linux/arch/ia64
Christoph Hellwig dacbe41f77 ptrace: move user_enable_single_step & co prototypes to linux/ptrace.h
While in theory user_enable_single_step/user_disable_single_step/
user_enable_blockstep could also be provided as an inline or macro there's
no good reason to do so, and having the prototype in one places keeps code
size and confusion down.

Roland said:

  The original thought there was that user_enable_single_step() et al
  might well be only an instruction or three on a sane machine (as if we
  have any of those!), and since there is only one call site inlining
  would be beneficial.  But I agree that there is no strong reason to care
  about inlining it.

  As to the arch changes, there is only one thought I'd add to the
  record.  It was always my thinking that for an arch where
  PTRACE_SINGLESTEP does text-modifying breakpoint insertion,
  user_enable_single_step() should not be provided.  That is,
  arch_has_single_step()=>true means that there is an arch facility with
  "pure" semantics that does not have any unexpected side effects.
  Inserting a breakpoint might do very unexpected strange things in
  multi-threaded situations.  Aside from that, it is a peculiar side
  effect that user_{enable,disable}_single_step() should cause COW
  de-sharing of text pages and so forth.  For PTRACE_SINGLESTEP, all these
  peculiarities are the status quo ante for that arch, so having
  arch_ptrace() itself do those is one thing.  But for building other
  things in the future, it is nicer to have a uniform "pure" semantics
  that arch-independent code can expect.

  OTOH, all such arch issues are really up to the arch maintainer.  As
  of today, there is nothing but ptrace using user_enable_single_step() et
  al so it's a distinction without a practical difference.  If/when there
  are other facilities that use user_enable_single_step() and might care,
  the affected arch's can revisit the question when someone cares about
  the quality of the arch support for said new facility.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-12 15:52:38 -08:00
..
configs [IA64] Remove COMPAT_IA32 support 2010-02-08 10:42:17 -08:00
dig x86, ia64: convert to use generic dma_map_ops struct 2009-01-06 14:06:57 +01:00
hp ACPI: replace acpi_integer by u64 2010-01-28 01:47:33 -05:00
include/asm ptrace: move user_enable_single_step & co prototypes to linux/ptrace.h 2010-03-12 15:52:38 -08:00
kernel Driver core: Constify struct sysfs_ops in struct kobj_type 2010-03-07 17:04:49 -08:00
kvm Merge branch 'kvm-updates/2.6.34' of git://git.kernel.org/pub/scm/virt/kvm/kvm 2010-03-05 13:12:34 -08:00
lib [IA64] fix csum_ipv6_magic() 2009-09-02 09:14:48 -07:00
mm mm: change anon_vma linking to fix multi-process server scalability issue 2010-03-06 11:26:26 -08:00
oprofile [IA64] implement ticket locks for Itanium 2009-09-25 08:42:16 -07:00
pci PCI: augment bus resource table with a list 2010-02-23 09:43:37 -08:00
scripts ia64/pv_ops/pvchecker: support mov = ar.itc paravirtualization 2009-03-26 10:50:09 -07:00
sn [IA64] Fix broken sn2 build 2010-02-23 16:07:25 -08:00
uv [IA64] wrong attribute of HUB chip written in uv_setup() 2010-02-26 11:20:41 -08:00
xen [IA64] Remove COMPAT_IA32 support 2010-02-08 10:42:17 -08:00
Kconfig [IA64] Remove COMPAT_IA32 support 2010-02-08 10:42:17 -08:00
Kconfig.debug
Makefile [IA64] Remove COMPAT_IA32 support 2010-02-08 10:42:17 -08:00
install.sh kbuild: use INSTALLKERNEL to select customized installkernel script 2009-09-20 12:18:14 +02:00
module.lds