From: Hari Bathini <hbathini@linux.ibm.com>
To: Naveen N Rao <naveen@kernel.org>
Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
Madhavan Srinivasan <maddy@linux.ibm.com>,
Christophe Leroy <christophe.leroy@csgroup.eu>,
Michael Ellerman <mpe@ellerman.id.au>,
linux-trace-kernel@vger.kernel.org,
Mark Rutland <mark.rutland@arm.com>,
Steven Rostedt <rostedt@goodmis.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
llvm@lists.linux.dev, Maryam Moghadas <maryammo@ca.ibm.com>
Subject: Re: [PATCH 3/3] powerpc64/ftrace: workaround clang recording GEP in __patchable_function_entries
Date: Mon, 8 Dec 2025 21:38:46 +0530 [thread overview]
Message-ID: <874f8ec4-4f3f-402d-a9f2-4267d37a5bc9@linux.ibm.com> (raw)
In-Reply-To: <sjheprnafkraauotmi2fwjz6l6fha5te7jdp74t4zfh3jvs2if@vjpey276fsti>
On 24/11/25 11:25 am, Naveen N Rao wrote:
> On Sun, Nov 09, 2025 at 02:34:05AM +0530, Hari Bathini wrote:
>> Support for -fpatchable-function-entry on ppc64le was added in Clang
>> with [1]. However, when no prefix NOPs are specified - as is the case
>> with CONFIG_PPC_FTRACE_OUT_OF_LINE - the first NOP is emitted at LEP,
>> but Clang records the Global Entry Point (GEP) unlike GCC which does
>> record the Local Entry Point (LEP). Issue [2] has been raised to align
>> Clang's behavior with GCC. As a temporary workaround to ensure ftrace
>
> Any reason to put in a "temporary" workaround rather than waiting for
> this to be fixed?
Pushing for this temporary workaround as the fix ETA for clang is not
available at the moment and the temporary workaround is likely
harmless even on a clang version with the fix included..
- Hari
prev parent reply other threads:[~2025-12-08 16:09 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-08 21:04 [PATCH 0/3] powerpc64/ftrace: fixes clang build issues Hari Bathini
2025-11-08 21:04 ` [PATCH 1/3] powerpc64: make clang cross-build friendly Hari Bathini
2025-11-24 5:49 ` Naveen N Rao
2025-12-08 16:02 ` Hari Bathini
2026-01-09 13:50 ` Naveen N Rao
2025-11-08 21:04 ` [PATCH 2/3] powerpc64/ftrace: fix OOL stub count with clang Hari Bathini
2025-11-08 21:04 ` [PATCH 3/3] powerpc64/ftrace: workaround clang recording GEP in __patchable_function_entries Hari Bathini
2025-11-24 5:55 ` Naveen N Rao
2025-12-08 16:08 ` Hari Bathini [this message]
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