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Message-ID: <594df6bc-0207-46f6-aa81-dcf1f3665917@ghiti.fr>
Date: Wed, 20 Dec 2023 22:14:59 +0100
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Subject: Re: [PATCH] riscv: put va_kernel_xip_pa_offset into CONFIG_XIP_KERNEL
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To: Yunhui Cui <cuiyunhui@bytedance.com>, paul.walmsley@sifive.com,
 palmer@dabbelt.com, aou@eecs.berkeley.edu, ajones@ventanamicro.com,
 alexghiti@rivosinc.com, anup@brainfault.org, samitolvanen@google.com,
 rppt@kernel.org, panqinglin2020@iscas.ac.cn,
 linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org
References: <20231220103428.61758-1-cuiyunhui@bytedance.com>
From: Alexandre Ghiti <alex@ghiti.fr>
In-Reply-To: <20231220103428.61758-1-cuiyunhui@bytedance.com>
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Hi Yunhui,

On 20/12/2023 11:34, Yunhui Cui wrote:
> opitmize the kernel_mapping_pa_to_va() and kernel_mapping_va_to_pa().
>
> Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
> ---
>   arch/riscv/include/asm/page.h | 33 ++++++++++++++++++++-------------
>   1 file changed, 20 insertions(+), 13 deletions(-)
>
> diff --git a/arch/riscv/include/asm/page.h b/arch/riscv/include/asm/page.h
> index 5488ecc337b6..0d2b479d02cd 100644
> --- a/arch/riscv/include/asm/page.h
> +++ b/arch/riscv/include/asm/page.h
> @@ -113,8 +113,8 @@ struct kernel_mapping {
>   	unsigned long va_pa_offset;
>   	/* Offset between kernel mapping virtual address and kernel load address */
>   	unsigned long va_kernel_pa_offset;
> -	unsigned long va_kernel_xip_pa_offset;
>   #ifdef CONFIG_XIP_KERNEL
> +	unsigned long va_kernel_xip_pa_offset;
>   	uintptr_t xiprom;
>   	uintptr_t xiprom_sz;
>   #endif
> @@ -134,12 +134,25 @@ extern phys_addr_t phys_ram_base;
>   #else
>   void *linear_mapping_pa_to_va(unsigned long x);
>   #endif
> -#define kernel_mapping_pa_to_va(y)	({					\
> -	unsigned long _y = (unsigned long)(y);					\
> -	(IS_ENABLED(CONFIG_XIP_KERNEL) && _y < phys_ram_base) ?			\
> -		(void *)(_y + kernel_map.va_kernel_xip_pa_offset) :		\
> -		(void *)(_y + kernel_map.va_kernel_pa_offset + XIP_OFFSET);	\
> -	})
> +
> +#ifdef CONFIG_XIP_KERNEL
> +#define kernel_mapping_pa_to_va(y)							\
> +	(((unsigned long)(y) < phys_ram_base) ?						\
> +		(void *)((unsigned long)(y) + kernel_map.va_kernel_xip_pa_offset) :	\
> +		(void *)((unsigned long)(y) + kernel_map.va_kernel_pa_offset + XIP_OFFSET))
> +
> +#define kernel_mapping_va_to_pa(y)						\
> +	(((unsigned long)(y) < kernel_map.virt_addr + XIP_OFFSET) ?		\
> +		((unsigned long)(y) - kernel_map.va_kernel_xip_pa_offset) :	\
> +		((unsigned long)(y) - kernel_map.va_kernel_pa_offset - XIP_OFFSET))
> +#else
> +#define kernel_mapping_pa_to_va(y)						\
> +	((void *)((unsigned long)(y) + kernel_map.va_kernel_pa_offset + XIP_OFFSET))
> +
> +#define kernel_mapping_va_to_pa(y)						\
> +	((unsigned long)(y) - kernel_map.va_kernel_pa_offset - XIP_OFFSET)
> +#endif
> +
>   #define __pa_to_va_nodebug(x)		linear_mapping_pa_to_va(x)
>   
>   #ifndef CONFIG_DEBUG_VIRTUAL
> @@ -147,12 +160,6 @@ void *linear_mapping_pa_to_va(unsigned long x);
>   #else
>   phys_addr_t linear_mapping_va_to_pa(unsigned long x);
>   #endif
> -#define kernel_mapping_va_to_pa(y) ({						\
> -	unsigned long _y = (unsigned long)(y);					\
> -	(IS_ENABLED(CONFIG_XIP_KERNEL) && _y < kernel_map.virt_addr + XIP_OFFSET) ? \
> -		(_y - kernel_map.va_kernel_xip_pa_offset) :			\
> -		(_y - kernel_map.va_kernel_pa_offset - XIP_OFFSET);		\
> -	})
>   
>   #define __va_to_pa_nodebug(x)	({						\
>   	unsigned long _x = x;							\


Not sure using #ifdef optimizes anything since the compiler should do 
the same with the IS_ENABLED(CONFIG_XIP_KERNEL) and it does not really 
improve the readability of this file which is already overloaded with 
#ifdef, so I don't think this change is needed.

Thanks,

Alex