Hi Greg !
On 06/06/2024 16:33, Greg Ungerer wrote:
Hi Jean-Michel,
On 3/6/24 20:54, Jean-Michel Hautbois wrote:
Hi there !
I managed to get really far in my boot process, as I can now try to
execute bash. I had to change the elf.h file because if I don't do
that, it is not working.
Here is the diff (on v6.9.1):
diff --git a/arch/m68k/include/asm/elf.h b/arch/m68k/include/asm/elf.h
index 2def06a99b08..38acb928fa81 100644
--- a/arch/m68k/include/asm/elf.h
+++ b/arch/m68k/include/asm/elf.h
@@ -78,8 +78,10 @@ typedef struct user_m68kfp_struct elf_fpregset_t;
the loader. We need to make sure that it is out of the way of
the program
that it will "exec", and that there is sufficient room for the
brk. */
-#ifndef CONFIG_SUN3
+#if !defined(CONFIG_SUN3) && !defined(CONFIG_COLDFIRE)
#define ELF_ET_DYN_BASE 0xD0000000UL
+#elif defined(CONFIG_COLDFIRE)
+#define ELF_ET_DYN_BASE (TASK_UNMAPPED_BASE + 0x10000000)
Thats interesting. How did you determine this value to use?
Let's be honest :-) I used the one found in the NXP kernel I have as a
reference (2.6 based). I finally found this is the root cause but I
don't know exactly why this value is used.
#else
#define ELF_ET_DYN_BASE 0x0D800000UL
#endif
Without the patch:
[ 3.020000] Freeing unused kernel image (initmem) memory: 96K
[ 3.030000] This architecture does not have kernel memory protection.
[ 3.030000] Run /bin/bash as init process
[ 3.320000] Kernel panic - not syncing: Requested init /bin/bash
failed (error -12).
[ 3.320000] CPU: 0 PID: 1 Comm: bash Not tainted
6.9.2stmark2-001-00013-gcf0217bae3ae #285
[ 3.320000] Stack from 41845f70:
[ 3.320000] 41845f70 413bccd1 413bccd1 00000001 413f2700
41008a68 413151f2 413bccd1
[ 3.320000] 4130e630 41845fb0 413f2700 00000003 00000001
4130eeda 00000000 00000000
[ 3.320000] 41315a2e 413b303d 4febbf1e fffffff4 4131598e
410033f4 00000000 00000000
[ 3.320000] 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000
[ 3.320000] 00000000 00000000 00002000 00000000
[ 3.320000] Call Trace: arch_local_irq_disable
(./arch/m68k/include/asm/irqflags.h:20)
[ 3.320000] dump_stack (lib/dump_stack.c:124)
[ 3.320000] panic (kernel/panic.c:267 kernel/panic.c:369)
[ 3.320000] _printk (kernel/printk/printk.c:2368)
[ 3.320000] kernel_init (init/main.c:1500)
[ 3.320000] kernel_init (init/main.c:1436)
[ 3.320000] ret_from_kernel_thread (arch/m68k/kernel/entry.S:142)
[ 3.320000]
[ 3.320000] ---[ end Kernel panic - not syncing: Requested init
/bin/bash failed (error -12). ]---
With the patch, the /bin/bash file is executed, but then any command
will fail with a segfault:
[ 3.000000] Freeing unused kernel image (initmem) memory: 96K
[ 3.010000] This architecture does not have kernel memory protection.
[ 3.020000] Run /bin/bash as init process
bash: cannot set terminal process group (-1): Inappropriate ioctl for
device
bash: no job control in this shell
bash-5.2# ls
bin home linuxrc opt run tmp
dev lib media 7.250000] Unable to handle kernel NULL
pointer dereference at virtual address 00000000
[ 7.250000] Oops: 00000000
[ 7.250000] PC: 0x0
[ 7.250000] SR: 2000 SP: (ptrval) a2: 41c58000
[ 7.250000] d0: 00000028 d1: 00000003 d2: 6017a000 d3:
414d9419
[ 7.250000] d4: 41b5c800 d5: 4fed3730 a0: 00000000 a1:
413227a0
[ 7.250000] Process ls (pid: 27, task=(ptrval))
[ 7.250000] Frame format=4 eff addr=41055826 pc=420516cc
[ 7.250000] Stack from 41b85dfc:
[ 7.250000] 4fed3730 41b85f1e 4106e3ac 4fed3730 00000000
ffffffff fffffffe 41b85ea2
[ 7.250000] 6017e000 00000001 412fbafc 4106dfe4 412fbafc
4fed3730 00000001 41b85ea2
[ 7.250000] 41b90600 6017e000 41b90600 41b6c340 6017dfff
41b84000 41b6c36c 00000000
[ 7.250000] 00000000 00000000 00000000 41b85f60 4106e5ea
41b85f1e 41b5c800 6017a000
[ 7.250000] 6017e000 41b85ea2 41b6c36c 41b85efa 41b85f1e
4102a3e8 41b6c344 41b5c4c0
[ 7.250000] 41b6c340 41b50000 00000100 00000003 41073130
41b85f1e 41b85efa 41b5c4c0
[ 7.250000] Call Trace: unmap_page_range (mm/memory.c:1482
mm/memory.c:1563 mm/memory.c:1605 mm/memory.c:1722 mm/memory.c:1751
mm/memory.c:1772 mm/memory.c:1793)
[ 7.250000] mas_find (lib/maple_tree.c:6061)
[ 7.250000] unmap_page_range (mm/memory.c:1782)
[ 7.250000] mas_find (lib/maple_tree.c:6061)
[ 7.250000] unmap_vmas (mm/memory.c:1839 mm/memory.c:1883)
[ 7.250000] up_read (kernel/locking/rwsem.c:1620)
[ 7.250000] exit_mmap (./include/linux/mmap_lock.h:173 mm/mmap.c:3268)
[ 7.250000] arch_local_irq_enable
(./arch/m68k/include/asm/irqflags.h:35)
[ 7.250000] arch_local_irq_disable
(./arch/m68k/include/asm/irqflags.h:20)
[ 7.250000] __mmput (kernel/fork.c:1348)
[ 7.250000] do_exit (./arch/m68k/include/asm/thread_info.h:46
kernel/exit.c:570 kernel/exit.c:865)
[ 7.250000] sys_exit_group (kernel/exit.c:1038 kernel/exit.c:1036)
[ 7.250000] do_group_exit (kernel/exit.c:1008)
[ 7.250000] pid_child_should_wake (kernel/exit.c:1503)
[ 7.250000] system_call (arch/m68k/coldfire/entry.S:80)
[ 7.250000]
[ 7.250000] Code: ffff ffff ffff ffff ffff ffff ffff ffff Bad PC value.
m68k-buildroot-linux-gnu-objdump: '/tmp/tmp.vO4KvxtnKV.o': No such file
Code starting with the faulting instruction
===========================================
[ 7.250000] Disabling lock debugging due to kernel taint
[ 7.250000] note: ls[27] exited with irqs disabled
Is there a compiler to use ? I built one with buildroot, but maybe is
there a gcc version somewhere to use for the Coldfire 54418 ? Could it
be related ?
I would expect you could use any modern version of gcc targeted for
m68k-linux.
For the past few years to generate code for 5475 based platform I use a
gcc-8.3.0
toolchain.
I have never had any of the 5441x based devices, so I couldn't say for
sure on that.
Well I found the root cause here too. But again, I don't know exactly why:
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 12c9297ed4a7..c2a48592c258 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -2857,7 +2857,9 @@ bool folio_mark_dirty(struct folio *folio)
*/
if (folio_test_reclaim(folio))
folio_clear_reclaim(folio);
- return mapping->a_ops->dirty_folio(mapping, folio);
+ if (mapping->a_ops->dirty_folio)
+ return mapping->a_ops->dirty_folio(mapping, folio);
+ return noop_dirty_folio(mapping, folio);
}
return noop_dirty_folio(mapping, folio);
I intend to propose a few patches as RFC in order to know more and have
the correct solution (I suspect this is not the good one :-p).
Now, this is working correctly, with the toolchain I built. I have a few
issues like in NFC (I had to modify the vf610_nfc driver for it to take
the driver_data) or the FEC (this is not buildable for M5441x while it
should be AFAIK).
I will try to send a few patches shortly.
Thanks,
JM
