linux.git/arch/um/kernel, branch v2.6.15

[PATCH] uml skas0: stop gcc's insanity

2005-12-18T19:19:44+00:00

With Paolo 'Blaisorblade' Giarrusso 

UML skas0 stub has been miscompiling for many people (incidentally not
the authors), depending on the used GCC versions.

I think (and testing on some GCC versions shows) this patch avoids the
fundamental issue which is behind this, namely gcc using the stack when
we have just replaced it, behind gcc's back.  The remapping and storage
of the return value is hidden in a blob of asm, hopefully giving gcc no
room for creativity.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso 
Signed-off-by: Linus Torvalds

[PATCH] uml: fix compile error for tt

2005-12-12T16:57:43+00:00

arch/um/kernel/tt/uaccess.c: In function `copy_from_user_tt':
arch/um/kernel/tt/uaccess.c:11: error: `FIXADDR_USER_START' undeclared (first use in this function)
arch/um/kernel/tt/uaccess.c:11: error: (Each undeclared identifier is reported only once
arch/um/kernel/tt/uaccess.c:11: error: for each function it appears in.)

I get the compile error when I disable CONFIG_MODE_SKAS.

Signed-off-by: Pekka Enberg 
Acked-by: Paolo Giarrusso 
Cc: Jeff Dike 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] uml: eliminate use of libc PAGE_SIZE

2005-11-22T17:13:41+00:00

On some systems, libc PAGE_SIZE calls getpagesize, which can't happen from a
stub.  So, I use UM_KERN_PAGE_SIZE, which is less variable in its definition,
instead.

Signed-off-by: Jeff Dike 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] uml: eliminate use of local in clone stub

2005-11-22T17:13:41+00:00

We have a bug in the i386 stub_syscall6 which pushes ebp before the system
call and pops it afterwards.  Because we use syscall6 to remap the stack, the
old contents of the stack (and the former value of ebp) are no longer
available.  Some versions of gcc make from a real local, accessed through ebp,
despite my efforts to make it obvious that references to from are really
constants.  This patch attempts to make it even more obvious by eliminating
from and using a macro to access the stub's data explicitly with constants.

My original thinking on this was to replace syscall6 with a remap_stack
interface which saved ebp someplace and restored it afterwards.  The problem
is that there are no registers to put it in, except for esp.  That could work,
since we can store a constant in esp after the mmap because we just replaced
the stack.  However, this approach seems a tad cleaner.

Signed-off-by: Jeff Dike 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] uml: fix access_ok

2005-11-14T02:14:15+00:00

The access_ok_tt() macro is bogus, in that a read access is unconditionally
considered valid.

I couldn't find in SCM logs the introduction of this check, but I went back to
2.4.20-1um and the definition was the same.

Possibly this was done to avoid problems with missing set_fs() calls, but
there can't be any I think because they would fail with SKAS mode.
TT-specific code is still to check.

Also, this patch joins common code together, and makes the "address range
wrapping" check happen for all cases, rather than for only some.

This may, possibly, be reoptimized at some time, but the current code doesn't
seem clever, just confused.

* Important: I've also had to change references to access_ok_{tt,skas} back to
  access_ok - the kernel wasn't that happy otherwise.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso 
Acked-by: Jeff Dike 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] uml: remove bogus WARN_ON, triggerable harmlessly on a page fault race

2005-11-14T02:14:14+00:00

The below warning was added in place of pte_mkyoung(); if (is_write)
pte_mkdirty();

In fact, if the PTE is not marked young/dirty, our dirty/accessed bit
emulation would cause the TLB permission not to be changed, and so we'd loop,
and given we don't support preemption yet, we'd busy-hang here.

However, I've seen this warning trigger without crashes during a loop of
concurrent kernel builds, at random times (i.e. like a race condition), and I
realized that two concurrent faults on the same page, one on read and one on
write, can trigger it. The read fault gets serviced and the PTE gets marked
writable but clean (it's possible on a shared-writable mapping), while the
generic code sees the PTE was already installed and returns without action. In
this case, we'll see another fault and service it normally.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso 
Acked-by: Jeff Dike 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] kfree cleanup: arch

2005-11-07T15:54:06+00:00

This is the arch/ part of the big kfree cleanup patch.

Remove pointless checks for NULL prior to calling kfree() in arch/.

Signed-off-by: Jesper Juhl 
Acked-by: Grant Grundler 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] consolidate sys_ptrace()

2005-11-07T15:53:42+00:00

The sys_ptrace boilerplate code (everything outside the big switch
statement for the arch-specific requests) is shared by most architectures.
This patch moves it to kernel/ptrace.c and leaves the arch-specific code as
arch_ptrace.

Some architectures have a too different ptrace so we have to exclude them.
They continue to keep their implementations.  For sh64 I had to add a
sh64_ptrace wrapper because it does some initialization on the first call.
For um I removed an ifdefed SUBARCH_PTRACE_SPECIAL block, but
SUBARCH_PTRACE_SPECIAL isn't defined anywhere in the tree.

Signed-off-by: Christoph Hellwig 
Acked-by: Paul Mackerras 
Acked-by: Ralf Baechle 
Acked-By: David Howells 
Acked-by: Russell King 
Acked-by: Paul Mundt 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] uml: fix hardcoded ZONE_* constants in zone setup

2005-11-07T15:53:32+00:00

Remove usage of hardcoded constants in paging_init().

By chance I spotted a bug in zones_setup involving a change to ZONE_*
constants, due to the ZONE_DMA32 patch from Andi Kleen (which is in -mm).
So, possibly, instead of zones_size[2] you will find zones_size[3] in the
code, but that change is wrong and this patch is still correct.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso 
Cc: Jeff Dike 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] uml: big memory fixes

2005-11-07T15:53:31+00:00

A number of fixes to improve behavior when large physical memory sizes
are specified:

- libc files need -D_FILE_OFFSET_BITS=64 because there are unavoidable uses
  of non-64 interfaces in libc

- some %d need to be %u

Signed-off-by: Jeff Dike 
Cc: Paolo Giarrusso 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds