On Wed, 2006-09-13 at 17:54, Keith Owens wrote: > Zou Nan hai (on 13 Sep 2006 12:55:25 +0800) wrote: > >MCA dispatch code take physical address of GP passed from SAL, > >then call DATA_PA_TO_VA twice on GP before call into C code. > >The first time is in ia64_set_kernel_register, the second time is in > >VIRTUAL_MODE_ENTER. > >The gp is changed to a virtual address in region 7 because DATA_PA_TO_VA > >is implemented > >by dep instruction. > > > >However when notify blocks were called from MCA handler code, > >because notify blocks are supported by callback function pointers, > >gp value value was switched to region 5 again. > > > > > >The patch set gp register to kernel gp of region 5 at entry of MCA > >dispatch. > > > >Signed-off-by: Zou Nan hai <nanhai.zou@xxxxxxxxx> > > The idea is right, but there is no need to pass __gp to > VIRTUAL_MODE_ENTER. There will never be a case of VIRTUAL_MODE_ENTER > followed by entry to a module, so just hard code 'movl r1 = __gp' into > VIRTUAL_MODE_ENTER and drop it from the parameter list. OK, I felt a little weird to put hard code in a macro.., but I think it does not matter much since the macro is only used 2 times. the updated patch Signed-off-by: Zou Nan hai <nanhai.zou@xxxxxxxxx> diff -Nraup linux-2.6.18-rc6/arch/ia64/kernel/mca_asm.S linux-2.6.18-rc6-fix/arch/ia64/kernel/mca_asm.S --- linux-2.6.18-rc6/arch/ia64/kernel/mca_asm.S 2006-09-14 10:33:08.000000000 +0800 +++ linux-2.6.18-rc6-fix/arch/ia64/kernel/mca_asm.S 2006-09-14 10:35:49.000000000 +0800 @@ -1025,18 +1025,13 @@ ia64_old_stack: ia64_set_kernel_registers: add temp3=MCA_SP_OFFSET, r3 - add temp4=MCA_SOS_OFFSET+SOS(OS_GP), r3 mov b0=r2 // save return address GET_IA64_MCA_DATA(temp1) ;; - add temp4=temp4, temp1 // &struct ia64_sal_os_state.os_gp add r12=temp1, temp3 // kernel stack pointer on MCA/INIT stack add r13=temp1, r3 // set current to start of MCA/INIT stack add r20=temp1, r3 // physical start of MCA/INIT stack ;; - ld8 r1=[temp4] // OS GP from SAL OS state - ;; - DATA_PA_TO_VA(r1,temp1) DATA_PA_TO_VA(r12,temp2) DATA_PA_TO_VA(r13,temp3) ;; diff -Nraup linux-2.6.18-rc6/include/asm-ia64/mca_asm.h linux-2.6.18-rc6-fix/include/asm-ia64/mca_asm.h --- linux-2.6.18-rc6/include/asm-ia64/mca_asm.h 2006-06-18 09:49:35.000000000 +0800 +++ linux-2.6.18-rc6-fix/include/asm-ia64/mca_asm.h 2006-09-14 10:36:33.000000000 +0800 @@ -197,9 +197,9 @@ movl temp2 = start_addr; \ ;; \ mov cr.iip = temp2; \ + movl gp = __gp \ ;; \ DATA_PA_TO_VA(sp, temp1); \ - DATA_PA_TO_VA(gp, temp2); \ srlz.i; \ ;; \ nop 1; \ - 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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