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[PATCH] uml: SYSEMU: slight cleanup and speedup

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As a follow-up to "UML Support - Ptrace: adds the host SYSEMU support, for
UML and general usage" (i.e.  uml-support-* in current mm).

Avoid unconditionally jumping to work_pending and code copying, just reuse
the already existing resume_userspace path.

One interesting note, from Charles P.  Wright, suggested that the API is
improvable with no downsides for UML (except that it will have to support
yet another host API, since dropping support for the current API, for UML,
is not reasonable from users' point of view).

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
CC: Charles P. Wright <cwright@cs.sunysb.edu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Paolo 'Blaisorblade' Giarrusso 2005-09-03 15:57:22 -07:00 committed by Linus Torvalds
parent ab1c23c244
commit 640aa46e25
1 changed files with 1 additions and 7 deletions
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8
arch/i386/kernel/entry.S
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@ -339,18 +339,12 @@ syscall_trace_entry:
xorl %edx,%edx
call do_syscall_trace
cmpl $0, %eax
jne syscall_skip # ret != 0 -> running under PTRACE_SYSEMU,
jne resume_userspace # ret != 0 -> running under PTRACE_SYSEMU,
# so must skip actual syscall
movl ORIG_EAX(%esp), %eax
cmpl $(nr_syscalls), %eax
jnae syscall_call
jmp syscall_exit
syscall_skip:
cli # make sure we don't miss an interrupt
# setting need_resched or sigpending
# between sampling and the iret
movl TI_flags(%ebp), %ecx
jmp work_pending
# perform syscall exit tracing
ALIGN