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From: guoren@kernel.org
To: arnd@arndb.de, palmer@rivosinc.com, rostedt@goodmis.org,
	andy.chiu@sifive.com, greentime.hu@sifive.com,
	zong.li@sifive.com, jrtc27@jrtc27.com, mingo@redhat.com,
	palmer@dabbelt.com
Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-riscv@lists.infradead.org, guoren@kernel.org,
	Guo Ren <guoren@linux.alibaba.com>
Subject: [PATCH V2 0/3] riscv: ftrace: Fixup ftrace detour code
Date: Tue, 20 Sep 2022 23:49:07 -0400	[thread overview]
Message-ID: <20220921034910.3142465-1-guoren@kernel.org> (raw)

From: Guo Ren <guoren@linux.alibaba.com>

The previous ftrace detour implementation fc76b8b8011 ("riscv: Using
PATCHABLE_FUNCTION_ENTRY instead of MCOUNT") contain three problems. The
most horrible bug is preemption panic which found by Andy [1]. Let's
disable preemption for ftrace first, and Andy could continue the
ftrace preemption work.

[1]: https://lpc.events/event/16/contributions/1171/

V2:
 - Add Signed-off for preemption fixup.

V1:
https://lore.kernel.org/linux-riscv/20220916103817.9490-1-guoren@kernel.org/

Andy Chiu (1):
  riscv: ftrace: Fixup panic by disabling preemption

Guo Ren (2):
  riscv: ftrace: Remove wasted nops for !RISCV_ISA_C
  riscv: ftrace: Reduce the detour code size to half

 arch/riscv/Kconfig              |  2 +-
 arch/riscv/Makefile             |  6 ++-
 arch/riscv/include/asm/ftrace.h | 46 ++++++++++++++++++-----
 arch/riscv/kernel/ftrace.c      | 65 ++++++++++-----------------------
 arch/riscv/kernel/mcount-dyn.S  | 43 +++++++++-------------
 5 files changed, 78 insertions(+), 84 deletions(-)

-- 
2.36.1


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             reply	other threads:[~2022-09-21  3:49 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-21  3:49 guoren [this message]
2022-09-21  3:49 ` [PATCH V2 1/3] riscv: ftrace: Fixup panic by disabling preemption guoren
2022-09-21  3:49 ` [PATCH V2 2/3] riscv: ftrace: Remove wasted nops for !RISCV_ISA_C guoren
2022-09-21  3:49 ` [PATCH V2 3/3] riscv: ftrace: Reduce the detour code size to half guoren
2022-11-22  8:56   ` Song Shuai

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