[PATCH v2 1/1] clk/sophgo: Using BUG() instead of unreachable() in mmux_get_parent_id()

[PATCH v2 1/1] clk/sophgo: Using BUG() instead of unreachable() in mmux_get_parent_id()

[Li Qiang]

In general it's a good idea to avoid using bare unreachable() because it
introduces undefined behavior in compiled code. but it caused a compilation warning,
Using BUG() instead of unreachable() to resolve compilation warnings.

Fixes the following warnings:
    drivers/clk/sophgo/clk-cv18xx-ip.o: warning: objtool: mmux_round_rate() falls through to next function bypass_div_round_rate()

Fixes: 80fd61ec46124 ("clk: sophgo: Add clock support for CV1800 SoC")
Signed-off-by: Li Qiang <liqiang01@kylinos.cn>
---
 drivers/clk/sophgo/clk-cv18xx-ip.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/clk/sophgo/clk-cv18xx-ip.c b/drivers/clk/sophgo/clk-cv18xx-ip.c
index 805f561725ae..b186e64d4813 100644
--- a/drivers/clk/sophgo/clk-cv18xx-ip.c
+++ b/drivers/clk/sophgo/clk-cv18xx-ip.c
@@ -613,7 +613,7 @@ static u8 mmux_get_parent_id(struct cv1800_clk_mmux *mmux)
 			return i;
 	}
 
-	unreachable();
+	BUG();
 }
 
 static int mmux_enable(struct clk_hw *hw)
-- 
2.25.1

Re: [PATCH v2 1/1] clk/sophgo: Using BUG() instead of unreachable() in mmux_get_parent_id()

[Chen Wang]

On 2024/7/9 14:36, Li Qiang wrote:
> In general it's a good idea to avoid using bare unreachable() because it
> introduces undefined behavior in compiled code. but it caused a compilation warning,
> Using BUG() instead of unreachable() to resolve compilation warnings.
>
> Fixes the following warnings:
>      drivers/clk/sophgo/clk-cv18xx-ip.o: warning: objtool: mmux_round_rate() falls through to next function bypass_div_round_rate()

I tried to build this drivers/clk/sophgo/clk-cv18xx-ip.c but don't see 
the warning. I'm using make W=1 with gcc 13.2.0

What's the meaning of this warning message and how to reproduce this?

>
> Fixes: 80fd61ec46124 ("clk: sophgo: Add clock support for CV1800 SoC")
> Signed-off-by: Li Qiang <liqiang01@kylinos.cn>
> ---
>   drivers/clk/sophgo/clk-cv18xx-ip.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/clk/sophgo/clk-cv18xx-ip.c b/drivers/clk/sophgo/clk-cv18xx-ip.c
> index 805f561725ae..b186e64d4813 100644
> --- a/drivers/clk/sophgo/clk-cv18xx-ip.c
> +++ b/drivers/clk/sophgo/clk-cv18xx-ip.c
> @@ -613,7 +613,7 @@ static u8 mmux_get_parent_id(struct cv1800_clk_mmux *mmux)
>   			return i;
>   	}
>   
> -	unreachable();
> +	BUG();
>   }
>   
>   static int mmux_enable(struct clk_hw *hw)

Re: [PATCH v2 1/1] clk/sophgo: Using BUG() instead of unreachable() in mmux_get_parent_id()

[Stephen Boyd]

Quoting Li Qiang (2024-07-08 23:36:38)
> In general it's a good idea to avoid using bare unreachable() because it
> introduces undefined behavior in compiled code. but it caused a compilation warning,
> Using BUG() instead of unreachable() to resolve compilation warnings.
> 
> Fixes the following warnings:
>     drivers/clk/sophgo/clk-cv18xx-ip.o: warning: objtool: mmux_round_rate() falls through to next function bypass_div_round_rate()
> 
> Fixes: 80fd61ec46124 ("clk: sophgo: Add clock support for CV1800 SoC")
> Signed-off-by: Li Qiang <liqiang01@kylinos.cn>
> ---

Applied to clk-next