On 12/15/2020 8:53 AM, Dmitry Osipenko wrote:
> 15.12.2020 19:40, Florian Fainelli пишет:
>>
>>
>> On 12/15/2020 8:17 AM, Dmitry Osipenko wrote:
>>> 15.12.2020 19:04, Florian Fainelli пишет:
>>>>
>>>>
>>>> On 12/15/2020 5:52 AM, Dmitry Osipenko wrote:
>>>>> The tegra_uart_config of the DEBUG_LL code is now placed right at the
>>>>> start of the .text section after commit which enabled debug output in the
>>>>> decompressor. Tegra devices are not booting anymore if DEBUG_LL is enabled
>>>>> since tegra_uart_config data is executes as a code. Fix the misplaced
>>>>> tegra_uart_config storage by embedding it into the code.
>>>>>
>>>>> Cc: stable@xxxxxxxxxxxxxxx
>>>>> Fixes: 2596a72d3384 ("ARM: 9009/1: uncompress: Enable debug in head.S")
>>>>> Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
>>>>> ---
>>>>> arch/arm/include/debug/tegra.S | 54 +++++++++++++++++-----------------
>>>>> 1 file changed, 27 insertions(+), 27 deletions(-)
>>>>
>>>> Looks like arch/arm/include/debug/brcmstb.S would need the same
>>>> treatment since the implementation was copied from tegra.S.
>>>>
>>>
>>> Good catch, will you be able to test the brcm and make a patch?
>>
>> Yes, absolutely, building a kernel to test right now.
>>
>
> Thank you.
>
> BTW, I noticed that the problem is more visible on a thumb2 kernel
> build, i.e. you should get a more reliable hang on boot. On a non-thumb2
> kernel the hanging behaviour seems depends on a device / bootloader. I
> haven't tried to figure out what exactly makes the difference, perhaps
> it should be a memory layout / state.
To build with a CONFIG_THUMB2_KERNEL I had to fetch:
https://www.armlinux.org.uk/developer/patches/viewpatch.php?id=9018/2
to avoid a build error, too bad this missed v5.10 final but hopefully it
can make it soon.
With CONFIG_THUMB2_KERNEL=y, I am not getting the head.S output where it
prints the start/end of the compressed kernel:
C:0x420800C0-0x4321B0E0->0x4212AB00-0x432C5B20
Uncompressing Linux... done, booting the kernel.
[ 0.000000] Booting Linux on physical CPU 0x0
[ 0.000000] Linux version 5.10.0-g148842c98a24
(fainelli@fainelli-desktop) (arm-linux-gcc (GCC) 8.3.0, GNU ld (GNU
Binutils) 2.32) #71 SMP Tue Dec 15 09:53:09 PST 2020
I am only getting:
Uncompressing Linux... done, booting the kernel.
Is that the same for you?
Looking at the disassembly of head.o it definitively has
brcmstb_uart_config in the .text section as the beginning just like you
mentioned in your commit message.
Disassembly of section .text:
00000000 <brcmstb_uart_config>:
0: 00000001 andeq r0, r0, r1
...
c: 467c mov r4, pc
e: f004 4478 and.w r4, r4, #4160749568 ; 0xf8000000
12: f504 4400 add.w r4, r4, #32768 ; 0x8000
16: 4678 mov r0, pc
18: 42a0 cmp r0, r4
1a: bf3f itttt cc
1c: 48d4 ldrcc r0, [pc, #848] ; (370 <LC1+0x8>)
1e: 4478 addcc r0, pc
20: 4284 cmpcc r4, r0
22: f044 0401 orrcc.w r4, r4, #1
26: bf28 it cs
28: f000 f9aa blcs 380 <cache_on>
however after applying a fix similar to yours, we do end-up with the
expected data embedded within the code and given brcmstb.S would be
subject to the same issue as tegra.S, it would not hurt.
--
Florian
