v3.11-rc4: OMAP1/Amstrad Delta (E3) crash

[Aaro Koskinen]

Hi,

On Thu, Aug 08, 2013 at 12:01:08PM +0100, Russell King - ARM Linux wrote:
> On Wed, Aug 07, 2013 at 02:26:09AM +0300, Aaro Koskinen wrote:
> > [    0.258589] [ffff1224] *pgd=00000000, *pte=11fff0cb000001f1, *ppte=11fff00a00000000
> 
> BTW, your oops dump is interesting for another reason - the above.
> You seem to have 64-bit page table entries above.

Yes, this is worrying...

> Now, this is totally legal C:
> 
> 	unsigned int val = 0x12345678;
> 
> 	printk("%08llx\n", (long long)val);
> 
> and it should produce "12345678" but I'm willing to bet with your compiler
> it produces "12345678xxxxxxxx" where xxxxxxxx is just what happens to be
> sitting in some register.  IOW, I think you have a compiler bug here.  Can
> you investigate what's going on with this yourself please?

I made a quick check and added that to the fault handler, and yes,
the result is crap:

+unsigned int test_bar = 0x12345678;
 void show_pte(struct mm_struct *mm, unsigned long addr)
 {
        pgd_t *pgd;
 
+       printk(KERN_INFO "%d\n", 0);
+       printk(KERN_INFO "%llx\n", (long long)test_bar);
+       printk(KERN_INFO "%d %llx\n", 1, (long long)test_bar);
[...]
[    0.261788] 0
[    0.263849] 1234567800000000
[    0.267201] 1 0

However, addings similar prints to early boot produces correct results:

+unsigned int test_foo = 0x12345678;
 void __init smp_setup_processor_id(void)
[...]
        printk(KERN_INFO "Booting Linux on physical CPU 0x%x\n", mpidr);
+       printk(KERN_INFO "%llx\n", (long long)test_foo);
+       printk(KERN_INFO "%d %llx\n", 1, (long long)test_foo);
[...]
[    0.000000] Booting Linux on physical CPU 0x0
[    0.000000] 12345678
[    0.000000] 1 12345678

So I'm pretty confused. Anyway, I'll continue investigating this next week...

A.