linux-toradex.git/include/asm-generic/pgtable.h, branch v2.6.35-rc3

asm-generic: add dummy pgprot_noncached()

2009-06-23T12:34:30+00:00

Most architectures now provide a pgprot_noncached(), the
remaining ones can simply use an dummy default implementation,
except for cris and xtensa, which should override the
default appropriately.

Signed-off-by: Arnd Bergmann 
Cc: Jesper Nilsson 
Cc: Chris Zankel 
Cc: Magnus Damm

x86/paravirt: finish change from lazy cpu to context switch start/end

2009-03-30T06:36:01+00:00

Impact: fix lazy context switch API

Pass the previous and next tasks into the context switch start
end calls, so that the called functions can properly access the
task state (esp in end_context_switch, in which the next task
is not yet completely current).

Signed-off-by: Jeremy Fitzhardinge 
Acked-by: Peter Zijlstra

x86/pvops: replace arch_enter_lazy_cpu_mode with arch_start_context_switch

2009-03-30T06:35:59+00:00

Impact: simplification, prepare for later changes

Make lazy cpu mode more specific to context switching, so that
it makes sense to do more context-switch specific things in
the callbacks.

Signed-off-by: Jeremy Fitzhardinge 
Acked-by: Peter Zijlstra

x86 PAT: change track_pfn_vma_new to take pgprot_t pointer param

2009-01-13T18:13:01+00:00

Impact: cleanup

Change the protection parameter for track_pfn_vma_new() into a pgprot_t pointer.
Subsequent patch changes the x86 PAT handling to return a compatible
memtype in pgprot_t, if what was requested cannot be allowed due to conflicts.
No fuctionality change in this patch.

Signed-off-by: Venkatesh Pallipadi 
Signed-off-by: Suresh Siddha 
Signed-off-by: Ingo Molnar

x86: PAT: move track untrack pfnmap stubs to asm-generic

2008-12-19T23:40:30+00:00

Impact: Cleanup and branch hints only.

Move the track and untrack pfn stub routines from memory.c to asm-generic.
Also add unlikely to pfnmap related calls in fork and exit path.

Signed-off-by: Venkatesh Pallipadi 
Signed-off-by: Suresh Siddha 
Signed-off-by: H. Peter Anvin

x86: PAT: add pgprot_writecombine() interface for drivers - v3

2008-12-18T21:30:16+00:00

Impact: New mm functionality.

Add pgprot_writecombine. pgprot_writecombine will be aliased to
pgprot_noncached when not supported by the architecture.

Signed-off-by: Venkatesh Pallipadi 
Signed-off-by: Suresh Siddha 
Signed-off-by: H. Peter Anvin

mm: fix build on non-mmu machines

2008-07-15T20:58:40+00:00

Commit 1ea0704e0d aka "mm: add a ptep_modify_prot transaction abstraction"

caused:

|  CC      init/main.o
|In file included from include2/asm/pgtable.h:68,
|                 from /home/bigeasy/git/linux-2.6-m68k/include/linux/mm.h:39,
|                 from include2/asm/uaccess.h:8,
|                 from /home/bigeasy/git/linux-2.6-m68k/include/linux/poll.h:13,
|                 from /home/bigeasy/git/linux-2.6-m68k/include/linux/rtc.h:113,
|                 from /home/bigeasy/git/linux-2.6-m68k/include/linux/efi.h:19,
|                 from /home/bigeasy/git/linux-2.6-m68k/init/main.c:43:
|/linux-2.6/include/asm-generic/pgtable.h: In function '__ptep_modify_prot_start':
|/linux-2.6/include/asm-generic/pgtable.h:209: error: implicit declaration of function 'ptep_get_and_clear'
|/linux-2.6/include/asm-generic/pgtable.h:209: error: incompatible types in return
|/linux-2.6/include/asm-generic/pgtable.h: In function '__ptep_modify_prot_commit':
|/linux-2.6/include/asm-generic/pgtable.h:220: error: implicit declaration of function 'set_pte_at'
|make[2]: *** [init/main.o] Error 1
|make[1]: *** [init] Error 2
|make: *** [sub-make] Error 2

on my m68knommu box.

Acked-by: Jeremy Fitzhardinge 
Cc: Linus Torvalds 
Cc: Hugh Dickins 
Cc: Ingo Molnar 
Signed-off-by: Sebastian Siewior 
Signed-off-by: Linus Torvalds

mm: add a ptep_modify_prot transaction abstraction

2008-06-25T13:15:53+00:00

This patch adds an API for doing read-modify-write updates to a pte's
protection bits which may race against hardware updates to the pte.
After reading the pte, the hardware may asynchonously set the accessed
or dirty bits on a pte, which would be lost when writing back the
modified pte value.

The existing technique to handle this race is to use
ptep_get_and_clear() atomically fetch the old pte value and clear it
in memory.  This has the effect of marking the pte as non-present,
which will prevent the hardware from updating its state.  When the new
value is written back, the pte will be present again, and the hardware
can resume updating the access/dirty flags.

When running in a virtualized environment, pagetable updates are
relatively expensive, since they generally involve some trap into the
hypervisor.  To mitigate the cost of these updates, we tend to batch
them.

However, because of the atomic nature of ptep_get_and_clear(), it is
inherently non-batchable.  This new interface allows batching by
giving the underlying implementation enough information to open a
transaction between the read and write phases:

ptep_modify_prot_start() returns the current pte value, and puts the
  pte entry into a state where either the hardware will not update the
  pte, or if it does, the updates will be preserved on commit.

ptep_modify_prot_commit() writes back the updated pte, makes sure that
  any hardware updates made since ptep_modify_prot_start() are
  preserved.

ptep_modify_prot_start() and _commit() must be exactly paired, and
used while holding the appropriate pte lock.  They do not protect
against other software updates of the pte in any way.

The current implementations of ptep_modify_prot_start and _commit are
functionally unchanged from before: _start() uses ptep_get_and_clear()
fetch the pte and zero the entry, preventing any hardware updates.
_commit() simply writes the new pte value back knowing that the
hardware has not updated the pte in the meantime.

The only current user of this interface is mprotect

Signed-off-by: Jeremy Fitzhardinge 
Acked-by: Linus Torvalds 
Acked-by: Hugh Dickins 
Signed-off-by: Ingo Molnar

flush icache before set_pte() on ia64: flush icache at set_pte

2007-10-16T16:42:59+00:00

Current ia64 kernel flushes icache by lazy_mmu_prot_update() *after*
set_pte().  This is too late.  This patch removes lazy_mmu_prot_update and
add modfied set_pte() for flushing if necessary.

This patch flush icache of a page when
	new pte has exec bit.
	&& new pte has present bit
	&& new pte is user's page.
	&& (old *ptep is not present
            || new pte's pfn is not same to old *ptep's ptn)
	&& new pte's page has no Pg_arch_1 bit.
	   Pg_arch_1 is set when a page is cache consistent.

I think this condition checks are much easier to understand than considering
"Where sync_icache_dcache() should be inserted ?".

pte_user() for ia64 was removed by http://lkml.org/lkml/2007/6/12/67 as
clean-up. So, I added it again.

Signed-off-by: KAMEZAWA Hiroyuki 
Cc: "Luck, Tony" 
Cc: Christoph Lameter 
Cc: Hugh Dickins 
Cc: Nick Piggin 
Acked-by: David S. Miller 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

changing include/asm-generic/pgtable.h for non-mmu

2007-08-11T22:47:42+00:00

There are some parts of include/asm-generic/pgtable.h that are relevant to
the non-mmu architectures.  To make it easier to include this from them I
would like to ifdef the relevant parts.

Without this there is a handful of functions that are referenced in here
that are not defined on many non-mmu architectures.  They could be defined
out of course, as an alternative approach.

Cc: David Howells 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds