linux-kernel - Re: [PATCH v3 2/5] riscv/bug: Add ARCH_WARN_ASM macro for BUG/WARN asm code sharing with Rust

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Message-ID: <608d690a-54ad-4c1e-bf4b-b21c81792cfd@ghiti.fr>
Date: Fri, 28 Feb 2025 11:13:32 +0100
From: Alexandre Ghiti <alex@...ti.fr>
To: FUJITA Tomonori <fujita.tomonori@...il.com>,
 linux-kernel@...r.kernel.org, rust-for-linux@...r.kernel.org
Cc: x86@...nel.org, linux-riscv@...ts.infradead.org,
 linux-arm-kernel@...ts.infradead.org, loongarch@...ts.linux.dev,
 tglx@...utronix.de, mingo@...hat.com, bp@...en8.de,
 dave.hansen@...ux.intel.com, peterz@...radead.org, hpa@...or.com,
 paul.walmsley@...ive.com, palmer@...belt.com, aou@...s.berkeley.edu,
 catalin.marinas@....com, will@...nel.org, chenhuacai@...nel.org,
 kernel@...0n.name, tangyouling@...ngson.cn, hejinyang@...ngson.cn,
 yangtiezhu@...ngson.cn, ojeda@...nel.org, alex.gaynor@...il.com,
 boqun.feng@...il.com, gary@...yguo.net, bjorn3_gh@...tonmail.com,
 benno.lossin@...ton.me, a.hindborg@...nel.org, aliceryhl@...gle.com,
 tmgross@...ch.edu
Subject: Re: [PATCH v3 2/5] riscv/bug: Add ARCH_WARN_ASM macro for BUG/WARN
 asm code sharing with Rust

Hi FUJITA,

On 13/02/2025 14:57, FUJITA Tomonori wrote:
> Add new ARCH_WARN_ASM macro for BUG/WARN assembly code sharing with
> Rust to avoid the duplication.
>
> No functional changes.
>
> Signed-off-by: FUJITA Tomonori <fujita.tomonori@...il.com>
> ---
>   arch/riscv/include/asm/bug.h | 37 +++++++++++++++++++++---------------
>   1 file changed, 22 insertions(+), 15 deletions(-)
>
> diff --git a/arch/riscv/include/asm/bug.h b/arch/riscv/include/asm/bug.h
> index 1aaea81fb141..6ab13b56feb0 100644
> --- a/arch/riscv/include/asm/bug.h
> +++ b/arch/riscv/include/asm/bug.h
> @@ -31,40 +31,45 @@ typedef u32 bug_insn_t;
>   
>   #ifdef CONFIG_GENERIC_BUG_RELATIVE_POINTERS
>   #define __BUG_ENTRY_ADDR	RISCV_INT " 1b - ."
> -#define __BUG_ENTRY_FILE	RISCV_INT " %0 - ."
> +#define __BUG_ENTRY_FILE(file)	RISCV_INT " " file " - ."
>   #else
>   #define __BUG_ENTRY_ADDR	RISCV_PTR " 1b"
> -#define __BUG_ENTRY_FILE	RISCV_PTR " %0"
> +#define __BUG_ENTRY_FILE(file)	RISCV_PTR " " file
>   #endif
>   
>   #ifdef CONFIG_DEBUG_BUGVERBOSE
> -#define __BUG_ENTRY			\
> +#define __BUG_ENTRY(file, line, flags)	\
>   	__BUG_ENTRY_ADDR "\n\t"		\
> -	__BUG_ENTRY_FILE "\n\t"		\
> -	RISCV_SHORT " %1\n\t"		\
> -	RISCV_SHORT " %2"
> +	__BUG_ENTRY_FILE(file) "\n\t"	\
> +	RISCV_SHORT " " line "\n\t"	\
> +	RISCV_SHORT " " flags
>   #else
> -#define __BUG_ENTRY			\
> -	__BUG_ENTRY_ADDR "\n\t"		\
> -	RISCV_SHORT " %2"
> +#define __BUG_ENTRY(file, line, flags)		\
> +	__BUG_ENTRY_ADDR "\n\t"			\
> +	RISCV_SHORT " " flags
>   #endif
>   
>   #ifdef CONFIG_GENERIC_BUG
> -#define __BUG_FLAGS(flags)					\
> -do {								\
> -	__asm__ __volatile__ (					\
> +
> +#define ARCH_WARN_ASM(file, line, flags, size)			\
>   		"1:\n\t"					\
>   			"ebreak\n"				\
>   			".pushsection __bug_table,\"aw\"\n\t"	\
>   		"2:\n\t"					\
> -			__BUG_ENTRY "\n\t"			\
> -			".org 2b + %3\n\t"                      \
> -			".popsection"				\
> +		__BUG_ENTRY(file, line, flags) "\n\t"		\
> +			".org 2b + " size "\n\t"                \
> +			".popsection\n"				\
> +
> +#define __BUG_FLAGS(flags)					\
> +do {								\
> +	__asm__ __volatile__ (					\
> +		ARCH_WARN_ASM("%0", "%1", "%2", "%3")		\
>   		:						\
>   		: "i" (__FILE__), "i" (__LINE__),		\
>   		  "i" (flags),					\
>   		  "i" (sizeof(struct bug_entry)));              \
>   } while (0)
> +
>   #else /* CONFIG_GENERIC_BUG */
>   #define __BUG_FLAGS(flags) do {					\
>   	__asm__ __volatile__ ("ebreak\n");			\
> @@ -78,6 +83,8 @@ do {								\
>   
>   #define __WARN_FLAGS(flags) __BUG_FLAGS(BUGFLAG_WARNING|(flags))
>   
> +#define ARCH_WARN_REACHABLE
> +
>   #define HAVE_ARCH_BUG
>   
>   #include <asm-generic/bug.h>


This looks good to me so:

Acked-by: Alexandre Ghiti <alexghiti@...osinc.com>

Thanks,

Alex