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Commit 640aa46e authored by Paolo 'Blaisorblade' Giarrusso's avatar Paolo 'Blaisorblade' Giarrusso Committed by Linus Torvalds
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[PATCH] uml: SYSEMU: slight cleanup and speedup 



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: default avatarPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
CC: Charles P. Wright <cwright@cs.sunysb.edu>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent ab1c23c2

arch/i386/kernel/entry.S

+1 −7
Original line number Diff line number Diff line
@@ -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