Le 14/08/2023 à 19:27, Erhard Furtner a écrit :

On Mon, 14 Aug 2023 09:40:44 +0000
Christophe Leroy [off-list ref] wrote:

quoted

Interesting. That means we get stuck somewhere around  MMU_init()

We know that MMU_init_hw() is called and runs at least until:

	pr_info("Total memory = %lldMB; using %ldkB for hash table\n",
		(unsigned long long)(total_memory >> 20), Hash_size >> 10);

But we never reach the print in setup_kuap() which is itself called by
set_kup():
	pr_info("Activating Kernel Userspace Access Protection\n");


Could you try to narrow more the issue by spreading pr_info() at places
in the code below and/or the called functions ? Either we never come
back from MMU_init_hw(), or one of mapin_ram() btext_unmap()
kasan_mmu_init() fails.

So the piece of code we are interested in is located in
arch/powerpc/mm/init_32.c and is:

	/* Initialize the MMU hardware */
	if (ppc_md.progress)
		ppc_md.progress("MMU:hw init", 0x300);
==>	MMU_init_hw();

	/* Map in all of RAM starting at KERNELBASE */
	if (ppc_md.progress)
		ppc_md.progress("MMU:mapin", 0x301);
	mapin_ram();

	/* Initialize early top-down ioremap allocator */
	ioremap_bot = IOREMAP_TOP;

	if (ppc_md.progress)
		ppc_md.progress("MMU:exit", 0x211);

	/* From now on, btext is no longer BAT mapped if it was at all */
#ifdef CONFIG_BOOTX_TEXT
	btext_unmap();
#endif

	kasan_mmu_init();

==>	setup_kup();

I added a pr_info(); right after MMU_init_hw(); and another one right after setup_kup();.

Output of PPC_EARLY_DEBUG changes so that I get an additional black blank line after
[    0.000000] printk: bootconsole [udbg0] enabled
[    0.000000] Total memory = 2048MB; using 4096kB for hash table

and the freeze afterwards. So it looks like we return from MMU_init_hw() but not from setup_kup().

I just sent a patch with additional pr_info() in order to help locate 
the issue, please provide output with that patch.

Thanks
Christophe