diff options
| author | Luis R. Rodriguez <mcgrof@kernel.org> | 2018-08-18 01:46:29 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-08-18 02:20:29 +0300 |
| commit | a3266bd49c721e2e0a71f352d83713fbd60caadb (patch) | |
| tree | 2a1fd45483467ffd8687f60e06c9b497dc40aee0 /include | |
| parent | 3172e5e61c8a78f690c50f221fdeedce35d0b1e4 (diff) | |
| download | linux-a3266bd49c721e2e0a71f352d83713fbd60caadb.tar.xz | |
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@kernel.org
Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/asm-generic/pgtable.h | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h index a75cb371cd19..62bbd6f23c35 100644 --- a/include/asm-generic/pgtable.h +++ b/include/asm-generic/pgtable.h @@ -1095,6 +1095,20 @@ static inline bool arch_has_pfn_modify_check(void) } #endif /* !_HAVE_ARCH_PFN_MODIFY_ALLOWED */ +/* + * 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 |