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SubjectRe: [PATCH][retry 1] 2.6.27-rc2: invalidate caches before going into suspend

(please keep Cc:s intact)

* Mark Langsdorf <mark.langsdorf@amd.com> wrote:

> @@ -104,6 +103,7 @@ static inline void play_dead(void)
> * With physical CPU hotplug, we should halt the cpu
> */
> local_irq_disable();
> + wbinvd();
> while (1)
> halt();

hm, why not do what i suggested in my first mail:

if (cpu >= i486)
asm("cli; wbinvd; cli; 1: hlt; jmp 1b")
else
halt();

perhaps turn it into a wbivd_halt() primitive, to make it clean and even
more obvious.

This sequence does matter to reliable suspend/resume, and in theory gcc
could insert something before a halt() as well.

[ i only have a pretty far-fetched example that in all likelyhood wont
happen in practice: for example halt could be decided to be uninlined
by a braindead compiler, ftrace could hook in there, and dirty some
state. But still - the point is that we had a difficult bug in this
code for a long time and in such situations we should just over-do
robustness by default. ]

Ingo


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