id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	field_blocks	field_dependson	field_seealso
148	__hypercall_fast_ret1 trusts the contents of %o1 (too much)	Jakub Jermář	Pavel Rimsky	"In the sun4v branch, there is:

{{{
  static inline uint64_t
__hypercall_fast_ret1(const uint64_t p1, const uint64_t p2, const uint64_t p3,
    const uint64_t p4, const uint64_t p5, const uint64_t function_number,
    uint64_t * const ret1)
{
	uint64_t errno = __hypercall_fast(p1, p2, p3, p4, p5, function_number);
	if (ret1 != NULL) {
		asm volatile (""mov %%o1, %0\n"" : ""=r"" (*ret1));
	}
	return errno;
}
}}}

It seems like the asm statement is making unjustified assumptions about the register %o1. %o1 is a scratch register and the function can do pretty much anything with it between the call to !__hypercall_fast() and the asm statement.

Noticed by Petr Tuma."	defect	closed	major	0.4.2	helenos/kernel/sparc64	mainline	fixed