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SubjectRe: [patch 04/15] Generic Mutex Subsystem, add-atomic-call-func-x86_64.patch

* Zwane Mwaikambo <zwane@arm.linux.org.uk> wrote:

> On Mon, 19 Dec 2005, Ingo Molnar wrote:
>
> > +#define atomic_dec_call_if_negative(v, fn_name) \
> > +do { \
> > + fastcall void (*__tmp)(atomic_t *) = fn_name; \
> > + \
> > + (void)__tmp; \
> > + typecheck(atomic_t *, v); \
> > + \
> > + __asm__ __volatile__( \
> > + LOCK "decl (%%rdi)\n" \
> > + "js 2f\n" \
> > + "1:\n" \
> > + LOCK_SECTION_START("") \
> > + "2: call "#fn_name"\n\t" \
> > + "jmp 1b\n" \
> > + LOCK_SECTION_END \
> > + : \
> > + :"D" (v) \
> > + :"memory"); \
> > +} while (0)
>
> Hi Ingo,
> Doesn't this corrupt caller saved registers?

good catch - i correctly marked them clobbered on i386, but not on
x86_64. The function using this code uses nothing else, so this bug
caused no real corruption - but that was just pure luck.

Ingo
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