RE: LuaJIT 2.0 beta 9 on PPC GCC 4.4.6 uClibc 0.9.29 mpc8248 PowerQuicc II processor

["Solinsky, Jeff - PAL" <Jeff.Solinsky@...>]

I'm replying to my last post here...

Solinsky, Jeff - Wrote:
> Tomorrow I will set the options to enable the _dl_if_debug_dprint() and
> sprinkle a bit of that to see what is going wrong.  I'm thinking more info
> is needed to make a good guess as to what is going wrong, as one of the
> addresses could have been clobbered; I wonder if the problem might still
> be related to the cache sync function in the kernel.  

The crash is occurring when unmapping linux-vdso32.so.1, which is a decent indication that maybe I did something wrong in __kernel_sync_dicache() when I added the code that also invalidates the instruction cache instead of only the data cache? Or perhaps anything that links linux-vdso32.so.1 is crashing on exit regardless of whether __kernel_sync_dicache() is executed, I'll have to check that tomorrow also.

The output now when the crash occurs when LuaJIT 2 exits:
calling FINI: /lib/libdl.so.0

do_dlclose():522: /lib/linux-vdso32.so.1: usage count: 1
do_dlclose():547: unmapping: /lib/linux-vdso32.so.1
Segmentation fault

So I expect the crash is in this code:

_dl_if_debug_print("unmapping: %s\n", tpnt->libname);
end = 0;
for (i = 0, ppnt = tpnt->ppnt;
		i < tpnt->n_phent; ppnt++, i++) {
	if (ppnt->p_type != PT_LOAD)
		continue;
	if (end < ppnt->p_vaddr + ppnt->p_memsz)
		end = ppnt->p_vaddr + ppnt->p_memsz;
}
_dl_munmap((void*)tpnt->loadaddr, end);
/* Free elements in RTLD_LOCAL scope list */ 
for (runp = tpnt->rtld_local; runp; runp = tmp) {
	tmp = runp->next;
	free(runp);
}

Tomorrow, I will see more exactly where in this code it is dying.

> Would it do any good to post the powerpc assembly code I'm using to
> implement __kernel_sync_dicache()? It's basically a merge of what linux 
> 2.6.29 was doing into the 2.6.20 kernel source we are using.

V_FUNCTION_BEGIN(__kernel_sync_dicache)
.cfi_startproc
	mr      r11,r3
  
	li   	  r7,32
	addi    r5,r7,-1
	andc	  r6,r3,r5	/* round low to line bdy */
	subf	  r8,r6,r4	/* compute length */
	add	  r8,r8,r5	/* ensure we get enough */
	srwi.	  r8,r8,5	/* compute line count */
	crclr	  cr0*4+so
	beqlr			/* nothing to do? */
	mtctr	  r8
1: 	dcbst   0,r6
	add     r6,r6,r7
	bdnz    1b
	sync

/* Now invalidate the instruction cache */
	li      r7,32
	addi    r5,r7,-1
	andc    r6,r11,r5     /* round low to line bdy */
	subf    r8,r6,r4      /* compute length */
	add     r8,r8,r5
	li      r9,5
	srw.    r8,r8,r9      /* compute line count */
	crclr   cr0*4+so
	beqlr                 /* nothing to do? */
	mtctr   r8
2:  	icbi    0,r6
	add     r6,r6,r7
	bdnz    2b
	isync
	li	  r3,0
	blr
  .cfi_endproc
V_FUNCTION_END(__kernel_sync_dicache)

Any help is much appreciated.  I'm so close to working LuaJIT 2 on MPC8248.

~ Jeff