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From: Paul Walmsley <pjw@kernel.org>
To: duchangbin <changbin.du@huawei.com>,
	Alexandre Ghiti <alex@ghiti.fr>,
	 andybnac@gmail.com
Cc: Paul Walmsley <paul.walmsley@sifive.com>,
	 Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	 "linux-riscv@lists.infradead.org"
	<linux-riscv@lists.infradead.org>,
	 "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] riscv: Prevent early kernel panic in instrumented apply_early_boot_alternatives
Date: Wed, 8 Oct 2025 20:01:54 -0600 (MDT)	[thread overview]
Message-ID: <2396743a-480e-2ab3-f7fe-569d8f2adfcf@kernel.org> (raw)
In-Reply-To: <d41d9c7a103f4600a4fc5beea77e0f4e@huawei.com>

Hi Alex, duchangbin, Andy,

On Wed, 25 Jun 2025, duchangbin wrote:

> On Tue, Jun 24, 2025 at 02:54:32PM +0200, Alexandre Ghiti wrote:
> > Hi Changbin,
> > 
> > On 6/24/25 13:30, Changbin Du wrote:
> > > Under FTRACE=y, DYNAMIC_FTRACE=n, and RISCV_ALTERNATIVE_EARLY=n, the kernel
> > 
> > 
> > Your above config works fine for me, I guess you meant FUNCTION_TRACER &&
> > !DYNAMIC_FTRACE (which fails).
> >
> Yes, it's FUNCTION_TRACER.
> 
> > We were just talking with Andy about this configuration (FUNCTION_TRACER &&
> > !DYNAMIC_FTRACE): do we really want to support static ftrace? Andy should
> > send a patch soon to remove this possibility as IMO we don't want to support
> > it. Let's wait for this patch and the discussion that will follow before
> > merging your fix. I'll keep it in my list for 6.16 just in case someone
> > comes up with a good argument to keep it.
> > 
> No problem. I'm unable to enable DYNAMIC_FTRACE because GCC_SUPPORTS_DYNAMIC_FTRACE=n
> and CC_HAS_MIN_FUNCTION_ALIGNMENT=n are set. It seems that my GCC version (13.3.0)
> does not support the option -fmin-function-alignment=8.
> 
> By the way, this change also eliminates an empty function call.

Working on cleaning out Patchwork.  Was there any further conclusion 
reached on this patch, or more broadly, static ftrace ?


- Paul

_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

WARNING: multiple messages have this Message-ID (diff)
From: Paul Walmsley <pjw@kernel.org>
To: duchangbin <changbin.du@huawei.com>,
	Alexandre Ghiti <alex@ghiti.fr>,
	 andybnac@gmail.com
Cc: Paul Walmsley <paul.walmsley@sifive.com>,
	 Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	 "linux-riscv@lists.infradead.org"
	<linux-riscv@lists.infradead.org>,
	 "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] riscv: Prevent early kernel panic in instrumented apply_early_boot_alternatives
Date: Wed, 8 Oct 2025 20:01:54 -0600 (MDT)	[thread overview]
Message-ID: <2396743a-480e-2ab3-f7fe-569d8f2adfcf@kernel.org> (raw)
In-Reply-To: <d41d9c7a103f4600a4fc5beea77e0f4e@huawei.com>

Hi Alex, duchangbin, Andy,

On Wed, 25 Jun 2025, duchangbin wrote:

> On Tue, Jun 24, 2025 at 02:54:32PM +0200, Alexandre Ghiti wrote:
> > Hi Changbin,
> > 
> > On 6/24/25 13:30, Changbin Du wrote:
> > > Under FTRACE=y, DYNAMIC_FTRACE=n, and RISCV_ALTERNATIVE_EARLY=n, the kernel
> > 
> > 
> > Your above config works fine for me, I guess you meant FUNCTION_TRACER &&
> > !DYNAMIC_FTRACE (which fails).
> >
> Yes, it's FUNCTION_TRACER.
> 
> > We were just talking with Andy about this configuration (FUNCTION_TRACER &&
> > !DYNAMIC_FTRACE): do we really want to support static ftrace? Andy should
> > send a patch soon to remove this possibility as IMO we don't want to support
> > it. Let's wait for this patch and the discussion that will follow before
> > merging your fix. I'll keep it in my list for 6.16 just in case someone
> > comes up with a good argument to keep it.
> > 
> No problem. I'm unable to enable DYNAMIC_FTRACE because GCC_SUPPORTS_DYNAMIC_FTRACE=n
> and CC_HAS_MIN_FUNCTION_ALIGNMENT=n are set. It seems that my GCC version (13.3.0)
> does not support the option -fmin-function-alignment=8.
> 
> By the way, this change also eliminates an empty function call.

Working on cleaning out Patchwork.  Was there any further conclusion 
reached on this patch, or more broadly, static ftrace ?


- Paul

  reply	other threads:[~2025-10-09  2:02 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-06-24 11:30 [PATCH] riscv: Prevent early kernel panic in instrumented apply_early_boot_alternatives Changbin Du
2025-06-24 11:30 ` Changbin Du
2025-06-24 12:54 ` Alexandre Ghiti
2025-06-24 12:54   ` Alexandre Ghiti
2025-06-25  3:10   ` duchangbin
2025-06-25  3:10     ` duchangbin
2025-10-09  2:01     ` Paul Walmsley [this message]
2025-10-09  2:01       ` Paul Walmsley
2025-10-09  6:31       ` Vivian Wang
2025-10-09  6:31         ` Vivian Wang
2025-10-09 23:33         ` Paul Walmsley
2025-10-09 23:33           ` Paul Walmsley

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