Messages in this thread | | | Date | Fri, 18 Jun 2010 21:56:56 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH] x86: OLPC: add support for calling into OpenFirmware (v5) |
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* H. Peter Anvin <hpa@zytor.com> wrote:
> On 06/18/2010 12:42 PM, Andres Salomon wrote: > > + > > + /* install OFW's PDE permanently into the kernel's pgtable */ > > + set_pgd(&swapper_pg_dir[OLPC_OFW_PDE_NR], *ofw_pde); > > + flush_tlb(); > > + early_iounmap(base, sizeof(olpc_ofw_pgd) * PTRS_PER_PGD); > > I just realized... this flush_tlb() is actually not necessary since on x86 > it is always legal to go from a less permissive configuration to a more > permissive, and the initial configuration is "not present" which is > maximally nonpermissive. > > Could you take it out and make sure it still works?
small nit: an optimization barrier would still be needed if the result is being relied on by the kernel.
Thanks,
Ingo
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