the functions added to asm-generic/pgtable.h are only used by
mm/mprotect.c (a MMU-only file), but they were not added inside of the
CONFIG_MMU ifdef block. since the functions rely on things inside of
CONFIG_MMU (the lines just above in pgtable.h), we get build failure
on all no-mmu setups:
CC init/main.o
In file included from include/asm/pgtable.h:94,
from include/linux/mm.h:39,
from include/asm/dma.h:39,
from include/linux/bootmem.h:8,
from init/main.c:27:
include/asm-generic/pgtable.h: In function '__ptep_modify_prot_start':
include/asm-generic/pgtable.h:210: error: implicit declaration of
function 'ptep_get_and_clear'
include/asm-generic/pgtable.h:210: error: incompatible types in return
make[1]: *** [init/main.o] Error 1
make: *** [init/main.o] Error 2
-mike
Mike Frysinger wrote:
> the functions added to asm-generic/pgtable.h are only used by
> mm/mprotect.c (a MMU-only file), but they were not added inside of the
> CONFIG_MMU ifdef block. since the functions rely on things inside of
> CONFIG_MMU (the lines just above in pgtable.h), we get build failure
> on all no-mmu setups:
> CC init/main.o
> In file included from include/asm/pgtable.h:94,
> from include/linux/mm.h:39,
> from include/asm/dma.h:39,
> from include/linux/bootmem.h:8,
> from init/main.c:27:
> include/asm-generic/pgtable.h: In function '__ptep_modify_prot_start':
> include/asm-generic/pgtable.h:210: error: implicit declaration of
> function 'ptep_get_and_clear'
> include/asm-generic/pgtable.h:210: error: incompatible types in return
> make[1]: *** [init/main.o] Error 1
> make: *** [init/main.o] Error 2
> -mike
>
Uh, OK. What does mprotect do on a nommu system? Would it be
sufficient to move the definitions of __ptep_modify_prot_start/commit
out of a CONFIG_MMU block, or provide separate no-op versions?
J
On Thu, Jul 03, 2008 at 08:53:52AM -0700, Jeremy Fitzhardinge wrote:
> Mike Frysinger wrote:
>> the functions added to asm-generic/pgtable.h are only used by
>> mm/mprotect.c (a MMU-only file), but they were not added inside of the
>> CONFIG_MMU ifdef block. since the functions rely on things inside of
>> CONFIG_MMU (the lines just above in pgtable.h), we get build failure
>> on all no-mmu setups:
>> CC init/main.o
>> In file included from include/asm/pgtable.h:94,
>> from include/linux/mm.h:39,
>> from include/asm/dma.h:39,
>> from include/linux/bootmem.h:8,
>> from init/main.c:27:
>> include/asm-generic/pgtable.h: In function '__ptep_modify_prot_start':
>> include/asm-generic/pgtable.h:210: error: implicit declaration of
>> function 'ptep_get_and_clear'
>> include/asm-generic/pgtable.h:210: error: incompatible types in return
>> make[1]: *** [init/main.o] Error 1
>> make: *** [init/main.o] Error 2
>> -mike
>>
>
> Uh, OK. What does mprotect do on a nommu system? Would it be
> sufficient to move the definitions of __ptep_modify_prot_start/commit
> out of a CONFIG_MMU block, or provide separate no-op versions?
FYI:
The compile error now moved into Linus' tree, and broke at least the
blackfin and m68knommu ports.
> J
cu
Adrian
--
"Is there not promise of rain?" Ling Tan asked suddenly out
of the darkness. There had been need of rain for many days.
"Only a promise," Lao Er said.
Pearl S. Buck - Dragon Seed
On Thu, Jul 3, 2008 at 11:53 AM, Jeremy Fitzhardinge wrote:
> Mike Frysinger wrote:
>> the functions added to asm-generic/pgtable.h are only used by
>> mm/mprotect.c (a MMU-only file), but they were not added inside of the
>> CONFIG_MMU ifdef block. since the functions rely on things inside of
>> CONFIG_MMU (the lines just above in pgtable.h), we get build failure
>> on all no-mmu setups:
>> CC init/main.o
>> In file included from include/asm/pgtable.h:94,
>> from include/linux/mm.h:39,
>> from include/asm/dma.h:39,
>> from include/linux/bootmem.h:8,
>> from init/main.c:27:
>> include/asm-generic/pgtable.h: In function '__ptep_modify_prot_start':
>> include/asm-generic/pgtable.h:210: error: implicit declaration of
>> function 'ptep_get_and_clear'
>> include/asm-generic/pgtable.h:210: error: incompatible types in return
>> make[1]: *** [init/main.o] Error 1
>> make: *** [init/main.o] Error 2
>
> Uh, OK. What does mprotect do on a nommu system?
it depends on the port. by default, i'm pretty sure mprotect on all
nommu systems are realistically pretty much noops. the Blackfin can
do real protection (CONFIG_MPU), but with significant performance
degradation (since the page fault handler is not in hardware nor
hardware assisted in any way).
> Would it be sufficient to
> move the definitions of __ptep_modify_prot_start/commit out of a CONFIG_MMU
> block, or provide separate no-op versions?
simply move them into CONFIG_MMU for now
-mike
Fixes build problem:
the functions added to asm-generic/pgtable.h are only used by
mm/mprotect.c (a MMU-only file), but they were not added inside of the
CONFIG_MMU ifdef block. since the functions rely on things inside of
CONFIG_MMU (the lines just above in pgtable.h), we get build failure
on all no-mmu setups:
CC init/main.o
In file included from include/asm/pgtable.h:94,
from include/linux/mm.h:39,
from include/asm/dma.h:39,
from include/linux/bootmem.h:8,
from init/main.c:27:
include/asm-generic/pgtable.h: In function '__ptep_modify_prot_start':
include/asm-generic/pgtable.h:210: error: implicit declaration of
function 'ptep_get_and_clear'
include/asm-generic/pgtable.h:210: error: incompatible types in return
make[1]: *** [init/main.o] Error 1
make: *** [init/main.o] Error 2
Signed-off-by: Jeremy Fitzhardinge <[email protected]>
Cc: Adrian Bunk <[email protected]>
Cc: Mike Frysinger <[email protected]>
---
include/asm-generic/pgtable.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
===================================================================
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -195,7 +195,6 @@
}
return 0;
}
-#endif /* CONFIG_MMU */
static inline pte_t __ptep_modify_prot_start(struct mm_struct *mm,
unsigned long addr,
@@ -253,6 +252,7 @@
__ptep_modify_prot_commit(mm, addr, ptep, pte);
}
#endif /* __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION */
+#endif /* CONFIG_MMU */
/*
* A facility to provide lazy MMU batching. This allows PTE updates and
On Tue, Jul 15, 2008 at 01:39:07PM -0700, Jeremy Fitzhardinge wrote:
> Fixes build problem: the functions added to asm-generic/pgtable.h are
> only used by
> mm/mprotect.c (a MMU-only file), but they were not added inside of the
> CONFIG_MMU ifdef block. since the functions rely on things inside of
> CONFIG_MMU (the lines just above in pgtable.h), we get build failure
> on all no-mmu setups:
> CC init/main.o
> In file included from include/asm/pgtable.h:94,
> from include/linux/mm.h:39,
> from include/asm/dma.h:39,
> from include/linux/bootmem.h:8,
> from init/main.c:27:
> include/asm-generic/pgtable.h: In function '__ptep_modify_prot_start':
> include/asm-generic/pgtable.h:210: error: implicit declaration of
> function 'ptep_get_and_clear'
> include/asm-generic/pgtable.h:210: error: incompatible types in return
> make[1]: *** [init/main.o] Error 1
> make: *** [init/main.o] Error 2
>...
Thanks, seems to work fine.
cu
Adrian
--
"Is there not promise of rain?" Ling Tan asked suddenly out
of the darkness. There had been need of rain for many days.
"Only a promise," Lao Er said.
Pearl S. Buck - Dragon Seed