{
diff -puN include/asm-generic/pgtable.h~mm-provide-a-fallback-for-page_kernel_ro-for-architectures include/asm-generic/pgtable.h
--- a/include/asm-generic/pgtable.h~mm-provide-a-fallback-for-page_kernel_ro-for-architectures
+++ a/include/asm-generic/pgtable.h
@@ -1083,6 +1083,20 @@ int phys_mem_access_prot_allowed(struct
static inline void init_espfix_bsp(void) { }
#endif
+/*
+ * Architecture PAGE_KERNEL_* fallbacks
+ *
+ * Some architectures don't define certain PAGE_KERNEL_* flags. This is either
+ * because they really don't support them, or the port needs to be updated to
+ * reflect the required functionality. Below are a set of relatively safe
+ * fallbacks, as best effort, which we can count on in lieu of the architectures
+ * not defining them on their own yet.
+ */
+
+#ifndef PAGE_KERNEL_RO
+# define PAGE_KERNEL_RO PAGE_KERNEL
+#endif
+
#endif /* !__ASSEMBLY__ */
#ifndef io_remap_pfn_range
_
Patches currently in -mm which might be from mcgrof@xxxxxxxxxx are
mm-provide-a-fallback-for-page_kernel_ro-for-architectures.patch
mm-provide-a-fallback-for-page_kernel_exec-for-architectures.patch
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