linux-kernel - Re: hppa64-linux-ld: mm/hugetlb.o(.text+0x50dc): cannot reach printk

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Date:   Mon, 25 Jan 2021 16:08:37 -0500
From:   John David Anglin <dave.anglin@...l.net>
To:     Helge Deller <deller@....de>
Cc:     Nick Desaulniers <ndesaulniers@...gle.com>,
        James Bottomley <James.Bottomley@...senpartnership.com>,
        linux-parisc@...r.kernel.org, kbuild-all@...ts.01.org,
        LKML <linux-kernel@...r.kernel.org>,
        Ingo Molnar <mingo@...nel.org>,
        Kees Cook <keescook@...omium.org>,
        kernel test robot <lkp@...el.com>
Subject: Re: hppa64-linux-ld: mm/hugetlb.o(.text+0x50dc): cannot reach printk

I would suggest the following for this hunk:

+    ldil    L%intr_restore, %r2
+    BL    preempt_schedule_irq
+    ldo     R%intr_restore(%r2), %r2

    ldil    L%intr_restore, %r1
    b,l    preempt_schedule_irq,%r2
    ldo     R%intr_restore(%r1), %r2

On PA 2.0 hardware that gives a 22-bit call.

Dave

On 2021-01-25 3:59 p.m., Helge Deller wrote:
> On 1/25/21 9:47 PM, Helge Deller wrote:
>>>>> On Sat, Jan 16, 2021 at 6:37 AM kernel test robot <lkp@...el.com> wrote:
>>>>>> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
>>>>>> head:   1d94330a437a573cfdf848f6743b1ed169242c8a
>>>>>> commit: eff8728fe69880d3f7983bec3fb6cea4c306261f vmlinux.lds.h: Add PGO and AutoFDO input sections
>>>>>> date:   5 months ago
>>>>>> config: parisc-randconfig-r032-20210116 (attached as .config)
>>>>>> compiler: hppa64-linux-gcc (GCC) 9.3.0
>>>>>> reproduce (this is a W=1 build):
>>>>>>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>>>>>>         chmod +x ~/bin/make.cross
>>>>>>         # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=eff8728fe69880d3f7983bec3fb6cea4c306261f
>>>>>>         git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
>>>>>>         git fetch --no-tags linus master
>>>>>>         git checkout eff8728fe69880d3f7983bec3fb6cea4c306261f
>>>>>>         # save the attached .config to linux build tree
>>>>>>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=parisc
>>>>>>
>>>>>> If you fix the issue, kindly add following tag as appropriate
>>>>>> Reported-by: kernel test robot <lkp@...el.com>
>>>>>>
>>>>>> All errors (new ones prefixed by >>):
>>>>>>
>>>>>>    hppa64-linux-ld: mm/page_alloc.o(.ref.text+0x110): cannot reach unknown
>>>>>>    hppa64-linux-ld: mm/memblock.o(.text+0x27c): cannot reach __warn_printk
>>>>>>    hppa64-linux-ld: mm/memblock.o(.meminit.text+0xc4): cannot reach printk
>> ....
>>
>> The problem with this .config is, that both CONFIG_MODULES and
>> CONFIG_MLONGCALLS are set to "n".
>> The Kconfig autodetection needs fixing to enable CONFIG_MLONGCALLS in
>> this case.
>>
>>
>> This patch fixes it for me:
>>
>> [PATCH] Require -mlong-calls gcc option for !CONFIG_MODULES
>>
>> When building a kernel without module support, the CONFIG_MLONGCALL
>> option needs to be enabled. This patch fixes the autodetection in the
>> Kconfig script and uses a far call to preempt_schedule_irq() in
>> intr_do_preempt().
>>
>> Signed-off-by: Helge Deller <deller@....de>
>> Reported-by: kernel test robot <lkp@...el.com>
> There's a small bug in the code below:
> 	BL	preempt_schedule_irq
> needs to be
> 	BL	preempt_schedule_irq, %r0
>
> I'll do some more testing and will push the final version
> through the parisc tree.
>
> Helge
>
>
>> ---
>>
>> diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig
>> index 78b17621ee4a..278462186ac4 100644
>> --- a/arch/parisc/Kconfig
>> +++ b/arch/parisc/Kconfig
>> @@ -202,9 +202,8 @@ config PREFETCH
>>  	depends on PA8X00 || PA7200
>>
>>  config MLONGCALLS
>> -	bool "Enable the -mlong-calls compiler option for big kernels"
>> -	default y if !MODULES || UBSAN || FTRACE
>> -	default n
>> +	def_bool y if !MODULES || UBSAN || FTRACE
>> +	bool "Enable the -mlong-calls compiler option for big kernels" if MODULES && !UBSAN && !FTRACE
>>  	depends on PA8X00
>>  	help
>>  	  If you configure the kernel to include many drivers built-in instead
>> diff --git a/arch/parisc/kernel/entry.S b/arch/parisc/kernel/entry.S
>> index beba9816cc6c..6320f6a8397c 100644
>> --- a/arch/parisc/kernel/entry.S
>> +++ b/arch/parisc/kernel/entry.S
>> @@ -997,10 +997,19 @@ intr_do_preempt:
>>  	bb,<,n	%r20, 31 - PSW_SM_I, intr_restore
>>  	nop
>>
>> -	BL	preempt_schedule_irq, %r2
>> -	nop
>> +	/* ssm PSW_SM_I done later in intr_restore */
>> +#ifdef CONFIG_MLONGCALLS
>> +	ldil    L%intr_restore, %r2
>> +	load32	preempt_schedule_irq, %r1
>> +	bv	%r0(%r1)
>> +	ldo     R%intr_restore(%r2), %r2
>> +#else
>> +	ldil    L%intr_restore, %r2
>> +	BL	preempt_schedule_irq
>> +	ldo     R%intr_restore(%r2), %r2
>> +#endif
>> +
>>
>> -	b,n	intr_restore		/* ssm PSW_SM_I done by intr_restore */
>>  #endif /* CONFIG_PREEMPTION */
>>
>>  	/*
>>
>>


-- 
John David Anglin  dave.anglin@...l.net