[PATCH V3 3/5] riscv: ftrace: Reduce the detour code size to half

[Conor Dooley]

On Wed, Nov 23, 2022 at 10:39:48AM -0500, guoren at kernel.org wrote:
> From: Guo Ren <guoren at 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 at gmail.com>
> Signed-off-by: Guo Ren <guoren at linux.alibaba.com>
> Signed-off-by: Guo Ren <guoren at 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.