Re: ide_delay_50ms() freezing on PPC?

[Michel Lanners <mlan@cpu.lu>]

Hi all,

On  27 Jun, this message from Benjamin Herrenschmidt echoed through cyberspace:
> Can you check the generated code for the loop ? Does it actually re-dead
> jiffies from memory or not ? (Did the compiler wrongly tried to optimise
> it ?).

Here is the code as it appears in vmlinux:

c00ba91c <ide_delay_50ms>:
c00ba91c:       3d 20 c0 21     lis     r9,-16351
c00ba920:       81 69 c1 ec     lwz     r11,-15892(r9)
c00ba924:       39 6b 00 06     addi    r11,r11,6
c00ba928:       80 09 c1 ec     lwz     r0,-15892(r9)
c00ba92c:       7d 40 58 51     subf.   r10,r0,r11
c00ba930:       41 81 ff f8     bgt     c00ba928 <ide_delay_50ms+0xc>
c00ba934:       4e 80 00 20     blr

I suppose r9 points to a symbol table somewhere, and the lwz loads a
specific symbol in there, which in this case should be the value of
jiffies. AFAICS, the jiffies value is thus correctly reloaded at
c00ba928. Looks OK to me, no?

Michel

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