Subject: Re: [PATCH 1/2] riscv, crash: don't export some symbols when CONFIG_MMU=n

From: Randy Dunlap <[email-masked]>
Date: Tue, 5 Dec 2023 09:08:37 -0800

On 12/4/23 23:18, Baoquan He wrote:
> On 12/04/23 at 11:14am, Randy Dunlap wrote:

[]

>>
>> Both riscv 32-bit and 64-bit complain:
>>
>> ../arch/riscv/kernel/crash_core.c: In function 'arch_crash_save_vmcoreinfo':
>> ../arch/riscv/kernel/crash_core.c:11:58: warning: format '%lx' expects argument of type 'long unsigned int', but argument 2 has type 'int' [-Wformat=]
>>    11 |         vmcoreinfo_append_str("NUMBER(VMALLOC_START)=0x%lx\n", VMALLOC_START);
>>       |                                                        ~~^
>>       |                                                          |
>>       |                                                          long unsigned int
>>       |                                                        %x
> 
> Thanks for all these testing.
> 
> This warning is irrelevant to the kexec patch, it's becasue 
> VMALLOC_START is defined as 0 which is int when CONFIG_MMU=n.
> 
> Below patch can fix the warning.
> 
> From 46984a0287e5f1b41ae3e9adfcfa0d26b71db8f4 Mon Sep 17 00:00:00 2001
> From: Baoquan He <[email-masked]>
> Date: Tue, 5 Dec 2023 11:02:55 +0800
> Subject: [PATCH] riscv: fix VMALLC_START definition
> Content-type: text/plain
> 
> When below config items are set, compiler complained:
> 
> --------------------
> CONFIG_CRASH_CORE=y
> CONFIG_KEXEC_CORE=y
> CONFIG_CRASH_DUMP=y
> ......
> -----------------------
> 
> -------------------------------------------------------------------
> arch/riscv/kernel/crash_core.c: In function 'arch_crash_save_vmcoreinfo':
> arch/riscv/kernel/crash_core.c:11:58: warning: format '%lx' expects argument of type 'long unsigned int', but argument 2 has type 'int' [-Wformat=]
> 11 |         vmcoreinfo_append_str("NUMBER(VMALLOC_START)=0x%lx\n", VMALLOC_START);
>    |                                                        ~~^
>    |                                                          |
>    |                                                          long unsigned int
>    |                                                        %x
> ----------------------------------------------------------------------
> 
> This is because on riscv macro VMALLOC_START has different type when
> CONFIG_MMU is set or unset.
> 
> arch/riscv/include/asm/pgtable.h:
> --------------------------------------------------
> 
> Changing it to _AC(0, UL) in case CONFIG_MMU=n can fix the warning.
> 
> Signed-off-by: Baoquan He <[email-masked]>

Reported-by: Randy Dunlap <[email-masked]>
Acked-by: Randy Dunlap <[email-masked]>
Tested-by: Randy Dunlap <[email-masked]> # build-tested

Thanks.

> ---
>  arch/riscv/include/asm/pgtable.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
> index 294044429e8e..ab00235b018f 100644
> --- a/arch/riscv/include/asm/pgtable.h
> +++ b/arch/riscv/include/asm/pgtable.h
> @@ -899,7 +899,7 @@ static inline pte_t pte_swp_clear_exclusive(pte_t pte)
>  #define PAGE_KERNEL		__pgprot(0)
>  #define swapper_pg_dir		NULL
>  #define TASK_SIZE		0xffffffffUL
> -#define VMALLOC_START		0
> +#define VMALLOC_START		_AC(0, UL)
>  #define VMALLOC_END		TASK_SIZE
>  
>  #endif /* !CONFIG_MMU */

-- 
~Randy