Cleanup of the dispatch mechanism. Now syscall returns and the final
request to shutdown valgrind are done with the client request
mechanism too. This is much better than having to check all
call/return addresses.
git-svn-id: svn://svn.valgrind.org/valgrind/trunk@57 a5019735-40e9-0310-863c-91ae7b9d1cf9
diff --git a/coregrind/vg_startup.S b/coregrind/vg_startup.S
index 3fa965c..2ac2e6d 100644
--- a/coregrind/vg_startup.S
+++ b/coregrind/vg_startup.S
@@ -112,14 +112,29 @@
# Note that we will enter here on the synthetic CPU, not
# the real one! So the interpreter must notice when this
# procedure is called, and use that as its cue to switch
- # back to the real CPU. That means the code placed here is
- # utterly irrelevant, since it will never get run, but I
- # place a RET here anyway, since it is the traditional way
- # to return from a subroutine :-)
+ # back to the real CPU. As usual we have a client request
+ # to do this. To make sense of this you need to read the
+ # definition of VALGRIND_MAGIC_SEQUENCE in valgrind.h.
+ pushl %eax
+ pushl %edx
+ subl $20, %esp # allocate arg block
+ movl %esp, %eax # %eax == &_zzq_args[0]
+ movl $VG_USERREQ__SHUTDOWN_VALGRIND, 0(%eax) # request
+ # dont bother to fill in arg1 .. 4, not important
+ # and now the magic sequence itself:
+ roll $29, %eax
+ roll $3, %eax
+ rorl $27, %eax
+ rorl $5, %eax
+ roll $13, %eax
+ roll $19, %eax
+ # valgrind now exits. the following insns are
+ # executed on the real CPU.
+ addl $20, %esp
+ popl %edx
+ popl %eax
ret
-
-
-
+
.global VG_(switch_to_real_CPU)
VG_(switch_to_real_CPU):
# Once Valgrind has decided it needs to exit, either
@@ -216,6 +231,7 @@
.Lend_of_swizzle:
.size VG_(swizzle_esp_then_start_GDB), .Lend_of_swizzle-VG_(swizzle_esp_then_start_GDB)
+
##--------------------------------------------------------------------##
##--- end vg_startup.S ---##
##--------------------------------------------------------------------##