> -----Original Message----- > From: linux-ia64-owner@xxxxxxxxxxxxxxx > [mailto:linux-ia64-owner@xxxxxxxxxxxxxxx] On Behalf Of Takao Indoh > Sent: 2006年9月7日 22:49 > To: Yu, Luming > Cc: fastboot@xxxxxxxxxxxxxx; Keith Owens; linux-ia64@xxxxxxxxxxxxxxx > Subject: RE: [Fastboot] [PATCH]IA64 kexec/kdump patch for INIT > > On Thu, 7 Sep 2006 21:01:17 +0800, "Yu, Luming" wrote: > > >>>Did saved Os gp in SAL OS state somehow get overridden before > >>>ia64_set_kernel_registers prior to invocation of ia64_init_handler? > >>> > >>>I assume the following code (in ia64_set_kernel_registers ) > >>should restore > >>>correct GP value. > >>> > >>>ia64_set_kernel_registers: > >>> ... > >>> ;; > >>> ld8 r1=[temp4] // OS GP from SAL OS state > >> > >>Yes, but this gp value is physical address. > >>In the next line, gp is changed to virtual address. > >> > >>DATA_PA_TO_VA(r1,temp1) > >> > >>This macro just sets region7 bit, so gp value becomes region7 address. > > > >Ok, could you please confirm what is the value of r1 before > >DATA_PA_TO_VA(r1, temp1)? > >I guess we need to set r1 = __gp in ia64_set_kernel_registers. > >If not, this is a bug. Am I right? > > In the ia64_mca_init, the value of ia64_tpa(ia64_getreg(_IA64_REG_GP) > is registered as gp value. When cpu comes into the above code, r1 is set > to this value, I think. Therefore, r1 has physical address of __gp > before DATA_PA_TO_VA(r1, temp1). How do you think? > > I think you are right, I also think r1 has to be set to __gp before > calling ia64_init_handler. > Yes, I agree GP should be set to __gp before calling into ia64_init_handler, not only the region issue. E.g. If an OS_INIT happen in the context of a module, the GP value could be point to the modules GP. Thanks Zou Nan hai > Regards, > Takao Indoh > > - > To unsubscribe from this list: 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 - To unsubscribe from this list: 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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