Messages in this thread | ![/](/images/icornerl.gif) | | Date | Wed, 30 Apr 2003 18:21:52 -0700 (PDT) | From | Linus Torvalds <> | Subject | Re: [PATCH] Fix prefetch patching in 2.5-bk |
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On Thu, 1 May 2003, Andi Kleen wrote: > > If your machine BUG()s in apply_alternatives at booting > or module loading you need this patch.
I applied it, but I don't have to like it..
How about doing this differently, and having something like this:
#define nop_alternative(newinstr, feature) \ ".section .altinstructions,\"a\"\n" \ " .align 4\n" " .long 660f\n" " .long 663f\n" " .byte %c0\n" " .byte 0\n" " .byte 664f-663f\n" ".previous\n" ".section .altinstr_replacement",\"ax\"\n" "663:\n\t" newinstr "\n664:\n" ".previous" "660:\n\t" ".rept 664b-663b, 0x90\n\t"
and making "sourcelen==0" a special case for replacement (replace with the proper destination length nop, instead of having that "0x90 0x90 0x90" sequence).
This allows you to use arbitrary-sized things without having to worry about having to have the size right, or without having to use unnecessarily long nop-sequences. You'll always get the right-size nop.
Linus
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