Re: ERLITE frozen in rc script after switching to GCC 5.4

On 10/23/16 01:06, Rin Okuyama wrote:
> On 2016/10/22 6:56, Rin Okuyama wrote:
>> These results indicate that the problem does not simply come from the
>> optimization errors nor mips/syscall.c. Now I'm worried if there are
>> much more serious regressions in GCC5 than I imagined.
>
> In order to examine whether this is a problem with GCC5, I tested
> kernels compiled by GCC 4.8.5 from netbsd-7 branch.
>
> (1) Kernel compiled with -O2 seems to work well.
>
> (2) Kernel compiled with -O1 fails into random freezes.
>
> (3) Kernel compiled with -O0 panics due to assertion failure in
> mips/syscall.c:
>
>     init: copying out path `/sbin/init' 11
>     pid 1(init): ABI set to N32 (e_flags=0x20000027)
>     panic: kernel diagnostic assertion "l->l_blcnt == 0" failed: file 
> "../../../../arch/mips/mips/syscall.c", line 364
>     kernel: breakpoint trap
>     Stopped in pid 4.1 (sh) at netbsd:cpu_Debugger+0x10:       or      
> sp,s8,zero
>
> (4) Kernel compiled with "-O0 -DMIPS_SYSCALL_DEBUG" panics due
> to address error in kernel mode:
>
>     pid 1(init): ABI set to N32 (e_flags=0x20000027)
>     syscall 197: [0]=0 [1]=0x8000 [2]=0x3 [3]=0x1002 
> [4]=0xffffffffffffffff [5]=0 [6]=0
>     ...(snip)...
>     syscall 197: return v0=0x78770000 v1=0xffffffffffffffff
>     pid 0(system): trap: cpu0, address error (load or I-fetch) in 
> kernel mode
>     status=0xffa3, cause=0x10, epc=0xffffffff804504b0, 
> vaddr=0x3002c000feaee68
>     tf=0x980000041093bca0 ksp=0x980000041093bde0 ra=0xffffffff804504b0 
> ppl=0x3002c00
>     kernel: address error (load or I-fetch) trap
>     Stopped in pid 0.28 (system) at netbsd:sleepq_block+0x154:      
> lw      v0,48(s8)
>
> May this mean kernel compiled by GCC 4.8.5 with -O2 flag works
> just accidentally?

I wonder if the stuff in

     sys/arch/mips/mips/mips_fixup.c

is doing the wrong thing here.... try disabling it.

Also, it might be best to start with a 5.4 compiled kernel and 
copy/compile in certain
files with 4.8.5 -O2 until it starts working to help narrow down where 
the problem
is.

Nick