linux-kernel - Re: [PATCH V2] riscv: ftrace: Fix the logic issue in DYNAMIC_FTRACE selection

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Message-ID: <b6dbdcbc-08b5-4de0-9955-cf2b048dbb38@ghiti.fr>
Date: Fri, 11 Jul 2025 09:55:25 +0200
From: Alexandre Ghiti <alex@...ti.fr>
To: Miao Chen <chenmiao.ku@...il.com>
Cc: kernel test robot <lkp@...el.com>,
 Linux RISCV <linux-riscv@...ts.infradead.org>,
 oe-kbuild-all@...ts.linux.dev, Paul Walmsley <paul.walmsley@...ive.com>,
 Palmer Dabbelt <palmer@...belt.com>, Albert Ou <aou@...s.berkeley.edu>,
 Steven Rostedt <rostedt@...dmis.org>, Masami Hiramatsu
 <mhiramat@...nel.org>, Mark Rutland <mark.rutland@....com>,
 Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
 Heiko Carstens <hca@...ux.ibm.com>, Pu Lehui <pulehui@...wei.com>,
 linux-kernel@...r.kernel.org, linux-trace-kernel@...r.kernel.org
Subject: Re: [PATCH V2] riscv: ftrace: Fix the logic issue in DYNAMIC_FTRACE
 selection

Hi,

On 7/10/25 17:56, Miao Chen wrote:
> Hello Alex,
>
> I found where the error is, but there's a problem here:
>
> config PORTABLE
>    bool
>    default !NONPORTABLE
>    select EFI
>    select MMU
>    select OF
>
> select HAVE_DYNAMIC_FTRACE if !XIP_KERNEL && MMU &&
> (CLANG_SUPPORTS_DYNAMIC_FTRACE || GCC_SUPPORTS_DYNAMIC_FTRACE)
>
> Because HAVE_DYNAMIC_FTRACE depends on the MMU—of course, it's
> reasonable for DYNAMIC_FTRACE to depend on the MMU—*but since
> NONPORTABLE is enabled by default, this causes PORTABLE to default to
> n, thereby preventing the MMU from being enabled*. So, should I change
> NONPORTABLE to default to n?

NONPORTABLE is not enabled by default and PORTABLE=n does not prevent 
MMU from being enabled.

IIUC, it seems like you don't have HAVE_DYNAMIC_FTRACE enabled but 
that's probably because of your toolchain, not !MMU, can you check that 
in your .config?

Thanks,

Alex

>
> Thanks,
>
> Alex
>
> Alexandre Ghiti <alex@...ti.fr> 于2025年7月10日周四 22:33写道：
>>
>> On 7/10/25 14:34, Miao Chen wrote:
>>> Hello Alex,
>>>
>>> Sure, I'll checkout it. Btw, this is my first commit, so can u tell
>>> how to reproduce failed case? Using the reproduce and .config.gz gived
>>> by build-bot?
>>
>> Yes exactly!
>>
>>
>>> Thanks,
>>>
>>> Chen Miao
>>>
>>> Alexandre Ghiti <alex@...ti.fr> 于2025年7月10日周四 19:53写道：
>>>> Hi ChenMiao,
>>>>
>>>> On 7/9/25 03:08, kernel test robot wrote:
>>>>> Hi ChenMiao,
>>>>>
>>>>> kernel test robot noticed the following build errors:
>>>>>
>>>>> [auto build test ERROR on fda589c286040d9ba2d72a0eaf0a13945fc48026]
>>>>>
>>>>> url:    https://github.com/intel-lab-lkp/linux/commits/ChenMiao/riscv-ftrace-Fix-the-logic-issue-in-DYNAMIC_FTRACE-selection/20250706-231907
>>>>> base:   fda589c286040d9ba2d72a0eaf0a13945fc48026
>>>>> patch link:    https://lore.kernel.org/r/20250706151830.25091-1-chenmiao.ku%40gmail.com
>>>>> patch subject: [PATCH V2] riscv: ftrace: Fix the logic issue in DYNAMIC_FTRACE selection
>>>>> :::::: branch date: 2 days ago
>>>>> :::::: commit date: 2 days ago
>>>>> config: riscv-randconfig-r112-20250708 (attached as .config)
>>>>> compiler: clang version 19.1.7 (https://github.com/llvm/llvm-project cd708029e0b2869e80abe31ddb175f7c35361f90)
>>>>> reproduce: (attached as reproduce)
>>>>>
>>>>> If you fix the issue in a separate patch/commit (i.e. not just a new version of
>>>>> the same patch/commit), kindly add following tags
>>>>> | Reported-by: kernel test robot <lkp@...el.com>
>>>>> | Closes: https://lore.kernel.org/oe-kbuild-all/202507090650.YGY56SIA-lkp@intel.com/
>>>>>
>>>>> All errors (new ones prefixed by >>):
>>>>>
>>>>>>> <instantiation>:1:14: error: operand must be a symbol with %lo/%pcrel_lo/%tprel_lo modifier or an integer in the range [-2048, 2047]
>>>>>       addi sp, sp, -FREGS_SIZE_ON_STACK
>>>>>                    ^
>>>>>       arch/riscv/kernel/mcount-dyn.S:185:2: note: while in macro instantiation
>>>>>        SAVE_ABI_REGS
>>>>>        ^
>>>>>>> <instantiation>:2:18: error: unexpected token
>>>>>        sw t0, FREGS_EPC(sp)
>>>>>                        ^
>>>>>       arch/riscv/kernel/mcount-dyn.S:185:2: note: while in macro instantiation
>>>>>        SAVE_ABI_REGS
>>>>>        ^
>>>>>       <instantiation>:3:17: error: unexpected token
>>>>>        sw x1, FREGS_RA(sp)
>>>>>                       ^
>>>>>       arch/riscv/kernel/mcount-dyn.S:185:2: note: while in macro instantiation
>>>>>        SAVE_ABI_REGS
>>>>>        ^
>>>>>       <instantiation>:7:17: error: unexpected token
>>>>>        sw x6, FREGS_T1(sp)
>>>>>                       ^
>>>>>       arch/riscv/kernel/mcount-dyn.S:185:2: note: while in macro instantiation
>>>>>        SAVE_ABI_REGS
>>>>>        ^
>>>>>       <instantiation>:9:17: error: unexpected token
>>>>>        sw x7, FREGS_T2(sp)
>>>>>                       ^
>>>>>       arch/riscv/kernel/mcount-dyn.S:185:2: note: while in macro instantiation
>>>>>        SAVE_ABI_REGS
>>>>>        ^
>>>>>       <instantiation>:10:18: error: unexpected token
>>>>>        sw x28, FREGS_T3(sp)
>>>>>                        ^
>>>>>       arch/riscv/kernel/mcount-dyn.S:185:2: note: while in macro instantiation
>>>>>        SAVE_ABI_REGS
>>>>>        ^
>>>>>       <instantiation>:11:18: error: unexpected token
>>>>>        sw x29, FREGS_T4(sp)
>>>>>                        ^
>>>>>       arch/riscv/kernel/mcount-dyn.S:185:2: note: while in macro instantiation
>>>>>        SAVE_ABI_REGS
>>>>>        ^
>>>>>       <instantiation>:12:18: error: unexpected token
>>>>>        sw x30, FREGS_T5(sp)
>>>>>                        ^
>>>>>       arch/riscv/kernel/mcount-dyn.S:185:2: note: while in macro instantiation
>>>>>        SAVE_ABI_REGS
>>>>>        ^
>>>>>       <instantiation>:13:18: error: unexpected token
>>>>>        sw x31, FREGS_T6(sp)
>>>>>                        ^
>>>>>       arch/riscv/kernel/mcount-dyn.S:185:2: note: while in macro instantiation
>>>>>        SAVE_ABI_REGS
>>>>>        ^
>>>>>       <instantiation>:16:18: error: unexpected token
>>>>>        sw x10, FREGS_A0(sp)
>>>>>                        ^
>>>>>       arch/riscv/kernel/mcount-dyn.S:185:2: note: while in macro instantiation
>>>>>        SAVE_ABI_REGS
>>>>>        ^
>>>>>       <instantiation>:17:18: error: unexpected token
>>>>>        sw x11, FREGS_A1(sp)
>>>>>                        ^
>>>>>       arch/riscv/kernel/mcount-dyn.S:185:2: note: while in macro instantiation
>>>>>        SAVE_ABI_REGS
>>>>>        ^
>>>>>       <instantiation>:18:18: error: unexpected token
>>>>>        sw x12, FREGS_A2(sp)
>>>>>                        ^
>>>>>       arch/riscv/kernel/mcount-dyn.S:185:2: note: while in macro instantiation
>>>>>        SAVE_ABI_REGS
>>>>>        ^
>>>>>       <instantiation>:19:18: error: unexpected token
>>>>>        sw x13, FREGS_A3(sp)
>>>>>                        ^
>>>>>       arch/riscv/kernel/mcount-dyn.S:185:2: note: while in macro instantiation
>>>>>        SAVE_ABI_REGS
>>>>>        ^
>>>>>       <instantiation>:20:18: error: unexpected token
>>>>>        sw x14, FREGS_A4(sp)
>>>>>                        ^
>>>>>       arch/riscv/kernel/mcount-dyn.S:185:2: note: while in macro instantiation
>>>>>        SAVE_ABI_REGS
>>>>>        ^
>>>>>       <instantiation>:21:18: error: unexpected token
>>>>>        sw x15, FREGS_A5(sp)
>>>>>                        ^
>>>>>       arch/riscv/kernel/mcount-dyn.S:185:2: note: while in macro instantiation
>>>>>        SAVE_ABI_REGS
>>>>>        ^
>>>>>       <instantiation>:22:18: error: unexpected token
>>>>>        sw x16, FREGS_A6(sp)
>>>>>                        ^
>>>>>       arch/riscv/kernel/mcount-dyn.S:185:2: note: while in macro instantiation
>>>>>        SAVE_ABI_REGS
>>>>>        ^
>>>>>       <instantiation>:23:18: error: unexpected token
>>>>>        sw x17, FREGS_A7(sp)
>>>>>                        ^
>>>>>       arch/riscv/kernel/mcount-dyn.S:185:2: note: while in macro instantiation
>>>>>        SAVE_ABI_REGS
>>>>>        ^
>>>>>       <instantiation>:25:15: error: operand must be a symbol with %lo/%pcrel_lo/%tprel_lo modifier or an integer in the range [-2048, 2047]
>>>>>        addi a0, a0, FREGS_SIZE_ON_STACK
>>>>>                     ^
>>>>>       arch/riscv/kernel/mcount-dyn.S:185:2: note: while in macro instantiation
>>>>>        SAVE_ABI_REGS
>>>>>
>>>>> Kconfig warnings: (for reference only)
>>>>>       WARNING: unmet direct dependencies detected for DYNAMIC_FTRACE
>>>>>       Depends on [n]: FTRACE [=y] && FUNCTION_TRACER [=y] && HAVE_DYNAMIC_FTRACE [=n]
>>>>>       Selected by [y]:
>>>>>       - RISCV [=y] && FUNCTION_TRACER [=y]
>>>> To avoid that, we should check HAVE_DYNAMIC_FTRACE too:
>>>>
>>>> select DYNAMIC_FTRACE if FUNCTION_TRACER && HAVE_DYNAMIC_FTRACE
>>>>
>>>> That fixes the build error for me. Can you send a v3 with this change?
>>>>
>>>> Thanks,
>>>>
>>>> Alex
>>>>
>>>>
>>> _______________________________________________
>>> linux-riscv mailing list
>>> linux-riscv@...ts.infradead.org
>>> http://lists.infradead.org/mailman/listinfo/linux-riscv
> _______________________________________________
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> linux-riscv@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-riscv

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