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From: Conor Dooley <conor@kernel.org>
To: guoren@kernel.org
Cc: anup@brainfault.org, paul.walmsley@sifive.com,
	palmer@dabbelt.com, conor.dooley@microchip.com, heiko@sntech.de,
	rostedt@goodmis.org, mhiramat@kernel.org, jolsa@redhat.com,
	bp@suse.de, jpoimboe@kernel.org, suagrfillet@gmail.com,
	andy.chiu@sifive.com, linux-riscv@lists.infradead.org,
	linux-kernel@vger.kernel.org, Guo Ren <guoren@linux.alibaba.com>
Subject: Re: [PATCH V3 3/5] riscv: ftrace: Reduce the detour code size to half
Date: Wed, 23 Nov 2022 20:00:51 +0000	[thread overview]
Message-ID: <Y35783GmAtJ+JuGW@spud> (raw)
In-Reply-To: <20221123153950.2911981-4-guoren@kernel.org>

On Wed, Nov 23, 2022 at 10:39:48AM -0500, guoren@kernel.org wrote:
> From: Guo Ren <guoren@linux.alibaba.com>
> 
> Use a temporary register to reduce the size of detour code from
> 16 bytes to 8 bytes. The previous implementation is from
> afc76b8b8011 ("riscv: Using PATCHABLE_FUNCTION_ENTRY instead of
> MCOUNT").
> 
> Before the patch:
> <func_prolog>:
>  0: REG_S  ra, -SZREG(sp)
>  4: auipc  ra, ?
>  8: jalr   ?(ra)
> 12: REG_L  ra, -SZREG(sp)
>  (func_boddy)
> 
> After the patch:
> <func_prolog>:
>  0: auipc  t0, ?
>  4: jalr   t0, ?(t0)
>  (func_boddy)
> 
> Link: https://lore.kernel.org/linux-riscv/20221122075440.1165172-1-suagrfillet@gmail.com/
> Co-developed-by: Song Shuai <suagrfillet@gmail.com>
> Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
> Signed-off-by: Guo Ren <guoren@kernel.org>

FYI missing a sign-off from Song Shuai. They were happy with you folding
their patch in during the discussion linked above - so I suppose that is
an accidental omission?

Thanks,
Conor.


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  reply	other threads:[~2022-11-23 20:01 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-23 15:39 [PATCH V3 0/5] riscv: ftrace: Fixup ftrace detour code & Optimization guoren
2022-11-23 15:39 ` [PATCH V3 1/5] riscv: ftrace: Fixup panic by disabling preemption guoren
2022-11-23 20:07   ` Conor Dooley
2022-11-24  2:10     ` Guo Ren
2022-11-23 15:39 ` [PATCH V3 2/5] riscv: ftrace: Remove wasted nops for !RISCV_ISA_C guoren
2022-11-23 15:39 ` [PATCH V3 3/5] riscv: ftrace: Reduce the detour code size to half guoren
2022-11-23 20:00   ` Conor Dooley [this message]
2022-11-24  2:11     ` Guo Ren
2022-11-23 15:39 ` [PATCH V3 4/5] riscv: ftrace: Add ftrace_graph_func guoren
2022-11-23 15:39 ` [PATCH V3 5/5] riscv: ftrace: Make ftrace_caller call ftrace_graph_func guoren

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