On Wed, Feb 17, 2016 at 01:33:32PM +0530, Anshuman Khandual wrote: > On 02/17/2016 12:46 PM, Balbir Singh wrote: > >> > It might be a little better to do this: > >> > > >> > bugaddr = regs->nip; > >> > if (REGION_ID(bugaddr) == 0 && !(regs->msr & MSR_IR)) > >> > bugaddr += PAGE_OFFSET; > >> > > >> > It is possible to execute from addresses with the 0xc000... on top in > >> > real mode, because the CPU ignores the top 4 address bits in real > >> > mode. > > Good catch! Thank you > > > > Changelog: > > Don't add PAGE_OFFSET blindly, check if REGION_ID is 0 > > Cant we use USER_REGION_ID directly ?
If we use USER_REGION_ID then the reader needs to know that the user region is region 0 to understand the code. Thus I think it is clearer to use REGION_ID(bugaddr) == 0. Whether or not the address is a user region address is not really relevant to the question of whether it's a physical address being accessed directly in real mode vs. a kernel virtual address, which is what we're trying to determine. Paul. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
