Re: [PATCH 6/6] riscv: remove asmlinkage from updated functions

From: Charlie Jenkins <charlie@rivosinc.com>
To: Jisheng Zhang <jszhang@kernel.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Samuel Holland <samuel.holland@sifive.com>,
	linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 6/6] riscv: remove asmlinkage from updated functions
Date: Mon, 24 Jun 2024 11:53:36 -0700	[thread overview]
Message-ID: <ZnnAsN9qW4Y9nL+/@ghost> (raw)
In-Reply-To: <20240616170553.2832-7-jszhang@kernel.org>

On Mon, Jun 17, 2024 at 01:05:53AM +0800, Jisheng Zhang wrote:
> Now that the callers of these functions have moved into C, they no longer
> need the asmlinkage annotation. Remove it

A couple of the functions here can be inlined as well now that they are
not called by assembly, this will allow the compiler to get rid of the
stack setup/tear down code and eliminate a handful of instructions. The
functions that can be inlined are riscv_v_context_nesting_start() and
do_irq().

- Charlie

> 
> Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
> ---
>  arch/riscv/include/asm/asm-prototypes.h |  6 +++---
>  arch/riscv/kernel/traps.c               | 16 ++++++++--------
>  2 files changed, 11 insertions(+), 11 deletions(-)
> 
> diff --git a/arch/riscv/include/asm/asm-prototypes.h b/arch/riscv/include/asm/asm-prototypes.h
> index 81a1f27fa54f..70b86a825922 100644
> --- a/arch/riscv/include/asm/asm-prototypes.h
> +++ b/arch/riscv/include/asm/asm-prototypes.h
> @@ -37,7 +37,7 @@ asmlinkage void riscv_v_context_nesting_end(struct pt_regs *regs);
>  
>  #endif /* CONFIG_RISCV_ISA_V */
>  
> -#define DECLARE_DO_ERROR_INFO(name)	asmlinkage void name(struct pt_regs *regs)
> +#define DECLARE_DO_ERROR_INFO(name)	void name(struct pt_regs *regs)
>  
>  DECLARE_DO_ERROR_INFO(do_trap_unknown);
>  DECLARE_DO_ERROR_INFO(do_trap_insn_misaligned);
> @@ -53,8 +53,8 @@ DECLARE_DO_ERROR_INFO(do_trap_ecall_m);
>  DECLARE_DO_ERROR_INFO(do_trap_break);
>  
>  asmlinkage void handle_bad_stack(struct pt_regs *regs);
> -asmlinkage void do_page_fault(struct pt_regs *regs);
> -asmlinkage void do_irq(struct pt_regs *regs);
> +void do_page_fault(struct pt_regs *regs);
> +void do_irq(struct pt_regs *regs);
>  asmlinkage void do_traps(struct pt_regs *regs);
>  
>  #endif /* _ASM_RISCV_PROTOTYPES_H */
> diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c
> index b44d4a8d4083..ddca8e74fb72 100644
> --- a/arch/riscv/kernel/traps.c
> +++ b/arch/riscv/kernel/traps.c
> @@ -147,7 +147,7 @@ static void do_trap_error(struct pt_regs *regs, int signo, int code,
>  #define __trap_section noinstr
>  #endif
>  #define DO_ERROR_INFO(name, signo, code, str)					\
> -asmlinkage __visible __trap_section void name(struct pt_regs *regs)		\
> +__visible __trap_section void name(struct pt_regs *regs)			\
>  {										\
>  	if (user_mode(regs)) {							\
>  		irqentry_enter_from_user_mode(regs);				\
> @@ -167,7 +167,7 @@ DO_ERROR_INFO(do_trap_insn_misaligned,
>  DO_ERROR_INFO(do_trap_insn_fault,
>  	SIGSEGV, SEGV_ACCERR, "instruction access fault");
>  
> -asmlinkage __visible __trap_section void do_trap_insn_illegal(struct pt_regs *regs)
> +__visible __trap_section void do_trap_insn_illegal(struct pt_regs *regs)
>  {
>  	bool handled;
>  
> @@ -198,7 +198,7 @@ asmlinkage __visible __trap_section void do_trap_insn_illegal(struct pt_regs *re
>  DO_ERROR_INFO(do_trap_load_fault,
>  	SIGSEGV, SEGV_ACCERR, "load access fault");
>  
> -asmlinkage __visible __trap_section void do_trap_load_misaligned(struct pt_regs *regs)
> +__visible __trap_section void do_trap_load_misaligned(struct pt_regs *regs)
>  {
>  	if (user_mode(regs)) {
>  		irqentry_enter_from_user_mode(regs);
> @@ -219,7 +219,7 @@ asmlinkage __visible __trap_section void do_trap_load_misaligned(struct pt_regs
>  	}
>  }
>  
> -asmlinkage __visible __trap_section void do_trap_store_misaligned(struct pt_regs *regs)
> +__visible __trap_section void do_trap_store_misaligned(struct pt_regs *regs)
>  {
>  	if (user_mode(regs)) {
>  		irqentry_enter_from_user_mode(regs);
> @@ -294,7 +294,7 @@ void handle_break(struct pt_regs *regs)
>  		die(regs, "Kernel BUG");
>  }
>  
> -asmlinkage __visible __trap_section void do_trap_break(struct pt_regs *regs)
> +__visible __trap_section void do_trap_break(struct pt_regs *regs)
>  {
>  	if (user_mode(regs)) {
>  		irqentry_enter_from_user_mode(regs);
> @@ -311,7 +311,7 @@ asmlinkage __visible __trap_section void do_trap_break(struct pt_regs *regs)
>  	}
>  }
>  
> -asmlinkage __visible __trap_section  __no_stack_protector
> +__visible __trap_section  __no_stack_protector
>  void do_trap_ecall_u(struct pt_regs *regs)
>  {
>  	if (user_mode(regs)) {
> @@ -355,7 +355,7 @@ void do_trap_ecall_u(struct pt_regs *regs)
>  }
>  
>  #ifdef CONFIG_MMU
> -asmlinkage __visible noinstr void do_page_fault(struct pt_regs *regs)
> +__visible noinstr void do_page_fault(struct pt_regs *regs)
>  {
>  	irqentry_state_t state = irqentry_enter(regs);
>  
> @@ -378,7 +378,7 @@ static void noinstr handle_riscv_irq(struct pt_regs *regs)
>  	irq_exit_rcu();
>  }
>  
> -asmlinkage void noinstr do_irq(struct pt_regs *regs)
> +void noinstr do_irq(struct pt_regs *regs)
>  {
>  	irqentry_state_t state = irqentry_enter(regs);
>  
> -- 
> 2.43.0
> 
> 
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