David Mosberger-Tang wrote:
On 4/3/06, Zoltan Menyhart <Zoltan.Menyhart@xxxxxxxx> wrote:The problem is that the most frequently used trap handler contains the unsafe walk of the rx = IA64_KR_PT_BASE -> pgd[i] -> pud[j] -> pmd[k] -> pte[l] chain...Please, everybody step back a minute. Hint: consider that x86 does the page-table walk in hardware...
Telling the truth: I'm not an x86 expert :-) What I could dig up in 5 minutes is:
IA-32 Intel® Architecture Software Developer’s Manual Volume 3A: 7.1.2.1 Automatic Locking "When updating page-directory and page-table entries: When updating page-directory and page-table entries, the processor uses locked cycles to set the accessed and dirty flag in the page-directory and page-table entries." I guess the TLB load is auto-locked, too. Anyway, what can we conclude from this for the ia64 architecture? Can you _prove_ that walking that chain of pointers is safe? Thanks, Zoltan - : send the line "unsubscribe linux-ia64" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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