linux.git/arch/powerpc/kernel, branch v2.6.26-rc7

Reinstate ZERO_PAGE optimization in 'get_user_pages()' and fix XIP

2008-06-20T18:18:25+00:00

KAMEZAWA Hiroyuki and Oleg Nesterov point out that since the commit
557ed1fa2620dc119adb86b34c614e152a629a80 ("remove ZERO_PAGE") removed
the ZERO_PAGE from the VM mappings, any users of get_user_pages() will
generally now populate the VM with real empty pages needlessly.

We used to get the ZERO_PAGE when we did the "handle_mm_fault()", but
since fault handling no longer uses ZERO_PAGE for new anonymous pages,
we now need to handle that special case in follow_page() instead.

In particular, the removal of ZERO_PAGE effectively removed the core
file writing optimization where we would skip writing pages that had not
been populated at all, and increased memory pressure a lot by allocating
all those useless newly zeroed pages.

This reinstates the optimization by making the unmapped PTE case the
same as for a non-existent page table, which already did this correctly.

While at it, this also fixes the XIP case for follow_page(), where the
caller could not differentiate between the case of a page that simply
could not be used (because it had no "struct page" associated with it)
and a page that just wasn't mapped.

We do that by simply returning an error pointer for pages that could not
be turned into a "struct page *".  The error is arbitrarily picked to be
EFAULT, since that was what get_user_pages() already used for the
equivalent IO-mapped page case.

[ Also removed an impossible test for pte_offset_map_lock() failing:
  that's not how that function works ]

Acked-by: Oleg Nesterov 
Acked-by: Nick Piggin 
Cc: KAMEZAWA Hiroyuki 
Cc: Hugh Dickins 
Cc: Andrew Morton 
Cc: Ingo Molnar 
Cc: Roland McGrath 
Signed-off-by: Linus Torvalds

[POWERPC] 4xx: Clear new TLB cache attribute bits in Data Storage vector

2008-06-18T11:40:43+00:00

A recent commit added support for the new 440x6 and 464 cores that have the
added WL1, IL1I, IL1D, IL2I, and ILD2 bits for the caching attributes in the
TLBs.  The new bits were cleared in the finish_tlb_load function, however a
similar bit of code was missed in the DataStorage interrupt vector.

Signed-off-by: Josh Boyer 
Signed-off-by: Paul Mackerras

[POWERPC] Remove ppc32's export of console_drivers

2008-06-16T05:00:56+00:00

There are no in-tree uses of the export any more and in linux-next there
is a change that exports it globally which causes warnings:

WARNING: vmlinux: 'console_drivers' exported twice. Previous export was in vmlinux

and in one case (mpc85xx_defconfig) a build error:

kernel/built-in.o: In function `__crc_console_drivers':
(*ABS*+0x1eb0e6f5): multiple definition of `__crc_console_drivers'

So remove the export now.  Also, there is no longer any need to include
linux/console.h.

Signed-off-by: Stephen Rothwell 
Signed-off-by: Paul Mackerras

[POWERPC] Fix -Os kernel builds with newer gcc versions

2008-06-16T05:00:54+00:00

GCC 4.4.x looks to be adding support for generating out-of-line register
saves/restores based on:

http://gcc.gnu.org/ml/gcc-patches/2008-04/msg01678.html

This breaks the kernel if we enable CONFIG_CC_OPTIMIZE_FOR_SIZE.  To fix
this we add the use the save/restore code from gcc and simplified it down
for our needs (integer only).

Additionally, we have to link this code into each module.  The other
solution was to add EXPORT_SYMBOL() which meant going through the
trampoline which seemed nonsensical for these out-of-line routines.

Finally, we add some checks to prom_init_check.sh to ignore the
out-of-line save/restore functions.

Signed-off-by: Kumar Gala 
Signed-off-by: Paul Mackerras

[POWERPC] Fix return value check logic in debugfs virq_mapping setup

2008-06-16T05:00:25+00:00

debugfs_create_file() returns a non-NULL (non-zero) value in case of
success, not a NULL value.

This fixes this non-critical boot-time debugging error message:

[    1.316386] calling  irq_debugfs_init+0x0/0x50
[    1.316399] initcall irq_debugfs_init+0x0/0x50 returned -12 after 0 msecs
[    1.316411] initcall irq_debugfs_init+0x0/0x50 returned with error code -12

Signed-off-by: Emil Medve 
Acked-by: Michael Ellerman 
Signed-off-by: Paul Mackerras

[POWERPC] Use dev_set_name in pci_64.c

2008-06-09T01:32:40+00:00

During the next merge window, pci_name()'s return value will become
const, so use the new dev_set_name() instead to avoid the warning (from
linux-next):

arch/powerpc/kernel/pci_64.c: In function 'of_create_pci_dev':
arch/powerpc/kernel/pci_64.c:193: warning: passing argument 1 of 'sprintf' discards qualifiers from pointer target type

Cc: Kay Sievers 
Cc: Greg KH 
Signed-off-by: Stephen Rothwell 
Signed-off-by: Paul Mackerras

[POWERPC] Fix incorrect enabling of VMX when building signal or user context

2008-06-09T01:32:36+00:00

When building a signal or a ucontext, we can incorrectly set the MSR_VEC
bit of the kernel pt_regs->msr before returning to userspace if the task
-ever- used VMX.

This can lead to funny result if that stack used it in the past, then
"lost" it (ie. it wasn't enabled after a context switch for example)
and then called get_context.  It can end up with VMX enabled and the
registers containing values from some other task.

Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Paul Mackerras

[POWERPC] Add kernstart_addr to list of allowed symbols in prom_init

2008-05-23T06:15:35+00:00

Since commit "85xx: Add support for relocatable kernel (and
booting at non-zero)" (37dd2badcfcec35f5e21a0926968d77a404f03c3),
PHYSICAL_START is #defined as kernstart_addr if RELOCATABLE
and FLATMEM is enabled.

PHYSICAL_START is used in prom_init.c and so kernstart_addr
needs to be added to the list of allowed symbols that
prom_init.c can access.

Signed-off-by: Michael Ellerman 
Acked-by: Kumar Gala 
Signed-off-by: Paul Mackerras

[PATCH] take init_files to fs/file.c

2008-05-16T21:22:20+00:00

Signed-off-by: Al Viro

[POWERPC] ppc: Don't run prom_init_check for arch/ppc builds

2008-05-12T10:27:50+00:00

arch/ppc doesn't have prom_init.o (anymore).

Signed-off-by: Segher Boessenkool 
Signed-off-by: Paul Mackerras