linux-toradex.git/include/asm-um, branch v2.6.22.6

uml: add asm/paravirt.h

2007-06-24T15:59:11+00:00

Add asm-um/paravirt.h so that i386 headers that get pulled into UML
don't cause build failures when they want asm/paravirt.h.

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

uml: use generic BUG

2007-06-24T15:59:11+00:00

Get UML to use the generic bug support rather than arch specific one.

If I insert an artificial bug right before loading init, I get this:

 Kernel panic - not syncing: Kernel mode signal 4

 EIP: 0023:[<0819d501>] CPU: 0 Not tainted ESP: 002b:f7fd4fbc EFLAGS: 00000246
    Not tainted
    EAX: 00000000 EBX: 00007870 ECX: 00000013 EDX: 00007870
    ESI: 0000786d EDI: 00000011 EBP: f7fd4fd8 DS: 002b ES: 002b
    08273bec:  [<0806e814>] show_regs+0x104/0x106
    08273c08:  [<08058927>] panic_exit+0x2c/0x4b
    08273c18:  [<08080ee7>] notifier_call_chain+0x32/0x5b
    08273c38:  [<08080fbd>] __atomic_notifier_call_chain+0x30/0x32
    08273c54:  [<08080fee>] atomic_notifier_call_chain+0x2f/0x31
    08273c70:  [<08073b88>] panic+0x75/0x131
    08273c94:  [<080586c7>] relay_signal+0x87/0x95
    08273cb0:  [<0806b9ee>] sig_handler_common_skas+0x9e/0x120
    08273cd8:  [<08067738>] sig_handler+0x28/0x4f
    08273cec:  [<0806792e>] handle_signal+0x53/0x89
    08273d0c:  [<08069f60>] hard_handler+0x18/0x28
    08273d1c:  [] transitions+0xf7d598b8/0xfffffff0

With this patch in place, this is how it looks:

 BUG: failure at init/main.c:779/init_post()!
 Kernel panic - not syncing: BUG!

 EIP: 0023:[<081a65d1>] CPU: 0 Not tainted ESP: 002b:f7f0dfbc EFLAGS: 00000246
    Not tainted
    EAX: 00000000 EBX: 000069db ECX: 00000013 EDX: 000069db
    ESI: 000069d8 EDI: 00000011 EBP: f7f0dfd8 DS: 002b ES: 002b
    098efedc:  [<0806e9a4>] show_regs+0x104/0x106
    098efef8:  [<080589c7>] panic_exit+0x2c/0x4b
    098eff08:  [<080818d7>] notifier_call_chain+0x32/0x5b
    098eff28:  [<080819ad>] __atomic_notifier_call_chain+0x30/0x32
    098eff44:  [<080819de>] atomic_notifier_call_chain+0x2f/0x31
    098eff60:  [<08073f28>] panic+0x75/0x131
    098eff84:  [<080541d5>] init_post+0xcd/0xe8
    098eff9c:  [<08048ad4>] kernel_init+0x8e/0x9a
    098effb4:  [<08066dee>] run_kernel_thread+0x41/0x53
    098effe0:  [<08058e75>] new_thread_handler+0x62/0x8b
    098efffc:  [] 0xa55a5a5a

[ jdike - added BUG_TABLE to linker script ]

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

uml: kill x86_64 STACK_TOP_MAX

2007-06-16T20:16:16+00:00

The x86_64 a.out.h got a definition of STACK_TOP_MAX, which interferes with
the UML version.  So, just undef it like STACK_TOP.

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

uml: iRQ stacks

2007-05-11T15:29:34+00:00

Add a separate IRQ stack.  This differs from i386 in having the entire
interrupt run on a separate stack rather than starting on the normal kernel
stack and switching over once some preparation has been done.  The underlying
mechanism, is of course, sigaltstack.

Another difference is that interrupts that happen in userspace are handled on
the normal kernel stack.  These cause a wait wakeup instead of a signal
delivery so there is no point in trying to switch stacks for these.  There's
no other stuff on the stack, so there is no extra stack consumption.

This quirk makes it possible to have the entire interrupt run on a separate
stack - process preemption (and calls to schedule()) happens on a normal
kernel stack.  If we enable CONFIG_PREEMPT, this will need to be rethought.

The IRQ stack for CPU 0 is declared in the same way as the initial kernel
stack.  IRQ stacks for other CPUs will be allocated dynamically.

An extra field was added to the thread_info structure.  When the active
thread_info is copied to the IRQ stack, the real_thread field points back to
the original stack.  This makes it easy to tell where to copy the thread_info
struct back to when the interrupt is finished.  It also serves as a marker of
a nested interrupt.  It is NULL for the first interrupt on the stack, and
non-NULL for any nested interrupts.

Care is taken to behave correctly if a second interrupt comes in when the
thread_info structure is being set up or taken down.  I could just disable
interrupts here, but I don't feel like giving up any of the performance gained
by not flipping signals on and off.

If an interrupt comes in during these critical periods, the handler can't run
because it has no idea what shape the stack is in.  So, it sets a bit for its
signal in a global mask and returns.  The outer handler will deal with this
signal itself.

Atomicity is had with xchg.  A nested interrupt that needs to bail out will
xchg its signal mask into pending_mask and repeat in case yet another
interrupt hit at the same time, until the mask stabilizes.

The outermost interrupt will set up the thread_info and xchg a zero into
pending_mask when it is done.  At this point, nested interrupts will look at
->real_thread and see that no setup needs to be done.  They can just continue
normally.

Similar care needs to be taken when exiting the outer handler.  If another
interrupt comes in while it is copying the thread_info, it will drop a bit
into pending_mask.  The outer handler will check this and if it is non-zero,
will loop, set up the stack again, and handle the interrupt.

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

Remove hardcoding of hard_smp_processor_id on UP systems

2007-05-09T19:30:48+00:00

With the advent of kdump, the assumption that the boot CPU when booting an UP
kernel is always the CPU with a particular hardware ID (often 0) (usually
referred to as BSP on some architectures) is not valid anymore.  The reason
being that the dump capture kernel boots on the crashed CPU (the CPU that
invoked crash_kexec), which may be or may not be that particular CPU.

Move definition of hard_smp_processor_id for the UP case to
architecture-specific code ("asm/smp.h") where it belongs, so that each
architecture can provide its own implementation.

Signed-off-by: Fernando Luis Vazquez Cao 
Cc: "Luck, Tony" 
Acked-by: Andi Kleen 
Cc: "Eric W. Biederman" 
Cc: Vivek Goyal 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

uml: fix build breakage

2007-05-09T19:30:48+00:00

UML now needs required-features.h to build - an empty one suffices.

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

x86: create asm/cmpxchg.h

2007-05-08T18:15:20+00:00

i386:

  Rearrange the cmpxchg code to allow atomic.h to get it without needing to
  include system.h.  This kills warnings in the UML build from atomic.h about
  implicit declarations of cmpxchg symbols.  The i386 build presumably isn't
  seeing this because a separate inclusion of system.h is covering it over.

  The cmpxchg stuff is moved to asm-i386/cmpxchg.h, with an include left in
  system.h for the benefit of generic code which expects cmpxchg there.

  Meanwhile, atomic.h includes cmpxchg.h.

  This causes no noticable damage to the i386 build.

x86_64:

  Move cmpxchg into its own header.  atomic.h already included system.h, so
  this is changed to include cmpxchg.h.

  This is purely cleanup - it's not fixing any warnings - so if the x86_64
  system.h isn't considered as cleanup-worthy as i386, then this can be
  dropped.

  It causes no noticable damage to the x86_64 build.

uml:

  The i386 and x86_64 cmpxchg patches require an asm-um/cmpxchg.h for the
  UML build.

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

move die notifier handling to common code

2007-05-08T18:15:04+00:00

This patch moves the die notifier handling to common code.  Previous
various architectures had exactly the same code for it.  Note that the new
code is compiled unconditionally, this should be understood as an appel to
the other architecture maintainer to implement support for it aswell (aka
sprinkling a notify_die or two in the proper place)

arm had a notifiy_die that did something totally different, I renamed it to
arm_notify_die as part of the patch and made it static to the file it's
declared and used at.  avr32 used to pass slightly less information through
this interface and I brought it into line with the other architectures.

[akpm@linux-foundation.org: build fix]
[akpm@linux-foundation.org: fix vmalloc_sync_all bustage]
[bryan.wu@analog.com: fix vmalloc_sync_all in nommu]
Signed-off-by: Christoph Hellwig 
Cc: 
Cc: Russell King 
Signed-off-by: Bryan Wu 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

uml: more page fault path trimming

2007-05-07T19:13:04+00:00

More trimming of the page fault path.

Permissions are passed around in a single int rather than one bit per
int.  The permission values are copied from libc so that they can be
passed to mmap and mprotect without any further conversion.

The register sets used by do_syscall_stub and copy_context_skas0 are
initialized once, at boot time, rather than once per call.

wait_stub_done checks whether it is getting the signals it expects by
comparing the wait status to a mask containing bits for the signals of
interest rather than comparing individually to the signal numbers.  It
also has one check for a wait failure instead of two.  The caller is
expected to do the initial continue of the stub.  This gets rid of an
argument and some logic.  The fname argument is gone, as that can be
had from a stack trace.

user_signal() is collapsed into userspace() as it is basically one or
two lines of code afterwards.

The physical memory remapping stuff is gone, as it is unused.

flush_tlb_page is inlined.

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

[PATCH] x86: PARAVIRT: add hooks to intercept mm creation and destruction

2007-05-02T17:27:14+00:00

Add hooks to allow a paravirt implementation to track the lifetime of
an mm.  Paravirtualization requires three hooks, but only two are
needed in common code.  They are:

arch_dup_mmap, which is called when a new mmap is created at fork

arch_exit_mmap, which is called when the last process reference to an
  mm is dropped, which typically happens on exit and exec.

The third hook is activate_mm, which is called from the arch-specific
activate_mm() macro/function, and so doesn't need stub versions for
other architectures.  It's called when an mm is first used.

Signed-off-by: Jeremy Fitzhardinge 
Signed-off-by: Andi Kleen 
Cc: linux-arch@vger.kernel.org
Cc: James Bottomley 
Acked-by: Ingo Molnar