SMP DevHlps supported on all kernels (of newer date) ?

[Lars Erdmann]

Hallo,

does anyone know if the DevHelps that were introduced with SMP:
DevHlp_CreateSpinLock 79h
DevHlp_FreeSpinLock 7Ah
DevHlp_AcquireSpinLock 71h
DevHlp_ReleaseSpinLock 72h
DevHlp_Port_IO
DevHlp_GetIRQMask
DevHlp_SetIRQMask

are available in all (later) kernels: Warp4, UNI, SMP ?
With "later" I mean kernels with High memory support, for Warp 4 kernel for
example, kernels >= fixpak13.

Lars

[scott g]

Yes, I know.

regards, Scott

p.s. the answer is yes, though I can't imagine why anyone would need to use
these functions for 95% of device drivers

[Ruediger Ihle]

On Tue, 3 Jun 2008 16:18:25 UTC, scott g
<scottego...@sbcglobal.boguspart.net> wrote:

Hi Scott,

> p.s. the answer is yes, though I can't imagine why anyone
> would need to use these functions for 95% of device drivers

It's probably more a question of compatibility between drivers
written for 2.11 SMP and current kernels...

BTW, how are the spinlocks introduced in KEE related to those
managed by DevHlp_xxxxSpinLock ? Does KEE just provide a thunking
layer for those or does it have it's own spinlock implementation ?

--
Ruediger "Rudi" Ihle [S&T Systemtechnik GmbH, Germany]
http://www.s-t.de
Please remove all characters left of the "R" in my email address

[Lars Erdmann]

Hallo,

thanks for your answer:

1.) I know that you know about the different kernels but maybe it was
not clear for others ...
2.) For the spinlock devhelps I thought it would still be necessary to
use them to serialize access to a resource instead of using cli/sti. Or
has the newer SMP kernel made this superfluous compared to the old OS/2
2.11 SMP kernel and cli/sti will do the job just as it did for single
processor systems ?
3.) for Port_IO, GetIRQMask, SetIRQMask question was just out of curiousity.

Lars

scott g schrieb:

[scott g]

> It's probably more a question of compatibility between drivers
> written for 2.11 SMP and current kernels...

Yes, that's what Lars intimates

> BTW, how are the spinlocks introduced in KEE related to those
> managed by DevHlp_xxxxSpinLock ? Does KEE just provide a thunking

> layer for those ...

Yes, exactly. It's just thunking.

Basically, CLI and STI will work fine exactly for the reason someone or other
mentioned in some other post -- at the time there was a lot of concern about
breaking existing drivers that used that mechanism. Basically, there are a
couple of spinlocks (the R0spinlock and one other, whose name I forget) that get
grabbed on behalf of drivers and kernel code. You really only need to mess with
spinlocks, etc. on rare occasions -- mainly having to do with the 32 bit filesys
code, if I recall correctly.

The same comment is NOT true, though for doing EOI -- you really do want to use
DH_EOI rather than just writing to whatever port that was (I forget). Also the
Port_IO call is worth using. The rest of them are pretty irrelevant unless
you're doing kbd/mouse (maybe), DASD drivers (at least ones that support
StratIII interface) and 32 bit FSDs.

Of course, after several years, I might be forgetting something. :-)

-Scott