Messages in this thread | | | Date | Thu, 27 Mar 2008 13:31:43 -0700 (PDT) | From | Linus Torvalds <> | Subject | Re: [git pull] x86 fixes |
| |
On Thu, 27 Mar 2008, Ingo Molnar wrote: > > Ingo Molnar (1): > x86: fix prefetch workaround ... > diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c > index fdc6674..c0c82bc 100644 > --- a/arch/x86/mm/fault.c > +++ b/arch/x86/mm/fault.c > @@ -92,7 +92,8 @@ static int is_prefetch(struct pt_regs *regs, unsigned long addr, > unsigned char *max_instr; > > #ifdef CONFIG_X86_32 > - if (!(__supported_pte_mask & _PAGE_NX)) > + /* Catch an obscure case of prefetch inside an NX page: */ > + if ((__supported_pte_mask & _PAGE_NX) && (error_code & 16)) > return 0; > #endif
Ingo, this patch makes no sense.
Two reasons:
- "error_code & 16" is senseless. Use PF_INSTR instead, which actually tells the reader something.
- this piece of crap code is immediately followed by
/* If it was a exec fault on NX page, ignore */ if (error_code & PF_INSTR) return 0;
which uses that *right* and readable PF_INSTR #define, and also shows that the newly modified code is totally insane (ie: if the new code triggers, then it would have returned 0 later _anyway_)
So I think it's just crap. I think it's duplication from the merging of the x86 code, and I think that the fact that the new code didn't use the right #define helper means that people didn't see that it was crap.
I pulled it, but this needs some resolution. The code makes no sense. Should that #ifdef and the code inside of it just be removed entirely?
Linus
| |