I'm building QEMU mipsel-linux-user with Ubuntu's GCC 4.4 on an x86
host. Whenever I try to run a trivial MIPS executable, QEMU segfaults
in cpu_loop() shortly after the call to cpu_mips_exec().
The problem seems to be that cpu_exec() doesn't preserve ebp. It tries to:
saved_env_reg = (host_reg_t) env;
where env is a global variable decorated with asm("ebp"). This saves
ebp to the stack, but later on, in some function inlined into
cpu_exec(), the value on the stack gets overwritten with something
else.
Has anyone else seen this?
The full GCC version string is:
gcc (Ubuntu 4.4.1-4ubuntu9) 4.4.1
The following versions of GCC don't seem to suffer from the same problem:
gcc-4.1 (GCC) 4.1.3 20080704 (prerelease) (Ubuntu 4.1.2-27ubuntu1)
gcc-4.2 (GCC) 4.2.4 (Ubuntu 4.2.4-5ubuntu1)
gcc-4.3 (Ubuntu 4.3.4-5ubuntu1) 4.3.4
Thanks,
Jay.
