Le 04/10/2018 à 10:23, Aneesh Kumar K.V a écrit :

On 10/4/18 1:50 PM, Christophe LEROY wrote:

quoted

Le 03/10/2018 à 06:24, Nicholas Piggin a écrit :

quoted

On Mon,  1 Oct 2018 12:30:19 +0000 (UTC)
Christophe Leroy [off-list ref] wrote:

quoted

When activating CONFIG_THREAD_INFO_IN_TASK, linux/sched.h
includes asm/current.h. This generates a circular dependency.
To avoid that, asm/processor.h shall not be included in mmu-hash.h

In order to do that, this patch moves into a new header called
asm/task_size.h the information from asm/processor.h requires by
mmu-hash.h

Doesn't look like you use this header in 32-bit code. Put task_size.h
in asm/64/ maybe?

There is no asm/64/ dir at the time being, only book3s/64/ and nohash/64/

I'm thinking about leaving it in asm/ but renaming it task_size_user64.h

Quiet a lot of that is book3s 64 specifi because we have there.

#if defined(CONFIG_PPC_BOOK3S_64) && defined(CONFIG_PPC_64K_PAGES)
/*
  * Max value currently used:
  */

We have an #if / #else

#if defined(CONFIG_PPC_BOOK3S_64) && defined(CONFIG_PPC_64K_PAGES)
/*
  * Max value currently used:
  */
#define TASK_SIZE_USER64		TASK_SIZE_4PB
#define DEFAULT_MAP_WINDOW_USER64	TASK_SIZE_128TB
#define TASK_CONTEXT_SIZE		TASK_SIZE_512TB

#else

#define TASK_SIZE_USER64		TASK_SIZE_64TB
#define DEFAULT_MAP_WINDOW_USER64	TASK_SIZE_64TB
/*
  * We don't need to allocate extended context ids for 4K page size, because
  * we limit the max effective address on this config to 64TB.
  */
#define TASK_CONTEXT_SIZE		TASK_SIZE_64TB
#endif

And processor .h derives several other consts applying to both BOOK3S64 
et BOOK3E64 from that.


And arch/powerpc/mm/pgtable-book3e.c has:

	BUILD_BUG_ON(TASK_SIZE_USER64 > PGTABLE_RANGE);


Christophe