Commit 640aa46e authored Sep 03, 2005 by Paolo 'Blaisorblade' Giarrusso Committed by Linus Torvalds Sep 05, 2005

[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: 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>

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

Admin message